WorldWideScience

Sample records for intermetallic compounds annual

  1. Prediction of intermetallic compounds

    International Nuclear Information System (INIS)

    Burkhanov, Gennady S; Kiselyova, N N

    2009-01-01

    The problems of predicting not yet synthesized intermetallic compounds are discussed. It is noted that the use of classical physicochemical analysis in the study of multicomponent metallic systems is faced with the complexity of presenting multidimensional phase diagrams. One way of predicting new intermetallics with specified properties is the use of modern processing technology with application of teaching of image recognition by the computer. The algorithms used most often in these methods are briefly considered and the efficiency of their use for predicting new compounds is demonstrated.

  2. Diffusion mechanisms in intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Larikov, L N [ANU, Inst. Metallofiziki, Kiev (Ukraine)

    1992-08-01

    Recent research aimed at the identification of the principal mechanisms of diffusion in intermetallics is reviewed. In particular, attention is given to the effect of the type of interatomic bond on the contribution of different mechanisms to diffusion in ordered metallic compounds. Results of an analysis of experimental determinations of diffusion coefficients D(A) and D(B) in binary intermetallics (CuZn, Cu3Sn, AuCd, AgZn, AgMg, InSb, GaSb, AlSb, Fe3Al, FeAl, FeAl3, Ni3Al, Ni3Nb, FeSn, FeSn2, Ni3Sn2, Ni3Sn4, Co3Sn2, CoSn, CoSn2, and CoGa) are presented, and it is shown that the D(A)/D(B) ratio differs substantially for different diffusion mechanisms. 60 refs.

  3. 2. Intermetallic compounds with lanthanides

    International Nuclear Information System (INIS)

    Elemans, J.B.A.A.

    1975-01-01

    Theoretical considerations are given concerning the structures of intermetallic compounds of the lanthanides and thorium (R) on the one hand, and with Fe, Co or Ni (M) on the other. They all derive from the parent composition RM 5 with the CaCu 5 hexagonal structure. This consists of alternate layers in which the M atoms are distinguished as M 1 and M 2 . The other compounds whose structures are studied are obtained by systematic replacement of R by M, or vice versa. In the first type, every third R is replaced by two M's yielding R 2 M 17 compounds. The substitution may be truly random or structured in two ways: so that either the hexagonal structure is maintained or that it is converted into a rhombihedral one. In the second type, one M (in a M 1 position) out of every five is replaced by one R, giving rise to RM 2 compounds which form Laves phases. In the third type, the M 1 's are replaced by R's, resulting in compounds RM 3 . In the fourth type, every third M is replaced by R, yielding R 2 M 7 compounds. With M = Co and R a light lanthanide, the compounds are ferromagnets; with R yttrium, thorium, or a heavy lanthanide, they are ferrimagnets. The preparation of the compounds in an arc-melting apparatus under an Ar-atmosphere followed by annealing is described

  4. Spin polarization in rare earth intermetallic compounds

    International Nuclear Information System (INIS)

    Steenwijk, F.J. van

    1976-01-01

    In this thesis the results of Moessbauer experiments performed on a series of intermetallic compounds of europium and gadolinium are reported. For each of these compounds the magnetic hyperfine field, the electric field gradient at the nuclear site and the isomer shift were determined. For most of the compounds the magnetic ordering temperature was also measured. For some of the europium compounds (e.g. EuAu 5 , EuAg 5 , and EuCu 5 ) it could be derived from the measurements that the easy direction of magnetization falls along the crystallographic c-axis. In a number of compounds (e.g. EuCu 5 , EuZn 5 , EuAu 2 and GdCu 5 ), the various contributions to the magnetic hyperfine field were disentangled by the investigation of suitable pseudobinary compounds that are dilute in Eu. The neighbour contribution Hsub(N) and the paramagnetic Curie temperature thetasub(p) were compared with each other in terms of the RKKY model for EuCu 5 and GdCu 5 . Since the correspondence was found to be poor it was concluded that the magnetic behaviour in these compounds cannot be described by a simple free electron picture as is the basis for the RKKY model

  5. Containerless automated processing of intermetallic compounds and composites

    Science.gov (United States)

    Johnson, D. R.; Joslin, S. M.; Reviere, R. D.; Oliver, B. F.; Noebe, R. D.

    1993-01-01

    An automated containerless processing system has been developed to directionally solidify high temperature materials, intermetallic compounds, and intermetallic/metallic composites. The system incorporates a wide range of ultra-high purity chemical processing conditions. The utilization of image processing for automated control negates the need for temperature measurements for process control. The list of recent systems that have been processed includes Cr, Mo, Mn, Nb, Ni, Ti, V, and Zr containing aluminides. Possible uses of the system, process control approaches, and properties and structures of recently processed intermetallics are reviewed.

  6. Crystal field in rare-earth metals and intermetallic compounds

    International Nuclear Information System (INIS)

    Ray, D.K.

    1978-01-01

    Reasons for the success of the crystal-field model for the rare-earth metals and intermetallic compounds are discussed. A review of some of the available experimental results is made with emphasis on cubic intermetallic compounds. Various sources of the origin of the crystal field in these metals are discussed in the background of the recent APW picture of the conduction electrons. The importance of the non-spherical part of the muffin-tin potential on the single-ion anisotropy is stressed. (author)

  7. Oxygen stabilized rare-earth iron intermetallic compounds

    International Nuclear Information System (INIS)

    Dariel, M.P.; Malekzadeh, M.; Pickus, M.R.

    1975-10-01

    A new, oxygen-stabilized intermetallic compound was identified in sintered, pre-alloyed rare-earth iron powder samples. Its composition corresponds to formula R 12 Fe 32 O 2 and its crystal structure belongs to space group Im3m. The presence of these compounds was observed, so far, in several R--Fe--O systems, with R = Gd, Tb, Dy, Ho, Er, and Y

  8. Hydrogenations of alloys and intermetallic compounds of magnesium

    International Nuclear Information System (INIS)

    Gavra, Z.

    1981-08-01

    A kinetic and thermodynamic study of the hydrogenation of alloys and intermetallic compounds of magnesium is presented. It was established that the addition of elements of the IIIA group (Al, Ga, In) to magnesium catalyses its hydrogenation. This is explained by the mechanism of diffusion of magnesium cation vacancies. The hydride Mg 2 NiH 4 was characterized by thermal analysis, x-ray diffraction and NMR measurements. The possibility of forming pseudo-binary compounds of Mg 2 Ni by the substitution of nickel or magnesium was examined. The hydrogenation of the inter-metallic compounds of the Mg-Al system was investigated. It was found that the addition of indium and nickel affected the hydrogenation kinetics. A preliminary study of the hydrogenation of various binary and ternary alloys of magnesium was carried out. (Author)

  9. Environmental embrittlement of intermetallic compounds in Fe-Al alloys

    Institute of Scientific and Technical Information of China (English)

    张建民; 张瑞林; S.H.YU; 余瑞璜

    1996-01-01

    First,it is proposed that hydrogen atoms occupy the interstitial sites in Fe3Al and FeAl.Then the environmental embrittlement of intermetallic compounds in Fe-Al alloys is studied in the light of calculated valence electron structures and bond energy of Fe3Al and FeAl containing hydrogen atoms.From the analyses it is found that the states of metal atoms will change,in which more lattice electrons will become covalent electrons to bond with hydrogen atoms when the atomic hydrogen diffuses into the intermetallic compounds in Fe-Al alloys,which will result in the decrease of local metallicity in Fe3Al and FeAl.Meanwhile,it is found that the crystal will easily cleave since solute hydrogen bonds with metal atoms and severely anisotropic bonds form.As a conclusion,these factors result in the environmental embrittlement of Fe3Al and FeAl.

  10. Intermetallic compound development for the 21st century

    International Nuclear Information System (INIS)

    Munroe, P.R.

    2000-01-01

    lntermetallic compounds have been vigorously researched for the past twenty years. As a result of these studies the fundamental behaviour of a number of transition metal aluminides and suicides is now well understood, and a number of alloys with commercially acceptable properties have been developed. Future challenges for these alloys, for example Ni 3 AI, TiAI and Fe 3 AI, are focused on the development of large-scale production routes. However, there remain a number of other intermetallic compounds, such as Laves phases, which exhibit some promising properties, but little is presently known about their intrinsic behaviour. For compounds such as these more fundamental studies are required

  11. Investigations on Ce- and Yb-based intermetallic compounds

    International Nuclear Information System (INIS)

    Elenbaas, R.A.

    1980-01-01

    The author describes investigations on a number of cerium- and ytterbium-based intermetallic compounds and alloys, yielding a lot of experimental results which could not always be put in a quantitative picture. All experimental data are consistent with a single-ion behaviour, where the 4f state is more or less modified by the conduction electrons. In the investigated systems several different features of the magnetism of cerium atoms in metals were studied. (Auth.)

  12. Lattice and magnetic anisotropies in uranium intermetallic compounds

    DEFF Research Database (Denmark)

    Havela, L.; Mašková, S.; Adamska, A.

    2013-01-01

    Examples of UNiAlD and UCoGe illustrate that the soft crystallographic direction coincides quite generally with the shortest U-U links in U intermetallics. Added to existing experimental evidence on U compounds it leads to a simple rule, that the easy magnetization direction and the soft crystall...... crystallographic direction (in the sense of highest compressibility under hydrostatic pressure) must be mutually orthogonal....

  13. The behavior of intermetallic compounds at large plastic strains

    International Nuclear Information System (INIS)

    Gray, G.T.; Embury, J.D.

    1993-01-01

    This paper contains a summary of a broad study of intermetallics which includes the following materials, Ni 3 Al, Ti-48Al-1V, Ti-24Al-11Nb, Ti-48Al-2Cr-2Nb, and Ti-24.5 Al-10.5Nb-1.5Mo. Much effort has been devoted to the study of ordered materials at modes plastic strains and the problem of premature failure. However by utilizing stress states other than simple tension it is possible to study the deformation of intermetallic compounds up to large plastic strains and to consider the behavior of these materials in the regime where stresses approach the theoretical stress. The current work outlines studies of the work hardening rate of a number of titanium and nickel-based intermetallic compounds deformed in compression. Attention is given to the structural basis of the sustained work hardening. The large strain plasticity of these materials is summarized in a series of diagrams. Fracture in these materials in compression occurs via catastrophic shear at stresses of the order of E/80 (where E is the elastic modulus)

  14. Rare earth intermetallic compounds produced by a reduction-diffusion process

    International Nuclear Information System (INIS)

    Cech, R.E.

    1975-01-01

    A reduction-diffusion process is given for producing novel rare earth intermetallic compounds, such as cobalt--rare earth intermetallic compounds, especially compounds useful in preparing permanent magnets. A particulate mixture of rare earth metal halide, cobalt and calcium hydride is heated to effect reduction of the rare earth metal halide and to diffuse the resulting rare earth metal into the cobalt to form the intermetallic compound

  15. An experimental study of praseodymium intermetallic compounds at low temperatures

    International Nuclear Information System (INIS)

    Greidanus, F.J.A.M.

    1982-01-01

    In this thesis the author studies the low temperature properties of praseodymium intermetallic compounds. In chapter 2 some of the techniques used for the experiments described in the subsequent chapters are discussed. A set-up to perform specific-heat experiments below 1 K and a technique for performing magnetic susceptibility measurments below 1 K, using a superconducting quantum interference device (SQUID) are described. Chapter 3 is devoted to the theory of interacting Pr 3+ ions. Both bilinear and biquadratic interactions are dealt with in a molecular-field approximation. It is shown that first as well as second-order phase transitions can occur, depending on the nature of the ground state, and on the ratio of magnetic to crystal-field interactions. In chapters 4, 5, 6 and 7 experimental results on the cubic Laves phase compounds PrRh 2 , PrIr 2 , PrPt 2 , PrRu 2 and PrNi 2 are presented. From inelastic neutron scattering experiments the crystalline electric field parameters of the above compounds are determined. In chapters 5 and 6 susceptibility, neutron-diffraction, hyperfine specific-heat, low-field magnetization, pulsed-field magnetization, specific-heat and resistivity measurements are presented. In chapter 7 the specific heat and differential susceptibility of PrNi 2 below 1 K are studied. Finally, in chapter 8 praseodymium intermetallic compounds with low-symmetry singlet ground states, and cubic compounds with magnetic doublet ground states are studied. (Auth.)

  16. NMR and domain wall mobility in intermetallic compounds

    International Nuclear Information System (INIS)

    Guimaraes, A.P.; Sampaio, L.C.; Cunha, S.F.; Alves, K.M.B.

    1991-01-01

    The technique of pulsed NMR can be used to study the distribution of hyperfine fields in a magnetic matrix. The dynamics of the domain walls are relevant to the generation of NMR signals. In the present study on the (R x Y 1-x ) Fe 2 intermetallic compounds, the reduction in the signals is associated to increased propagation fields. This indicates that a smaller domain wall mobility is at the origin of these effects. NMR spectra in this system show the importance of direct and indirect (i.e., mediated by Fe atoms) terms in the transferred hyperfine field. (author)

  17. Structural and Electronic Investigations of Complex Intermetallic Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Hyunjin [Iowa State Univ., Ames, IA (United States)

    2008-01-01

    In solid state chemistry, numerous investigations have been attempted to address the relationships between chemical structure and physical properties. Such questions include: (1) How can we understand the driving forces of the atomic arrangements in complex solids that exhibit interesting chemical and physical properties? (2) How do different elements distribute themselves in a solid-state structure? (3) Can we develop a chemical understanding to predict the effects of valence electron concentration on the structures and magnetic ordering of systems by both experimental and theoretical means? Although these issues are relevant to various compound classes, intermetallic compounds are especially interesting and well suited for a joint experimental and theoretical effort. For intermetallic compounds, the questions listed above are difficult to answer since many of the constituent atoms simply do not crystallize in the same manner as in their separate, elemental structures. Also, theoretical studies suggest that the energy differences between various structural alternatives are small. For example, Al and Ga both belong in the same group on the Periodic Table of Elements and share many similar chemical properties. Al crystallizes in the fcc lattice with 4 atoms per unit cell and Ga crystallizes in an orthorhombic unit cell lattice with 8 atoms per unit cell, which are both fairly simple structures (Figure 1). However, when combined with Mn, which itself has a very complex cubic crystal structure with 58 atoms per unit cell, the resulting intermetallic compounds crystallize in a completely different fashion. At the 1:1 stoichiometry, MnAl forms a very simple tetragonal lattice with two atoms per primitive unit cell, while MnGa crystallizes in a complicated rhombohedral unit cell with 26 atoms within the primitive unit cell. The mechanisms influencing the arrangements of atoms in numerous crystal structures have been studied theoretically by calculating electronic

  18. Electronic Structure of GdCuGe Intermetallic Compound

    Science.gov (United States)

    Lukoyanov, A. V.; Knyazev, Yu. V.; Kuz'min, Yu. I.

    2018-04-01

    The electronic structure of GdCuGe intermetallic compound has been studied. Spin-polarized energy spectrum calculations have been performed by the band method with allowance for strong electron correlations in the 4 f-shell of gadolinium ions. Antiferromagnetic ordering of GdCuGe at low temperatures has been obtained in a theoretical calculation, with the value of the effective magnetic moment of gadolinium ions reproduced in fair agreement with experimental data. The electronic density of states has been analyzed. An optical conductivity spectrum has been calculated for GdCuGe; it reveals specific features that are analogous to the ones discovered previously in the GdCuSi compound with a similar hexagonal structure.

  19. A spin echo study of A15 intermetallic compounds

    International Nuclear Information System (INIS)

    Schoep, G.K.

    1976-01-01

    This thesis mainly concerns the measurement of spin-lattice relaxation times in intermetallic compounds of the bcc lattice structure, having the formula V 3 X (C = Pt, Ir, Os, Pd, Rh, Ni, Co, Au). When, in a spin echo experiment, a two-pulse sequence was applied, several quadrupolar echoes were observed. Special attention is given to the 'forbidden' echoes (absol.(Δm')GT1) in V 3 Au and V 3 Co. In relation to the V 3 X compounds, several characteristics are discussed including temperature dependence and concentration dependence of spin relaxation times, superconductivity and the importance of d-state electrons in determination of the spin relaxation times. Finally, the above characteristics were determined for 6 different samples of the vanadium-gold alloy, V 3 Au, specifically

  20. Development of New Cryocooler Regenerator Materials-Ductile Intermetallic Compounds

    International Nuclear Information System (INIS)

    Gschneidner, K.A.; Pecharsky, A.O.; Pecharsky, V.K.

    2004-01-01

    The volumetric heat capacities of a number of binary and ternary Er- and Tm-based intermetallic compounds, which exhibited substantial ductilities, were measured from ∼3 to ∼350 K. They have the RM stoichiometry (where R = Er or Tm, and M is a main group or transition metal) and crystallize in the CsCl-type structure. The heat capacities of the Tm-based compounds are in general larger than the corresponding Er-based materials. Many of them have heat capacities which are significantly larger than those of the low temperature ( 2 , Er 3 Ni and ErNi. Utilization of the new materials as regenerators in the various cryocoolers should improve the performance of these refrigeration units for cooling below 15 K

  1. Diffusion in intermetallic compounds studied using short-lived radioisotopes

    CERN Multimedia

    Diffusion – the long range movement of atoms – plays an important role in materials processing and in determining suitable applications for materials. Conventional radiotracer methods for measuring diffusion can determine readily how distributions of radioactive probe atoms in samples evolve under varying experimental conditions. It is possible to obtain limited information about atomic jump rates and pathways from these measurements; however, it is desirable to make more direct observations of the atomic jumps by using experimental methods that are sensitive to atomic scale processes. One such method is time-differential perturbed $\\gamma$–$\\gamma$-angular correlation spectroscopy (PAC). Two series of PAC experiments using $^{111m}$Cd are proposed to contribute to fundamental understanding of diffusion in intermetallic compounds. The goal of the first is to determine the dominant vacancy species in several Li$_{2}$-structured compounds and see if the previously observed change in diffusion mechanism th...

  2. Experimental formation enthalpies for intermetallic phases and other inorganic compounds

    Science.gov (United States)

    Kim, George; Meschel, S. V.; Nash, Philip; Chen, Wei

    2017-01-01

    The standard enthalpy of formation of a compound is the energy associated with the reaction to form the compound from its component elements. The standard enthalpy of formation is a fundamental thermodynamic property that determines its phase stability, which can be coupled with other thermodynamic data to calculate phase diagrams. Calorimetry provides the only direct method by which the standard enthalpy of formation is experimentally measured. However, the measurement is often a time and energy intensive process. We present a dataset of enthalpies of formation measured by high-temperature calorimetry. The phases measured in this dataset include intermetallic compounds with transition metal and rare-earth elements, metal borides, metal carbides, and metallic silicides. These measurements were collected from over 50 years of calorimetric experiments. The dataset contains 1,276 entries on experimental enthalpy of formation values and structural information. Most of the entries are for binary compounds but ternary and quaternary compounds are being added as they become available. The dataset also contains predictions of enthalpy of formation from first-principles calculations for comparison. PMID:29064466

  3. Effects of elastic anisotropy on mechanical behavior of intermetallic compounds

    International Nuclear Information System (INIS)

    Yoo, M.H.

    1991-01-01

    Fundamental aspects of the deformation and fracture behavior of ordered intermetallic compounds are examined within the framework of linear anisotropic elasticity theory of dislocations and cracks. The orientation dependence and the tension/compression asymmetry of yield stress are explained in terms of the anisotropic coupling effect of non-glide stresses to the glide strain. The anomalous yield behavior is related to the disparity (edge/screw) of dislocation mobility and the critical stress required for the dislocation multiplication mechanism of Frank-Read type. The slip-twin conjugate relationship, extensive faulting, and pseudo-twinning (martensitic transformation) at a crack tip can be enhanced also by the anisotropic coupling effect, which may lead to transformation toughening of shear type

  4. Electronic and magnetic properties of intermetallic compound YCo5

    International Nuclear Information System (INIS)

    Zhang, G.W.; Feng, Y.P.; Ong, C.K.

    1998-01-01

    The electronic and magnetic properties of the intermetallic compound YCo 5 have been studied using density functional theory with the local spin density approximation. The calculated magnetic moments of Y, Co(2c) and Co(3g) are -0.61, 1.68 and 2.04 μ B , respectively, and the total magnetic moment is about 8.87 μ B per formula unit, which agrees well with the previous experimental results. The dependence of the magnetic moments of Y, Co(2c) and Co(3g) on the lattice spacing has been investigated. The local electronic structure of Y, Co(2c) and Co(3g) are discussed in detail. The local magnetic susceptibilities of Y, Co(2c) and Co(3g) are calculated. Based on our results, YCo 5 was found to have characteristic of a strong ferromagnet. (orig.)

  5. Effect of Flux onto Intermetallic Compound Formation and Growth

    Directory of Open Access Journals (Sweden)

    Idris Siti Rabiatull Aisha

    2016-01-01

    Full Text Available In this study, the effect of different composition of no-clean flux onto intermetallic compound (IMC formation and growth was investigated. The solder joint between Sn-3Ag-0.5Cu solder alloy and printed circuit board (PCB was made through reflow soldering. They were further aged at 125°C and 150°C for up to 1000 hours. Results showed that fluxes significantly affect the IMC thickness and growth. In addition, during aging, the scallop and columnar morphology of IMC changed to a more planar type for both type of flux during isothermal aging. It was observed that the growth behavior of IMC was closely related to initial soldering condition.

  6. Magnetic and electronic properties of some actinide intermetallic compounds

    International Nuclear Information System (INIS)

    Yaar, Ilan

    1992-06-01

    The electronic structure and magnetic properties of the light actinide intermetallic compounds are often related to interplay between localized and itinerant (band like) behavior of the 5f- electrons. In the present work, the properties of some actinide, mainly Np, intermetallic compounds were studied by Mossbauer effect, ac and dc susceptibility, X-ray and Neutron diffraction techniques. 1. NpX 2 (X=Ga,Si) - Both compounds order ferromagnetically at TC=55(2) and 48(2) K respectively. A comparison of our data with the results for other NpX 2 (X=Al,As,Sb,Tl) compounds indicates that NpGa 2 is a highly localized 5f electron system, whereas in NpSi 2 the 5f electrons are partially delocalized. The magnetic properties of NpX 2 compounds can neither be consistently explained within the conventional crystal electric field picture (CEF) nor by takink into account hybridization dressing of local spin density models. 2. NpX 3 (X=Ga,Si,In,Al) in the cubic AuCu 3 (Pm3m) crystallographic structure - From the Mossbauer isomer shift (IS) data we argue that the Np ion in the NpX 3 family is close to the formal 3+ (5I 4 ) charge state. The magnetic moment of the Np in NpSi 3 is totally suppressed whereas in NpGa 3 and NpAl 3 a localized (narrow band) moment is established. However, in NpIn 3 at 4.2 K, a modulated magnetic moment (0-1.5μB) is observed. Comparing the magnetic behavior of the NpX 3 family (X=Si,Ge,Ga, Al,In and Sn), we find an impressive variation of the magnetic properties, from temperature independent paramagnetism (TIP), localized and modulated ordered moments, to the formation of a concentrated Kondo lattice. Hybridization of 5f electrons with ligand electrons appears to play a crucial role in establishing these magnetic properties. However, at present a consistent theoretical picture can not be drawn. 3. XFe 4 Al 8 (X=Ho,Np,U) spin galss (SG) systems in the ThMn 12 (I 4 /mmm) crystallographic structure - Localized and itinerant behaviour of the f electrons

  7. Computer simulations of disordering and amorphization kinetics in intermetallic compounds

    International Nuclear Information System (INIS)

    Spaczer, M.; Victoria, M.

    1995-01-01

    Molecular dynamics computer simulations on three intermetallic compounds, Cu 3 Au, Ni 3 Al and NiAl, have been performed to investigate the kinetics of the disordering and amorphization processes. These systems were chosen because reliable embedded atom potentials were developed for the constituent species and their alloys, and also because extended experimental results are available for them. Previous simulations of collision cascades with 5 keV Cu and Ni primary knock-out atom (PKA) showed a significant difference between the evolution of the short range order (SRO) and the crystalline order (CO) parameters in all of the intermetallics: a complete loss of the crystalline structure and only partial chemical disorder in the core of the cascade [T. Diaz de la Rubia et al., Phys. Rev. B 47 (1993) 11483; M. Spaczer et al., Phys. Rev. B 50 (1994) 13204]. The present paper deals with the simulation of the amorphization process in NiAl by 5 and 15 keV Ni PKAs. The kinetic energy of the atoms in the simulated systems was removed on different time scales to mimic strong or weak coupling between electrons and phonons. No evidence of amorphization was found at the end of the cascades created by the 5 keV recoils. However, the 15 keV PKA events showed that (i) in the no-coupling case the system evolved to a highly disordered state, (ii) an amorphous region with about 100 non-lattice atoms was found in the case of weak coupling, (iii) the locally melted and recrystallized region collapsed to a small dislocation loop when medium coupling was used and (iv) a highly ordered state resulted in the case of strong coupling. (orig.)

  8. Microstructure and tribological properties of Ti–Cu intermetallic compound coating

    International Nuclear Information System (INIS)

    Guo, Chun; Zhou, Jiansong; Yu, Youjun; Wang, Lingqian; Zhou, Huidi; Chen, Jianmin

    2012-01-01

    Highlights: ► Ti–Cu coating has been synthesized on pure Ti substrate by laser cladding. ► Microstructure and tribological properties of Ti–Cu coating were analyzed. ► The prepared Ti–Cu intermetallic compound coating has excellent wear resistance. -- Abstract: Ti–Cu intermetallic compound coating has been in situ synthesized successfully on pure Ti substrate by laser cladding using copper powder as the precursor. It has been found that the prepared coating mainly contains of TiCu, TiCu 3 , Ti 3 Cu, and Ti phases. The transmission electron microscopy results conform further the existence of Ti–Cu intermetallic compound in the fabricated coating. Tribological properties of the prepared Ti–Cu intermetallic compound coating were systematically evaluated. It was found that normal loads and sliding speeds have a strong influence on the friction coefficient and wear rate of Ti–Cu intermetallic compound coating. Namely, the friction coefficient of the Ti–Cu intermetallic compound coating decreased with increasing normal load and sliding speed. The wear rate of the Ti–Cu intermetallic compound coating decreased rapidly with increasing sliding speed, while the wear rate increased as the normal load increased.

  9. Studies about interaction of hydrogen isotopes with metals and intermetallic compounds

    International Nuclear Information System (INIS)

    Vasut, F.; Anisoara, P.; Zamfirache, M.

    2003-01-01

    Hydrogen is a non-toxic but highly inflammable gas. Compared to other inflammable gases, its range of inflammability in air is much broader (4-74.5%) but it also vaporizes much more easily. Handling of hydrogen in form of hydrides enhances safety. The interaction of hydrogen with metals and intermetallic compounds is a major field within physical chemistry. Using hydride-forming metals and intermetallic compounds, for example, recovery, purification and storage of heavy isotopes in tritium containing system can solve many problems arising in the nuclear-fuel cycle. The paper presents the thermodynamics and the kinetics between hydrogen and metal or intermetallic compounds. (author)

  10. Microstructure and tribological properties of TiCu2Al intermetallic compound coating

    International Nuclear Information System (INIS)

    Guo Chun; Zhou Jiansong; Zhao Jierong; Wang Linqian; Yu Youjun; Chen Jianmin; Zhou Huidi

    2011-01-01

    TiCu 2 Al ternary intermetallic compound coating has been in situ synthesized successfully on pure Ti substrate by laser cladding. Tribological properties of the prepared TiCu 2 Al intermetallic compound coating were systematically evaluated. It was found that the friction coefficient and wear rate was closely related to the normal load and sliding speed, i.e., the friction coefficient of the prepared TiCu 2 Al intermetallic compound coating decreased with increasing normal load and sliding speed. The wear rate of the TiCu 2 Al intermetallic compound coating decreased rapidly with increasing sliding speed, while the wear rate first increased and then decreased at normal load from 5 to 15 N.

  11. Microstructure and tribological properties of TiCu{sub 2}Al intermetallic compound coating

    Energy Technology Data Exchange (ETDEWEB)

    Guo Chun, E-mail: guochun@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Zhou Jiansong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhao Jierong; Wang Linqian; Yu Youjun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Chen Jianmin; Zhou Huidi [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2011-04-15

    TiCu{sub 2}Al ternary intermetallic compound coating has been in situ synthesized successfully on pure Ti substrate by laser cladding. Tribological properties of the prepared TiCu{sub 2}Al intermetallic compound coating were systematically evaluated. It was found that the friction coefficient and wear rate was closely related to the normal load and sliding speed, i.e., the friction coefficient of the prepared TiCu{sub 2}Al intermetallic compound coating decreased with increasing normal load and sliding speed. The wear rate of the TiCu{sub 2}Al intermetallic compound coating decreased rapidly with increasing sliding speed, while the wear rate first increased and then decreased at normal load from 5 to 15 N.

  12. FY 1998 annual report on the improvement of toughness of silicide-based intermetallic compounds by controlling their composite structures; 1998 nendo fukugo soshikika ni yoru shirisaidokei kinzokukan kagobutsu no kyojinsei kaizen chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Intermetallic compounds, although attracting much attention as most promising materials serviceable at superhigh temperature, are very fragile at normal temperature, which is one of their major disadvantages. Structures of these compounds prepared by the melting method are controlled to improve their toughness by, e.g., changing phase ratio of the initial crystal for the Mo-Si-Nb system to prevent cracking during the melting and casting stages, addition of a third element (e.g., Zr, Ti or Hf) or a mixed component of Nb and Zr to control the structure of Mo{sub 5}Si{sub 3} considered to be a cause for the cracking, and controlling melting and solidification rates for the FZ melting method. The three-phase microstructures with added Hf or Zr show improved toughness, but need additional procedures for controlling solidification and cooling conditions. For the powder method, the MA conditions are investigated with a two-element system, and the effects of Al or Zr as the third element added to the base composition on the composite microstructures and constituent phases are also investigated. Unlike the melting method, the powder method causes no cracking problems during the stock preparation stage and hence is expected to be applicable to production of larger stocks. However, the products by this method are found to be insufficient both in toughness and high-temperature strength. It is necessary to develop methods for cutting down and controlling oxides in the grain boundaries, in order to prevent deterioration of their strength at high temperature. (NEDO)

  13. Effects of iron on intermetallic compound formation in scandium modified Al–Si–Mg Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Patakham, Ussadawut [National Metal and Materials Technology Center, National Science and Technology Development Agency, 114 Thailand Science Park, Klong Nueng, Klong Luang, Pathumthani 12120 (Thailand); Limmaneevichitr, Chaowalit, E-mail: chaowalit.lim@mail.kmutt.ac.th [Production Engineering Department, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, 126 Pracha-Utid Rd., Bangmod, Tungkhru, Bangkok 10140 (Thailand)

    2014-12-15

    Highlights: • Iron reduces the modification effects of scandium in Al–Si–Mg alloys. • Morphologies of Sc-rich intermetallic phases vary with Fe and Sc contents and the cooling rates. • Sc neutralizes effects of Fe by changing Fe-rich intermetallic phases from platelets to more cubic. - Abstract: In general, iron has a strong tendency to dissolve in molten aluminum. Iron has very low solid solubility in aluminum–silicon casting alloys, so it will form intermetallic compounds that cause detrimental effects on mechanical properties. In this work, the effects of iron on intermetallic compound formations in scandium modified Al–Si–Mg alloys were studied. There were two levels of iron addition (0.2 and 0.4 wt.%) and two levels of scandium addition (0.2 and 0.4 wt.%). We found that the effects of scandium modification decreased with increasing iron addition. The morphologies of the complex intermetallic compounds were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD) techniques. It was found that scandium changes the morphology of Fe-rich intermetallic compounds from β-phase (plate-like) to α-phase, which reduces the harmful effects of β-phase.

  14. Development of melting and casting process for Nb-Al intermetallic compounds and mechanical properties

    International Nuclear Information System (INIS)

    Kamata, Kinya; Degawa, Toru; Nagashima, Yoshinori

    1993-01-01

    The shaping methods of Nb-Al intermetallic compounds, especially melting and casting, have considerably different characteristics as compared with those for other metals and alloys. The authors have investigated melting and casting processes for Nb-Al compounds to develop precision casting processes for these intermetallics. Fundamental properties of Nb-Al compound castings have been also investigated for high temperature structural use in this work. An advanced Induction Skull Melting (ISM) furnace has been developed and the advantages of ISM have been recognized as a result of this study. The mechanical properties, such as hardness and compression strength, are dependent upon the Al content in Nb-Al binary compounds

  15. Large positive magnetoresistance in intermetallic compound NdCo2Si2

    Science.gov (United States)

    Roy Chowdhury, R.; Dhara, S.; Das, I.; Bandyopadhyay, B.; Rawat, R.

    2018-04-01

    The magnetic, magneto-transport and magnetocaloric properties of antiferromagnetic intermetallic compound NdCo2Si2 (TN = 32K) have been studied. The compound yields a positive magnetoresistance (MR) of about ∼ 123 % at ∼ 5K in 8 T magnetic field. The MR value is significantly large vis - a - vis earlier reports of large MR in intermetallic compounds, and possibly associated with the changes in magnetic structure of the compound. The large MR value can be explained in terms of field induced pseudo-gaps on Fermi surface.

  16. The influence of pressure on diffusion leading to intermetallic compounds

    International Nuclear Information System (INIS)

    Adda, Y.; Beyeler, M.; Kirianenko, A.; Pernot, B.

    1961-01-01

    Some investigators A.D. LE CLAIRE, J.L. ZAMBROW, L. CASTLEMAN, have shown that the application of uniaxial pressure parallel to the direction of diffusion may notably modify the kinetics of growth of the intermediate phases which can be formed in this direction. The interpretation of this phenomenon being obscure, an attempt is made to explain it by detailed analysis of the experimental facts. The microscopic studies of the kinetics of growth of the zones formed shows particularly in the couples Uranium-Copper and Uranium-Nickel that it is influenced in a similar manner by a uniaxial pressure and a hydrostatic one. On the other hand the rate of growth of these zones increases as a function of the applied pressure in the systems Uranium-Copper, Uranium-Nickel and Uranium-Aluminium (this effect being particularly marked in Uranium-Aluminium). To determine with precision the limits of the range of stability of the intermetallic compounds, the curves of concentration penetration characteristics of the diffusion have been established by means of the CASTAING electronic microanalyser. The examination of the results indicates that when diffusion takes place without external pressure (couples U-Cu and U-Ni) or with a pressure less than 300 kg/cm 2 (couple U-Al) the concentration varies notably in the compounds obtained, which theoretically are stoichiometric. Thus, when crossing the zone of diffusion of one base metal to another one notes a continual passage of: UCu 4.70 to UCu 5.25 in the couple U-Cu; UNi 4.75 to UNi 5.25 in the couple U-Ni; UAl 2.2 to UAl 3.3 in the couple U-Al. If an uniaxial or hydrostatic pressure above 500 kg/cm 2 is applied to the couples U-Cu and U-Ni, or above 1000 kg/cm 2 for the couple U-Al, the composition is then constant in the zones formed. It corresponds to: UCu 5 in the couple U-Cu; UNi 5 in the couple U-Ni; UAl 3 in the couple U-Al. These results are confirmed by an X-ray diffraction study, mainly in the U-Cu system. Experiments in

  17. Microstructure and tribological properties of TiAg intermetallic compound coating

    International Nuclear Information System (INIS)

    Guo Chun; Chen Jianmin; Zhou Jiansong; Zhao Jierong; Wang Linqian; Yu Youjun; Zhou Huidi

    2011-01-01

    TiAg intermetallic compound coating has been in situ synthesized successfully on pure Ti substrate by laser cladding using Ag powder as the precursor. It has been found that the prepared coating mainly comprised TiAg and Ti phases. The high resolution transmission electron microscopy results further conform the existence of TiAg intermetallic compound in the prepared coating. The magnified high resolution transmission electron microscopy images shown that the laser cladding coating contains TiAg nanocrystalline with the size of about 4 nm. Tribological properties of the prepared TiAg intermetallic compound coating were systematically evaluated. It was found that the friction coefficient and wear rate was closely related to the normal load and sliding speed, i.e., the friction coefficient of the prepared TiAg intermetallic compound coating decreased with increasing normal load and sliding speed. The wear rate of the TiAg intermetallic compound coating decreased rapidly with increasing sliding speed, while the wear rate increased as the normal load increased.

  18. Microstructure and tribological properties of TiAg intermetallic compound coating

    Energy Technology Data Exchange (ETDEWEB)

    Guo Chun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Chen Jianmin, E-mail: chenjm@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhou Jiansong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhao Jierong; Wang Linqian; Yu Youjun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Zhou Huidi [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2011-10-01

    TiAg intermetallic compound coating has been in situ synthesized successfully on pure Ti substrate by laser cladding using Ag powder as the precursor. It has been found that the prepared coating mainly comprised TiAg and Ti phases. The high resolution transmission electron microscopy results further conform the existence of TiAg intermetallic compound in the prepared coating. The magnified high resolution transmission electron microscopy images shown that the laser cladding coating contains TiAg nanocrystalline with the size of about 4 nm. Tribological properties of the prepared TiAg intermetallic compound coating were systematically evaluated. It was found that the friction coefficient and wear rate was closely related to the normal load and sliding speed, i.e., the friction coefficient of the prepared TiAg intermetallic compound coating decreased with increasing normal load and sliding speed. The wear rate of the TiAg intermetallic compound coating decreased rapidly with increasing sliding speed, while the wear rate increased as the normal load increased.

  19. X-Ray Diffraction of Intermetallic Compounds: A Physical Chemistry Laboratory Experiment

    Science.gov (United States)

    Varberg, Thomas D.; Skakuj, Kacper

    2015-01-01

    Here we describe an experiment for the undergraduate physical chemistry laboratory in which students synthesize the intermetallic compounds AlNi and AlNi3 and study them by X-ray diffractometry. The compounds are synthesized in a simple one-step reaction occurring in the solid state. Powder X-ray diffractograms are recorded for the two compounds…

  20. Real structure and selected properties of the superconducting intermetallic compound V3Si

    International Nuclear Information System (INIS)

    Kleinstueck, K.; Kraemer, U.; Paufler, P.; Ullrich, H.J.

    1980-01-01

    Plasticity and electro-plastic effects have been detected at temperatures above 1200 0 C in the intermetallic compound V 3 Si which can not plastically be deformed under normal conditions. The mechanisms of plastic deformation were elucidated. The critical temperature and the critical current density could be altered by plastic deformation. It was found that the mechanisms of plastic deformation as well as the alteration of the critical parameters are dependent on the chemical composition of the intermetallic compound within the range of homogeneity. For measuring such alterations Kossel's interference method was used. Intense plastic deformation of crystals resulted in an influence on the martensite transformation

  1. Investigations of intermetallic alloy hydriding mechanisms. Annual progress report, May 1 1979-April 30, 1980

    International Nuclear Information System (INIS)

    Livesay, B.R.; Larsen, J.W.

    1980-05-01

    Investigations are being conducted on mechanisms involved with the hydrogen-metal interactions which control the absorption and desorption processes in intermetallic compounds. The status of the following investigations is reported: modeling of hydride formation; microbalance investigations; microstructure investigations; flexure experiments; resistivity experiments; and nuclear backscattering measurements. These investigations concern fundamental hydrogen interaction mechanisms involved in storage alloys

  2. Characterization of intermetallic compounds in Cu-Al ball bonds: layer growth, mechanical properties and oxidation

    NARCIS (Netherlands)

    Kouters, M.H.M.; Gubbels, G.H.M.; O'Halloran, O.; Rongen, R.

    2011-01-01

    In high power automotive electronics copper wire bonding is regarded as most promising alternative for gold wire bonding in 1 st level interconnects and therefore subjected to severe functional requirements. In the Cu-Al ball bond interface the growth of intermetallic compounds may deteriorate the

  3. Mechanism of forming interfacial intermetallic compounds at interface for solid state diffusion bonding of dissimilar materials

    International Nuclear Information System (INIS)

    He, P.; Liu, D.

    2006-01-01

    The formation of brittle intermetallic compounds at the interfaces of diffusion bonds is the main cause which leads to poor bond strength. Therefore, it is very important to study and establish the formation and growth model of intermetallic compounds at the interfaces for the control process of diffusion bonding. In this paper, according to the diffusion kinetics and the thermodynamics, the principle of formation of intermetallic compounds at interfaces in the multi-component diffusion couple, the flux-energy principle, is put forward. In the light of diffusion theory, the formation capacity of the phase at the interfaces is determined by specific properties of the composition in the diffusion couple and the composition ratio of the formed phase is in agreement with the diffusion flux. In accordance with the flux-energy principle, the microstructure of the Ni/TC4 interface is Ni/TiNi 3 /TiNi/Ti 2 Ni/TC4, the microstructure of the TC4/00Cr18Ni9Ti interface is 00Cr18Ni9Ti/TiFe 2 /TiFe/Ti 2 Fe/TC4, and the microstructure of the TiAl/40Cr interface is 40Cr/TiC/Ti 3 Al + FeAl + FeAl 2 /TiAl. Multi-intermetallic compounds with the equivalent flux-energy can be formed at the interfaces at the same time

  4. Pressure effect on magnetic and magnetotransport properties of intermetallic and colossal magnetoresistance oxide compounds

    Czech Academy of Sciences Publication Activity Database

    Arnold, Zdeněk; Ibarra, M. R.; Algarabel, P. A.; Marquina, C.; De Teresa, J. M.; Morellon, L.; Blasco, J.; Magen, C.; Prokhnenko, Olexandr; Kamarád, Jiří; Ritter, C.

    2005-01-01

    Roč. 17, - (2005), S3035-S3055 ISSN 0953-8984 Institutional research plan: CEZ:AV0Z10100521 Keywords : pressure effect * intermetallic compounds * magnetic properties * magnetic phase transitions * magnetotransport properties * oxides Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.145, year: 2005

  5. Charge and spin density in s-stable rare earth intermetallic compounds

    International Nuclear Information System (INIS)

    Graaf, H. de.

    1982-01-01

    This thesis deals with a study of the electronic structure of rare earth intermetallic compounds, in particular the electronic charge and spin density distribution. These are closely related to the properties of the rare earth ions, which carry the partly filled 4f shell. In chapter 1 a survey of the theory of hyperfine interaction as far as it has a bearing on the Moessbauer effect of 155 Gd and 151 Eu is given. Also some details of the Moessbauer spectra, which have practical importance are discussed. In chapter 2 the experimental set-up is described. Special attention is paid to the gamma radiation source and gamma detection requirements. In chapter 3 the author introduces the theoretical framework which will be used to interpret the measurements. In chapter 4 the results of the 155 Gd Moessbauer measurements are presented. Also it is discussed how the result can be understood in terms of the charge and spin density in rare earth intermetallic compounds. In order to lend support to the picture emerging from the previous chapter, in chapter 5 the conduction electron band structure of some representative Gd intermetallics is computed with an approximate semi-empirical LCAO method. The results are compared with those from chapter 4. Finally, in chapter 6, the 151 Eu resonance is used to investigate the temperature dependence of the hyperfine field and line width in the Eu intermetallic compounds Eu 2 Mg 17 and EuMg 5 . (Auth.)

  6. Preparation of Ti3Al intermetallic compound by spark plasma sintering

    Science.gov (United States)

    Ito, Tsutomu; Fukui, Takahiro

    2018-04-01

    Sintered compacts of single phase Ti3Al intermetallic compound, which have excellent potential as refractory materials, were prepared by spark plasma sintering (SPS). A raw powder of Ti3Al intermetallic compound with an average powder diameter of 176 ± 56 μm was used in this study; this large powder diameter is disadvantageous for sintering because of the small surface area. The samples were prepared at sintering temperatures (Ts) of 1088, 1203, and 1323 K, sintering stresses (σs) of 16, 32, and 48 MPa, and a sintering time (ts) of 10 min. The calculated relative densities based on the apparent density of Ti3Al provided by the supplier were approximately 100% under all sintering conditions. From the experimental results, it was evident that SPS is an effective technique for dense sintering of Ti3Al intermetallic compounds in a short time interval. In this report, the sintering characteristics of Ti3Al intermetallic compacts are briefly discussed and compared with those of pure titanium compacts.

  7. Thermochemical investigations on intermetallic UMe3 compounds (Me=Ru,Rh,Pd)

    International Nuclear Information System (INIS)

    Wijbenga, G.

    1981-10-01

    The subject of this thesis is the determination of the thermodynamic properties of the intermetallic compounds of uranium with the light platinum metals, ruthenium, rhodium and palladium. These intermetallics are formed as very stable compounds during fission in nuclear fuel by the reaction of the fission products Ru, Rh and Pd with the matrix. Methods for the preparation of URu 3 , URh 3 and UPd 3 , experiments showing the chemical reactivities of these compounds, and studies of the stoichiometry of hexagonal UPd 3 by X-ray diffraction of solubility experiments of UN and palladium in UPd 3 , are described. Thermodynamic properties of the UMe 3 compounds have been obtained using several experimental thermodynamic techniques: fluorine bomb calorimetry, low-temperature cryogenic calorimetry, high-temperature drop calorimetry and EMF measurements of reversible cells. (Auth.)

  8. Synthesis, Characterization and Properties of Nanoparticles of Intermetallic Compounds

    Energy Technology Data Exchange (ETDEWEB)

    DiSalvo, Francis J. [Cornell Univ., Ithaca, NY (United States)

    2015-03-12

    The research program from 2010 to the end of the grant focused on understanding the factors important to the synthesis of single phase intermetallic nano-particles (NPs), their size, crystalline order, surface properties and electrochemical activity. The synthetic method developed is a co-reduction of mixtures of single metal precursors by strong, soluble reducing agents in a non-protic solvent, tetrahydrofuran (THF). With some exceptions, the particles obtained by room temperature reduction are random alloys that need to be annealed at modest temperatures (200 to 600 °C) in order to develop an ordered structure. To avoid significant particle size growth and agglomeration, the particles must be protected by surface coatings. We developed a novel method of coating the metal nanoparticles with KCl, a by-product of the reduction reaction if the proper reducing agents are employed. In that case, a composite product containing individual metal nanoparticles in a KCl matrix is obtained. The composite can be heated to at least 600 °C without significant agglomeration or growth in particle size. Washing the annealed product in the presence of catalyst supports in ethylene glycol removes the KCl and deposits the particles on the support. Six publications present the method and its application to producing and studying new catalyst/support combinations for fuel cell applications. Three publications concern the use of related methods to explore new lithium-sulfur battery concepts.

  9. Computer simulations of disordering kinetics in irradiated intermetallic compounds

    International Nuclear Information System (INIS)

    Spaczer, M.; Caro, A.; Victoria, M.; Diaz de la Rubia, T.

    1994-01-01

    Molecular-dynamics computer simulations of collision cascades in intermetallic Cu 3 Au, Ni 3 Al, and NiAl have been performed to study the nature of the disordering processes in the collision cascade. The choice of these systems was suggested by the quite accurate description of the thermodynamic properties obtained using embedded-atom-type potentials. Since melting occurs in the core of the cascades, interesting effects appear as a result of the superposition of the loss (and subsequent recovery) of the crystalline order and the evolution of the chemical order, both processes being developed on different time scales. In our previous simulations on Ni 3 Al and Cu 3 Au [T. Diaz de la Rubia, A. Caro, and M. Spaczer, Phys. Rev. B 47, 11 483 (1993)] we found a significant difference between the time evolution of the chemical short-range order (SRO) and the crystalline order in the cascade core for both alloys, namely the complete loss of the crystalline structure but only partial chemical disordering. Recent computer simulations in NiAl show the same phenomena. To understand these features we study the liquid phase of these three alloys and present simulation results concerning the dynamical melting of small samples, examining the atomic mobility, the relaxation time, and the saturation value of the chemical short-range order. An analytic model for the time evolution of the SRO is given

  10. Pressure effect on magnetic and magnetotransport properties of intermetallic and colossal magnetoresistance oxide compounds

    International Nuclear Information System (INIS)

    Arnold, Z; Ibarra, M R; Algarabel, P A; Marquina, C; Teresa, Jose MarIa de; Morellon, L; Blasco, J; Magen, C; Prokhnenko, O; Kamarad, J; Ritter, C

    2005-01-01

    The joint power of neutron diffraction and pressure techniques allows us to characterize under unique conditions the nature and different role of basic interactions in solids. We have covered a broad phenomenology in archetypical compounds: intermetallics and magnetic oxides. We have selected compounds in which the effect of moderate pressure is able to modify the electronic structure and bond angles that in turn are in the bases of magnetic and structural transitions. Complex magnetic and structural phase diagrams are reported for compounds with magnetic (Tb 1-X Y X Mn 2 ) and structural (RE 5 Si 4-X Ge X ) instabilities. Pressure-induced change of the magnetic structure in (R 2 Fe 17 ) intermetallics and the effect on the colossal magnetoresistance manganites are described

  11. Thermal Expansion of Ni3Al Intermetallic Compound: Experiment and Simulation

    International Nuclear Information System (INIS)

    Wang Hai-Peng; Lü Peng; Zhou Kai; Wei Bing-Bo

    2016-01-01

    The thermal expansion of Ni 3 Al intermetallic compound is determined by a thermal dilatometer and simulated by the molecular dynamics method. The results of the linear thermal expansion coefficients are presented from 200 K up to the maximum temperature of 1600 K. The single phase of Ni 3 Al intermetallic compound is confirmed by x-ray diffraction together with DSC melting and solidification peaks, from which the solidus and the liquidus temperatures are obtained to be 1660 and 1695 K, respectively. The measured linear thermal expansion coefficient increases from 1.5 × 10 −5 to 2.7 × 10 −5 K −1 in the experimental temperature range, in good agreement with the data obtained by the molecular dynamics simulation, just a slight difference from the temperature dependence coefficient. Furthermore, the atomic structure and position are presented to reveal the atom distribution change during thermal expansion of Ni 3 Al compound. (paper)

  12. Temperature effects in the valence fluctuation of europium intermetallic compounds

    International Nuclear Information System (INIS)

    Menezes, O.L.T. de; Troper, A.; Gomes, A.A.

    1978-03-01

    A previously reported model for valence fluctuations in europium compound in order to account for thermal occupation effect. Experimental results are critically discussed and new experiments are suggested

  13. Structure and properties of intermetallic ternary rare earth compounds

    International Nuclear Information System (INIS)

    Casper, Frederick

    2008-01-01

    The so called material science is an always growing field in modern research. For the development of new materials not only the experimental characterization but also theoretical calculation of the electronic structure plays an important role. A class of compounds that has attracted a great deal of attention in recent years is known as REME compounds. These compounds are often referred to with RE designating rare earth, actinide or an element from group 1-4, M representing a late transition metal from groups 8-12, and E belonging to groups 13-15. There are more than 2000 compounds with 1:1:1 stoichiometry belonging to this class of compounds and they offer a broad variety of different structure types. Although many REME compounds are know to exist, mainly only structure and magnetism has been determined for these compounds. In particular, in the field of electronic and transport properties relatively few efforts have been made. The main focus in this study is on compounds crystallizing in MgAgAs and LiGaGe structure. Both structures can only be found among 18 valence electron compounds. The f electrons are localized and therefor not count as valence electrons. A special focus here was also on the magnetoresistance effects and spintronic properties found among the REME compounds. An examination of the following compounds was made: GdAuE (E=In,Cd,Mg), GdPdSb, GdNiSb, REAuSn (RE=Gd,Er,Tm) and RENiBi (RE=Pr,Sm,Gd-Tm,Lu). The experimental results were compared with theoretic band structure calculations. The first half metallic ferromagnet with LiGaGe structure (GdPdSb) was found. All semiconducting REME compounds with MgAgAs structure show giant magnetoresistance (GMR) at low temperatures. The GMR is related to a metal-insulator transition, and the value of the GMR depends on the value of the spin-orbit coupling. Inhomogeneous DyNiBi samples show a small positive MR at low temperature that depends on the amount of metallic impurities. At higher fields the samples show a

  14. Structure and properties of intermetallic ternary rare earth compounds

    Energy Technology Data Exchange (ETDEWEB)

    Casper, Frederick

    2008-12-17

    The so called material science is an always growing field in modern research. For the development of new materials not only the experimental characterization but also theoretical calculation of the electronic structure plays an important role. A class of compounds that has attracted a great deal of attention in recent years is known as REME compounds. These compounds are often referred to with RE designating rare earth, actinide or an element from group 1-4, M representing a late transition metal from groups 8-12, and E belonging to groups 13-15. There are more than 2000 compounds with 1:1:1 stoichiometry belonging to this class of compounds and they offer a broad variety of different structure types. Although many REME compounds are know to exist, mainly only structure and magnetism has been determined for these compounds. In particular, in the field of electronic and transport properties relatively few efforts have been made. The main focus in this study is on compounds crystallizing in MgAgAs and LiGaGe structure. Both structures can only be found among 18 valence electron compounds. The f electrons are localized and therefor not count as valence electrons. A special focus here was also on the magnetoresistance effects and spintronic properties found among the REME compounds. An examination of the following compounds was made: GdAuE (E=In,Cd,Mg), GdPdSb, GdNiSb, REAuSn (RE=Gd,Er,Tm) and RENiBi (RE=Pr,Sm,Gd-Tm,Lu). The experimental results were compared with theoretic band structure calculations. The first half metallic ferromagnet with LiGaGe structure (GdPdSb) was found. All semiconducting REME compounds with MgAgAs structure show giant magnetoresistance (GMR) at low temperatures. The GMR is related to a metal-insulator transition, and the value of the GMR depends on the value of the spin-orbit coupling. Inhomogeneous DyNiBi samples show a small positive MR at low temperature that depends on the amount of metallic impurities. At higher fields the samples show a

  15. Pitting Corrosion of Ni3(Si,Ti Intermetallic Compound at Various Chloride Concentrations

    Directory of Open Access Journals (Sweden)

    Gadang Priyotomo

    2013-10-01

    Full Text Available The pitting corrosion of Ni3(Si,Ti intermetallic compound was investigated as function of chloride concentration by using electrochemical method and scanning electron microscope in sodium chloride solutions at 293 K.  In addition, the pitting corrosion of type C276 alloy was also studied under the same experimental condition for comparison.  The pitting potential obtained for the intermetallic compound decreased with increasing chloride concentration.  The specific pitting potential and pitting potential of Ni3(Si,Ti were lower than those of C276 alloy, which means that the pitting corrosion resistance of C276 alloy was higher than that of Ni3(Si,Ti.

  16. Control of interfacial intermetallic compounds in Fe–Al joining by Zn addition

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J. [Key Laboratory of Robot and Welding Automation of Jiangxi Province, School of Mechanical and Electrical Engineering, Nanchang University, Nanchang, Jiangxi 330031 (China); Center for Advanced Materials Joining, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada); Li, Y.L., E-mail: liyulong1112ster@gmail.com [Key Laboratory of Robot and Welding Automation of Jiangxi Province, School of Mechanical and Electrical Engineering, Nanchang University, Nanchang, Jiangxi 330031 (China); Zhang, H. [Key Laboratory of Robot and Welding Automation of Jiangxi Province, School of Mechanical and Electrical Engineering, Nanchang University, Nanchang, Jiangxi 330031 (China); Guo, W. [Center for Advanced Materials Joining, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada); School of Mechanical Engineering and Automation, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Zhou, Y. [Center for Advanced Materials Joining, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada)

    2015-10-01

    By Zn addition to the fusion zone, the interfacial intermetallic compounds (IMCs) of laser Al/steel joint changed from layered Fe{sub 2}Al{sub 5} and needle-like FeAl{sub 3} to layered Fe{sub 2}Al{sub 5−x}Zn{sub x} and dispersed FeZn{sub 10} with minor Al-rich amorphous phase. This resulted in an improvement in the joint strength and the change of failure mode.

  17. Magnetic behavior of binary intermetallic compound YPd{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Abhishek [S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098 (India); Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Mazumdar, Chandan [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India)], E-mail: chandan.mazumdar@saha.ac.in; Ranganathan, R. [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India)

    2009-05-12

    We report the results of detailed magnetic studies on binary rare-earth-transition metal compound YPd{sub 3}. The results of temperature and magnetic field dependent DC-magnetic measurements along with the results of powder X-ray diffraction measurement and electrical transport have been discussed. The X-ray data suggest a well-defined ordered crystal lattice, free from any detectable impurity phase. Magnetization data exhibits predominant diamagnetic character at higher fields. However, the compound exhibits anomalous behavior at low fields.

  18. Process for the manufacture of a superconductor with an intermetallic compound

    International Nuclear Information System (INIS)

    Wilhelm, M.

    1980-01-01

    A superconductor with a superconducting intermetallic compound consisting of at least two elements can be manufactured by producing a conductor preproduct with a first component containing one element of the compound and a second component consisting of a carrier metal and the remaining element or elements of the alloy containing the compound, and by heat treating the conductor preproduct, so that the compound is formed by the reaction of the element of the first compound with the remaining element or elements of the second compound. In such a superconductor, one tries to increase the effective current density and critical current. The invention states that the heat treatment should be carried out in a hydrogen atmosphere. Superconductors produced by this process can be used for superconductor devices whose magnetic fields have a flux density above 10 Tesla. (orig.) [de

  19. A new method to estimate the atomic volume of ternary intermetallic compounds

    International Nuclear Information System (INIS)

    Pani, M.; Merlo, F.

    2011-01-01

    The atomic volume of an A x B y C z ternary intermetallic compound can be calculated starting from volumes of some proper A-B, A-C and B-C binary phases. The three methods by Colinet, Muggianu and Kohler, originally used to estimate thermodynamic quantities, and a new method here proposed, were tested to derive volume data in eight systems containing 91 ternary phases with the known structure. The comparison between experimental and calculated volume values shows the best agreement both for the Kohler method and for the new proposed procedure. -- Graphical abstract: Synopsys: the volume of a ternary intermetallic compound can be calculated starting from volumes of some binary phases, selected by the methods of Colinet, Muggianu, Kohler and a new method proposed here. The so obtained values are compared with the experimental ones for eight ternary systems. Display Omitted Research highlights: → The application of some thermodinamic methods to a crystallochemical problem. → The prevision of the average atomic volume of ternary intermetallic phases. → The proposal of a new procedure to select the proper starting set of binary phases.

  20. B2 intermetallic compounds of Zr. New class of the shape memory alloys

    International Nuclear Information System (INIS)

    Koval, Yu.N.; Delaey, L.; Jang, W.Y.

    1995-01-01

    It is known that the B2 equiatomic intermetallic compounds of Zr (ZrCo-based) undergo a martensitic transformation (MT) with wide temperature hysteresis. It was found that the MT is accompanied by the perfect shape memory effect (SME) for ZrCu and ZrRh. In this report we represent the results of structural analysis, electrical resistivity, calorimetric and SME measurements for ZrCu- and ZrCo-based compounds. Interrelation between structural, thermodynamical parameters of MT and SME in this alloys will be described. The shape memory aspects of this potential alloys for the application at high temperatures will be discussed. (orig.)

  1. Thermodynamic data for uranium and thorium intermetallic compounds: A historical perspective

    International Nuclear Information System (INIS)

    Alcock, C.B.

    1989-01-01

    The development of quantitative information concerning the stabilities of uranium and thorium intermetallic compounds since the publication of Rough and Bauer's phase diagram compilation are reviewed. During this era a number of high temperature measurement techniques have been developed, from gas/solid equilibration to mass spectrometry and from high temperature calorimetry to solid state electrochemistry, and the growth of quantitative information has run parallel to this evolution. The amount of experimental effort now appears to be declining, and the task presently of major importance is to integrate and rationalize the quantitative information, an effort which will undoubtedly lead to new experimental initiatives. (orig.)

  2. Properties of vacancies type defects in intermetallic compounds of the Al-Mo system

    International Nuclear Information System (INIS)

    Pascuet, M.I; Fernandez, J.R; Monti, A.M

    2006-01-01

    There are five intermetallic compounds in the Al-Mo system that are stable at low temperatures. Of these, the richest phases in some of the two components are the compounds Al 12 Mo and AlMo 3 , whose Pearson symbols are cI26 and cP8, respectively. In both structures, the atoms of the minority component occupy positions bcc and each one of them is surrounded by 12 atoms first neighbors of the other component. These 13 atoms form icosahedron shaped units or heaps. Unlike what occurs in Al 12 Mo, the AlMo 3 heaps are superposed by sharing atoms from the majority component. The neighboring environment of the majority component is mixed but differs considerably in one or another intermetallic. In each structure, the sites occupied by any given species are crystallographically equivalent, that is, they can self generate from one of the positions and from the crystalline structure's elements of symmetry. This work studies the energy of vacancies and antisites in both compounds and the atomic-jump processes to vacant sites. Computer simulation techniques were used based on minimizing the system's energy. Many-body embedded-atom potentials were used to represent the atomic interactions. The potential mixture used resulted in an adjustment to the crystalline structure of the AlMo 3 phase at low temperatures and to its formation energy (cw)

  3. On the valence state of Yb and Ce in transition metal intermetallic compounds

    International Nuclear Information System (INIS)

    Boer, F.R. de; Dijkman, W.H.; Mattens, W.C.M.

    1979-01-01

    In the pure state Yb is a divalent metal, similar to Ca; in alloys it can become trivalent like the majority of the rare earth metals. Using a value of 38 kJ (mol Yb) -1 for the energy difference between divalent and trivalent Yb metal and using model calculations for the heat of formation of intermetallic compounds, the authors are able to account for the existing information on the valence state of Yb in transition metal compounds. A similar analysis of compounds of Ce with transition metals shows that a model in which the 4f electron is treated as a core electron, i.e. being absent in the tetravalent modification of Ce and present as a fully localized electron in trivalent Ce, does not apply. (Auth.)

  4. The corrosion behavior of the T1 (Al2CuLi) intermetallic compound in aqueous environments

    Science.gov (United States)

    Buchheit, R. G.; Stoner, G. E.

    1989-01-01

    The intermetallic compound T1 (Al2CuLi) is suspected to play an important role in the localized corrosion at subgrain boundaries in Al-Li-Cu alloys. The intermetallic was synthesized for characterization of its corrosion behavior. Experiments performed included open circuit potential measurements, potentiodynamic polarization, and corrosion rate vs. pH in solutions whose pH was varied over the range of 3 to 11. Subgrain boundary pitting and continuous subgrain boundary corrosion are discussed in terms of the data obtained. Evidence suggesting the dealloying of copper from this compound is also presented.

  5. Effects of surface polishing and annealing on the optical conductivity of intermetallic compounds

    CERN Document Server

    Rhee, J Y

    1999-01-01

    The optical conductivity spectra of several intermetallic compounds were measured by spectroscopic ellipsometry. Three spectra were measured for each compound; just after the sample was mechanically polished, at high temperature, and after the sample was annealed at 110 .deg. C for at least one day and cooled to room temperature. An equiatomic FeTi alloy showed the typical effects of annealing after mechanical polishing of surface. The spectrum after annealing had a larger magnitude and sharper structures than the spectrum before annealing. We also observed shifts of peaks in the spectrum. A relatively low-temperature annealing gave rise to unexpectedly substantial effects, and the effects were explained by recrystallization and/or a disorder -> order transition of the surface of the sample which was damaged and, hence, became highly disordered by mechanical polishing. Similar effects were also observed when the sample temperature was lowered. The observed changes upon annealing could partly be explained by p...

  6. Discovery of Intermetallic Compounds from Traditional to Machine-Learning Approaches.

    Science.gov (United States)

    Oliynyk, Anton O; Mar, Arthur

    2018-01-16

    Intermetallic compounds are bestowed by diverse compositions, complex structures, and useful properties for many materials applications. How metallic elements react to form these compounds and what structures they adopt remain challenging questions that defy predictability. Traditional approaches offer some rational strategies to prepare specific classes of intermetallics, such as targeting members within a modular homologous series, manipulating building blocks to assemble new structures, and filling interstitial sites to create stuffed variants. Because these strategies rely on precedent, they cannot foresee surprising results, by definition. Exploratory synthesis, whether through systematic phase diagram investigations or serendipity, is still essential for expanding our knowledge base. Eventually, the relationships may become too complex for the pattern recognition skills to be reliably or practically performed by humans. Complementing these traditional approaches, new machine-learning approaches may be a viable alternative for materials discovery, not only among intermetallics but also more generally to other chemical compounds. In this Account, we survey our own efforts to discover new intermetallic compounds, encompassing gallides, germanides, phosphides, arsenides, and others. We apply various machine-learning methods (such as support vector machine and random forest algorithms) to confront two significant questions in solid state chemistry. First, what crystal structures are adopted by a compound given an arbitrary composition? Initial efforts have focused on binary equiatomic phases AB, ternary equiatomic phases ABC, and full Heusler phases AB 2 C. Our analysis emphasizes the use of real experimental data and places special value on confirming predictions through experiment. Chemical descriptors are carefully chosen through a rigorous procedure called cluster resolution feature selection. Predictions for crystal structures are quantified by evaluating

  7. Intermetallic nanoparticles

    Science.gov (United States)

    Singh, Dileep; Yusufoglu, Yusuf; Timofeeva, Elena; Routbort, Jules

    2015-07-14

    A process for preparing intermetallic nanoparticles of two or more metals is provided. In particular, the process includes the steps: a) dispersing nanoparticles of a first metal in a solvent to prepare a first metal solution, b) forming a reaction mixture with the first metal solution and a reducing agent, c) heating the reaction mixture to a reaction temperature; and d) adding a second metal solution containing a salt of a second metal to the reaction mixture. During this process, intermetallic nanoparticles, which contain a compound with the first and second metals are formed. The intermetallic nanoparticles with uniform size and a narrow size distribution is also provided. An electrochemical device such as a battery with the intermetallic nanoparticles is also provided.

  8. Contribution to the study of magnetic properties of rare-earth iron intermetallic compounds

    International Nuclear Information System (INIS)

    Morariu, M.

    1976-01-01

    The intermetallic binary compounds Ysub(x)Fesub(y)(YFe 2 ,YFe 3 ,Y 6 Fe 23 ,Y 2 Fe 17 ), RFe 2 (R=Gd,Tb,Dy,Ho,Er and Tm) and the intermetallic pseudobinary compounds (Gdsub(x)Ysub(1-x))Fe 2 and Dy(Fesub(x)Nisub(1-x)) 3 were studied, using magnetic measurements and Moessbauer spectroscopy, in order to obtain information on their magnetic behaviour. The different models which describe magnetic interactions in rare-earths with 3d transition element compounds are reviewed. The magnetic hyperfine field Hsub(n) at the Fe 57 nucleus, measured by Moessbauer spectroscopy, depends on the atom position in the lattice, being sensitive to magnetic interactions with neighbouring atoms. The mean value of the magnetic hyperfine field, average Hsub(n) is proportional to the mean magnetic moment of the iron atom: average Hsub(n)/average μsub(Fe) approximately 150 kOe. The comparative study of the temperature dependence of average Hsub(n) and average μsub(Fe) values shows that this relation is valid for the whole range of magnetic ordering (T>Tsub(c)). The mean magnetic hyperfine fields at the Fe 57 nucleus in RFe 2 compounds depend on the rare-earth partner and vary approximative linearly with the Gennes factor. The spin reorientation diagram for the (Gdsub(x)Ysub(1-x))Fe 2 system is obtained. All results on Moessbauer spectroscopy are in good agreement with the magnetic measurements. The magnetic behaviour of iron atoms is justified using a model in which the most electrons are in a narrow band, so they could be considered localized, and the magnetic interactions between these atoms take place through a fraction (<5%) of 3d itinerant electrons. (author)

  9. A theoretical search for intermetallic compounds and solution phases in the binary system Sn/Zn

    Energy Technology Data Exchange (ETDEWEB)

    Appen, Joerg von; Dronskowski, Richard; Hack, Klaus

    2004-10-06

    The binary system Sn/Zn was theoretically investigated by a classical thermodynamic analysis (CALPHAD approach) and by density-functional total-energy calculations on the basis of the LDA/GGA, plane waves/muffin-tin orbitals, and supercell geometries. In harmony with experimental data, both methods agree in that there is only very small solubility between the elements and no formation of a stable intermetallic phase over the entire compositional range. For the hypothetical composition Sn{sub 2}Zn, a total of 30 different crystal structures was quantum-mechanically optimized, and the chemical bondings of Sn{sub 2}Zn adopting the CaF{sub 2} and HgBr{sub 2} structures were analyzed in detail; generally, the more ionic structure types are better suited for the Sn{sub 2}Zn composition than typical intermetallic ones. Theoretical enthalphy-pressure diagrams were generated to explore high-pressure compound formation, and the observed transition pressures between the {alpha}, {beta} and {gamma} allotropes of tin were correctly reproduced by electronic structure theory.

  10. Electrochemical preparation of Al–Sm intermetallic compound whisker in LiCl–KCl Eutectic Melts

    International Nuclear Information System (INIS)

    Ji, De−Bin; Yan, Yong−De; Zhang, Mi−Lin; Li, Xing; Jing, Xiao−Yan; Han, Wei; Xue, Yun; Zhang, Zhi−Jian; Hartmann, Thomas

    2015-01-01

    Highlights: • The reduction process of Sm(III) was investigated in LiCl–KCl melt on an aluminum electrode at 773 K. • Al–Sm alloy with different phase structure (Al 2 Sm and Al 3 Sm) was prepared by potentiostatic electrolysis on an aluminum electrode with the change of electrolytic potentials and time in LiCl–KCl–SmCl 3 melts. • Al − Sm alloy containing whiskers (Al 4 Sm) was obtained by potentiostatic electrolysis (−2.10 V) on an aluminum electrode for 7 hours with the change of electrolytic temperature and cooling rate in LiCl–KCl–SmCl 3 (16.5 wt. %) melts. The results from micro–hardness test and potentiodynamic polarization test show the micro hardness and corrosion property are remarkably improved with the help of Al–Sm intermetallic compound whiskers. - Abstract: This work presents the electrochemical study of Sm(III) on an aluminum electrode in LiCl–KCl melts at 773 K by different electrochemical methods. Three electrochemical signals in cyclic voltammetry, square wave voltammetry, open circuit chronopotentiometry, and cathode polarization curve are attributed to different kinds of Al–Sm intermetallic compounds, Al 2 Sm, Al 3 Sm, and Al 4 Sm, respectively. Al–Sm alloy with different phase structure (Al 2 Sm and Al 3 Sm) could be obtained by the potentiostatic electrolysis with the change of electrolytic potentials and time. Al–Sm alloy containing whiskers (Al 4 Sm) was obtained by potentiostatic electrolysis (−2.10 V) on an aluminum electrode for 7 hours with the change of electrolytic temperature and cooling rate in LiCl–KCl–SmCl 3 (16.5 wt. %) melts. The XRD and SEM&EDS were employed to investigate the phase composition and microstructure of Al–Sm alloy. SEM analysis shows that lots of needle−like precipitates formed in Al–Sm alloy, and their ratios of length to diameter are found to be greater than 10 to 1. The TEM and electron diffraction pattern were performed to investigate the crystal structure of the

  11. Intermetallic compounds in 3D integrated circuits technology: a brief review

    Science.gov (United States)

    Annuar, Syahira; Mahmoodian, Reza; Hamdi, Mohd; Tu, King-Ning

    2017-12-01

    The high performance and downsizing technology of three-dimensional integrated circuits (3D-ICs) for mobile consumer electronic products have gained much attention in the microelectronics industry. This has been driven by the utilization of chip stacking by through-Si-via and solder microbumps. Pb-free solder microbumps are intended to replace conventional Pb-containing solder joints due to the rising awareness of environmental preservation. The use of low-volume solder microbumps has led to crucial constraints that cause several reliability issues, including excessive intermetallic compounds (IMCs) formation and solder microbump embrittlement due to IMCs growth. This article reviews technologies related to 3D-ICs, IMCs formation mechanisms and reliability issues concerning IMCs with Pb-free solder microbumps. Finally, future outlook on the potential growth of research in this area is discussed.

  12. Intermetallic compounds in 3D integrated circuits technology: a brief review.

    Science.gov (United States)

    Annuar, Syahira; Mahmoodian, Reza; Hamdi, Mohd; Tu, King-Ning

    2017-01-01

    The high performance and downsizing technology of three-dimensional integrated circuits (3D-ICs) for mobile consumer electronic products have gained much attention in the microelectronics industry. This has been driven by the utilization of chip stacking by through-Si-via and solder microbumps. Pb-free solder microbumps are intended to replace conventional Pb-containing solder joints due to the rising awareness of environmental preservation. The use of low-volume solder microbumps has led to crucial constraints that cause several reliability issues, including excessive intermetallic compounds (IMCs) formation and solder microbump embrittlement due to IMCs growth. This article reviews technologies related to 3D-ICs, IMCs formation mechanisms and reliability issues concerning IMCs with Pb-free solder microbumps. Finally, future outlook on the potential growth of research in this area is discussed.

  13. Sodium borohydride hydrolysis in the presence of intermetallic compound LaNi5

    International Nuclear Information System (INIS)

    Korobov, I.I.; Mozgina, N.G.

    1992-01-01

    Kinetics of catalytic hydrolysis of sodium borohydride in the 1 mol/l solution of caustic sodium within the range of 298-318 K in presence of LaNi 5 intermetallic compound is studied. It is established that the reaction has zero order by NaBH 4 and the first one by LaNi 5 . The apparent activation energy of NaBH 4 catalytic hydrolysis in presence of LaNi 5 , calculated on the basis of temperature dependence of reaction velocity, is constant within the temperature range under investigation and constitutes 56$+-$1.5 kJ/mol. Recombination of surface hydrogen on LaNi 5 in molecular one is limiting stage determining NaBH 4 hydrolysis rate

  14. Description of structure of Fe-Zn intermetalic compounds present in hot-dip galvanized coatings on steel

    Directory of Open Access Journals (Sweden)

    P. Pokorny

    2015-10-01

    Full Text Available The article is describing formation, composition, morphology and crystallographic characteristics of intermetalic compounds Fe - Zn present in the coating formed during the process of low-temperature hot-dip galvanizing of carbon steels. In mutual confrontation we introduce older bibliography and results of latest modern researches based on combination of most precise analytical methods.

  15. Characterization of intermetallic compounds in Cu-Al ball bonds: thermo-mechanical properties, interface delamination and corrosion

    NARCIS (Netherlands)

    Gubbels, G.H.M.; Kouters, M.H.M.; Dos Santos Ferreira, O.

    2012-01-01

    In high power automotive electronics copper wire bonding is regarded as the most promising alternative for gold wire bonding in 1st level interconnects. In the Cu-Al ball bond interface the growth of intermetallic compounds can deteriorate the electrical and mechanical properties of the

  16. Thermal expansion and thermal diffusivity properties of Co-Si solid solutions and intermetallic compounds

    International Nuclear Information System (INIS)

    Ruan, Ying; Li, Liuhui; Gu, Qianqian; Zhou, Kai; Yan, Na; Wei, Bingbo

    2016-01-01

    Highlights: • Length change difference between rapidly and slowly solidified Co-Si alloy occurs at high temperature. • Generally CTE increases with an increasing Si content. • The thermal diffusion abilities are CoSi 2 > Co 95 Si 5 > Co 90 Si 10 > Co 2 Si > CoSi if T exceeds 565 K. • All the CTE and thermal diffusivity variations with T satisfy linear or polynomial relations. - Abstract: The thermal expansion of Co-Si solid solutions and intermetallic compounds was measured via dilatometric method, compared with the results of first-principles calculations, and their thermal diffusivities were investigated using laser flash method. The length changes of rapidly solidified Co-Si alloys are larger than those of slowly solidified alloys when temperature increases to around 1000 K due to the more competitive atom motion. The coefficient of thermal expansion (α) of Co-Si alloy increases with an increasing Si content, except that the coefficient of thermal expansion of Co 95 Si 5 influenced by both metastable structure and allotropic transformation is lower than that of Co 90 Si 10 at a higher temperature. The thermal expansion abilities of Co-Si intermetallic compounds satisfy the relationship of Co 2 Si > CoSi > CoSi 2 , and the differences of the coefficients of thermal expansion between them increase with the rise of temperature. The thermal diffusivity of CoSi 2 is evidently larger than the values of other Co-Si alloys. If temperature exceeds 565 K, their thermal diffusion abilities are CoSi 2 > Co 95 Si 5 > Co 90 Si 10 > Co 2 Si > CoSi. All the coefficient of thermal expansion and thermal diffusivity variations with temperature satisfy linear or polynomial relations.

  17. The formation of intermetallic compounds during interdiffusion of Mg–Al/Mg–Ce diffusion couples

    International Nuclear Information System (INIS)

    Dai, Jiahong; Jiang, Bin; Li, Xin; Yang, Qingshan; Dong, Hanwu; Xia, Xiangsheng; Pan, Fusheng

    2015-01-01

    Graphical abstract: Al–Ce intermetallic compounds (IMCs) formed in Mg–Al/Mg–Ce diffusion couples. During the whole diffusion process, Al was the dominant diffusing species, and it substituted for Mg atoms of the Mg–Ce substrate. Five Al–Ce IMCs of Al 4 Ce, Al 11 Ce 3 , Al 3 Ce, Al 2 Ce, and AlCe were formed via the reaction of Al and Ce. - Highlights: • Al–Ce IMCs formation in the Mg–Al/Mg–Ce diffusion couples was studied. • Formation of Al 4 Ce as the first phase was rationalized using the Gibbs free energy. • The activation energy for the growth of the diffusion reaction zones was 36.6 kJ/mol. - Abstract: The formation of Al–Ce intermetallic compounds (IMCs) during interdiffusion of Mg–Al/Mg–Ce diffusion couples prepared by solid–liquid contact method was investigated at 623 K, 648 K and 673 K for 24 h, 48 h and 72 h, respectively. During the whole diffusion process, Al was the dominant diffusing species, and it substituted for Mg of the Mg–Ce substrate. Five Al–Ce IMCs of Al 4 Ce, Al 11 Ce 3 , Al 3 Ce, Al 2 Ce and AlCe were formed via the reaction of Al and Ce. The formation of Al 4 Ce as the first kind of IMC was rationalized on the basis of an effective Gibbs free energy model. The activation energy for the growth of the total diffusion reaction layer was 36.6 kJ/mol

  18. NMR measurements in milled GdCo2 and GdFe2 intermetallic compounds

    International Nuclear Information System (INIS)

    Tribuzy, C.V.B.; Guimaraes, A.P.; Biondo, A.; Larica, C.; Alves, K.M.B.

    1998-12-01

    We have used the nuclear magnetic resonance technique to study the magnetic and structural properties of the Gd-Co and Gd-Fe metallic systems, starting with the C15 laves phase intermetallic compounds, and submitting them to a high energy milling process. This leads to the amorphization of the samples, as determined by the X-ray diffraction spectra. For the Gd-Co system the NMR study used the 59 Co nucleus; in the Gd-Fe system, 155,157 Gd and 57 Fe were used. Both systems showed segregation of the pure elements, after a few hours of milling. In the Gd-Co system, a single line, of increasing width, was observed in the 59 Co spectrum. In the Gd-Fe system, the 155 Gd and 157 Gd resonances show three lines, arising from electrical quadrupole interaction. With increasing milling time, the lines broaden, and extra lines appear attributed to a cubic phase of Gd; this interpretation is supported by the X-ray analysis of the samples. The 57 Fe NMR spectrum of this system also informs on the direction of magnetization of the samples in the early stages of milling. From 1 h to 7 h of milling, a spectrum of α-Fe was observed. The study of the NMR line intensity as a function of radio frequency (r.f.) power in Gd Co 2 suggests the existence of regions of the samples with different degrees of disorder. We have observed the persistence of NMR signals from the original intermetallic compounds in the samples with up to 10 h and 7 h of milling, respectively, for Gd Co 2 and Gd Fe 2 . (author)

  19. Magneto-caloric effect in the pseudo-binary intermetallic YPrFe{sub 17} compound

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Pablo [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Gorria, Pedro, E-mail: pgorria@uniovi.es [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Sanchez Llamazares, Jose L. [Division de Materiales Avanzados, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la presa San Jose 2055, CP 78216, San Luis Potosi (Mexico); Perez, Maria J. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Franco, Victorino [Departamento de Fisica de la Materia Condensada, ICMSE-CSIC, Universidad de Sevilla, P.O. Box 1065, 41080 Sevilla (Spain); Reiffers, Marian; Kovac, Jozef [Institute of Experimental Physics, Watsonova 47, SK-04001 Kosice (Slovakia); Puente-Orench, Ines [Institute Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble (France); Blanco, Jesus A. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer YPrFe{sub 17} exhibits a broad {Delta}S{sub M}(T) associated with the ferro-to-paramagnetic phase transition (T{sub C} Almost-Equal-To 290 K). Black-Right-Pointing-Pointer We obtain |{Delta}S{sub M}| Almost-Equal-To 2.3 J kg{sup -1} K{sup -1} and RCP Almost-Equal-To 100 J kg{sup -1}for a magnetic field change of 1.5 T. Black-Right-Pointing-Pointer A single master curve for {Delta}S{sub M} is found when compared with other isostructural R{sub 2}Fe{sub 17} binary alloys. - Abstract: We have synthesized the intermetallic YPrFe{sub 17} compound by arc-melting. X-ray and neutron powder diffraction show that the crystal structure is rhombohedral with R3{sup Macron }m space group (Th{sub 2}Zn{sub 17}-type). The investigated compound exhibits a broad isothermal magnetic entropy change {Delta}S{sub M}(T) associated with the ferro-to-paramagnetic phase transition (T{sub C} Almost-Equal-To 290 K). The |{Delta}S{sub M}| ( Almost-Equal-To 2.3 J kg{sup -1} K{sup -1}) and the relative cooling power ( Almost-Equal-To 100 J kg{sup -1}) have been calculated for applied magnetic field changes up to 1.5 T. A single master curve for {Delta}S{sub M} under different values of the magnetic field change can be obtained by a rescaling of the temperature axis. The results are compared and discussed in terms of the magneto-caloric effect in the isostructural R{sub 2}Fe{sub 17} (R = Y, Pr and Nd) binary intermetallic alloys.

  20. The effect of crystal structure stability on the mobility of gas bubbles in intermetallic uranium compounds

    International Nuclear Information System (INIS)

    Rest, J.; Hofman, G.L.; Birtcher, R.C.

    1988-01-01

    Irradiation experiments with certain low-enrichment, high-density, uranium-base intermetallic alloys that are candidate reactor fuel materials, such as U 3 Si and U 6 Fe, have revealed extraordinarily large voids at low and medium fuel burnup. This phenomenon of breakaway swelling does not occur in other fuel types, such as U 3 Si 2 and UAl 3 , where a distribution of relatively small and stable fission gas bubbles forms. In situ transmission electron microscope observations of ion radiation-induced rapid swelling of intermetallic materials are consistent with growth by plastic flow. Large radiation enhancement of plastic flow in amorphous materials has been observed in several independent experiments and is thought to be a general materials phenomenon. The basis for a microscopic theory of fission gas bubble behavior in irradiated amorphous compounds has been formulated. The assumption underlying the overall theory is that the evolution of the porosity from that observed in the crystalline material to that observed in irradiated amorphous U 3 Si as a function of fluence is due to a softening of the irradiated amorphous material. Bubble growth in the low-viscosity material has been approximated by an effective enhanced diffusivity. Mechanisms are included for the radiation-induced softening of the amorphous material, and for a relation between gas atom mobilities and radiation-induced (defect-generated) changes in the material. Results of the analysis indicate that the observed rapid swelling in U 3 Si arises directly from enhanced bubble migration and coalescence due to plastic flow. 34 refs., 11 figs

  1. Void formation and its impact on Cu−Sn intermetallic compound formation

    International Nuclear Information System (INIS)

    Ross, Glenn; Vuorinen, Vesa; Paulasto-Kröckel, Mervi

    2016-01-01

    Void formation in the Cu−Sn system has been identified as a major reliability issue with small volume electronic interconnects. Voids form during the interdiffusion of electrochemically deposited Cu and Sn, with varying magnitude and density. Electroplating parameters include the electrolytic chemistry composition and the electroplating current density, all of which appear to effect the voiding characteristics of the Cu−Sn system. In addition, interfacial voiding affects the growth kinetics of the Cu_3Sn and Cu_6Sn_5 intermetallic compounds of the Cu−Sn system. The aim here is to present voiding data as a function of electroplating chemistry and current density over a duration (up to 72 h) of isothermal annealing at 423 K (150 °C). Voiding data includes the average interfacial void size and average void density. Voids sizes grew proportionally as a function of thermal annealing time, whereas the void density grew initially very quickly but tended to saturate at a fixed density. A morphological evolution analysis called the physicochemical approach is utilised to understand the processes that occur when a voided Cu/Cu_3Sn interface causes changes to the IMC phase growth. The method is used to simulate the intermetallic thickness growths' response to interfacial voiding. The Cu/Cu_3Sn interface acts as a Cu diffusion barrier disrupting the diffusion of Cu. This resulted in a reduction in the Cu_3Sn thickness and an accelerated growth rate of Cu_6Sn_5. - Highlights: • Average void size is proportional linearly to thermal annealing time. • Average void density grows initially very rapidly followed by saturation. • Voids located close to the Cu/Cu_3Sn interface affect IMC growth rates. • Voids act as a diffusion barrier inhibiting Cu diffusion towards Sn. • Voids located at the interface cause Cu_3Sn to be consumed by Cu_6Sn_5.

  2. Effects of filling material and laser power on the formation of intermetallic compounds during laser-assisted friction stir butt welding of steel and aluminum alloys

    Science.gov (United States)

    Fei, Xinjiang; Jin, Xiangzhong; Peng, Nanxiang; Ye, Ying; Wu, Sigen; Dai, Houfu

    2016-11-01

    In this paper, two kinds of materials, Ni and Zn, are selected as filling material during laser-assisted friction stir butt welding of Q235 steel and 6061-T6 aluminum alloy, and their influences on the formation of intermetallic compounds on the steel/aluminum interface of the joints were first studied. SEM was used to analyze the profile of the intermetallic compound layer and the fractography of tensile fracture surfaces. In addition, EDS was applied to investigate the types of the intermetallic compounds. The results indicate that a thin iron-abundant intermetallic compound layer forms and ductile fracture mode occurs when Ni is added, but a thick aluminum-abundant intermetallic compound layer generates and brittle fracture mode occurs when Zn is added. So the tensile strength of the welds with Ni as filling material is greater than that with Zn as filling material. Besides, the effect of laser power on the formation of intermetallic compound layer when Ni is added was investigated. The preheated temperature field produced by laser beam in the cross section of workpiece was calculated, and the tensile strength of the joints at different laser powers was tested. Results show that only when suitable laser power is adopted, can suitable preheating temperature of the steel reach, then can thin intermetallic compound layer form and high tensile strength of the joints reach. Either excessive or insufficient laser power will reduce the tensile strength of the joints.

  3. New intermetallic compounds Ln(Ag, AL)4 (Ln-Y, Gd, Tb, Dy) and their structure

    International Nuclear Information System (INIS)

    Kuz'ma, Yu.B.; Stel'makhovich, B.M.

    1990-01-01

    By the methods of X-ray analysis crystal structure of compounds Ln(Ag,Al) 4 , where Ln-Y, Gd, Tb, Dy, posessing rhombic structure, is determined. The intermetallics have been prepared for the first time. Ways of atom distribution and their coordinates in DyAg 0.55 Al 3.45 structure (a=0.4296(1), b=04179(1), c=0.9995(3), R=0.093) are specified. Other compounds are formed in case of LnAgAl 3 compositions. Interatomic distances in Dy(Ag,Al) 4 structure are considered. A supposition is made on the formation in Ln-Ag-Al systems of a greater number of intermetallic compounds

  4. Effects of surface polishing and annealing on the optical conductivity of intermetallic compounds

    International Nuclear Information System (INIS)

    Rhee, Joo Yull

    1999-01-01

    The optical conductivity spectra of several intermetallic compounds were measured by spectroscopic ellipsometry. Three spectra were measured for each compound; just after the sample was mechanically polished, at high temperature, and after the sample was annealed at 110 .deg. C for at least one day and cooled to room temperature. An equiatomic FeTi alloy showed the typical effects of annealing after mechanical polishing of surface. The spectrum after annealing had a larger magnitude and sharper structures than the spectrum before annealing. We also observed shifts of peaks in the spectrum. A relatively low-temperature annealing gave rise to unexpectedly substantial effects, and the effects were explained by recrystallization and/or a disorder → order transition of the surface of the sample which was damaged and, hence, became highly disordered by mechanical polishing. Similar effects were also observed when the sample temperature was lowered. The observed changes upon annealing could partly be explained by presumption that the recrystallization would be realized in such a way that the average atomic spacing would be reduced

  5. Theoretical study of elastic, mechanical and thermodynamic properties of MgRh intermetallic compound

    Directory of Open Access Journals (Sweden)

    S. Boucetta

    2014-03-01

    Full Text Available In the last years, Magnesium alloys are known to be of great technological importance and high scientific interest. In this work, density functional theory plane-wave pseudo potential method, with local density approximation (LDA and generalized gradient approximation (GGA are used to perform first-principles quantum mechanics calculations in order to investigate the structural, elastic and mechanical properties of the intermetallic compound MgRh with a CsCl-type structure. Comparison of the calculated equilibrium lattice constant and experimental data shows good agreement. The elastic constants were determined from a linear fit of the calculated stress–strain function according to Hooke's law. From the elastic constants, the bulk modulus B, shear modulus G, Young's modulus E, Poisson's ratio σ, anisotropy factor A and the ratio B/G for MgRh compound are obtained. The sound velocities and Debye temperature are also predicted from elastic constants. Finally, the linear response method has been used to calculate the thermodynamic properties. The temperature dependence of the enthalpy H, free energy F, entropy S, and heat capacity at constant volume Cv of MgRh crystal in a quasi-harmonic approximation have been obtained from phonon density of states and discussed for the first report. This is the first quantitative theoretical prediction of these properties.

  6. Influence of low Co substitution on magnetoelastic properties of HoFe11Ti intermetallic compound

    International Nuclear Information System (INIS)

    Motevalizadeh, L.; Tajabor, N.; Sanavi Khoshnoud, D.; Fruchart, D.; Pourarian, F.

    2012-01-01

    The thermal expansion and magnetostriction of HoFe 11−x Co x Ti (x=0, 0.3, 0.7 and 1) intermetallic compounds were measured, using the strain gauge method in the temperature range 77–590 K under applied magnetic fields up to 1.5 T. Results show that for samples with x=0 and 0.3, both linear thermal expansion and linear thermal expansion coefficient exhibit anomalies below the Curie temperature. Below room temperature, the spontaneous volume magnetostriction decreases with Co content. For all compounds studied, the anisotropic magnetostriction shows similar behaviour in the measured temperature range. The magnetostriction compensation occurs above room temperature in all samples. The volume magnetostriction shows a linear dependence on the applied field and by approaching the Curie temperature this trend changes to parastrictive behaviour. The results of the spontaneous magnetostriction are discussed based on the local magnetic moment model. The contribution of magnetostriction attributed to the magnetic sublattices R and T (Fe or Co) is discussed. - Highlights: ► Magnetostriction of HoFe 11−x Co x Ti have been measured by using strain gauge method. ► The measurement was carried in 77–590 K under applied magnetic fields up to 1.5 T. ► Spontaneous volume magnetostriction and Invar effect decrease with Co substitution. ► Ho sublattice has negative contribution to spontaneous volume magnetostriction. ► Absolute values of anisotropic magnetostriction decrease slightly with Co content.

  7. Calorimetric study of the intermetallic compounds UAl2 and PuAl2

    International Nuclear Information System (INIS)

    Trainor, R.J.; Brodsky, M.B.; Knapp, G.S.

    1975-01-01

    Results of low temperature specific heat measurements are presented on the strongly paramagnetic intermetallic compounds UAl 2 and PuAl 2 in the temperature intervals 0.9 to 20 0 K, respectively. These compounds are characterized by very narrow 5f bands near the Fermi energy. The low-temperature properties of UAl 2 and PuAl 2 are dominated by long lived spin fluctuations within these narrow bands. In UAl 2 a nearly field-independent T 3 logT contribution dominates the specific heat below 10 0 K, consistent with the predictions of ferromagnetic spin-fluctuation theory. The specific heat, static susceptibility, and electrical resistivity are mutually consistent with T/sub sf/ = 25 +- 10 0 K, where T/sub sf/ is the characteristic spin-fluctuation temperature of the system. Below 20 0 K, the specific heat of PuAl 2 contains a very large linear term, C greater than or approximately equal to 260T (mJ/mole- 0 K), which is approximately four times the magnitude of the measured susceptibility, when both quantities are expressed in the same units. The specific heat of PuAl 2 exhibits no anomalous behavior below 10 0 K, where a resistivity anomaly has been previously obser []ed. The properties of PuAl 2 are qualitatively discussed in terms of antiferromagnetic spin fluctuations. (auth)

  8. Microstructural evaluation of interfacial intermetallic compounds in Cu wire bonding with Al and Au pads

    International Nuclear Information System (INIS)

    Kim, Hyung Giun; Kim, Sang Min; Lee, Jae Young; Choi, Mi Ri; Choe, Si Hyun; Kim, Ki Hong; Ryu, Jae Sung; Kim, Sangshik; Han, Seung Zeon; Kim, Won Yong; Lim, Sung Hwan

    2014-01-01

    A comparative study on the difference in interfacial behavior of thermally aged Cu wire bonding with Al and Au pads was conducted using transmission electron microscopy. During high-temperature lifetime testing of Cu wire bonding with Al and Au pads at 175 °C for up to 2000 h, different growth rates and growth characteristics were investigated in the Cu–Al intermetallic compounds (IMCs), including CuAl 2 , CuAl and Cu 9 Al 4 , and in the Cu–Au IMCs, including (Au,Cu), Cu 3 Au and (Cu,Au). Because of the lower growth rates and greater ductility of Cu–Au IMCs compared to those of Cu–Al IMCs, the Cu wire bonding with the Au pad showed relatively better thermal aging properties of bond pull strength and ball shear strength than those with the Al pad counterpart. In this study, the coherent interfaces were found to retard the growth of IMCs, and a variety of orientation relationships between wire, pad and interfacial IMCs were identified

  9. Effects of Fragmented Fe Intermetallic Compounds on Ductility in Al-Si-Mg Alloys.

    Science.gov (United States)

    Kim, JaeHwang; Kim, DaeHwan

    2018-03-01

    Fe is intentionally added in order to form the Fe intermetallic compounds (Fe-IMCs) during casting. Field emission scanning electron microscope with energy dispersive spectrometer (EDS) was conducted to understand microstructural changes and chemical composition analyses. The needlelike Fe-IMCs based on two dimensional observation with hundreds of micro size are modified to fragmented particles with the minimum size of 300 nm through clod rolling with 80% thickness reduction. The ratio of Fe:Si on the fragmented Fe-IMCs after 80% reduction is close to 1:1, representing the β-Al5FeSi. The yield and tensile strengths are increased with increasing reduction rate. On the other hand, the elongation is decreased with the 40% reduction, but slightly increased with the 60% reduction. The elongation is dramatically increased over two times for the specimen of 80% reduction compared with that of the as-cast. Fracture behavior is strongly affected by the morphology and size of Fe-IMCs. The fracture mode is changed from brittle to ductile with the microstructure modification of Fe-IMCs.

  10. Improving of Corrosion Resistance of Aluminum Alloys by Removing Intermetallic Compound

    Energy Technology Data Exchange (ETDEWEB)

    Seri, Osami [Muroran it., Hokkaido (Japan)

    2008-06-15

    It is well known that iron is one of the most common impurity elements sound in aluminum and its alloys. Iron in the aluminum forms an intermetallic compounds such as FeAl{sub 3}. The FeAl{sub 3} particles on the aluminum surface are one of the most detrimental phases to the corrosion process and anodizing procedure for aluminum and its alloys. Trial and error surface treatment will be carried out to find the preferential and effective removal of FeAl{sub 3} particles on the surfaces without dissolution of aluminum matrix around the particles. One of the preferable surface treatments for the aim of getting FeAl{sub 3} free surface was an electrochemical treatment such as cathodic current density of -2 kAm{sup -2} in a 20-30 mass% HNO{sub 3} solution for the period of 300s. The corrosion characteristics of aluminum surface with FeAl{sub 3} free particles are examined in a 0.1 kmol/m{sup 3} NaCl solution. It is found that aluminum with free FeAl{sub 3} particles shows higher corrosion resistance than aluminum with FeAl{sub 3} particles.

  11. Improving of Corrosion Resistance of Aluminum Alloys by Removing Intermetallic Compound

    International Nuclear Information System (INIS)

    Seri, Osami

    2008-01-01

    It is well known that iron is one of the most common impurity elements sound in aluminum and its alloys. Iron in the aluminum forms an intermetallic compounds such as FeAl 3 . The FeAl 3 particles on the aluminum surface are one of the most detrimental phases to the corrosion process and anodizing procedure for aluminum and its alloys. Trial and error surface treatment will be carried out to find the preferential and effective removal of FeAl 3 particles on the surfaces without dissolution of aluminum matrix around the particles. One of the preferable surface treatments for the aim of getting FeAl 3 free surface was an electrochemical treatment such as cathodic current density of -2 kAm -2 in a 20-30 mass% HNO 3 solution for the period of 300s. The corrosion characteristics of aluminum surface with FeAl 3 free particles are examined in a 0.1 kmol/m 3 NaCl solution. It is found that aluminum with free FeAl 3 particles shows higher corrosion resistance than aluminum with FeAl 3 particles

  12. First-principles screening of structural properties of intermetallic compounds on martensitic transformation

    Science.gov (United States)

    Lee, Joohwi; Ikeda, Yuji; Tanaka, Isao

    2017-11-01

    Martensitic transformation with good structural compatibility between parent and martensitic phases are required for shape memory alloys (SMAs) in terms of functional stability. In this study, first-principles-based materials screening is systematically performed to investigate the intermetallic compounds with the martensitic phases by focusing on energetic and dynamical stabilities as well as structural compatibility with the parent phase. The B2, D03, and L21 crystal structures are considered as the parent phases, and the 2H and 6M structures are considered as the martensitic phases. In total, 3384 binary and 3243 ternary alloys with stoichiometric composition ratios are investigated. It is found that 187 alloys survive after the screening. Some of the surviving alloys are constituted by the chemical elements already widely used in SMAs, but other various metallic elements are also found in the surviving alloys. The energetic stability of the surviving alloys is further analyzed by comparison with the data in Materials Project Database (MPD) to examine the alloys whose martensitic structures may cause further phase separation or transition to the other structures.

  13. Intermetallic Compound Growth and Stress Development in Al-Cu Diffusion Couple

    Science.gov (United States)

    Mishler, M.; Ouvarov-Bancalero, V.; Chae, Seung H.; Nguyen, Luu; Kim, Choong-Un

    2018-01-01

    This paper reports experimental observations evidencing that the intermetallic compound phase interfaced with Cu in the Al-Cu diffusion couple is most likely α2-Cu3Al phase, not γ-Cu9Al4 phase as previously assumed, and that its growth to a critical thickness may result in interface failure by stress-driven fracture. These conclusions are made based on an interdiffusion study of a diffusion couple made of a thick Cu plate coated with ˜ 2- μm-thick Al thin film. The interface microstructure and lattice parameter were characterized using scanning electron microscopy and x-ray diffraction analysis. Specimens aged at temperature between 623 K (350°C) and 723 K (450°C) for various hours produced consistent results supporting the main conclusions. It is found that disordered α2-Cu3Al phase grows in a similar manner to solid-state epitaxy, probably owing to its structural similarity to the Cu lattice. The increase in the interface strain that accompanies the α2-Cu3Al phase growth ultimately leads to interface fracture proceeding from crack initiation and growth along the interface. This mechanism provides the most consistent explanation for interface failures observed in other studies.

  14. Moessbauer Study of the Ball Milling Disordering Process of FeAl Intermetallic Compounds

    International Nuclear Information System (INIS)

    Oleszak, Dariusz; Bruna, Pere; Crespo, Daniel; Pradell, Trinitat

    2005-01-01

    Structural changes during ball milling of ordered Fe50Al50 intermetallic compounds were studied. X-Ray diffraction allowed the computation of a Long Range Order parameter (LRO) which dropped to zero after a short milling time. The initial B2 ordered structure gradually transforms into a disordered BCC structure, with a final crystallite size of about 25 nm. Moessbauer spectroscopy was used for obtaining a Chemical Short Range Order parameter (CSRO). Using a semiempirical n-body noncentral potential a model of the partially disordered B2 structure was built allowing computing the distribution of Quadrupole Splitting during the disordering process. Comparison between experimental and simulated Moessbauer spectra shows a maximum of disorder in the system for 5h milling, related to the highest value of the lattice spacing and the broader quadrupole hyperfine distribution. However, after milling for times longer than 5h, there is a change on the behavior of the experimental data that cannot be explained by the simple disordering process

  15. Mictomagnetic, ferromagnetic, and antiferromagnetic transitions in La(FexAl1–x)13 intermetallic compounds

    NARCIS (Netherlands)

    Palstra, T.T.M.; Nieuwenhuys, G.J.; Mydosh, J.A.; Buschow, K.H.J.

    1985-01-01

    Cubic La(FexAl1–x)13 intermetallic compounds can be stabilized with iron concentration x between 0.46 and 0.92 in the NaZn13-type structure (D23) with Fm3c (Oh6) space-group symmetry. Here the Fe-Fe coordination number can increase up to 12. At low x values, a mictomagnetic regime occurs with

  16. The system analysis of temperature and melting enthalpy of intermetallic compounds of antimony-lanthanoids system of Sb Ln, Sb2Ln composition

    International Nuclear Information System (INIS)

    Badalova, M.A.; Chamanova, M.; Dodkhoev, E.S.; Badalov, A.; Abdusalyamova, M.N.

    2015-01-01

    Present article is devoted to system analysis of temperature and melting enthalpy of intermetallic compounds of antimony-lanthanoids system of Sb Ln, Sb 2 Ln composition. The melting enthalpy was estimated. The temperature value was determined.

  17. Void formation and its impact on Cu−Sn intermetallic compound formation

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Glenn, E-mail: Glenn.Ross@aalto.fi; Vuorinen, Vesa; Paulasto-Kröckel, Mervi

    2016-08-25

    Void formation in the Cu−Sn system has been identified as a major reliability issue with small volume electronic interconnects. Voids form during the interdiffusion of electrochemically deposited Cu and Sn, with varying magnitude and density. Electroplating parameters include the electrolytic chemistry composition and the electroplating current density, all of which appear to effect the voiding characteristics of the Cu−Sn system. In addition, interfacial voiding affects the growth kinetics of the Cu{sub 3}Sn and Cu{sub 6}Sn{sub 5} intermetallic compounds of the Cu−Sn system. The aim here is to present voiding data as a function of electroplating chemistry and current density over a duration (up to 72 h) of isothermal annealing at 423 K (150 °C). Voiding data includes the average interfacial void size and average void density. Voids sizes grew proportionally as a function of thermal annealing time, whereas the void density grew initially very quickly but tended to saturate at a fixed density. A morphological evolution analysis called the physicochemical approach is utilised to understand the processes that occur when a voided Cu/Cu{sub 3}Sn interface causes changes to the IMC phase growth. The method is used to simulate the intermetallic thickness growths' response to interfacial voiding. The Cu/Cu{sub 3}Sn interface acts as a Cu diffusion barrier disrupting the diffusion of Cu. This resulted in a reduction in the Cu{sub 3}Sn thickness and an accelerated growth rate of Cu{sub 6}Sn{sub 5}. - Highlights: • Average void size is proportional linearly to thermal annealing time. • Average void density grows initially very rapidly followed by saturation. • Voids located close to the Cu/Cu{sub 3}Sn interface affect IMC growth rates. • Voids act as a diffusion barrier inhibiting Cu diffusion towards Sn. • Voids located at the interface cause Cu{sub 3}Sn to be consumed by Cu{sub 6}Sn{sub 5}.

  18. Structure evolution of multilayer materials of heat-resistant intermetallic compounds under the influence of temperature in the process of diffusion welding under pressure and their mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Korzhov, Valeriy P.; Karpov, Michael I.; Prokhorov, Dmitriy V. [Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka (Russian Federation)

    2013-07-01

    Multilayer materials of high-resistant intermetallic compounds of some transition metals with aluminum and silicon were obtained by diffusion welding of packages, collected from a large number of the respective foils, such as niobium and aluminum. Materials of intermetallics with silicon were obtained by the welding of packages built from metal foils with Si-coating. The change in the structure according to the temperature of the welding was studied, and the high-temperature bending strength was determined. Key words: multilayer composite, high-resistant material, intermetallic compound, diffusion welding, package rolling, layered structure, bending strength.

  19. Microstructural evolution of Ni40Zr60 alloy during early stage of mechanical alloying of intermetallic compounds NiZr2 and Ni11Zr9

    International Nuclear Information System (INIS)

    Lee Peeyew; Koch, C.C.

    1994-01-01

    The microstructural change of Ni 40 Zr 60 alloy during mechanical alloying of mixtures of the intermetallic compounds NiZr 2 and Ni 11 Zr 9 has been studied by transmission electron microscopy. A specific ''cauliflower'' phase was formed during early stage of mechanical alloying process. It is suggested that the solid state reaction between intermetallic compounds NiZr 2 and Ni 11 Zr 9 is not the only origin for the formation of the ''cauliflower'' phase. ((orig.))

  20. Four-branched compounds coupled Si and iron-rich intermetallics in near eutectic Al-Si alloys

    International Nuclear Information System (INIS)

    Wu, Yuying; Liu, Xiangfa; Jiang, Binggang; Bian, Xiufang

    2007-01-01

    Many four-branched compounds coupled Si and iron-rich intermetallics were observed in near eutectic Al-Si alloy modified with Al-P master alloy. Such four-branched compounds have never been reported before, but in our case it seems to be commonly observed. In this work the growth characterization of the four-branched compounds are scrutinized with a JXA-8800 electron microprobe (EPMA). More deep study of the formation of four-branched compounds is performed by SEM and TEM analysis. The characterization of the four-branched compounds is that of a primary silicon in the center with four iron-rich intermetallics around. Experimental results also show that the precipitation of primary silicon is the key factor for the formation of four-branched compounds. And WHS-theory explains the growth mechanism of the four-branched compounds. In detail, subsequent twinning within the primary silicon provides four-fold coordination sites on the surface, and then the α-Al(Fe,Mn)-Si phase nucleates on the surface of the primary silicon

  1. The atomic structure of low-index surfaces of the intermetallic compound InPd

    Energy Technology Data Exchange (ETDEWEB)

    McGuirk, G. M.; Ledieu, J.; Gaudry, É.; Weerd, M.-C.; Fournée, V. de, E-mail: vincent.fournee@univ-lorraine.fr [Institut Jean Lamour (UMR 7198 CNRS-Université de Lorraine), Parc de Saurupt, F-54011 Nancy Cedex (France); Hahne, M.; Gille, P. [Department of Earth and Environmental Sciences, Crystallography Section, Ludwig-Maximilians-Universität München, Theresienstrasse 41, D-80333 München (Germany); Ivarsson, D. C. A.; Armbrüster, M. [Faculty of Natural Sciences, Institute of Chemistry, Materials for Innovative Energy Concepts, Technische Universität Chemnitz, D-09107 Chemnitz (Germany); Ardini, J.; Held, G. [Department of Chemistry, University of Reading, Reading RG6 6AD (United Kingdom); Diamond Light Source Ltd, Didcot OX11 0DE (United Kingdom); Maccherozzi, F. [Diamond Light Source Ltd, Didcot OX11 0DE (United Kingdom); Bayer, A. [Lehrstuhl für Physikalische Chemie II, Universität Erlangen-Nürnberg, Egerlandstraße 3, D-91058 Erlangen (Germany); Lowe, M. [Surface Science Research Centre and Department of Physics, The University of Liverpool, Liverpool L69 3BX (United Kingdom); Pussi, K. [Department of Mathematics and Physics, Lappeenranta University of Technology, P.O. Box 20, FIN-53851 Lappeenranta (Finland); Diehl, R. D. [Department of Physics, Penn State University, University Park, Pennsylvania 16802 (United States)

    2015-08-21

    The intermetallic compound InPd (CsCl type of crystal structure with a broad compositional range) is considered as a candidate catalyst for the steam reforming of methanol. Single crystals of this phase have been grown to study the structure of its three low-index surfaces under ultra-high vacuum conditions, using low energy electron diffraction (LEED), X-ray photoemission spectroscopy (XPS), and scanning tunneling microscopy (STM). During surface preparation, preferential sputtering leads to a depletion of In within the top few layers for all three surfaces. The near-surface regions remain slightly Pd-rich until annealing to ∼580 K. A transition occurs between 580 and 660 K where In segregates towards the surface and the near-surface regions become slightly In-rich above ∼660 K. This transition is accompanied by a sharpening of LEED patterns and formation of flat step-terrace morphology, as observed by STM. Several superstructures have been identified for the different surfaces associated with this process. Annealing to higher temperatures (≥750 K) leads to faceting via thermal etching as shown for the (110) surface, with a bulk In composition close to the In-rich limit of the existence domain of the cubic phase. The Pd-rich InPd(111) is found to be consistent with a Pd-terminated bulk truncation model as shown by dynamical LEED analysis while, after annealing at higher temperature, the In-rich InPd(111) is consistent with an In-terminated bulk truncation, in agreement with density functional theory (DFT) calculations of the relative surface energies. More complex surface structures are observed for the (100) surface. Additionally, individual grains of a polycrystalline sample are characterized by micro-spot XPS and LEED as well as low-energy electron microscopy. Results from both individual grains and “global” measurements are interpreted based on comparison to our single crystals findings, DFT calculations and previous literature.

  2. Statistical thermodynamics -- A tool for understanding point defects in intermetallic compounds

    International Nuclear Information System (INIS)

    Ipser, H.; Krachler, R.

    1996-01-01

    The principles of the derivation of statistical-thermodynamic models to interpret the compositional variation of thermodynamic properties in non-stoichiometric intermetallic compounds are discussed. Two types of models are distinguished: the Bragg-Williams type, where the total energy of the crystal is taken as the sum of the interaction energies of all nearest-neighbor pairs of atoms, and the Wagner-Schottky type, where the internal energy, the volume, and the vibrational entropy of the crystal are assumed to be linear functions of the numbers of atoms or vacancies on the different sublattices. A Wagner-Schottky type model is used for the description of two examples with different crystal structures: for β'-FeAl (with B2-structure) defect concentrations and their variation with composition are derived from the results of measurements of the aluminum vapor pressure, the resulting values are compared with results of other independent experimental methods; for Rh 3 Te 4 (with an NiAs-derivative structure) the defect mechanism responsible for non-stoichiometry is worked out by application of a theoretical model to the results of tellurium vapor pressure measurements. In addition it is shown that the shape of the activity curve indicates a certain sequence of superstructures. In principle, there are no limitations to the application of statistical thermodynamics to experimental thermodynamic data as long as these are available with sufficient accuracy, and as long as it is ensured that the distribution of the point defects is truly random, i.e. that there are no aggregates of defects

  3. A study of atomic distribution in the intermetallic compound by AP-FIM

    International Nuclear Information System (INIS)

    Ren, D.G.

    1993-01-01

    This paper reports a study of the atomic distributions in the intermetallic compound by field ion microscope and atom probe (AP-FIM). The samples used in this work had nearly stoichiometry composition of Ni 3 Al with boron and without boron. The samples of TiAl also had nearly stoichiometry composition and adding Zr and Mn. The field ion image of Ni 3 Al without boron displays essentially the ordered f.c.c. crystal structure (Ll 2 ) with the center of (001) face. The field ion image of B-doped Ni 3 Al shows that the extent of ordering is reduced by addition of boron. The results of AP analysis show that the distribution of boron atom in Ni 3 Al is approximately homogeneous for the low boron contents. The atomic arrangements of Ni and Al in Ni 3 Al crystal lattice were changed by addition of boron. It is shown in the probability of consecutive evaporative sequence Al-Al and Ni-Ni is increased with B-doping. The field ion image of TiAl shows two regions with ordered f.c.t crystal structure (r-TiAl) and disordered. The distributions of Ti and Al atoms in the TiAl alloy show that the structure of a lamellar mixture were confirmed by AP profiles. The results of AP analysis show that distributions of Ti, Al, Mn and Zr in the alloy essentially is homogeneous. The results of AP analysis also exhibit that the interface of an oxide exists in the alloys. These interfaces of oxides consist of TiO and AlO in the TiAl, NiO in the Ni 3 Al. The broadness of the oxides interface were estimated about 8-10nm

  4. Effects of Metallic Nanoparticles on Interfacial Intermetallic Compounds in Tin-Based Solders for Microelectronic Packaging

    Science.gov (United States)

    Haseeb, A. S. M. A.; Arafat, M. M.; Tay, S. L.; Leong, Y. M.

    2017-10-01

    Tin (Sn)-based solders have established themselves as the main alternative to the traditional lead (Pb)-based solders in many applications. However, the reliability of the Sn-based solders continues to be a concern. In order to make Sn-based solders microstructurally more stable and hence more reliable, researchers are showing great interest in investigating the effects of the incorporation of different nanoparticles into them. This paper gives an overview of the influence of metallic nanoparticles on the characteristics of interfacial intermetallic compounds (IMCs) in Sn-based solder joints on copper substrates during reflow and thermal aging. Nanocomposite solders were prepared by mechanically blending nanoparticles of nickel (Ni), cobalt (Co), zinc (Zn), molybdenum (Mo), manganese (Mn) and titanium (Ti) with Sn-3.8Ag-0.7Cu and Sn-3.5Ag solder pastes. The composite solders were then reflowed and their wetting characteristics and interfacial microstructural evolution were investigated. Through the paste mixing route, Ni, Co, Zn and Mo nanoparticles alter the morphology and thickness of the IMCs in beneficial ways for the performance of solder joints. The thickness of Cu3Sn IMC is decreased with the addition of Ni, Co and Zn nanoparticles. The thickness of total IMC layer is decreased with the addition of Zn and Mo nanoparticles in the solder. The metallic nanoparticles can be divided into two groups. Ni, Co, and Zn nanoparticles undergo reactive dissolution during solder reflow, causing in situ alloying and therefore offering an alternative route of alloy additions to solders. Mo nanoparticles remain intact during reflow and impart their influence as discrete particles. Mechanisms of interactions between different types of metallic nanoparticles and solder are discussed.

  5. Magnetism in rare-earth metals and rare-earth intermetallic compounds

    International Nuclear Information System (INIS)

    Johansson, B.; Nordstroem, L.; Eriksson, O.; Brooks, M.S.S.

    1991-01-01

    Some of out recent local spin density electronic structure calculations for a number of ferromagnetic rare-earth systems are reviewed. A simplified model of the level densities for rare-earth (R) transition metal (M) intermetallic compounds, R m M n , is used to describe in a simple way the main features of their basic electronic structure. Explicit calculations for LuFe 2 and RFe 2 (R=Gd-Yb) systems are presented, where a method to treat simultaneously the localized 4f and the conduction electron spin magnetism is introduced. Thereby it becomes possible to calculate the K RM exchange coupling constant. This method is also used to study theoretically the permanent magnet material Nd 2 Fe 14 B. The electronic structure of the anomalous ferromagnets CeFe 2 and CeCo 5 is discussed and an induced 4f itinerant magnetism is predicted. The γ-α transition in cerium metal is considered, and results from calculations including orbital polarization are presented, where a volume collapse of 10% is obtained. On one side of the transition the 4f electrons are calculated to be essentially non-bonding (localized) and on the other side they are found to contribute to the metallic bonding and this difference in behaviour gives rise to the volume collapse. Recent calculations by Wills, Eriksson and Boring for the crystal structure changes in cerium metal under high pressure are discussed. Their successful results imply an itinerant picture for the 4f electrons in α-cerium. Consequently this strongly supports the view that the γ-α phase transformation is caused by a Mott transition of the 4f electrons. (orig.)

  6. Intermetallic compounds of Ni and Ga as catalysts for the synthesis of methanol

    DEFF Research Database (Denmark)

    Sharafutdinov, Irek; Elkjær, Christian Fink; de Carvalho, Hudson Wallace Pereira

    2014-01-01

    In this work, we present a detailed study of the formation of supported intermetallic Ni–Ga catalysts for CO2 hydrogenation to methanol. The bimetallic phase is formed during a temperature-programmed reduction of the metal nitrates. By utilizing a combination of characterization techniques......, in particular in situ and ex situ X-ray diffraction, in situ X-ray absorption spectroscopy, transmission electron microscopy combined with electron energy loss spectroscopy and X-ray fluorescence, we have studied the formation of intermetallic Ni–Ga catalysts of two compositions: NiGa and Ni5Ga3. These methods...... demonstrate that the catalysts with the desired intermetallic phase and composition are formed upon reduction in hydrogen and enable us to propose a mechanism of the Ni–Ga nanoparticles formation. By studying the effect of calcination prior to catalyst reduction, we show that the reactivity depends...

  7. Magnetic anisotropy in intermetallic compounds containing both uranium and 3d-metal

    Czech Academy of Sciences Publication Activity Database

    Andreev, Alexander V.; Tereshina, Evgeniya; Gorbunov, Denis; Šantavá, Eva; Šebek, Josef; Žáček, Martin; Homma, Y.; Shiokawa, Y.; Satoh, I.; Yamamura, Y.; Komatsubara, T.; Watanabe, K.; Koyama, K.

    2013-01-01

    Roč. 114, č. 9 (2013), s. 727-733 ISSN 0031-918X R&D Projects: GA ČR GAP204/12/0150 Institutional support: RVO:68378271 Keywords : uranium intermetallics * magnetic anisotropy * ferromagnetism Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.605, year: 2013

  8. Longitudinal recording on FePt and FePtX (X = B, Ni) intermetallic compounds

    Science.gov (United States)

    Li, Ning

    1999-11-01

    Near field recording on high coercivity FePt intermetallic compound media using a high Bsat write element was investigated. Untextured FePt media were prepared by magnetron sputtering on ZrO2 disks at a substrate temperature of 450°C, with post annealing at 450°C for 8 hrs. Both multilayer and cosputtered precursors produced the ordered tetragonal L10 phase with high coercivity between 5kOe and 12kOe. To improve readback noise decrease magnetic domain size, FePtB media were subsequently prepared by cosputtering. Over-write, roll-off, signal to noise ratio and non-linear transition shift (NLTS) ere measured by both metal in gap (MIG) and merged MR heads. FePtB media showed similar NLTS to commercial CoCrPtTa longitudinal media, but 5dB lower signal to noise ratio. By operating recording transducers in near contact, reasonable values of (>30dB) could be obtained. VSM Rotational Transverse Magnetization has been used for measuring the anisotropy field of magnetic thin films. Magnetization reversal during rotation of a 2D isotropic an applied field is discussed. The relationship between the transverse magnetization My and the applied field H was numerically solved. An excellent approximation for the transverse magnetization is found to be: My/Ms=A(1- H/Hk) 2.5, where A = 1.1434, and Hk is the anisotropy field. For curve fitting to experimental data, both A and Hk were used as fitting parameters. Comparison between a constructed torque hysteresis method and this VSM RTM method have been made theoretically and experimentally. Both results showed that VSM RTM will give better extrapolation of the anisotropy field. The torque measurement will slightly overestimate the anisotropy field. The anisotropy fields of FePt and FePtX (X = B, Ni) films were characterized using this VSM RTM technique with comparison to a CoCrTaPt disk. Anisotropy energy was derived. Hc/Hk was used as an indicator for coherent rotation of a single domain. Interactions between magnetic domains were

  9. Anomalous magnetic aftereffect in Nd3(Fe,T)29 (T = Ti or Re) intermetallic compounds

    International Nuclear Information System (INIS)

    Collocott, S.J.; Dunlop, J.B.; Gwan, P.B.

    1999-01-01

    Full text: The intermetallic compounds Nd 3 (Fe,Ti) 29 and Nd 3 (Fe,Re) 29 order ferromagnetically with Curie Temperatures, T c , of 430 and 370 K respectively. They have a monoclinic crystal structure, space group A2/m (Nd 3 (Fe,Ti) 29 type) with two rare earth sites and eleven Fe(T) sites, which is an intermediate structure between the rhombohedral Th 2 Zn 17 and tetragonal ThMn 12 structures, and is closely related to hexagonal CaCu 5 . Ferromagnetic materials, depending on their magnetic prehistory, may exhibit a time dependent magnetisation. The term 'magnetic aftereffect' is used to describe this behaviour, which may fall into three categories: 1. Reversible or diffusion aftereffect which is associated with the diffusion of impurity atoms or holes within the ferromagnetic lattice. 2. The irreversible or fluctuation aftereffect, which results in a logarithmic time dependence of magnetisation, J(t)=J(0)+Sln(t+t 0 ), where S is the magnetic viscosity and t 0 a parameter to establish the origin of the time scale measurements. 3. Quantum tunnelling of magnetisation which is observed at very low temperatures. A range of magnetic aftereffects have been observed in both Nd 3 (Fe,Ti) 29 and Nd 3 (Fe,Re) 29 . Of particular interest is the case where the material is fully saturated by application of a field in the positive direction, the applied field is then reversed to trace out part of the major demagnetisation curve into the third quadrant, and thence along a recoil curve, such that in zero applied field the magnetisation is zero (H=0, J=0). (This corresponds to dc field magnetisation.) This magnetic prehistory results in two interesting effects; spontaneous remagnetisation e.g. remagnetisation without application of an external field, and thermal remagnetisation e.g. an increase in magnetisation as the temperature is increased. Additionally, the behaviour of the magnetic viscosity has been explored on the major demagnetisation curve as a function of temperature

  10. Effects of metallic nanoparticle doped flux on the interfacial intermetallic compounds between lead-free solder ball and copper substrate

    International Nuclear Information System (INIS)

    Sujan, G.K.; Haseeb, A.S.M.A.; Afifi, A.B.M.

    2014-01-01

    Lead free solders currently in use are prone to develop thick interfacial intermetallic compound layers with rough morphology which are detrimental to the long term solder joint reliability. A novel method has been developed to control the morphology and growth of intermetallic compound layers between lead-free Sn–3.0Ag–0.5Cu solder ball and copper substrate by doping a water soluble flux with metallic nanoparticles. Four types of metallic nanoparticles (nickel, cobalt, molybdenum and titanium) were used to investigate their effects on the wetting behavior and interfacial microstructural evaluations after reflow. Nanoparticles were dispersed manually with a water soluble flux and the resulting nanoparticle doped flux was placed on copper substrate. Lead-free Sn–3.0Ag–0.5Cu solder balls of diameter 0.45 mm were placed on top of the flux and were reflowed at a peak temperature of 240 °C for 45 s. Angle of contact, wetting area and interfacial microstructure were studied by optical microscopy, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. It was observed that the angle of contact increased and wetting area decreased with the addition of cobalt, molybdenum and titanium nanoparticles to flux. On the other hand, wettability improved with the addition of nickel nanoparticles. Cross-sectional micrographs revealed that both nickel and cobalt nanoparticle doping transformed the morphology of Cu 6 Sn 5 from a typical scallop type to a planer one and reduced the intermetallic compound thickness under optimum condition. These effects were suggested to be related to in-situ interfacial alloying at the interface during reflow. The minimum amount of nanoparticles required to produce the planer morphology was found to be 0.1 wt.% for both nickel and cobalt. Molybdenum and titanium nanoparticles neither appear to undergo alloying during reflow nor have any influence at the solder/substrate interfacial reaction. Thus, doping of flux

  11. Effects of metallic nanoparticle doped flux on the interfacial intermetallic compounds between lead-free solder ball and copper substrate

    Energy Technology Data Exchange (ETDEWEB)

    Sujan, G.K., E-mail: sgkumer@gmail.com; Haseeb, A.S.M.A., E-mail: haseeb@um.edu.my; Afifi, A.B.M., E-mail: amalina@um.edu.my

    2014-11-15

    Lead free solders currently in use are prone to develop thick interfacial intermetallic compound layers with rough morphology which are detrimental to the long term solder joint reliability. A novel method has been developed to control the morphology and growth of intermetallic compound layers between lead-free Sn–3.0Ag–0.5Cu solder ball and copper substrate by doping a water soluble flux with metallic nanoparticles. Four types of metallic nanoparticles (nickel, cobalt, molybdenum and titanium) were used to investigate their effects on the wetting behavior and interfacial microstructural evaluations after reflow. Nanoparticles were dispersed manually with a water soluble flux and the resulting nanoparticle doped flux was placed on copper substrate. Lead-free Sn–3.0Ag–0.5Cu solder balls of diameter 0.45 mm were placed on top of the flux and were reflowed at a peak temperature of 240 °C for 45 s. Angle of contact, wetting area and interfacial microstructure were studied by optical microscopy, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. It was observed that the angle of contact increased and wetting area decreased with the addition of cobalt, molybdenum and titanium nanoparticles to flux. On the other hand, wettability improved with the addition of nickel nanoparticles. Cross-sectional micrographs revealed that both nickel and cobalt nanoparticle doping transformed the morphology of Cu{sub 6}Sn{sub 5} from a typical scallop type to a planer one and reduced the intermetallic compound thickness under optimum condition. These effects were suggested to be related to in-situ interfacial alloying at the interface during reflow. The minimum amount of nanoparticles required to produce the planer morphology was found to be 0.1 wt.% for both nickel and cobalt. Molybdenum and titanium nanoparticles neither appear to undergo alloying during reflow nor have any influence at the solder/substrate interfacial reaction. Thus, doping

  12. The nuclear quadrupole interaction of {sup 181}Ta in the intermetallic compound Hf{sub 2}Rh

    Energy Technology Data Exchange (ETDEWEB)

    Ivanovic, N.; Koicki, S.; Cekic, B.; Manasijevic, M.; Koteski, V.; Marjanovic, D. [Institute of Nuclear Sciences VINCA, Laboratory for Nuclear and Plasma Physics, PO Box 522, Belgrade (Yugoslavia)

    1999-01-11

    The time differential perturbed angular correlation technique has been used to measure the electric field gradient at {sup 181}Ta impurities in the intermetallic compound Hf{sub 2}Rh. The results of the measurements show the presence of two independent quadrupole interactions. At room temperature the interaction frequencies are {omega}{sub Q1} = 58 Mrad s{sup -1} and {omega}{sub Q2} = 239 Mrad s{sup -1}. The electric field gradient V{sub 22}, the corresponding asymmetry parameter {eta} and the distribution parameter {delta} exhibit a pronounced temperature dependence from 78 to 1223 K. (author)

  13. Determination of the enthalpy of formation of Ni-Al intermetallic compounds using differential scanning calorimetry technique

    International Nuclear Information System (INIS)

    Kubaski, Evaldo Toniolo; Capocchi, Jose Deodoro Trani; Cintho, Osvaldo Mitsuyuki

    2010-01-01

    The compositions Ni20Al80, Ni25Al75, Ni40Al60, Ni50Al50, Ni60Al40 and Ni75Al25 (at. %) were heated in a calibrated thermal analysis equipment. All runs were conducted at a heating rate of 10 deg C/min under a dynamic argon atmosphere. Each composition was heated until the completion of the corresponding exothermic reaction responsible for intermetallic compound formation, and, also heated to 1480 deg C. The products obtained were characterized using X ray diffraction in order to identify the intermetallic compounds that were synthesized. Moreover, the results were evaluated using variance analysis. As a result, enthalpies of formation of Ni 2 Al 3 and Ni 3 Al compounds were determined by means of this methodology. Experimental values were 167 kJ/mol and 93 kJ/mol for Ni 2 Al 3 and Ni 3 Al, respectively. The former is 18% lower than the value found on literature, while the latter is 6% greater. (author)

  14. Stability of molybdenum nanoparticles in Sn-3.8Ag-0.7Cu solder during multiple reflow and their influence on interfacial intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Haseeb, A.S.M.A., E-mail: haseeb@um.edu.my; Arafat, M.M., E-mail: arafat_mahmood@yahoo.com; Johan, Mohd Rafie, E-mail: mrafiej@um.edu.my

    2012-02-15

    This work investigates the effects of molybdenum nanoparticles on the growth of interfacial intermetallic compound between Sn-3.8Ag-0.7Cu solder and copper substrate during multiple reflow. Molybdenum nanoparticles were mixed with Sn-3.8Ag-0.7Cu solder paste by manual mixing. Solder samples were reflowed on a copper substrate in a 250 Degree-Sign C reflow oven up to six times. The molybdenum content of the bulk solder was determined by inductive coupled plasma-optical emission spectrometry. It is found that upon the addition of molybdenum nanoparticles to Sn-3.8Ag-0.7Cu solder, the interfacial intermetallic compound thickness and scallop diameter decreases under all reflow conditions. Molybdenum nanoparticles do not appear to dissolve or react with the solder. They tend to adsorb preferentially at the interface between solder and the intermetallic compound scallops. It is suggested that molybdenum nanoparticles impart their influence on the interfacial intermetallic compound as discrete particles. The intact, discrete nanoparticles, by absorbing preferentially at the interface, hinder the diffusion flux of the substrate and thereby suppress the intermetallic compound growth. - Highlights: Black-Right-Pointing-Pointer Mo nanoparticles do not dissolve or react with the SAC solder during reflow. Black-Right-Pointing-Pointer Addition of Mo nanoparticles results smaller IMC thickness and scallop diameter. Black-Right-Pointing-Pointer Mo nanoparticles influence the interfacial IMC through discrete particle effect.

  15. The role of zinc on the chemistry of complex intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Weiwei [Iowa State Univ., Ames, IA (United States)

    2014-01-01

    Combining experiments and electronic structure theory provides the framework to design and discover new families of complex intermetallic phases and to understand factors that stabilize both new and known phases. Using solid state synthesis and multiple structural determinations, ferromagnetic β-Mn type Co8+xZn12–x was analyzed for their crystal and electronic structures.

  16. Thermal, structural, and magnetic studies of metals and intermetallic compounds. Final report

    International Nuclear Information System (INIS)

    Wallace, W.E.; Craig, R.S.; Rao, V.U.S.

    1976-01-01

    The powerful magnetism of certain intermetallics, e.g., SmCo 5 , has been established to originate with the powerful magnetic anisotropy of SmCo 5 , not its large magnetization. The anisotropy is, in turn, a crystal field effect. The crystal field interaction has been elucidated by the method of quantum mechanics. Studies of the systems RFe 2 , RFe 3 , RCo 3 , and R 2 Co 7 (R = a rare earth, Y or Th) reveals them to be important for hydrogen storage. In addition, important effects associated with hydrogenation of metals have been found--great enhancement of magnetization of certain systems (e.g., ErFe 2 ) and substantial increase in superconducting transition temperatures (e.g., Zr/sub .5/H/sub .5/V 2 ). Results of studies suggest that the surfaces of rare earth intermetallics are atypical. The spectrum of properties exhibited by the rare earth intermetallics suggests their utility in the efficient capture and storage of solar energy and the use of it for powering a vehicle. These aspects of the systems warrant further attention

  17. Effect of Co on Si and Fe-containing intermetallic compounds (IMCs) in Al-20Si-5Fe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fatih Kilicaslan, M. [Department of Physics, Faculty of Art and Science, Kastamonu University, Kastamonu (Turkey); Yilmaz, Fikret [Department of Physics, Faculty of Art and Science, Gaziosmanpasa University, Tokat (Turkey); Hong, Soon-Jik, E-mail: hongsj@kongju.ac.kr [Division of Advanced Materials Engineering, Institute for Rare Metals, Kongju National University, Cheonan 331717 (Korea, Republic of); Uzun, Orhan, E-mail: orhan.uzun@gop.edu.tr [Department of Physics, Faculty of Art and Science, Gaziosmanpasa University, Tokat (Turkey)

    2012-10-30

    The effects of cobalt addition on microstructure and mechanical properties of Al-20Si-5Fe-XCo (X=0, 1, 3, and 5) alloys were reported in this study. The alloys were produced by both conventional sand casting and melt-spinning at 20 m/s disk velocity. Microstructures of the samples were investigated using X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Vickers micro-hardness tester was used for hardness measurements. Results showed that Co addition can alter morphology of Fe-bearing intermetallic compounds (IMCs) from long rod/needle-like structures to short rod-like ones, and lead to a more homogenous distribution in the microstructure. Addition of 5 wt% Co leads to a decrease in average size of the primary silicon phases in as-cast Al-Si alloys. In melt-spun alloys, with the addition of Co, the microstructure became finer and more homogenously distributed, while thickness of the featureless zone has seen great increase. The optimum Fe to Co ratio was found to be 1 for suppressing the undesirable effect of Fe-bearing acicular/needle-like intermetallic compounds.

  18. Effect of Co on Si and Fe-containing intermetallic compounds (IMCs) in Al–20Si–5Fe alloys

    International Nuclear Information System (INIS)

    Fatih Kilicaslan, M.; Yilmaz, Fikret; Hong, Soon-Jik; Uzun, Orhan

    2012-01-01

    The effects of cobalt addition on microstructure and mechanical properties of Al–20Si–5Fe–XCo (X=0, 1, 3, and 5) alloys were reported in this study. The alloys were produced by both conventional sand casting and melt-spinning at 20 m/s disk velocity. Microstructures of the samples were investigated using X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Vickers micro-hardness tester was used for hardness measurements. Results showed that Co addition can alter morphology of Fe-bearing intermetallic compounds (IMCs) from long rod/needle-like structures to short rod-like ones, and lead to a more homogenous distribution in the microstructure. Addition of 5 wt% Co leads to a decrease in average size of the primary silicon phases in as-cast Al–Si alloys. In melt-spun alloys, with the addition of Co, the microstructure became finer and more homogenously distributed, while thickness of the featureless zone has seen great increase. The optimum Fe to Co ratio was found to be 1 for suppressing the undesirable effect of Fe-bearing acicular/needle-like intermetallic compounds.

  19. Reaction of intermetallic compounds of the ScT composition (T=Ag, Cu, Zn, Ni) with hydrogen

    International Nuclear Information System (INIS)

    Shilkin, S.P.; Volkova, L.S.; Tarasov, B.P.

    1995-01-01

    Reaction of intermetallic compounds of ScT composition (T=Ag, Cu, Zn, Ni), crystallized in CsCl structural type, with hydrogen at 0.2-10 MPa pressure and 293-673 K temperature is studied by chemical, x-ray phase and complex thermogravimetry analysis methods. It is shown that under such conditions hydrogen absorption by ScAg and ScCu is accompanied by the decay of their source matrices into scandium dihydride and metal silver and copper respectively. For ScZn a fine-dispersion mixture of scandium dihydride with zinc and hydride phase of a new zinc-containing intermetallic compound appears to be the finite reaction product. In case of ScNi a hydride phase of ScNiH 2.6 composition is produced, which is crystallized in a rhombic syngony with the lattice periods: a=0.5281±0.0007, b=0.7393±0.0009 and c=0.3327±0.0004 nm. 9 refs.; 2 tabs

  20. Structural, electronic and elastic properties of RERu{sub 2} (RE=Pr and Nd) Laves phase intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Shrivastava, Deepika, E-mail: deepika89shrivastava@gmail.com; Sanyal, Sankar P. [Department of Physics, Barkatullah university, Bhopal, 462026 (India)

    2016-05-06

    We have performed the first-principles calculations to study the structural, electronic and elastic properties of RERu{sub 2} (RE = Pr and Nd) Laves phase intermetallic compounds using full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT) within the generalized gradient approximation (GGA) for exchange and correlation potential. The optimized lattices constant are in reasonable agreement with available experimental data. The electronic properties are analyzed in terms of band structures, total and partial density of states, which confirm their metallic character. The calculated elastic constants infer that these compounds are mechanically stable in C15 (MgCu{sub 2} type) structure and found to be ductile in nature.

  1. Ab-initio thermodynamic and elastic properties of AlNi and AlNi3 intermetallic compounds

    Science.gov (United States)

    Yalameha, Shahram; Vaez, Aminollah

    2018-04-01

    In this paper, thermodynamic and elastic properties of the AlNi and AlNi3 were investigated using density functional theory (DFT). The full-potential linearized augmented plane-wave (APW) in the framework of the generalized gradient approximation as used as implemented in the Wien2k package. The temperature dependence of thermal expansion coefficient, bulk modulus and heat capacity in a wide range of temperature (0-1600 K) were investigated. The calculated elastic properties of the compounds show that both intermetallic compounds of AlNi and AlNi3 have surprisingly negative Poisson’s ratio (NPR). The results were compared with other experimental and computational data.

  2. Interaction of intermetallic compounds formed by rare earths, scandium, yttrium and 3d-transition metals, with gaseous ammonia

    International Nuclear Information System (INIS)

    Shilkin, S.P.; Volkova, L.S.

    1992-01-01

    Interaction of the RT n intermetallic compounds, where R Sc, Y, rare earths, T = Fe, Co, Ni; n = 2,3,5, with gaseous ammonia under pressure of 1MPa and at temperatures of 293, 723 and 798 K is studied. It is established on the basis of roentgenographic studied, chemical analysis data, X-ray photoelectron spectroscopy and specific surface measurements that metallic matrixes of intermetallides decompose into nitrides and transition metal phases at temperatures of 723 and 798 K under effect of ammonia and independent of structural types of the source materials; partial or complete decomposition of intermetallides through ammonia with formation of transition metal mixture, binary hydrides and nitrides of the most electropositive metal the above systems occurs at the temperature of 293 K depending on the heat of the source compounds and their tendency to decomposition under ammonia effect

  3. Computer simulation of disordering kinetics in irradiated A3B intermetallic compounds

    International Nuclear Information System (INIS)

    Spaczer, M.; Caro, A.; Victoria, M.; De la Rubia, T.

    1994-01-01

    Molecular dynamics computer simulations of collision cascades on intermetallic Ni 3 Al, Cu 3 Au and NiAl have been performed to study the nature of the disordering processes in the cascade. The evolution of the crystalline and chemical order parameters show different time scales. To understand these features we study the liquid phase of these three alloys and present simulation results concerning the dynamical melting of small samples, examining the relaxation time and saturation value of the chemical short range order, SRO. A theoretical model for the time evolution of the SRO is given. ((orig.))

  4. FP-LAPW based investigation of structural, electronic and mechanical properties of CePb{sub 3} intermetallic compound

    Energy Technology Data Exchange (ETDEWEB)

    Pagare, Gitanjali, E-mail: gita-pagare@yahoo.co.in; Jain, Ekta, E-mail: jainekta05@gmail.com [Department of Physics, Government M. L. B. Girls P. G. Autonomous College, Bhopal 462002 (India); Abraham, Jisha Annie, E-mail: disisjisha@yahoo.com [Department of Physics, National Defence Academy, Pune 411023 (India); Sanyal, Sankar P., E-mail: sps.physicsbu@gmail.com [Department of Physics, Barkatullah University, Bhopal 462026 (India)

    2015-08-28

    A theoretical study of structural, electronic, elastic and mechanical properties of CePb{sub 3} intermetallic compound has been investigated systematically using first principles density functional theory. The calculations are carried out within the three different forms of generalized gradient approximation (GGA) and LSDA for the exchange correlation potential. The ground state properties such as lattice parameter (a{sub 0}), bulk modulus (B) and its pressure derivative (B′) are calculated and obtained lattice parameter of this compound shows well agreement with the experimental results. We have calculated three independent second order elastic constants (C{sub 11}, C{sub 12} and C{sub 44}), which has not been calculated and measured yet. From energy dispersion curves, it is found that the studied compound is metallic in nature. Ductility of this compound is analyzed using Pugh’s criteria and Cauchy's pressure (C{sub 11}-C{sub 12}). The mechanical properties such as Young's modulus, shear modulus, anisotropic ratio, Poison's ratio have been calculated for the first time using the Voigt–Reuss–Hill (VRH) averaging scheme. The average sound velocities (v{sub m}), density (ρ) and Debye temperature (θ{sub D}) of this compound are also estimated from the elastic constants.

  5. Syntheses and properties of several metastable and stable hydrides derived from intermetallic compounds under high hydrogen pressure

    Energy Technology Data Exchange (ETDEWEB)

    Filipek, S.M., E-mail: sfilipek@unipress.waw.pl [Institute of High Pressure Physics PAS, ul. Sokolowska 29, 01-142 Warsaw (Poland); Paul-Boncour, V. [ICMPE-CMTR, CNRS-UPEC, 2-8 rue Henri Dunant, 94320 Thiais (France); Liu, R.S. [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Jacob, I. [Unit Nuclear Eng., Ben Gurion University of the Negev, Beer-Sheva (Israel); Tsutaoka, T. [Dept. of Sci. Educ., Grad. School of Educ., Hiroshima University, Hiroshima (Japan); Budziak, A. [Institute of Nuclear Physics PAS, 31-342 Kraków (Poland); Morawski, A. [Institute of High Pressure Physics PAS, ul. Sokolowska 29, 01-142 Warsaw (Poland); Sugiura, H. [Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027 (Japan); Zachariasz, P. [Institute of Electron Technology Cracow Division, ul. Zablocie 39, 30-701 Krakow (Poland); Dybko, K. [Institute of Physics, PAS, 02-668 Warsaw (Poland); Diduszko, R. [Tele and Radio Research Institute, ul. Ratuszowa 11, Warsaw (Poland)

    2016-12-01

    Brief summary of our former work on high hydrogen pressure syntheses of novel hydrides and studies of their properties is supplemented with new results. Syntheses and properties of a number of hydrides (unstable, metastable or stable in ambient conditions) derived under high hydrogen pressure from intermetallic compounds, like MeT{sub 2}, MeNi{sub 5}, Me{sub 7}T{sub 3}, Y{sub 6}Mn{sub 23} and YMn{sub 12} (where Me = zirconium, yttrium or rare earth; T = transition metal) are presented. Stabilization of ZrFe{sub 2}H{sub 4} due to surface phenomena was revealed. Unusual role of manganese in hydride forming processes is pointed out. Hydrogen induced phase transitions, suppression of magnetism, antiferromagnetic-ferromagnetic and metal-insulator or semimetal-metal transitions are described. Equations of state (EOS) of hydrides submitted to hydrostatic pressures up to 30 GPa are presented and discussed.

  6. Dependence of intermetallic compound formation on the sublayer stacking sequence in Ag–Sn bilayer thin films

    International Nuclear Information System (INIS)

    Rossi, P.J.; Zotov, N.; Bischoff, E.; Mittemeijer, E.J.

    2016-01-01

    Intermetallic compound (IMC) formation in thermally-evaporated Ag–Sn bilayer thin films has been investigated employing especially X-ray diffraction (XRD) and (S)TEM methods. The specific IMCs that are present in the as-deposited state depend sensitively on the stacking sequence of the sublayers. In case of Sn on top of Ag, predominantly Ag 3 Sn is formed, whereas Ag 4 Sn is predominantly present in the as-deposited state for Ag on top of Sn. In the latter case this is accompanied by an extremely fast uptake of a large amount of Sn by the Ag sublayer, leaving behind macroscopic voids in the Sn sublayer. The results are discussed on the basis of the thermodynamics and kinetics of (IMC) product-layer growth in thin films. It is shown that both thermodynamic and kinetic arguments explain the contrasting phenomena observed.

  7. DO22-(Cu,Ni)3Sn intermetallic compound nanolayer formed in Cu/Sn-nanolayer/Ni structures

    International Nuclear Information System (INIS)

    Liu Lilin; Huang, Haiyou; Fu Ran; Liu Deming; Zhang Tongyi

    2009-01-01

    The present work conducts crystal characterization by High Resolution Transmission Electron Microscopy (HRTEM) on Cu/Sn-nanolayer/Ni sandwich structures associated with the use of Energy Dispersive X-ray (EDX) analysis. The results show that DO 22 -(Cu,Ni) 3 Sn intermetallic compound (IMC) ordered structure is formed in the sandwich structures at the as-electrodeposited state. The formed DO 22 -(Cu,Ni) 3 Sn IMC is a homogeneous layer with a thickness about 10 nm. The DO 22 -(Cu,Ni) 3 Sn IMC nanolayer is stable during annealing at 250 deg. C for 810 min. The formation and stabilization of the metastable DO 22 -(Cu,Ni) 3 Sn IMC nanolayer are attributed to the less strain energy induced by lattice mismatch between the DO 22 IMC and fcc Cu crystals in comparison with that between the equilibrium DO 3 IMC and fcc Cu crystals.

  8. Molecular dynamics simulations of radiation damage in D019 Ti3Al intermetallic compound

    International Nuclear Information System (INIS)

    Voskoboinikov, Roman E.

    2013-01-01

    Molecular dynamics (MD) has been applied to simulate the radiation damage created in displacement cascades in D0 19 Ti 3 Al structural intermetallics. Collision cascades formed by the recoil of either Al or Ti primary knock-on atoms (PKA) with energy E PKA = 5, 10, 15 or 20 keV were considered in Ti 3 Al single crystals at T = 100, 300, 600 and 900 K. At least 24 different cascades for each (E PKA , T, PKA type) set were simulated. A comprehensive treatment of the modelling results has been carried out. We have evaluated the number of Frenkel pairs, fraction of Al and Ti vacancies, self-interstitial atoms and anti-sites as a function of (E PKA ,T, PKA type). Preferred formation of both Al vacancies and self-interstitial atoms in D0 19 Ti 3 Al exposed to irradiation has been detected

  9. Two stages of Kondo effect and competition between RKKY and Kondo in Gd-based intermetallic compound

    Energy Technology Data Exchange (ETDEWEB)

    Vaezzadeh, Mehdi [Department of Physics, K.N.Toosi University of Technology, P.O. Box 15875-4416, Tehran (Iran, Islamic Republic of)]. E-mail: mehdi@kntu.ac.ir; Yazdani, Ahmad [Tarbiat Modares University, P.O. Box 14155-4838, Tehran (Iran, Islamic Republic of); Vaezzadeh, Majid [Department of Physics, K.N.Toosi University of Technology, P.O. Box 15875-4416, Tehran (Iran, Islamic Republic of); Daneshmand, Gissoo [Department of Physics, K.N.Toosi University of Technology, P.O. Box 15875-4416, Tehran (Iran, Islamic Republic of); Kanzeghi, Ali [Department of Physics, K.N.Toosi University of Technology, P.O. Box 15875-4416, Tehran (Iran, Islamic Republic of)

    2006-05-01

    The magnetic behavior of Gd-based intermetallic compound (Gd{sub 2}Al{sub (1-x)}Au{sub x}) in the form of the powder and needle, is investigated. All the samples are an orthorhombic crystal structure. Only the compound with x=0.4 shows the Kondo effect (other compounds have a normal behavior). Although, for the compound in the form of powder, with x=0.4, the susceptibility measurement {chi}(T) shows two different stages. Moreover for (T>T{sub K2}) a fall of the value of {chi}(T) is observable, which indicates a weak presence of ferromagnetic phase. About the two stages of Kondo effect, we observe at the first (T{sub K1}) an increase of {chi}(T) and in the second stage (T{sub K2}) a new remarkable decrease of {chi}(T) (T{sub K1}>T{sub K2}). For the sample in the form of needles, the first stage is observable only under high magnetic field. This first stage could be corresponds to a narrow resonance between Kondo cloud and itinerant electron. The second stage, which is remarkably visible for the sample in the form of the powder, can be attribute to a complete polarization of Kondo cloud. Observation of these two Kondo stages could be due to the weak presence of RKKY contribution.

  10. Two stages of Kondo effect and competition between RKKY and Kondo in Gd-based intermetallic compound

    International Nuclear Information System (INIS)

    Vaezzadeh, Mehdi; Yazdani, Ahmad; Vaezzadeh, Majid; Daneshmand, Gissoo; Kanzeghi, Ali

    2006-01-01

    The magnetic behavior of Gd-based intermetallic compound (Gd 2 Al (1-x) Au x ) in the form of the powder and needle, is investigated. All the samples are an orthorhombic crystal structure. Only the compound with x=0.4 shows the Kondo effect (other compounds have a normal behavior). Although, for the compound in the form of powder, with x=0.4, the susceptibility measurement χ(T) shows two different stages. Moreover for (T>T K2 ) a fall of the value of χ(T) is observable, which indicates a weak presence of ferromagnetic phase. About the two stages of Kondo effect, we observe at the first (T K1 ) an increase of χ(T) and in the second stage (T K2 ) a new remarkable decrease of χ(T) (T K1 >T K2 ). For the sample in the form of needles, the first stage is observable only under high magnetic field. This first stage could be corresponds to a narrow resonance between Kondo cloud and itinerant electron. The second stage, which is remarkably visible for the sample in the form of the powder, can be attribute to a complete polarization of Kondo cloud. Observation of these two Kondo stages could be due to the weak presence of RKKY contribution

  11. Complex magnetic behaviour and evidence of a superspin glass state in the binary intermetallic compound Er5Pd2

    Science.gov (United States)

    Sharma, Mohit K.; Yadav, Kavita; Mukherjee, K.

    2018-05-01

    The binary intermetallic compound Er5Pd2 has been investigated using dc and ac magnetic susceptibilities, magnetic memory effect, isothermal magnetization, non-linear dc susceptibility, heat capacity and magnetocaloric effect studies. Interestingly, even though the compound does not show geometrical frustration it undergoes glassy magnetic phase transition below 17.2 K. Investigation of dc magnetization and heat capacity data divulged absence of long-ranged magnetic ordering. Through the magnetic memory effect, time dependent magnetization and ac susceptibility studies it was revealed that the compound undergoes glass-like freezing below 17.2 K. Analysis of frequency dependence of this transition temperature through scaling and Arrhenius law; along with the Mydosh parameter indicate, that the dynamics in Er5Pd2 are due to the presence of strongly interacting superspins rather than individual spins. This phase transition was further investigated by non-linear dc susceptibility and was characterized by static critical exponents γ and δ. Our results indicate that this compound shows the signature of superspin glass at low temperature. Additionally, both conventional and inverse magnetocaloric effect was observed with a large value of magnetic entropy change and relative cooling power. Our results suggest that Er5Pd2 can be classified as a superspin glass system with large magnetocaloric effect.

  12. Homogeneous (Cu, Ni)6Sn5 intermetallic compound joints rapidly formed in asymmetrical Ni/Sn/Cu system using ultrasound-induced transient liquid phase soldering process.

    Science.gov (United States)

    Li, Z L; Dong, H J; Song, X G; Zhao, H Y; Tian, H; Liu, J H; Feng, J C; Yan, J C

    2018-04-01

    Homogeneous (Cu, Ni) 6 Sn 5 intermetallic compound (IMC) joints were rapidly formed in asymmetrical Ni/Sn/Cu system by an ultrasound-induced transient liquid phase (TLP) soldering process. In the traditional TLP soldering process, the intermetallic joints formed in Ni/Sn/Cu system consisted of major (Cu, Ni) 6 Sn 5 and minor Cu 3 Sn IMCs, and the grain morphology of (Cu, Ni) 6 Sn 5 IMCs subsequently exhibited fine rounded, needlelike and coarse rounded shapes from the Ni side to the Cu side, which was highly in accordance with the Ni concentration gradient across the joints. However, in the ultrasound-induced TLP soldering process, the intermetallic joints formed in Ni/Sn/Cu system only consisted of the (Cu, Ni) 6 Sn 5 IMCs which exhibited an uniform grain morphology of rounded shape with a remarkably narrowed Ni concentration gradient. The ultrasound-induced homogeneous intermetallic joints exhibited higher shear strength (61.6 MPa) than the traditional heterogeneous intermetallic joints (49.8 MPa). Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Phase transitions and magnetocaloric effects in intermetallic compounds MnFeX (X=P, As, Si, Ge)

    International Nuclear Information System (INIS)

    Tegus, O.; Bao Li-Hong; Song Lin

    2013-01-01

    Since the discovery of giant magnetocaloric effect in MnFeP 1−x As x compounds, much valuable work has been performed to develop and improve Fe 2 P-type transition-metal-based magnetic refrigerants. In this article, the recent progress of our studies on fundamental aspects of theoretical considerations and experimental techniques, effects of atomic substitution on the magnetism and magnetocalorics of Fe 2 P-type intermetallic compounds MnFeX (X=P, As, Ge, Si) is reviewed. Substituting Si (or Ge) for As leads to an As-free new magnetic material MnFeP 1−x Si(Ge) x . These new materials show large magnetocaloric effects resembling MnFe(P, As) near room temperature. Some new physical phenomena, such as huge thermal hysteresis and ‘virgin’ effect, were found in new materials. On the basis of Landau theory, a theoretical model was developed for studying the mechanism of phase transition in these materials. Our studies reveal that MnFe(P, Si) compound is a very promising material for room-temperature magnetic refrigeration and thermo-magnetic power generation. (topical review - magnetism, magnetic materials, and interdisciplinary research)

  14. The influence of the magnetic state on the thermal expansion in 1:2 rare earth intermetallic compounds

    International Nuclear Information System (INIS)

    Gratz, E.; Lindbaum, A.

    1994-01-01

    The attempt is made to demonstrate on some selected rare earth intermetallics the influence of the magnetic state on the thermal expansion. Using the X-ray powder diffraction method we investigated the thermal expansion of some selected nonmagnetic compounds (YAl 2 , YNi 2 and YCo 2 ) and some magnetic RE (rare earth) - cobalt compounds (RCo 2 ) in the temperature range from 4 up to 450 K. All these compounds crystallize in the C15-type structure (cubic Laves phase structure). By comparing the nonmagnetic Y-based compounds we could show that there is an enhanced contribution of the 3d electrons to the thermal expansion in YCo 2 . In the magnetic RCo 2 compounds the induced 3d magnetism gives rise to large volume anomalies at the magnetic ordering temperature T c . Below T c there is in addition a distortion of the cubic unit cell due to the interaction of the magnetically ordered RE ions with the anisotropic crystal field.The thermal expansion of the orthorhombic TmCu 2 , GdCu 2 and YCu 2 compounds has also been investigated for comparison. The influence of the crystal field on the thermal expansion in TmCu 2 in the paramagnetic range (TmCu 2 orders magnetically at T N =6.3 K) has been determined by comparing the thermal expansion of the nonmagnetic YCu 2 with that of TmCu 2 . The data thus obtained are compared with a theoretical model. GdCu 2 , for which the influence of the crystal field can be neglected, has been investigated in order to study the influence of the exchange interaction in the magnetically ordered state (below 42 K). ((orig.))

  15. Core-level XPS studies of Ce and La intermetallic compounds and their implications for the 4f levels of Ce compounds

    International Nuclear Information System (INIS)

    Freiburg, C.; Fuggle, J.C.; Hillebrecht, F.U.; Zolnierek, Z.; Laesser, R.

    1983-01-01

    The 3d core hole X-ray photoelectron spectra (XPS) of approximately 30 intermetallic compounds of La and Ce are reported. Transitions to final states with approximately f 0 , f 1 and f 2 character are observed in some Ce compounds (f 0 and f 1 for La compounds). The results are discussed in terms of the current ideas of the influence of f-counts and f-levels hybridization on core level lineshapes. We cannot find an explanatoin of the observed spectra consisted with the ''promotial model'' where the 4f-count varies and 4f electron was thought to be entirely promoted to the Ce 5d6s valence bands in some compounds. There may be some small charge transfer from the f level, however. In conjunction with ideas on screening processes in XPS the observed lineshapes suggest coupling of the 4f electrons to other states is strongest in those compounds previously thought to have f 0 character. This coupling increases despite a large increase in the Ce-Ce distance when Ce is diluted with Ni or Pd. Thus it cannot be due to direct f-f interaction and must be attributed to coupling with the other valence electrons; possibly those centred on the partner sites. (orig./EZ) [de

  16. Design and fabrication of a mechanical alloying system for preparing intermetallic, nanocrystalline, amorphous and quasicrystalline compounds

    International Nuclear Information System (INIS)

    Bonifacio M, J.; Iturbe G, J.L.; Castaneda J, G.

    2002-01-01

    In this work a grinding system was designed and fabricated which allowed to improve the operation conditions in time, frequency, temperature and selection of the grinding media and that allow the contamination decrease of the compounds. By means of this method of mechanical alloying new metallic compounds can be produced, starting from elemental powders, with fine and controlled microstructures. These compounds prepared by this method are going to be used as materials for the hydrogen storage. (Author)

  17. Magnetic, transport and magnetocaloric properties in the Laves phase intermetallic Ho (Co1−xAlx)2 compounds

    International Nuclear Information System (INIS)

    Ivanova, T.I.; Nikitin, S.A.; Tskhadadze, G.A.; Koshkid’ko, Yu.S.; Suski, W.; Iwasieczko, W.; Badurski, D.

    2014-01-01

    Highlights: • The Al influence on magnetic properties of the Ho (Co 1-x Al x ) 2 compounds is analyzed. • The first-order magnetic transition appears in sample with Al concentrations x ≤ 0.06. • The MCE and Curie temperature TC demonstrate complex Al concentration dependences. • The magnetoresistance for sample with Al concentration x = 0.06 (58%) is maximum. • High magnetic fields changes the Curie temperature T c of the Ho (Co 1−x Al x ) 2 compounds. - Abstract: The magnetization, magnetoresistivity and magnetocaloric effect (MCE) of the Ho (Co 1−x Al x ) 2 Laves phase intermetallic compounds for x ⩽ 0.2 have been investigated. Complex measurements have been carried out in order to determine the influence of substitution in the Co sublattice by Al on the Co moment, type of the magnetic transition and related properties of these compounds. A comparative analysis of the magnetic, transport and magnetocaloric properties of Ho (Co 1−x Al x ) 2 alloys under various Al concentration is represented. Substitutions at the Co site by Al are found to result in the appearance of itinerant electron metamagnetism (IEM) at the small Al concentrations and in positive magnetovolume effect, leading to an initial increase in the ordering temperature; on the other hand the magnetic phase transition temperature as well as ΔT (MCE) do not depend in direct way on the Al concentration. The 16% increase of magnetocaloric effect for the alloy with x = 0.02 is detected in relation to maternal HoCo 2 . A giant value of magnetoresistivity (58%) is observed for the alloy with the same Al concentration

  18. Synthesis, growth, and studies (crystal chemistry, magnetic chemistry) of actinide-based intermetallic compounds and alloys with a 1.1.1 stoichiometry

    International Nuclear Information System (INIS)

    Kergadallan, Yann

    1993-01-01

    The first part of this research thesis reports the study of the synthesis and reactivity of intermetallic compounds with a 1.1.1 stoichiometry. It presents the thermal properties of 1.1.1 compounds: general presentation of physical transitions, and of solid solutions and formation heat, application to actinides (reactivity analysis from phase diagrams, techniques of crystal synthesis and crystal growth. It describes experimental techniques: synthesis, determination of fusion temperature by dilatometry, methods used for crystal growth, characterisation techniques (metallography, X ray diffraction on powders, dilatometry). It discusses the obtained results in terms of characterisation of synthesised samples, of crystal growth, and of measurements of fusion temperature. The second part addresses crystal chemistry studies: structure of compounds with a 1.1.1 stoichiometry (Laves structures, Zr, Ti and Pu compounds), techniques of analysis by X-ray diffraction (on powders and on single crystals), result interpretation (UNiX compounds, AnTAl compounds with T being a metal from group VIII, AnTGa compounds, AnNiGe compounds, distance comparison, structure modifications under pressure). The third part concerns physical issues. The author addresses the following topics: physical properties of intermetallic 1.1.1 compounds (magnetism of yttrium phases, behaviour of uranium-based Laves phases, analysis of pseudo-binary diagrams, physical characteristics of uranium-based 1.1.1 compounds, predictions of physical measurements), analysis techniques (Moessbauer spectroscopy, SQUID for Superconducting Quantum Interference Device), and result interpretation

  19. Inhibition of the formation of intermetallic compounds in aluminum-steel welded joints by friction stir welding

    Directory of Open Access Journals (Sweden)

    Torres López, Edwar A.

    2015-12-01

    Full Text Available Formation of deleterious phases during welding of aluminum and steel is a challenge of the welding processes, for decades. Friction Stir Welding (FSW has been used in an attempt to reduce formation of intermetallic compounds trough reducing the heat input. In this research, dissimilar joint of 6063-T5 aluminum alloy and AISI-SAE 1020 steel were welded using this technique. The temperature of welded joints was measured during the process. The interface of the welded joints was characterized using optical microscopy, scanning and transmission electron microscopy. Additionally, composition measurements were carried out by X-EDS and DRX. The experimental results revealed that the maximum temperature on the joint studied is less than 360 °C. The microstructural characterization in the aluminum-steel interface showed the absence of intermetallic compounds, which is a condition attributed to the use of welding with low thermal input parameters.La unión de juntas aluminio-acero, sin la formación de fases deletéreas del tipo FexAly, ha sido, por décadas, un desafío para los procesos de soldadura. La soldadura por fricción-agitación ha sido empleada para intentar reducir el aporte térmico y evitar la formación de compuestos intermetálicos. Usando esta técnica fueron soldadas juntas disimilares de aluminio 6063-T5 y acero AISI-SAE 1020. La soldadura fue acompañada de medidas de temperatura durante su ejecución. La interfase de las juntas soldadas fue caracterizada utilizando microscopía óptica, electrónica de barrido y electrónica de transmisión. Adicionalmente fueron realizadas medidas puntuales X-EDS y DRX. Los resultados experimentales revelan que la temperatura máxima en la junta es inferior a 360 °C. La caracterización microestructural en la interfase aluminio-acero demostró la ausencia de compuestos intermetálicos, condición atribuida al uso de parámetros de soldadura con bajo aporte térmico.

  20. Synthesis and Characterization of Nanocrystalline Ni50Al50-xMox (X=0-5 Intermetallic Compound During Mechanical Alloying Process

    Directory of Open Access Journals (Sweden)

    A. Khajesarvi

    2015-07-01

    Full Text Available In the present study, nanocrystalline Ni50Al50-xMox (X = 0, 0.5, 1, 2.5, 5 intermetallic compound was produced through mechanical alloying of nickel, aluminum, and molybdenum powders. AlNi compounds with good and attractive properties such as high melting point, high strength to weight ratio and high corrosion resistance especially at high temperatures have attracted the attention of many researchers. Powders produced from milling were analyzed using scanning electron microscopy (SEM and X-ray diffractometry (XRD. The results showed that intermetallic compound of NiAl formed at different stage of milling operation. It was concluded that at first disordered solid solution of (Ni,Al was formed then it converted into ordered intermetallic compound of NiAl. With increasing the atomic percent of molybdenum, average grain size decreased from 3 to 0.5 μm. Parameter lattice and lattice strain increased with increasing the atomic percent of molybdenum, while the crystal structure became finer up to 10 nm. Also, maximum microhardness was obtained for NiAl49Mo1 alloy.

  1. On the nature of chromatic color of PdIn intermetallic compounds

    International Nuclear Information System (INIS)

    Nomerovannaya, L.V.; Kirillova, M.M.; Savitskij, E.M.; Polyakova, V.P.; Gorina, N.B.; Korenovskij, N.L.; AN SSSR, Moscow. Inst. Metallurgii)

    1979-01-01

    For the first time measured are the indexes of refraction and absorption of the six samples in the region of PdIn compound existence within the spectral range from 0.072 to 4.94 eV. The peculiarities of intersone light absoprtion are studied, the energy shift of absorption edge with the change of indium concentration is determined and the nature of the appearance of unusual colors of these compounds is explained. The refraction capacity for the normal light fall is calculated according to the values of refraction and absorption indexes. The refraction capacity curves for compounds with 42, 46, 50 at % indium content are presented, whose spectral dependence and high refraction (40-98%) show that PdIn compounds possess metallic conductivity

  2. Atomistic simulation of radiation-induced amorphization of the B2 ordered intermetallic compound NiTi

    International Nuclear Information System (INIS)

    Sabochick, M.J.

    1990-12-01

    Amorphization of the B2 intermetallic compound NiTi under electron irradiation has been investigated using molecular dynamics. The effect of irradiation was simulated using two processes: (1) Ni and Ti atoms were exchanged, resulting in chemical disorder, and (2) Frenkel pairs were introduced, leading to the formation of stable point defects and also chemical disorder upon mutual recombination of interstitials and vacancies. After ∼0.4 exchanges per atom, the first process resulted in an energy increase of approximately 0.11 eV/atom and a volume increase of 1.91%. On the other hand, after introducing ∼0.5 Frenkel pairs per atom, the second process led to smaller increases of 0.092 eV/atom in energy and 1.43% in volume. The calculated radial distribution functions (RDFs) were essentially identical to each other and to the calculated RDF of a quenched liquid. The structure factor, however, showed that long-range order was still present after atom exchanges, while the introduction of Frenkel pairs resulted in the loss of long-range order. It was concluded that point defects are necessary for amorphization to occur in NiTi, although chemical disorder alone is capable of storing enough energy to make the transition possible. 18 refs., 3 figs

  3. Microstructural analyses of intermetallic TiAl(Nb)-compounds prepared by arc melting and by powder metallurgy

    International Nuclear Information System (INIS)

    Chen, S.

    1988-01-01

    Intermetallic compounds based on TiAl with Nb or V as alloying additions prepared by powder metallurgy (P/M) and arc melting (A/M) techniques have been investigated with respect to their potential as new high temperature materials. All the alloys with nominal Al-concentrations 34-36 wt% contain two phases, γ-TiAl and α 2 -Ti 3 Al, but significant differences in the distribution of γ and α 2 were found between the P/M and A/M materials. The role of impurities during processing and the microstructural stability in the planned service temperature range 700-1000 0 C are discussed. In the P/M TiAl alloys two carbide precipitates have been found, which are the cubic Perovskite-AlTi 3 C phase in the γ-matrix and the hexagonal H-AlTi 2 (C, N) phase at grain boundaries. At high temperatures the AlTi 3 C phase dissolves and is replaced by more stable H-phase, and therefore no longer contributes to the high temperature strength of the material. Mechanical properties of both the P/M and A/M alloys are compared in association with the processing methods and the resulting microstructures. (orig.) With 71 figs., 22 tabs [de

  4. Powder metallurgical processing of magnetostrictive materials based on rare earth-iron intermetallic compounds

    International Nuclear Information System (INIS)

    Malekzadeh, M.

    1978-01-01

    Procedures are described for fabrication of high density rare earth-iron magnetostrictive compounds by powder metallurgical techniques. The fabrication involves a sequence of steps which includes preparing the pre-alloyed compounds, pulverizing them into a fine powder, compacting in suitable sizes and shapes, and sintering. Samples prepared by these procedures are carefully characterized by scanning electron microscopy, x-ray diffraction, dilatometry, and magnetic measurements. Process steps are found to exert important influences upon densities, microstructure and magnetic properties attained after densification. Investigations on a number of these process steps, including milling time and medium, sintering, and magnetic powder alignment are described

  5. Vacuum brazing of TiAl48Cr2Nb2 casting alloys based on TiAl (γ intermetallic compound

    Directory of Open Access Journals (Sweden)

    Z. Mirski

    2010-01-01

    Full Text Available A growing interest in modern engineering materials characterised by increasingly better operational parameters combined with a necessity to obtain joints of such materials representing good operation properties create important research and technological problems of today. These issues include also titanium joints or joints of titanium alloys based on intermetallic compounds. Brazing is one of the basic and sometimes even the only available welding method used for joining the aforesaid materials in production of various systems, heat exchangers and, in case of titanium alloys based on intermetallic compounds, turbine elements and space shuttle plating etc. This article presents the basic physical and chemical properties as well as the brazability of alloys based on intermetallic compounds. The work also describes the principle and mechanisms of diffusion-brazed joint formation as well as reveals the results of metallographic and strength tests involving diffusion-welded joints of TiAl48Cr3Nb2 casting alloy based on TiAl (γ phase with the use of sandwich-type layers of silver-based parent metal (grade B- Ag72Cu-780 (AG 401 and copper (grade CF032A. Structural examination was performed by means of light microscopy, scanning electron microscope (SEM and energy dispersion spectrometer (EDS. Furthermore, the article reveals the results of shear strength tests involving the aforementioned joints.

  6. Spontaneous growth of whiskers on RE-bearing intermetallic compounds of Sn-RE, In-RE, and Pb-RE

    Energy Technology Data Exchange (ETDEWEB)

    Liu Meng [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Science, 72 Wenhua Road, Shenyang 110016 (China); Xian Aiping, E-mail: ap.xian@imr.ac.c [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Science, 72 Wenhua Road, Shenyang 110016 (China)

    2009-11-03

    A phenomenon of the whiskers growth on the bulk rare earth (RE)-intermetallic compounds of NdSn{sub 3}, NdIn{sub 3}, and LaPb{sub 3} is reported. The whiskers formed spontaneously on all of the RE-intermetallic compounds after exposed to room ambience (21-28 deg. C/20-56% RH, relative humidity) for several days. Among the samples, the propensity of whisker growth for NdSn{sub 3} is the strongest, on which the tin whiskers were flourishing and covered all of the surfaces after exposed to room ambience for 22 days; while LaPb{sub 3} is the secondary and NdIn{sub 3} is the last one. Observed by SEM, the whiskers were exhibited as different morphology, size, and number density. The XRD analysis confirms the existence of RE(OH){sub 3} after whiskers formed, also, the weight gain curve of the samples exposed to room ambience supports that a spontaneous chemical reaction of the RE-intermetallic compounds with water in room ambience takes place. In discussion, it is proposed that the fresh metal atoms released by the chemical reaction could be causative to result in nucleation and spontaneous growth of the whiskers, while the anisotropy of crystal structure could be a reason to understand the difference of the whisker growth behaviors between Sn and Pb.

  7. Spontaneous growth of whiskers on RE-bearing intermetallic compounds of Sn-RE, In-RE, and Pb-RE

    International Nuclear Information System (INIS)

    Liu Meng; Xian Aiping

    2009-01-01

    A phenomenon of the whiskers growth on the bulk rare earth (RE)-intermetallic compounds of NdSn 3 , NdIn 3 , and LaPb 3 is reported. The whiskers formed spontaneously on all of the RE-intermetallic compounds after exposed to room ambience (21-28 deg. C/20-56% RH, relative humidity) for several days. Among the samples, the propensity of whisker growth for NdSn 3 is the strongest, on which the tin whiskers were flourishing and covered all of the surfaces after exposed to room ambience for 22 days; while LaPb 3 is the secondary and NdIn 3 is the last one. Observed by SEM, the whiskers were exhibited as different morphology, size, and number density. The XRD analysis confirms the existence of RE(OH) 3 after whiskers formed, also, the weight gain curve of the samples exposed to room ambience supports that a spontaneous chemical reaction of the RE-intermetallic compounds with water in room ambience takes place. In discussion, it is proposed that the fresh metal atoms released by the chemical reaction could be causative to result in nucleation and spontaneous growth of the whiskers, while the anisotropy of crystal structure could be a reason to understand the difference of the whisker growth behaviors between Sn and Pb.

  8. INVESTIGATING THE fFORMATION OF INTERMETALLIC COMPOUNDS AND THE VARIATION OF BOND STRENGTH BETWEEN Al-Cu LAYERS AFTER ANNEALING IN PRESENCE OF NICKEL BETWEEN LAYERS

    Directory of Open Access Journals (Sweden)

    A. Shabani

    2016-06-01

    Full Text Available In the present study, the effect of post-rolling annealing heat treatment on the formation of intermetallic compounds between Al-Cu strips, in the presence of nickel coating on the Cu strips, was investigated. In addition, the effect of post-rolling annealing and intermetallic compounds on the bond strength of Al-Cu strips was evaluated. In order to prepare samples, Cu strips were coated with nickel by electroplating process. After surface preparing, Cu strips were placed between two Al strips and roll bonded. This method is used for producing Al-Ni-Cu composites. Then the samples were annealed at 773K for 2 h. The formation of intermetallic compounds was studied using energy dispersive spectroscopy (EDS and X-ray diffraction (XRD. Also, in order to investigate bond strength of Al-Cu after post-rolling annealing heat treatment, samples were produced using nickel powder and nickel coating. Then bond strength of strips was investigated using peeling test. The results revealed that by post-rolling annealing of layers, the bond strength between Al-Cu strips decreases dramatically.

  9. Synthesis and reactivity of single-phase Be{sub 17}Ti{sub 2} intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae-Hwan, E-mail: kim.jaehwan@jaea.go.jp [Breeding Functional Materials Development Group, Sector of Fusion Research and Development, Japan Atomic Energy Agency (Japan); Iwakiri, Hirotomo; Furugen, Tatsuaki [Faculty of Education Elementary and Secondary School Teacher Training Program, University of the Ryukyus, Okinawa (Japan); Nakamichi, Masaru [Breeding Functional Materials Development Group, Sector of Fusion Research and Development, Japan Atomic Energy Agency (Japan)

    2016-01-15

    Highlights: • Preliminary synthesis of single-phase Be{sub 17}Ti{sub 2} was succeeded. • Reactivity difference between beryllium and beryllides may be caused by a lattice strain. • Oxidation of Be{sub 17}Ti{sub 2} at high temperatures results in the formation of TiO{sub 2}. • Simulation results reveal that a stable site for hydrogen at the center of tetrahedron exists. - Abstract: To investigate feasibility for application of Be{sub 17}Ti{sub 2} as a neutron multiplier as well as a refractory material, single-phase Be{sub 17}Ti{sub 2} intermetallic compounds were synthesized using an annealing heat treatment of the starting powder and a plasma sintering method. Scanning electron microscopic observations and X-ray diffraction measurements reveal that the single-phase Be{sub 17}Ti{sub 2} compounds were successfully synthesized. We examined the reactivity of Be{sub 17}Ti{sub 2} with 1% H{sub 2}O and discovered that a larger stoichiometric amount of Ti resulted in the formation of TiO{sub 2} on the surface at high temperatures. This oxidation may also contribute to an increase in both weight gain and generation of H{sub 2}. This suggests that the formation of the Ti-depleted Be{sub 17}Ti{sub 2−x} layer as a result of oxidation facilitates an increased reactivity with H{sub 2}O. To evaluate the safety aspects of Be{sub 17}Ti{sub 2}, we also investigated the hydrogen positions and solution energies based on the first principle. The calculations reveal that there are 10 theoretical sites, where 9 of these sites have hydrogen solution energies with a positive value (endothermic) and 1 site located at the center of a tetrahedron comprising two Be and two Ti atoms gives a negative value (exothermic).

  10. Magnetic properties of FeZr{sub 2} and Fe{sub 2}Zr intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Prajapat, C. L., E-mail: prajapat@barc.gov.in; Singh, M. R.; Mishra, P. K. [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, INDIA-400085 (India); Chattaraj, D. [Product Development Division, Bhabha Atomic Research Centre, Mumbai, INDIA-400085 (India); Mishra, R. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai, INDIA-400085 (India); Ravikumar, G. [Scientific Information Resources Division, Bhabha Atomic Research Centre, Mumbai, INDIA-400085 (India)

    2016-05-23

    Magnetic properties of Fe-Zr system, viz., FeZr{sub 2} and Fe{sub 2}Zr have been studied. Both the compounds show soft ferromagnetic behavior. Curie temperature is well above the room temperature. Lower saturation magnetization for the zirconium rich sample, FeZr{sub 2}, could be due to possible donation of electrons from the Zr-rich neighbors to Fe atoms or diminution of long range magnetic order by defects.

  11. Disorder-induced amorphization of intermetallic compounds: A molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Massobrio, C. (Ecole Polytechnique Federale, Lausanne (Switzerland). Inst. de Physique Experimentale); Pontikis, V.; Doan, N.V.; Martin, G. (CEA Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Physique des Particules Elementaires)

    The reaction of the crystalline compound NiZr{sub 2} to imposed chemical disorder has been studied by molecular dynamics in the isobaric canonical ensemble. The cohesive energy used is inspired by the second moment apporoximation of the local density of states in the tight binding model. Imposed chemical disorder induced swelling (3% for full disorder, 1% for 10% disorder). Above 10% disorder, the crystalline structure athermally collapses to an amorphous state which retains much of the local chemical order. (orig.).

  12. Disorder-induced amorphization of intermetallic compounds: A molecular dynamics study

    International Nuclear Information System (INIS)

    Massobrio, C.; Pontikis, V.; Doan, N.V.; Martin, G.

    1991-01-01

    The reaction of the crystalline compound NiZr 2 to imposed chemical disorder has been studied by molecular dynamics in the isobaric canonical ensemble. The cohesive energy used is inspired by the second moment apporoximation of the local density of states in the tight binding model. Imposed chemical disorder induced swelling (3% for full disorder, 1% for 10% disorder). Above 10% disorder, the crystalline structure athermally collapses to an amorphous state which retains much of the local chemical order. (orig.)

  13. Ab initio study of the structural, electronic, elastic and thermal properties of RMn{sub 2}Ge{sub 2} (R = Ca, Nd and Y) intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Miloud Abid, O.; Yakoubi, A. [Laboratoire d’Etudes des Matériaux et Instrumentations Expérimentales, Université Djilali Liabes de Sidi Bel-Abbes, 22000 (Algeria); Tadjer, A. [Modeling and Simulation in Materials Science Laboratory, Physics Department, University of Sidi Bel-Abbes, Sidi Bel-Abbes (Algeria); Khenata, R., E-mail: khenata_rabah@yahoo.fr [Laboratoire de Physique Quantique de la Modélisation Mathématique (LPQ3M), Université de Mascara, 29000 (Algeria); Ahmed, R. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, UTM Skudai, 81310 Johor (Malaysia); Murtaza, G. [Materials Modeling Laboratory, Department of Physics, Islamia College University, Peshawar (Pakistan); Bin Omran, S. [Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Azam, Sikander [New Technologies – Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic)

    2014-12-15

    Highlights: • The calculated structural parameters of RMn{sub 2}Ge{sub 2} (R = Ca, Nd and Y) compounds are found in good agreement with the experimental data. • The structural and band structure calculation reveals that these compounds are ferromagnetic brittle metals. • The elastic and thermodynamic properties for the herein studied compounds are investigated for the first time. - Abstract: Intermetallic RMn{sub 2}Ge{sub 2} ternary compounds have attracted considerable attention from researchers in recent years because they show strong indications for novel magnetic characteristics and they have the potential to reveal the mechanism of superlattices. The study of the paramagnetic, ferromagnetic and antiferromagnetic phases affirms the strong dependence to the distance between atomic species in these compounds. In this study, we investigated the structural, elastic, electronic and thermodynamic properties of the intermetallic RMn{sub 2}Ge{sub 2} (R = Ca, Nd and Y) compounds. To carry out this study, we used the full potential (FP) linearized (L) augmented plane wave plus local orbitals (APW + lo), a scheme of calculations developed within the frame work of density functional theory (DFT). To incorporate the exchange correlation (XC) energy and corresponding potential into the total energy calculations, local density approximation (LDA) parameterized by Perdew and Wang is taken into account. Analysis of the density of states (DOS) profile illustrates the conducting nature of these intermetallic compounds; with a predominantly contribution from the R and Mn-d states. At ambient conditions, calculations for elastic constants (C{sub 11}, C{sub 12}, C{sub 13}, C{sub 44}, C{sub 33} and C{sub 66}) are also performed, which point to their brittle character. In addition, the quasi harmonic Debye model was used to predict the thermal properties, together with relative expansion coefficients and heat capacity.

  14. Thermal expansion and spontaneous magnetostriction of R2Co7 intermetallic compounds

    International Nuclear Information System (INIS)

    Andreev, A.V.; Bartashevich, M.I.; Deryagin, A.V.; Zadvorkin, S.M.; Tarasov, E.N.

    1988-01-01

    Thermal expansion of R 2 Co 7 (R=Y, Nd, Gd, Tb) single crystals was invesigated by the method of X-ray dilatometry. Anomalous of thermal expansion, taking place during magnetic ordering and spin reorientation were used to determine linear and volumetric magnetistriction deformations. Constants of anisotropic magnetostriction of all R 2 Co 7 compounds with nonzero orbital moment of rare earth ion were calculated on the basis of single-ion model according to deformation values and with account of temperature dependences of the magnitude and direction of magnetic moment

  15. High pressure study of the intermetallic compound UFe2Al10

    International Nuclear Information System (INIS)

    Halevy, I.; Zenou, V.Y.; Salhov, S.; Caspi, E.N.; Schaefer, W.; Yaar, I.

    2006-01-01

    The crystallographic and electronic structure of UFe 2 Al 10 was studied as a function of pressure by combining X-ray diffraction results with the full potential linearized augmented plane wave (LAPW) calculations method. The volume-pressure reduction measured at 23.5 GPa is V/V 0 = 0.87, with a B 0 value of 132 ± 8 GPa. The uranium 5f electrons in this compound are located in a narrow and well-defined band above E Fermi , having a very weak interaction with the iron 3d band located below E Fermi . Consequently, the DOS at E Fermi is close to zero, indicating a close to zero-magnetic moment of the uranium atom at low temperature up to a pressure of 23.5 GPa, as expected from the layered crystallographic structure of this compound. The above assumption is supported by preliminary neutron diffraction data, where no long-range magnetic order was detected down to 3 K

  16. Fracture toughness of ordered intermetallic compounds exhibiting limited ductility and mechanical properties of ion-irradiated polycrystalline NiAl. Final report, July 1, 1986 - June 30, 1997

    International Nuclear Information System (INIS)

    Ardell, A.J.

    1997-09-01

    The focus of the research performed under the auspices of this grant changed several times during the lifetime of the project. The initial activity was an investigation of irradiation-induced amorphization of ordered intermetallic compounds, using energetic protons as the bombarding species. Two significant events stimulated a change of direction: (1) the proton accelerating facility that the authors had been using at the California State University at Los Angeles became unavailable late in 1988 because of a personnel matter involving the only individual capable of operating the machine; (2) they learned that disordering and amorphization of intermetallic compounds produced interesting effects on their mechanical properties. Loss of access t the local accelerator prompted a collaboration with Dr. Droa Pedraza of the Oak Ridge National Laboratory (ORNL), enabling access to the accelerator at ORNL. The influence of disordering and amorphization on mechanical properties ultimately stimulated the development of a miniaturized disk-bend testing (MDBT) facility, the intent of which was to provide semiquantitative and even quantitative measures of the mechanical behavior of ion-irradiated ordered intermetallic alloys. The second phase of the project involved the perfection and usage of the MDBT, and involved exploratory experiments on unirradiated materials like amorphous alloy ribbons and brittle grain boundaries in Ni 3 Al. This report is a brief summary of the research highlights of the project, organized according to the activity that was emphasized at the time

  17. An ab-initio investigation on SrLa intermetallic compound

    Science.gov (United States)

    Kumar, S. Ramesh; Jaiganesh, G.; Jayalakshmi, V.

    2018-05-01

    The electronic, elastic and thermodynamic property of CsCl-type SrLa are investigated through density functional theory. The energy-volume relation for this compound has been obtained. The band structure, density of states and charge density in (110) plane are also examined. The elastic constants (C11, C12 and C44) of SrLa is computed, then, using these elastic constants, the bulk moduli, shear moduli, Young's moduli and Poisson's ratio are also derived. The calculated results showed that CsCl-type SrLa is ductile at ambient conditions. The thermodynamic quantities such as free energy, entropy and heat capacity as a function of temperature are estimated and the results obtained are discussed.

  18. Magnetocaloric effect in textured rare earth intermetallic compound ErNi

    Directory of Open Access Journals (Sweden)

    Aparna Sankar

    2018-05-01

    Full Text Available Melt-spun ErNi crystallizes in orthorhombic FeB-type structure (Space group Pnma, no. 62 similar to the arc-melted ErNi compound. Room temperature X-ray diffraction (XRD experiments reveal the presence of texture and preferred crystal orientation in the melt-spun ErNi. The XRD data obtained from the free surface of the melt-spun ErNi show large intensity enhancement for (1 0 2 Bragg reflection. The scanning electron microscopy image of the free surface depicts a granular microstructure with grains of ∼1 μm size. The arc-melted and the melt-spun ErNi compounds order ferromagnetically at 11 K and 10 K (TC respectively. Field dependent magnetization (M-H at 2 K shows saturation behaviour and the saturation magnetization value is 7.2 μB/f.u. for the arc-melted ErNi and 7.4 μB/f.u. for the melt-spun ErNi. The isothermal magnetic entropy change (ΔSm close to TC has been calculated from the M-H data. The maximum isothermal magnetic entropy change, -ΔSmmax, is ∼27 Jkg-1K-1 and ∼24 Jkg-1K-1 for the arc-melted and melt-spun ErNi for 50 kOe field change, near TC. The corresponding relative cooling power values are ∼440 J/kg and ∼432 J/kg respectively. Although a part of ΔSm is lost to crystalline electric field (CEF effects, the magnetocaloric effect is substantially large at 10 K, thus rendering melt-spun ErNi to be useful in low temperature magnetic refrigeration applications such as helium gas liquefaction.

  19. Magnetocaloric effect in textured rare earth intermetallic compound ErNi

    Science.gov (United States)

    Sankar, Aparna; Chelvane, J. Arout; Morozkin, A. V.; Nigam, A. K.; Quezado, S.; Malik, S. K.; Nirmala, R.

    2018-05-01

    Melt-spun ErNi crystallizes in orthorhombic FeB-type structure (Space group Pnma, no. 62) similar to the arc-melted ErNi compound. Room temperature X-ray diffraction (XRD) experiments reveal the presence of texture and preferred crystal orientation in the melt-spun ErNi. The XRD data obtained from the free surface of the melt-spun ErNi show large intensity enhancement for (1 0 2) Bragg reflection. The scanning electron microscopy image of the free surface depicts a granular microstructure with grains of ˜1 μm size. The arc-melted and the melt-spun ErNi compounds order ferromagnetically at 11 K and 10 K (TC) respectively. Field dependent magnetization (M-H) at 2 K shows saturation behaviour and the saturation magnetization value is 7.2 μB/f.u. for the arc-melted ErNi and 7.4 μB/f.u. for the melt-spun ErNi. The isothermal magnetic entropy change (ΔSm) close to TC has been calculated from the M-H data. The maximum isothermal magnetic entropy change, -ΔSmmax, is ˜27 Jkg-1K-1 and ˜24 Jkg-1K-1 for the arc-melted and melt-spun ErNi for 50 kOe field change, near TC. The corresponding relative cooling power values are ˜440 J/kg and ˜432 J/kg respectively. Although a part of ΔSm is lost to crystalline electric field (CEF) effects, the magnetocaloric effect is substantially large at 10 K, thus rendering melt-spun ErNi to be useful in low temperature magnetic refrigeration applications such as helium gas liquefaction.

  20. The effect of high-temperature treatment on the formation of nanoscale intermetallic compounds of transition metals in Al-Cu-Mn-Zr alloy

    Science.gov (United States)

    Monastyrska, Tetiana O.; Berezina, Alla L.; Labur, Tetiana M.; Molebny, Oleh A.; Kotko, Andrii V.

    2018-02-01

    The precipitation of intermetallic compounds of transition metals during aging of the Al-5.8%Cu-0.3%Mn-0.1%Zr alloy has been studied using DSC, resistometry, X-ray and transmission electron microscopy. In these age hardenable alloys, the nanoscale metastable Θ″ and Θ' phases of the Al2Cu compound are the main strengthening phases, which are formed at low temperature aging of T stresses, etc.) on the aging with the precipitation of strengthening phases has been investigated.

  1. The effect of boron additions on irradiation-induced order changes in Ni3Al intermetallic compounds

    International Nuclear Information System (INIS)

    Njah, N.; Gilbon, D.; Dimitrov, O.

    1995-01-01

    The effects of boron additions (0.1 wt%) on the kinetics of atomic order changes in a Ni 76 Al 24 intermetallic compound, under 1 MeV electron irradiation, were investigated at temperatures of 293 K and 410 K and displacement rates of 0.09 x 10 -3 to 4.7 x 10 -3 dpa.s -1 . In these irradiation conditions, a state of residual order was obtained for long irradiation times, characterized by a steady state order parameter S∞; it corresponds to a competition between two opposite features: irradiation disordering and thermal reordering enhanced by irradiation. Boron additions did not affect the efficiency of irradiation-induced disordering: the disordering cross-section (or, equivalently, the number of replacements per displacement var-epsilon) were comparable with and without a boron addition. By contrast, the S∞ values at 293 K were much lower in the alloy containing boron. Since boron does not change the disordering rate, the large difference between the values obtained in undoped and in boron-doped alloys shows that the reordering rate is strongly reduced by the presence of boron. Thus, boron modifies the mobility of the defects responsible for the irradiation-enhanced diffusion. The data on dislocation-loop size and the reordering kinetics suggest that vacancies are trapped by boron at low temperatures and immobilized, probably by the formation of a boron-vacancy complex. The effect becomes weaker at higher displacement rates and higher temperatures, probably due to the boron-vacancy complexes becoming unstable. It is proposed that two different reordering mechanisms may be operative at 293 K, according to the presence of boron: reordering is promoted by vacancy migration in the Ni 76 Al 24 alloy, whereas in the Ni 76 Al 24 (0.1 wt%B) alloy, it is promoted by the migration of split-interstitials or/and of low-mobility vacancy-boron complexes

  2. Crystal growth of the intermetallic compound Nd{sub 2}PdSi{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Y. [IFW Dresden, Leibniz-Institut fuer Festkoerper- und Werkstoffforschung, Helmholtzstr. 20, 01171 Dresden (Germany); State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Loeser, W.; Blum, C.G.F.; Buechner, B. [IFW Dresden, Leibniz-Institut fuer Festkoerper- und Werkstoffforschung, Helmholtzstr. 20, 01171 Dresden (Germany); Tang, F. [Institut fuer Festkoerperphysik, Technische Universitaet Dresden, 01062 Dresden (Germany); Liu, L. [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China)

    2011-02-15

    Nd{sub 2}PdSi{sub 3} single crystals were grown by a vertical floating zone method with radiation heating at a zone traveling rate of 3 mm/h. The compound exhibits congruent melting behavior at a liquidus temperature of about 1790 C. The actual crystal composition (35.3 {+-} 0.5) at.% Nd, (16.2 {+-} 0.5) at.% Pd, and (48.5 {+-} 0.5) at.% Si is slightly depleted in Pd and Si with respect to the nominal stoichiometry. Therefore, the gradual accumulation of these elements in the traveling zone led to a decrease of the operating temperature during the growth process. Single crystalline samples exhibit a large anisotropy due to the crystal electric field effect and order ferromagnetically below the Curie temperature T{sub C}=15.1 K. The [001] orientation was identified as the magnetic easy axis at low temperatures. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Effects of Be additions on microstructures of TiAl intermetallic compounds

    International Nuclear Information System (INIS)

    Nonaka, Katsuhiko; Tanosaki, Kazuo; Kawabata, Takeshi; Nakajima, Hideo

    1997-01-01

    TiAl-0.1-3.0 mol%Be alloys made by the argon arc melting method were investigated to characterize microstructures in cast and annealed conditions using optical microscopy, SEM, EPMA and X-ray diffractometer. The addition of Be to TiAl resulted in a decrease of α 2 phase, thereby coarsening grains and a shift of γ/(γ+α 2 ) phase boundary to Ti-rich side. Two types of Be compound were observed: one was a few micron size of particles which contain a large amount of oxygen and the other was a coarse and eutectic-like phase (θ) which has an atomic ratio of Ti:Al:Be=41:30:29. The solubility limit of Be in TiAl was less than 0.1 mol%. In the (γ+θ) two phase and (γ+α 2 +θ) three phase regions, an increase of Be addition beyond the solubility limit resulted in a small increase of Ti/Al compositional ratio in γ phase. A volume fraction of lamellar structure in TiAl-Be ternary alloys was smaller in the cast structure but was larger in the annealed structure than that in TiAl binary alloys which have nearly the same Ti/Al ratio as that in the ternary alloys, because the Be addition may increase the stacking fault energy and will stabilize the lamellar twin boundaries, respectively. (author)

  4. FY 1992 Report on the survey results. Surveys on trends of research and development of advanced materials for severe environments (Intermetallic compounds); 1992 nendo chotaikankyosei senshin zairyo no kenkyu kaihatsu (kinzokukan kagobutsu) ni kakawaru kenkyu doko chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-03-01

    The trends of the ongoing researches on intermetallic compounds are surveyed through interviews and inquiries, in order to evaluate the results of the projects and research and development of the advanced materials for severe environments, and also to survey the research trends. The survey results are pigeonholed into 4 general categories; (1) research trends in the USA, UK and Germany, (2) notable topics of recent progress in intermetallic research and development, (3) evaluation of the projects, and (4) lists of the results of the researches on the Al-Ti and Al-Nb intermetallic compounds. The ongoing projects include those for intermetallic compounds of high specific strength and of high melting point, the former being represented by Al-Ti compounds and the latter by Al-Nb compounds, for aircraft and space development purposes. The projects are evaluated, viewed from materials and purposes/targets pursued by the projects, R and D organizations, and degree of attention the projects are attracting. The intermetallic compounds are extensively studied and attracting attention in various countries, but possibilities of achieving the set targets are rather pessimistic. (NEDO)

  5. Multifunctional phenomena in rare-earth intermetallic compounds with a laves phase structure: giant magnetostriction and magnetocaloric effect

    Czech Academy of Sciences Publication Activity Database

    Tereshina, I.; Cwik, J.; Tereshina, Evgeniya; Politova, G.; Burkhanov, G.; Chzhan, V.; Ilyushin, A.; Miller, M.; Zaleski, A.; Nenkov, K.; Schultz, L.

    2014-01-01

    Roč. 50, č. 11 (2014), s. 2504604 ISSN 0018-9464 Institutional support: RVO:68378271 Keywords : giant magnetostriction * Laves phase structure * magnetic anisotropy * magnetocaloric effect * rare-earth intermetallic Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.386, year: 2014

  6. Radiation-induced amorphization of intermetallic compounds: A molecular-dynamics study of CuTi and Cu4Ti3

    International Nuclear Information System (INIS)

    Lam, N.Q.; Okamoto, P.R.; Sabochick, M.J.

    1991-06-01

    In the present paper, important results of our recent computer simulation of radiation-induced amorphization in the ordered compounds CuTi and Cu 4 Ti 3 are summarized. The energetic, structural, thermodynamic and mechanical responses of these intermetallics during chemical disordering, point-defect production and heating were simulated, using molecular dynamics and embedded-atom potentials. From the atomistic details obtained, the critical role of radiation-induced structural disorder in driving the crystalline-to-amorphous phase transformation is discussed. 25 refs., 4 figs

  7. Structure and mechanical properties of parts obtained by selective laser melting of metal powder based on intermetallic compounds Ni3Al

    Science.gov (United States)

    Smelov, V. G.; Sotov, A. V.; Agapovichev, A. V.; Nosova, E. A.

    2018-03-01

    The structure and mechanical properties of samples are obtained from metal powder based on intermetallic compound by selective laser melting. The chemical analysis of the raw material and static tensile test of specimens were made. Change in the samples’ structure and mechanical properties after homogenization during four and twenty-four hours were investigated. A small-sized combustion chamber of a gas turbine engine was performed by the selective laser melting method. The print combustion chamber was subjected to the gas-dynamic test in a certain temperature and time range.

  8. First principle study on generalized-stacking-fault energy surfaces of B2-AlRE intermetallic compounds

    Science.gov (United States)

    Li, Shaorong; Wang, Shaofeng; Wang, Rui

    2011-12-01

    First-principles calculations are used to predict the generalized-stacking-fault energy (GSFE) surfaces of AlRE intermetallics. The calculations employ the projector augmented-wave (PAW) method within the generalized gradient approximation (GGA) using the density functional theory (DFT). GSFE curves along {1 1 0} direction, {1 1 0} direction and {1 1 0} direction have been calculated. The fitted GSFE surfaces have been obtained from the Fourier series based on the translational symmetry. In order to illuminate the reasonable of our computational accuracy, we have compared our theoretical results of B2 intermetallics YCu with the previous calculated results. The unstable-stacking-fault energy (γus) on the {1 1 0} plane has the laws of AlPr, and directions. For the antiphase boundary (APB) energy, that of AlSc is the lowest in the calculated AlRE intermetallics. So the superdislocation with the Burgers vector along direction of AlSc will easily split into two superpartials.

  9. Abrasive wear of intermetallics

    International Nuclear Information System (INIS)

    Hawk, J.A.; Alman, D.E.; Wilson, R.D.

    1995-01-01

    The US Bureau of Mines is investigating the wear behavior of a variety of advanced materials. Among the many materials under evaluation are intermetallic alloys based on the compounds: Fe 3 Al, Ti 3 Al, TiAl, Al 3 Ti, NiAl and MoSi 2 . The high hardness, high modulus, low density, and superior environmental stability of these compounds make them attractive for wear materials. This paper reports on the abrasive wear of alloys and composites based on the above compounds. The abrasive wear behavior of these alloys and composites are compared to other engineering materials used in wear applications

  10. Preparation and characterization of the Li(17)Pb(83) eutectic alloy and the LiPb intermetallic compound

    International Nuclear Information System (INIS)

    Jauch, U.; Karcher, V.; Schulz, B.

    1986-01-01

    Li(17)Pb(83) and LiPb were prepared from the pure elements in amounts of several hundred grams. The resolidified samples were characterized by melting points (eutectic temperature), chemical analysis and metallography. Using differential thermal analysis the heats of fusion were determined and the behaviour of the intermetallic phase LiPb in vacuum and high purified He was studied. The results from these investigations were applied to characterize Li(17)Pb(83) prepared in high amounts for technical application as a potential liquid breeder material. (orig.)

  11. The possibility of the mixed valence state in the uranium intermetallic compounds: UCoGa5, U2Ru2Sn and U2RuGa8

    International Nuclear Information System (INIS)

    Troc, Robert

    2007-01-01

    The mixed valence (MV) phenomenon has been observed so far in a large number of various compounds but containing only lanthanides. These properties are usually associated with the mixing of the localised f-state and the band states. The usual valence state for magnetic uranium intermetallics is the trivalent state 5f 3 or hybridised 5f 2 6d 1 , both are nearly degenerate in energy and can compete for a stability of the compound. In some cases a gain in an energy minimum may be achieved by very fast fluctuating between these two states with a time of 10 -14 s, which does not allow to yield the ordered state even if the exchange interactions (favourite the U-U distances) would be able for that. The latter cases seem to concern the described here intermetallics: one ternary compound based on Co, UCoGa 5 , and the two uranium ternary compounds based on Ru, namely U 2 Ru 2 Sn and U 2 RuGa 8 which all crystallize in a tetragonal unit cell. All these compounds show a maximum in their temperature dependences of the magnetic susceptibility measured along and perpendicular to the c-axis. Such a behaviour, which is reminiscent of a number of Ce (Sm, Eu) and Yb compounds for which χ(T) has in the past been considered by Sales and Wohlleben (SW) by applying their ICF model or by Lawrance et al. following their scaling procedure. It turned out that these phenomenological models can also be applied to the considered here two Ru-based uranium ternaries from which some reliable energy parameters could be found. In order to further support the mixing valence scenario for the first such cases in uranium compounds presented here, the transport and thermodynamic properties are also discussed. However, some of the most important results confirming the MV state, e.g., in U 2 RuGa 8 , has recently been achieved from the inelastic neutron scattering performed in the Rutherford Appleton Laboratory on the ISIS facility. From these measurements a characteristic gap of 60 meV has been

  12. Combined effects of ultrasonic vibration and manganese on Fe-containing inter-metallic compounds and mechanical properties of Al-17Si alloy with 3wt.%Fe

    Directory of Open Access Journals (Sweden)

    Lin Chong

    2013-05-01

    Full Text Available The research studied the combined effects of ultrasonic vibration (USV and manganese on the Fe-containing inter-metallic compounds and mechanical properties of Al-17Si-3Fe-2Cu-1Ni (wt.% alloys. The results showed that, without USV, the alloys with 0.4wt.% Mn or 0.8wt.% Mn both contain a large amount of coarse plate-like δ-Al4(Fe,MnSi2 phase and long needle-like β-Al5(Fe,MnSi phase. When the Mn content changes from 0.4wt.% to 0.8wt.% in the alloys, the amount and the length of needle-like β-Al5(Fe,MnSi phase decrease and the plate-like δ-Al4(Fe,MnSi2 phase becomes much coarser. After USV treatment, the Fe-containing compounds in the alloys are refined and exist mainly as δ-Al4(Fe,MnSi2 particles with an average grain size of about 20 μm, and only a small amount of β-Al5(Fe,MnSi phase remains. With USV treatment, the ultimate tensile strengths (UTS of the alloys containing 0.4wt.%Mn and 0.8wt.%Mn at room temperature are 253 MPa and 262 MPa, respectively, and the ultimate tensile strengths at 350 °C are 129 MPa and 135 MPa, respectively. It is considered that the modified morphology and uniform distribution of the Fe-containing inter-metallic compounds, which are caused by the USV process, are the main reasons for the increase in the tensile strength of these two alloys.

  13. Influence of Nickel Thickness and Annealing Time on the Mechanical Properties of Intermetallic Compounds Formed between Cu-Sn Solder and Substrate

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yiseul; Kwon, Jeehye; Yoo, Dayoung; Park, Sungkyu; Lee, Dajeong; Lee, Dongyun [Pusan National University, Busan (Korea, Republic of)

    2017-03-15

    Intermetallic compounds (IMCs) developed on the interface between a solder alloy and its bonding pads are an important factor in the failure of electronic circuits. In this study, the mechanical behaviors of the IMCs formed in the Cu-Ni-Sn ternary alloy system are investigated. Presumably, Ni can act as a diffusion barrier to Cu and Sn to form the IMCs. Detailed analysis of the microstructure is conducted using an electron probe micro-analyzer (EPMA). The addition of Ni softened the IMCs, which is determined based on the fracture toughness increasing (from 0.71 to 1.55 MPa√m) with the Ni layer thickness. However, above a critical amount of Ni involved in the Cu-Sn IMCs, the softening effect is diminished, and this could result from the segregation of Ni inside the IMCs. Therefore, the optimized condition must be determined in order to obtain a positive Ni effect on enhancing the reliability of the electronic circuits.

  14. Crystal structure and magnetic state of pseudo-binary intermetallic compounds Ho(Cosub(1-x)Nisub(x))sub(5)

    International Nuclear Information System (INIS)

    Chuev, V.V.; Kelarev, V.V.; Pirogov, A.N.; Sidorov, S.K.; Koryakova, V.S.

    1983-01-01

    In the range of 1.8-1000 K intermetallic compounds Ho(Cosub(1-x)Nisub(x))sub(5) have been investigated neutronographically and roentgenographically. Crystal structure of two series of samples: HoCosub(5.5-5.5x)Nisub(5x) and HoCosub(5-5x)Nisub(5x) is studied. It is shown that Ni atoms mainly occupy positions 2c, Co atoms - positions 3g; coordinates of atoms and position occupation of TbCu 7 type structure are specified. Analysis of magnetic structure is made, angles of magnetic momenta orientation as to crystallographic axes are determined. Magnetic phase diagram is built. Concentrational dependences of sublattice magnetization: Msub(Ho)(x), Mdsub(2c)(x), Mdsub(3g)(x) are determined

  15. Abnormal accumulation of intermetallic compound at cathode in a SnAg3.0Cu0.5 lap joint during electromigration

    International Nuclear Information System (INIS)

    Li Mingyu; Chang Hong; Pang Xiaochao; Wang Ling; Fu Yonggao

    2011-01-01

    Interfacial reactions in a SnAg 3.0 Cu 0.5 /Cu lap joint for naked and encompassed specimens were investigated contrastively under electric current stressing. After applying a constant direct current at 6.5 A for 144 h, an abnormal accumulation of bulk Cu 6 Sn 5 intermetallic compound was found at the cathode for the naked specimen. But normal polarization phenomenon arose for the encompassed specimen at the same current density for 504 h. The abnormal accumulation phenomenon was explained by the mechanism that thermomigration and stress migration induced by temperature gradient dominated the migration process. A three-dimensional joint simulation model was designed to demonstrate how current crowding and temperature gradient can enhance the local atomic flux.

  16. Intensive structural investigation of R{sub 2}Fe{sub 17-x}M{sub x} intermetallic compounds using high resolution powder neutron diffractometer

    Energy Technology Data Exchange (ETDEWEB)

    Mujamilah,; Ridwan, [Materials Science Research Center, National Atomic Energy Agency of Indonesia, Jakarta (Indonesia)

    1998-10-01

    The crystallographic and magnetic structure of R{sub 2}Fe{sub 17-x}M{sub x} intermetallic compounds system were refined by Rietveld analyses of the high resolution neutron powder diffraction data. The analyses results show that the substituent atoms were not distributed randomly over the Fe sites, but preferentially occupied some Fe sites. More further, it was also found that the substituent atoms which atomic radius smaller than Fe tend to avoid the 6c site at low concentration while the larger substituent atom tend to replace the Fe atom at this 6c site corresponding to their concentration. From these crystallographic data, it was suggested that the change of magnetic ordering temperature Tc, is not mainly determined by the change of short bond distance between this `dumb-bell` atoms, but it was also influenced by the nearest coordinated atoms to this site. (author)

  17. Influence of nanoparticle addition on the formation and growth of intermetallic compounds (IMCs) in Cu/Sn–Ag–Cu/Cu solder joint during different thermal conditions

    Science.gov (United States)

    Ting Tan, Ai; Wen Tan, Ai; Yusof, Farazila

    2015-01-01

    Nanocomposite lead-free solders are gaining prominence as replacements for conventional lead-free solders such as Sn–Ag–Cu solder in the electronic packaging industry. They are fabricated by adding nanoparticles such as metallic and ceramic particles into conventional lead-free solder. It is reported that the addition of such nanoparticles could strengthen the solder matrix, refine the intermetallic compounds (IMCs) formed and suppress the growth of IMCs when the joint is subjected to different thermal conditions such as thermal aging and thermal cycling. In this paper, we first review the fundamental studies on the formation and growth of IMCs in lead-free solder joints. Subsequently, we discuss the effect of the addition of nanoparticles on IMC formation and their growth under several thermal conditions. Finally, an outlook on the future growth of research in the fabrication of nanocomposite solder is provided. PMID:27877786

  18. Influence of nanoparticle addition on the formation and growth of intermetallic compounds (IMCs) in Cu/Sn–Ag–Cu/Cu solder joint during different thermal conditions

    International Nuclear Information System (INIS)

    Ting Tan, Ai; Wen Tan, Ai; Yusof, Farazila

    2015-01-01

    Nanocomposite lead-free solders are gaining prominence as replacements for conventional lead-free solders such as Sn–Ag–Cu solder in the electronic packaging industry. They are fabricated by adding nanoparticles such as metallic and ceramic particles into conventional lead-free solder. It is reported that the addition of such nanoparticles could strengthen the solder matrix, refine the intermetallic compounds (IMCs) formed and suppress the growth of IMCs when the joint is subjected to different thermal conditions such as thermal aging and thermal cycling. In this paper, we first review the fundamental studies on the formation and growth of IMCs in lead-free solder joints. Subsequently, we discuss the effect of the addition of nanoparticles on IMC formation and their growth under several thermal conditions. Finally, an outlook on the future growth of research in the fabrication of nanocomposite solder is provided. (review)

  19. Method to increase the transition temperature and for the critical magnetic field strength of the known intermetallic compounds of vanadium or niobium

    International Nuclear Information System (INIS)

    Winter, H.

    1977-01-01

    The invention deals with a method to raise the transition temperature and critical magnetic field strength of superconducting, intermetallic compounds of vanadium and niobium. For example, a niobium alloy with 4 wt.% Al in melted in vacuum electric arc and formed into a sheet of about 1 mm thick. Strips of this sheet are electrically heated up to 1,900 0 C for one hour in a high-vacuum oven. The strips are then annealed in evacuated quartz ampoules for 120 hours at 800 0 C. These strips have a transition temperature of 24 K and a critical magnetic field strength of 600 kg; the critical current density was 5 x 10 4 A/cm 2 . (HPOE) [de

  20. Influence of interstitial solutions (H, N) on cerium electronic state in Ce-Fe intermetallic compounds: X-ray Absorption Spectroscopy (XAS) study

    International Nuclear Information System (INIS)

    Chaboy, J.; Marcelli, A.; Bozukov, L.

    1995-03-01

    It is presented an x-ray absorption spectroscopy (XAS) investigation performed at the L-edges of the rare-earth and at the K-edge of iron in the R-Fe intermetallic compounds (La, Ce) 2 Fe 14 BH χ and Ce 2 Fe 17 (H,N) χ , to elucidate the role of the interstitial doping into the electronic and magnetic properties of these systems. Comparison with x-ray circular magnetic dichroism (XCMD) experiments has been carried out to clarify the localization of 4f magnetic moment at the Ce sites upon hydriding. Both XAS and XCMD results evidence the interplay between the structural and magnetic changes, that are associated to the modification of the hybridization between the Fe(3d) and Ce(5d) bands

  1. [Zn(NH3)4][PtCl6] and [Cd(NH3)4][PtCl6] as precursors for intermetallic compounds PtZn and PtCd

    International Nuclear Information System (INIS)

    Zadesenets, A.V.; Venediktov, A.B.; Shubin, Yu.V.; Korenev, S.V.

    2007-01-01

    Double complex salts (tetraamminezinc and tetraamminecadmium hexachloroplatinates) have been synthesized. Their thermal properties have been studied, as well as the products of their degradation in hydrogen and helium atmospheres. Optimal thermolysis schedules have been determined. Thermolysis under hydrogen yields intermetallic compounds PtZn and PtCd [ru

  2. A Comparative Discussion of the Catalytic Activity and CO2-Selectivity of Cu-Zr and Pd-Zr (Intermetallic Compounds in Methanol Steam Reforming

    Directory of Open Access Journals (Sweden)

    Norbert Köpfle

    2017-02-01

    Full Text Available The activation and catalytic performance of two representative Zr-containing intermetallic systems, namely Cu-Zr and Pd-Zr, have been comparatively studied operando using methanol steam reforming (MSR as test reaction. Using an inverse surface science and bulk model catalyst approach, we monitored the transition of the initial metal/intermetallic compound structures into the eventual active and CO2-selective states upon contact to the methanol steam reforming mixture. For Cu-Zr, selected nominal stoichiometries ranging from Cu:Zr = 9:2 over 2:1 to 1:2 have been prepared by mixing the respective amounts of metallic Cu and Zr to yield different Cu-Zr bulk phases as initial catalyst structures. In addition, the methanol steam reforming performance of two Pd-Zr systems, that is, a bulk system with a nominal Pd:Zr = 2:1 stoichiometry and an inverse model system consisting of CVD-grown ZrOxHy layers on a polycrystalline Pd foil, has been comparatively assessed. While the CO2-selectivity and the overall catalytic performance of the Cu-Zr system is promising due to operando formation of a catalytically beneficial Cu-ZrO2 interface, the case for Pd-Zr is different. For both Pd-Zr systems, the low-temperature coking tendency, the high water-activation temperature and the CO2-selectivity spoiling inverse WGS reaction limit the use of the Pd-Zr systems for selective MSR applications, although alloying of Pd with Zr opens water activation channels to increase the CO2 selectivity.

  3. Intermetallic semiconducting films

    CERN Document Server

    Wieder, H H

    1970-01-01

    Intermetallic Semiconducting Films introduces the physics and technology of AшВv compound films. This material is a type of a polycrystalline semiconductor that is used for galvanomagnetic device applications. Such material has a high electron mobility that is ideal for generators and magnetoresistors. The book discusses the available references on the preparation and identification of the material. An assessment of its device applications and other possible use is also enumerated. The book describes the structures and physical parts of different films. A section of the book covers the three t

  4. Magnetic properties of Fe-rich rare-earth intermetallic compounds with a ThMn12 structure

    International Nuclear Information System (INIS)

    Ohashi, K.; Tawara, Y.; Osugi, R.; Shimao, M.

    1988-01-01

    Sm(Fe/sub 1-//sub x/M/sub x/) 12 ternary compounds based on the tetragonal ThMn 12 structure where M is Ti, Si, V, Cr, and Mo were investigated. M atoms have a preference for site occupation. Ti atoms occupy the 8i or 8j site and Cr atoms occupy the 8i site. Curie temperatures on Sm(M,Fe) 12 compounds are around 590 K except for the SmMo 2 Fe 10 compound (T/sub c/ = 483 K). The SmTiFe 11 and SmSi 2 Fe 10 compounds have a high saturation magnetization and magnetic anisotropy

  5. Crystallographic features of the martensitic transformation and their impact on variant organization in the intermetallic compound Ni50Mn38Sb12 studied by SEM/EBSD.

    Science.gov (United States)

    Zhang, Chunyang; Zhang, Yudong; Esling, Claude; Zhao, Xiang; Zuo, Liang

    2017-09-01

    The mechanical and magnetic properties of Ni-Mn-Sb intermetallic compounds are closely related to the martensitic transformation and martensite variant organization. However, studies of these issues are very limited. Thus, a thorough crystallographic investigation of the martensitic transformation orientation relationship (OR), the transformation deformation and their impact on the variant organization of an Ni 50 Mn 38 Sb 12 alloy using scanning electron microscopy/electron backscatter diffraction (SEM/EBSD) was conducted in this work. It is shown that the martensite variants are hierarchically organized into plates, each possessing four distinct twin-related variants, and the plates into plate colonies, each containing four distinct plates delimited by compatible and incompatible plate interfaces. Such a characteristic organization is produced by the martensitic transformation. It is revealed that the transformation obeys the Pitsch relation ({0[Formula: see text]} A // {2[Formula: see text]} M and 〈0[Formula: see text]1〉 A // 〈[Formula: see text]2〉 M ; the subscripts A and M refer to austenite and martensite, respectively). The type I twinning plane K 1 of the intra-plate variants and the compatible plate interface plane correspond to the respective orientation relationship planes {0[Formula: see text]} A and {0[Formula: see text]} A of austenite. The three {0[Formula: see text]} A planes possessed by each pair of compatible plates, one corresponding to the compatible plate interface and the other two to the variants in the two plates, are interrelated by 60° and belong to a single 〈11[Formula: see text]〉 A axis zone. The {0[Formula: see text]} A planes representing the two pairs of compatible plates in each plate colony belong to two 〈11[Formula: see text]〉 A axis zones having one {0[Formula: see text]} A plane in common. This common plane defines the compatible plate interfaces of the two pairs of plates. The transformation strains to form the

  6. Magnetocaloric effects in RTX intermetallic compounds (R = Gd–Tm, T = Fe–Cu and Pd, X = Al and Si)

    International Nuclear Information System (INIS)

    Zhang Hu; Shen Bao-Gen

    2015-01-01

    The magnetocaloric effect (MCE) of RTSi and RT Al systems with R = Gd–Tm, T = Fe–Cu and Pd, which have been widely investigated in recent years, is reviewed. It is found that these RTX compounds exhibit various crystal structures and magnetic properties, which then result in different MCE. Large MCE has been observed not only in the typical ferromagnetic materials but also in the antiferromagnetic materials. The magnetic properties have been studied in detail to discuss the physical mechanism of large MCE in RTX compounds. Particularly, some RTX compounds such as ErFeSi, HoCuSi, HoCuAl exhibit large reversible MCE under low magnetic field change, which suggests that these compounds could be promising materials for magnetic refrigeration in a low temperature range. (topical review)

  7. NMR study of electron spin density distribution in rare-earth intermetallic compounds with iron and cobalt

    International Nuclear Information System (INIS)

    Vasil'kovskij, V.A.; Gorlenko, A.A.; Kupriyanov, A.K.; Ostrovskij, V.F.

    1988-01-01

    It is shown that in intermettalic compounds local fields in rare earth (RE) element nuclei directed by 3d-sublattice atoms depend on 3d-atom type but they practically do not depend on the value of its magnetic moment and the compound stoichiometry. The results are explained in the assumption concerning the presence of a system of collectivized electrons, their spin polarization determining the field in RE nuclei and contributing to 3d-atom magnetic moment

  8. Inhibition of the formation of intermetallic compounds in aluminum-steel welded joints by friction stir welding; Inhibicion de la formacion de compuestos intermetalicos en juntas aluminio-acero soldadas por friccion-agitacion

    Energy Technology Data Exchange (ETDEWEB)

    Torres Lopez, E. A.; Ramirez, A. J.

    2015-07-01

    Formation of deleterious phases during welding of aluminum and steel is a challenge of the welding processes, for decades. Friction Stir Welding (FSW) has been used in an attempt to reduce formation of intermetallic compounds trough reducing the heat input. In this research, dissimilar joint of 6063-T5 aluminum alloy and AISI-SAE 1020 steel were welded using this technique. The temperature of welded joints was measured during the process. The interface of the welded joints was characterized using optical microscopy, scanning and transmission electron microscopy. Additionally, composition measurements were carried out by X-EDS and DRX. The experimental results revealed that the maximum temperature on the joint studied is less than 360 degree centigrade. The microstructural characterization in the aluminum-steel interface showed the absence of intermetallic compounds, which is a condition attributed to the use of welding with low thermal input parameters. (Author)

  9. Effect of rapid quenching on the magnetism and magnetocaloric effect of equiatomic rare earth intermetallic compounds RNi (R = Gd, Tb and Ho)

    Energy Technology Data Exchange (ETDEWEB)

    Rajivgandhi, R. [Department of Physics, Indian Institute of Technology Madras, Chennai 600 036 (India); Arout Chelvane, J. [Defence Metallurgical Research Laboratory, Hyderabad 500 058 (India); Quezado, S.; Malik, S.K. [Departamento de F’ısica Teorica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59072-970 (Brazil); Nirmala, R., E-mail: nirmala@physics.iitm.ac.in [Department of Physics, Indian Institute of Technology Madras, Chennai 600 036 (India)

    2017-07-01

    Highlights: • Melt-spinning yields microcrystalline RNi (R = Gd, Tb and Ho) samples with texture. • The texture-induced anisotropy affects magnetic and magnetocaloric properties. • Melt-spinning helps one engineer magnetocaloric effect in rare-earth compounds. - Abstract: Magnetocaloric effect (MCE) in RNi (where R = Gd, Tb and Ho) compounds has been studied in their arc-melted and melt-spun forms. The compound GdNi has the orthorhombic CrB-type structure (Space group Cmcm, No. 63) and the compound HoNi has the orthorhombic FeB-type structure (Space group Pnma, No. 62) at room temperature regardless of their synthesis condition. However, arc-melted TbNi orders in a monoclinic structure (Space group P2{sub 1}/m, No. 11) and when it is rapidly quenched to a melt-spun form, it crystallizes in an orthorhombic structure (Space group Pnma, No. 62). The arc-melted GdNi, TbNi and HoNi compounds order ferromagnetically at ∼69 K, ∼67 K and ∼36 K (T{sub C}) respectively. While the melt-spun GdNi shows about 6 K increase in T{sub C}, the ordering temperature of TbNi remains nearly the same in both arc-melted and melt-spun forms. In contrast, a reduction in T{sub C} by about 8 K is observed in melt-spun HoNi, when compared to its arc-melted counterpart. Isothermal magnetic entropy change, ∆S{sub m}, calculated from the field dependent magnetization data indicates an enhanced relative cooling power (RCP) for melt-spun GdNi for field changes of 20 kOe and 50 kOe. A lowered RCP value is observed in melt-spun TbNi and HoNi. These changes could have resulted from the competing shape anisotropy and the granular microstructure induced by the melt-spinning process. Tailoring the MCE of rare earth intermetallic compounds by suitably controlled synthesis techniques is certainly one of the directions to go forward in the search of giant magnetocaloric materials.

  10. Concurrent nucleation, formation and growth of two intermetallic compounds (Cu6Sn5 and Cu3Sn) during the early stages of lead-free soldering

    International Nuclear Information System (INIS)

    Park, M.S.; Arróyave, R.

    2012-01-01

    This study investigates the concurrent nucleation, formation and growth of two intermetallic compounds (IMCs), Cu 6 Sn 5 (η) and Cu 3 Sn (ε), during the early stages of soldering in the Cu–Sn system. The nucleation, formation and growth of the IMC layers is simulated through a multiphase-field model in which the concurrent nucleation of both IMC phases is considered to be a stochastic Poisson process with nucleation rates calculated from classical nucleation theory. CALPHAD thermodynamic models are used to calculate the local contributions to the free energy of the system and the driving forces for precipitation of the IMC phases. The nucleation parameters of the η phase are estimated from experimental results and those of the ε phase are assumed to be similar. A parametric investigation of the effects of model parameters (e.g. grain boundary (GB) diffusion rates, interfacial and GB energies) on morphological evolution and IMC layer growth rate is presented and compared with previous works in which nucleation was ignored . In addition, the resulting growth rates are compared with the available literature and it is found that, for a certain range in the model parameters, the agreement is quite satisfactory. This work provides valuable insight into the dominant mechanisms for mass transport as well as morphological evolution and growth of IMC layers during early stages of Pb-free soldering.

  11. Soldering-induced Cu diffusion and intermetallic compound formation between Ni/Cu under bump metallization and SnPb flip-chip solder bumps

    Science.gov (United States)

    Huang, Chien-Sheng; Jang, Guh-Yaw; Duh, Jenq-Gong

    2004-04-01

    Nickel-based under bump metallization (UBM) has been widely used as a diffusion barrier to prevent the rapid reaction between the Cu conductor and Sn-based solders. In this study, joints with and without solder after heat treatments were employed to evaluate the diffusion behavior of Cu in the 63Sn-37Pb/Ni/Cu/Ti/Si3N4/Si multilayer structure. The atomic flux of Cu diffused through Ni was evaluated from the concentration profiles of Cu in solder joints. During reflow, the atomic flux of Cu was on the order of 1015-1016 atoms/cm2s. However, in the assembly without solder, no Cu was detected on the surface of Ni even after ten cycles of reflow. The diffusion behavior of Cu during heat treatments was studied, and the soldering-process-induced Cu diffusion through Ni metallization was characterized. In addition, the effect of Cu content in the solder near the solder/intermetallic compound (IMC) interface on interfacial reactions between the solder and the Ni/Cu UBM was also discussed. It is evident that the (Cu,Ni)6Sn5 IMC might form as the concentration of Cu in the Sn-Cu-Ni alloy exceeds 0.6 wt.%.

  12. Asymmetrical Precipitation of Ag3Sn Intermetallic Compounds Induced by Thermomigration of Ag in Pb-Free Microbumps During Solid-State Aging

    Science.gov (United States)

    Su, Yu-Ping; Wu, Chun-Sen; Ouyang, Fan-Yi

    2016-01-01

    Three-dimensional integrated circuit technology has become a major trend in electronics packaging in the microelectronics industry. To effectively remove heat from stacked integrated circuitry, a temperature gradient must be established across the chips. Furthermore, because of the trend toward higher device current density, Joule heating is more serious and temperature gradients across soldered joints are expected to increase. In this study we used heat-sink and heat-source devices to establish a temperature gradient across SnAg microbumps to investigate the thermomigration behavior of Ag in SnAg solder. Compared with isothermal conditions, small Ag3Sn particles near the hot end were dissolved and redistributed toward the cold end under a temperature gradient. The results indicated that temperature gradient-induced movement of Ag atoms occurred from the hot side toward the cold side, and asymmetrical precipitation of Ag3Sn resulted. The mechanism of growth of the intermetallic compound (IMC) Ag3Sn, caused by thermomigration of Ag, is discussed. The rate of growth Ag3Sn IMC at the cold side was found to increase linearly with solid-aging time under a temperature gradient. To understand the force driving Ag diffusion under the temperature gradient, the molar heat of transport ( Q*) of Ag in Sn was calculated as +13.34 kJ/mole.

  13. The effect of compositional changes on the structural and hydrogen storage properties of (La–Ce)Ni5 type intermetallics towards compounds suitable for metal hydride hydrogen compression

    International Nuclear Information System (INIS)

    Odysseos, M.; De Rango, P.; Christodoulou, C.N.; Hlil, E.K.; Steriotis, T.; Karagiorgis, G.; Charalambopoulou, G.; Papapanagiotou, T.; Ampoumogli, A.; Psycharis, V.; Koultoukis, E.; Fruchart, D.; Stubos, A.

    2013-01-01

    Graphical abstract: The effect of the partial substitution of La with Ce on the crystal structure and the final hydrogen storage properties of the alloys. Highlights: ► Absorption-based systems exploit the properties of reversible metal hydrides. ► AB5 intermetallics are mostly popular for thermal desorption compressors. ► Investigation of H2 absorption/desorption properties of LaNi5 and its derivatives. ► LaNi5 thermodynamic properties adjustment by partially replacing La with rare earths. -- Abstract: The present work has been aiming at the synthesis and study of a series of La 1−x Ce x Ni 5 (x = 0, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8) alloys in an attempt to investigate possible alterations of the hydrogen absorption/desorption properties The alloys were prepared by induction melting of the constituent elements. The systematic characterization of all new compounds by means of XRD and hydrogen sorption measurements revealed the effect of the partial substitution of La with Ce on the crystal structure and the final hydrogen storage properties of the alloys. Extensive absorption/desorption experiments (Van’t Hoff diagrams) have shown that such alloys can be used to build a metal hydride compressor (MHC), compressing H 2 gas from 0.2 MPa to 4.2 MPa using cold (20 °C) and hot (80 °C) water

  14. DO{sub 22}-(Cu,Ni){sub 3}Sn intermetallic compound nanolayer formed in Cu/Sn-nanolayer/Ni structures

    Energy Technology Data Exchange (ETDEWEB)

    Liu Lilin [School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Huang, Haiyou [Department of Mechanical Engineering, Hong Kong University of Science and Technology (HKUST) (Hong Kong); Hong Kong - Beijing Joint Research Center, HKUST Fok Ying Tung Graduate School, Nansha, Guangzhou (China); Fu Ran; Liu Deming [ASM Assembly Automation Ltd. (Hong Kong); Zhang Tongyi, E-mail: mezhangt@ust.h [Department of Mechanical Engineering, Hong Kong University of Science and Technology (HKUST) (Hong Kong); Hong Kong - Beijing Joint Research Center, HKUST Fok Ying Tung Graduate School, Nansha, Guangzhou (China)

    2009-11-03

    The present work conducts crystal characterization by High Resolution Transmission Electron Microscopy (HRTEM) on Cu/Sn-nanolayer/Ni sandwich structures associated with the use of Energy Dispersive X-ray (EDX) analysis. The results show that DO{sub 22}-(Cu,Ni){sub 3}Sn intermetallic compound (IMC) ordered structure is formed in the sandwich structures at the as-electrodeposited state. The formed DO{sub 22}-(Cu,Ni){sub 3}Sn IMC is a homogeneous layer with a thickness about 10 nm. The DO{sub 22}-(Cu,Ni){sub 3}Sn IMC nanolayer is stable during annealing at 250 deg. C for 810 min. The formation and stabilization of the metastable DO{sub 22}-(Cu,Ni){sub 3}Sn IMC nanolayer are attributed to the less strain energy induced by lattice mismatch between the DO{sub 22} IMC and fcc Cu crystals in comparison with that between the equilibrium DO{sub 3} IMC and fcc Cu crystals.

  15. A Correlation between the Ultimate Shear Stress and the Thickness Affected by Intermetallic Compounds in Friction Stir Welding of Dissimilar Aluminum Alloy–Stainless Steel Joints

    Directory of Open Access Journals (Sweden)

    Florent Picot

    2018-03-01

    Full Text Available In this work, Friction Stir Welding (FSW was applied to join a stainless steel 316L and an aluminum alloy 5083. Ranges of rotation and translation speeds of the tool were used to obtain welding samples with different heat input coefficients. Depending on the process parameters, the heat generated by FSW creates thin layers of Al-rich InterMetallic Compound (IMC mainly composed of FeAl3, identified by energy dispersive spectrometry. Traces of Fe2Al5 were also depicted in some samples by X-ray diffraction analysis and transmission electron microscopy. Monotonous tensile tests performed on the weld joint show the existence of a maximum mechanical resistance for a judicious choice of rotation and translation speeds. It can be linked to an affected zone of average thickness of 15 µm which encompass the presence of IMC and the chaotic mixing caused by plastic deformation in this area. A thickness of less than 15 µm is not sufficient to ensure a good mechanical resistance of the joint. For a thickness higher than 15 µm, IMC layers become more brittle and less adhesive due to high residual stresses which induces numerous cracks after cooling. This leads to a progressive decrease of the ultimate shear stress supported by the bond.

  16. Experimental and computational study of the morphological evolution of intermetallic compound (Cu6Sn5) layers at the Cu/Sn interface under isothermal soldering conditions

    International Nuclear Information System (INIS)

    Park, M.S.; Stephenson, M.K.; Shannon, C.; Cáceres Díaz, L.A.; Hudspeth, K.A.; Gibbons, S.L.; Muñoz-Saldaña, J.; Arróyave, R.

    2012-01-01

    Cu/Sn soldering alloys have emerged as a viable alternative to Pb-based solders, and thus have been extensively explored in the past decade, although the fine-scale behavior of the resulting intermetallic compounds (IMCs), particularly during the early stages of interface formation, is still a source of debate. In this work, the microstructural evolution of Cu 6 Sn 5 , in a Cu/Sn soldering reaction at 523 K, was experimentally investigated by dipping a single Cu sample into molten Sn at a near-constant speed, yielding a continuous set of time evolution samples. The thickness, coarsening and morphology evolution of the Cu 6 Sn 5 layer is investigated through the use of scanning electron microscopy. The experimental results are also compared to phase-field simulations of the microstructural evolution of the Cu 6 Sn 5 layer. The influence of model parameters on the kinetics and morphological evolution of the IMC layer was examined. In general, good qualitative agreement is found between experiments and simulations and for a limited parameter set there appears to be good quantitative agreement between the growth kinetics of the Cu 6 Sn 5 layer, the grain boundary (GB) effect on grain coarsening, and the substrate/IMC interface roughness evolution. Furthermore, the parametric investigations of the model suggests that good agreement between experiments and simulations is achieved when the dominant transport mechanism for the reacting elements (Cu and Sn) is GB diffusion.

  17. Self-propagating high-temperature synthesis flammable range and dominant parameters for synthesizing several ceramics and intermetallic compounds under heat-loss condition

    International Nuclear Information System (INIS)

    Makino, Atsushi

    1996-01-01

    Extensive comparisons have been conducted between experimental and theoretical results for the nonadiabatic self-propagating high-temperature synthesis combustion characteristics of many solid-solid systems subjected to volumetric heat loss. The nonadiabatic flame propagation theory--which describes the premixed mode of bulk flame propagation supported by the nonpremixed reaction of dispersed nonmetal (or higher-melting point metal) particles in the liquid metal, with finite-rate reaction at the particle surface and temperature-sensitive Arrhenius-type condensed-phase mass diffusivity--is used to compare with experimental results with heat loss. Systems examined are ceramics (TiC, TiB 2 , and ZrB 2 ) and intermetallic compounds (NiAl, TiCo, and TiNi). By using a consistent set of physicochemical parameters for these systems, satisfactory quantitative agreement is demonstrated for the flammable range (defined in terms of the mixture ratio, degree of dilution, particle size, and/or compact diameter)

  18. Simulation of the precipitation process of ordered intermetallic compounds in binary and ternary Ni-Al-based alloys by the phase-field model

    International Nuclear Information System (INIS)

    Hou Hua; Zhao Yuhong; Zhao Yuhui

    2009-01-01

    With the microscopic phase-field model, atomic-scale computer simulation programs for the precipitation mechanism of the ordered intermetallic compound γ' in binary Ni-15.5 at.%Al alloy, θ and γ' in ternary Ni 75 Al x V 25-x alloys were worked out based on the microscopic diffusion equation and non-equilibrium free energy. The simulation can be applied to the whole precipitation process and composition range. A prior assumptions on the new phase structure or transformation path was unnecessary, the possible non-equilibrium phases, atomic clustering and ordering could be described automatically, and atomic images, order parameters and volume fractions of precipitates were obtained. Computer simulation was performed systematically on the precipitation mechanism, precipitation sequence of θ and γ' in complicated system with ordering and clustering simultaneously. Through the simulated atomic images and chemical order parameters of precipitates, we can explain the complex precipitation mechanisms of θ (Ni 3 V) and γ' (Ni 3 Al) ordered phases. For the binary alloy, the precipitation mechanism of γ' phase has the characteristic of both non-classical nucleation and growth (NCNG) and congruent ordering and spinodal decomposition (COSD). For the ternary alloys, the precipitation characteristic of γ' phase transforms from NCNG to COSD gradually, otherwise, the precipitation characteristic of θ phase transforms from COSD to NCNG mechanism gradually

  19. Phase transformation and morphology of the intermetallic compounds formed at the Sn-9Zn-3.5Ag/Cu interface in aging

    International Nuclear Information System (INIS)

    Hon, M.-H.; Chang, T.-C.; Wang, M.-C.

    2008-01-01

    The morphology and phase transformation of the intermetallic compounds (IMCs) formed at the Sn-9Zn-3.5Ag/Cu interface in a solid-state reaction have been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The monoclinic η'-Cu 6 Sn 5 transforms to the hexagonal η-Cu 6 Sn 5 and the orthorhombic Cu 5 Zn 8 transforms to the body-centered cubic (bcc) γ-Cu 5 Zn 8 as aged at 180 deg. C. The scallop-shaped Cu 6 Sn 5 layer is retained after aging at 180 deg. C for 1000 h. In the solid-state reaction, Ag is repelled from η'-Cu 6 Sn 5 and reacts with Sn to form Ag 3 Sn, and the Cu 5 Zn 8 layer decomposes. Kirkendall voids are not observed at the Sn-9Zn-3.5Ag/Cu interface even after aging at 180 deg. C for 1000 h

  20. Phase transformation and morphology of the intermetallic compounds formed at the Sn-9Zn-3.5Ag/Cu interface in aging

    Energy Technology Data Exchange (ETDEWEB)

    Hon, M.-H. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Chang, T.-C. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Electronic and Optoelectronics Research Laboratories, Industrial Technology Research Institute, Bldg. 11, 195, Sec. 4, Chung-Hsing Road, Chutung, Hsinchu, 310, Taiwan (China); Wang, M.-C. [Faculty of Fragrance and Cosmetics, Kaohsiung Medical University, 100 Shi-Chuan 1st Road, Kaohsiung 807, Taiwan (China)], E-mail: mcwang@kmu.edu.tw

    2008-06-30

    The morphology and phase transformation of the intermetallic compounds (IMCs) formed at the Sn-9Zn-3.5Ag/Cu interface in a solid-state reaction have been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The monoclinic {eta}'-Cu{sub 6}Sn{sub 5} transforms to the hexagonal {eta}-Cu{sub 6}Sn{sub 5} and the orthorhombic Cu{sub 5}Zn{sub 8} transforms to the body-centered cubic (bcc) {gamma}-Cu{sub 5}Zn{sub 8} as aged at 180 deg. C. The scallop-shaped Cu{sub 6}Sn{sub 5} layer is retained after aging at 180 deg. C for 1000 h. In the solid-state reaction, Ag is repelled from {eta}'-Cu{sub 6}Sn{sub 5} and reacts with Sn to form Ag{sub 3}Sn, and the Cu{sub 5}Zn{sub 8} layer decomposes. Kirkendall voids are not observed at the Sn-9Zn-3.5Ag/Cu interface even after aging at 180 deg. C for 1000 h.

  1. Massive spalling of Cu-Zn and Cu-Al intermetallic compounds at the interface between solders and Cu substrate during liquid state reaction

    Science.gov (United States)

    Kotadia, H. R.; Panneerselvam, A.; Mokhtari, O.; Green, M. A.; Mannan, S. H.

    2012-04-01

    The interfacial intermetallic compound (IMC) formation between Cu substrate and Sn-3.8Ag-0.7Cu-X (wt.%) solder alloys has been studied, where X consists of 0-5% Zn or 0-2% Al. The study has focused on the effect of solder volume as well as the Zn or Al concentration. With low solder volume, when the Zn and Al concentrations in the solder are also low, the initial Cu-Zn and Al-Cu IMC layers, which form at the solder/substrate interface, are not stable and spall off, displaced by a Cu6Sn5 IMC layer. As the total Zn or Al content in the system increases by increasing solder volume, stable CuZn or Al2Cu IMCs form on the substrate and are not displaced. Increasing concentration of Zn has a similar effect of stabilizing the Cu-Zn IMC layer and also of forming a stable Cu5Zn8 layer, but increasing Al concentration alone does not prevent spalling of Al2Cu. These results are explained using a combination of thermodynamic- and kinetics-based arguments.

  2. Fermi surface properties of AB3 (A = Y, La; B = Pb, In, Tl) intermetallic compounds under pressure

    DEFF Research Database (Denmark)

    Ram, Swetarekha; Kanchana, V; Svane, Axel

    2013-01-01

    –correlation functional and including spin–orbit coupling. Fermi surface topology changes are found for all the isostructural AB3 compounds under compression (at V=V0 = 0.90 for LaPb3 (pressure = 8 GPa), at V=V0 = 0.98 for AIn3 (pressure = 1.5 GPa), at V=V0 = 0.80 for ATl3 (pressure in excess of 18 GPa)) apart from YPb3...

  3. Synthesis and characterization of Fe-Ti-Sb intermetallic compounds: Discovery of a new Slater-Pauling phase

    Science.gov (United States)

    Naghibolashrafi, N.; Keshavarz, S.; Hegde, Vinay I.; Gupta, A.; Butler, W. H.; Romero, J.; Munira, K.; LeClair, P.; Mazumdar, D.; Ma, J.; Ghosh, A. W.; Wolverton, C.

    2016-03-01

    Compounds of Fe, Ti, and Sb were prepared using arc melting and vacuum annealing. Fe2TiSb , expected to be a full Heusler compound crystallizing in the L 21 structure, was shown by XRD and SEM analyses to be composed of weakly magnetic grains of nominal composition Fe1.5TiSb with iron-rich precipitates in the grain boundaries. FeTiSb, a composition consistent with the formation of a half-Heusler compound, also decomposed into Fe1.5TiSb grains with Ti-Sb rich precipitates and was weakly magnetic. The dominant Fe1.5TiSb phase appears to crystallize in a defective L 21 -like structure with iron vacancies. Based on this finding, a first-principles DFT-based binary cluster expansion of Fe and vacancies on the Fe sublattice of the L 21 structure was performed. Using the cluster expansion, we computationally scanned >103 configurations and predict a novel, stable, nonmagnetic semiconductor phase to be the zero-temperature ground state. This new structure is an ordered arrangement of Fe and vacancies, belonging to the space group R 3 m , with composition Fe1.5TiSb , i.e., between the full- and half-Heusler compositions. This phase can be visualized as alternate layers of L 21 phase Fe2TiSb and C 1b phase FeTiSb, with layering along the [111] direction of the original cubic phases. Our experimental results on annealed samples support this predicted ground-state composition, but further work is required to confirm that the R 3 m structure is the ground state.

  4. Satelite structure in 59Co NMR spectrum of magnetically ordered Dysub(1-x)Ysub(x)Co2 intermetallic compound

    International Nuclear Information System (INIS)

    Yoshimura, Kazuyoshi; Hirosawa, Satoshi; Nakamura, Yoji

    1984-01-01

    The magnetic environment effect of cobalt in Dysub(1-x)Ysub(x)Co 2 has been studied by means of bulk magnetization and 59 Co spin-echo NMR measurements at 4.2K. Clearly resolved satellite structures of the NMR spectra have been observed. The hyperfine field distributions of 59 Co are decomposed into contributions of Co atoms in various nearest neighbor configurations of rare earth atoms. In this analysis the dipole field due to nearest neighbor rare earth moments plays an important role. The result indicates that the magnetic moment of Co in the RCo 2 cubic Laves phase pseudobinary compounds is quite sensitive to the nearest neighbor rare earth environment. (author)

  5. The effect of intermetallic compound morphology on Cu diffusion in Sn-Ag and Sn-Pb solder bump on the Ni/Cu Under-bump metallization

    Science.gov (United States)

    Jang, Guh-Yaw; Duh, Jenq-Gong

    2005-01-01

    The eutectic Sn-Ag solder alloy is one of the candidates for the Pb-free solder, and Sn-Pb solder alloys are still widely used in today’s electronic packages. In this tudy, the interfacial reaction in the eutectic Sn-Ag and Sn-Pb solder joints was investigated with an assembly of a solder/Ni/Cu/Ti/Si3N4/Si multilayer structures. In the Sn-3.5Ag solder joints reflowed at 260°C, only the (Ni1-x,Cux)3Sn4 intermetallic compound (IMC) formed at the solder/Ni interface. For the Sn-37Pb solder reflowed at 225°C for one to ten cycles, only the (Ni1-x,Cux)3Sn4 IMC formed between the solder and the Ni/Cu under-bump metallization (UBM). Nevertheless, the (Cu1-y,Niy)6Sn5 IMC was observed in joints reflowed at 245°C after five cycles and at 265°C after three cycles. With the aid of microstructure evolution, quantitative analysis, and elemental distribution between the solder and Ni/Cu UBM, it was revealed that Cu content in the solder near the solder/IMC interface played an important role in the formation of the (Cu1-y,Niy)6Sn5 IMC. In addition, the diffusion behavior of Cu in eutectic Sn-Ag and Sn-Pb solders with the Ni/Cu UBM were probed and discussed. The atomic flux of Cu diffused through Ni was evaluated by detailed quantitative analysis in an electron probe microanalyzer (EPMA). During reflow, the atomic flux of Cu was on the order of 1016-1017 atoms/cm2sec in both the eutectic Sn-Ag and Sn-Pb systems.

  6. Electric quadrupole and magnetic dipole interactions at {sup 181}Ta impurity in Zr{sub 2}Ni{sub 7} intermetallic compound: Experiment and first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Dey, C.C., E-mail: chandicharan.dey@saha.ac.in [Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); Srivastava, S.K. [Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur 721302 (India)

    2013-10-15

    Electric quadrupole interactions at {sup 181}Ta impurity in the intermetallic compound Zr{sub 2}Ni{sub 7} have been studied by perturbed angular correlation technique. It has been found that there are two electric field gradients (EFG) at the {sup 181}Ta site due to two different crystalline configurations in Zr{sub 2}Ni{sub 7}, while contradictory results were reported from previous investigations. The values of EFG at room temperature have been found to be V{sub zz}=7.9×10{sup 17} V/cm{sup 2} and 7.1×10{sup 17} V/cm{sup 2} corresponding to present experimental values of quadrupole frequencies and asymmetry parameters for the two sites: ω{sub Q}{sup 1}=70.7(1) Mrad/s, η=0.28(1), δ=0.8(2)% (site fraction 84%) and ω{sub Q}{sup 2}=63(1) Mrad/s, η=0.35(5), δ∼0 (site fraction 9%). Electric field gradients and asymmetry parameters have been computed from the complementary first-principles density functional theory (DFT) to compare with present experimental results. Our calculated values of EFG are found to be in close agreement with the experimental results. No magnetic interactions in Zr{sub 2}Ni{sub 7} have been observed at 298 and 77 K which implies that there is no ferromagnetic ordering in this material down to 77 K. This observation is corroborated by theoretical calculations, wherein no magnetic moment or hyperfine field is found at any atomic site.

  7. Valence behavior of Eu-ions in intermetallic compound Ce{sub 0.5}Eu{sub 0.5}Pd{sub 3}B{sub 0.5}

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Abhishek, E-mail: apandey@ameslab.gov [Experimental Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); S.N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098 (India); Mazumdar, Chandan, E-mail: chandan.mazumdar@saha.ac.in [S.N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098 (India); Ranganathan, R. [S.N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098 (India); Raghavendra Reddy, V.; Gupta, Ajay [UGC-DAE Consortium for Scientific Research, University Campus, Khandawa Road, Indore (India)

    2011-12-15

    We have studied the valence behavior of rare-earth ions, in particular Eu-ions, in a cubic intermetallic compound Ce{sub 0.5}Eu{sub 0.5}Pd{sub 3}B{sub 0.5} which is a homogeneous solid solution of two mixed-valent compounds CePd{sub 3} and EuPd{sub 3}B. Results of {sup 151}Eu Moessbauer spectroscopic measurements show that two different valence states, i.e., divalent- and trivalent-like states of Eu-ions exist in the compound. The possible reason for the observed heterogeneous valency vis-a-vis the variation in the chemical environment and the number of nearest-neighbor B atoms surrounding the Eu-ions has been discussed. Our results demonstrate that B incorporation in such Eu-based cubic intermetallic compounds leads to a situation where heterogeneous-valence state of Eu-ions is an energetically favorable ground state. - Highlights: > Intermetallic compound Ce{sub 0.5}Eu{sub 0.5}Pd{sub 3}B{sub 0.5} crystallizes in a single phase. > Eu-ions in Ce{sub 0.5}Eu{sub 0.5}Pd{sub 3}B{sub 0.5} are charge-ordered compared to +2.3 valency in Ce{sub 0.5}Eu{sub 0.5}Pd{sub 3}. > B incorporation makes charge-ordered state of Eu-ions energetically more favorable. > Nearest-neighbor chemical environment affects the Eu valency.

  8. Effect of Nb on plasticity and oxidation behavior of TiA1Nb intermetallic compound by density functional theory

    Institute of Scientific and Technical Information of China (English)

    LI Yan-feng; XU Hui; SONG Zhao-quan; MA Song-shan

    2010-01-01

    Based on the pseudo potential plane-wave method of density functional theory(DFT),Ti1-xNbxA1(x=0,0.062 5,0.083 3,0.125,0.250)crystals' geometry structure,elastic constants,electronic structure and Mulliken populations were calculated,and the effects of doping on the geometric structure,electronic structure and bond strength were systematically analyzed.The results show that the influence of Nb on the geometric structure is little in terms of the plasticity,and with the increase of Nb content,the covalent bond strength remarkably reduces,and Ti-A1,Nb-M(M=Ti,A1)and other hybrid bonds enhance; meanwhile,the peak district increases and the pseudo-energy gap first decreases and then increases,the overall band structure narrows,the covalent bond and direction of bonds reduce.The population analysis also shows that the results are consistent with the electronic structure analysis.The density of states of TiAlNb shows that Nb doping can enhance the activity of Al and benefit the form of Al2O3 film.All the calculations reveal that the room temperature plasticity and the antioxidation properties of the compounds can be improved with the Nb content of 8.33%-12.5%(mole fraction).

  9. R5T4 compounds - unique multifunctional intermetallics for basic research and applications

    Energy Technology Data Exchange (ETDEWEB)

    Mudryk, Yaroslav

    2016-10-01

    The unique properties of the rare-earth elements and their alloys have brought them from relative obscurity to high profile use in common high-tech applications. The broad technological impact of these remarkable materials may have never been known by the general public if not for the supply concerns that placed the rare-earth materials on the front page of newspapers and magazines. Neodymium and dysprosium, two essential components of Nd2Fe14B-based high-performance permanent magnets, have drawn much attention and have been deemed critical materials for many energy-related applications. Ironically, the notoriety of rare-earth elements and their alloys is the result of a global movement to reduce their use in industrial applications and, thus, ease concerns about their supply and ultimately to reduce their position in high-tech supply chains. Research into the applications of lanthanide alloys has been de-emphasized recently due to the perception that industry is moving away from the use of rare-earth elements in new products. While lanthanide supply challenges justify efforts to diversify the supply chain, a strategy to completely replace the materials overlooks the reasons rare earths became important in the first place -- their unique properties are too beneficial to ignore. Rare-earth alloys and compounds possess truly exciting potential for basic science exploration and application development such as solid-state caloric cooling. In this brief review, we touch upon several promising systems containing lanthanide elements that show important and interesting magnetism-related phenomena.

  10. RRh2Al10 (R = Ce, Yb): New intermetallic compounds in the 1 : 2 : 10 stoichiometry series

    Science.gov (United States)

    Strydom, A. M.; Djoumessi, R. F.; Blinova, M.; Tursina, A.; Nesterenko, S.; Avzuragova, V.

    2018-05-01

    The orthorhombic, space group Cmcm YbFe2Al10 structure type series of compounds are known to form with practically the entire series of rare-earth elements R, but only with the three d - electron elements Fe, Ru, and Os. The Ce-derivatives in particular have been of much interest since the first reports of their highly unusual physical properties. Classified as Kondo insulators, CeRu2Al10 and CeOs2Al10 controversially order magnetically and with uncharacteristically high Néel temperatures of ≃ 28 K. CeFe2Al10 on the other hand shows pronounced semiconducting and Kondo features but remains paramagnetic. As part of our ongoing studies into the rich physics of this class of materials we have succeeded in synthesizing new members of the 1:2:10 stoichiometry involving the chemical element Rh for the first time. CeRh2Al10 is found to crystallize in the tetragonal system with space group I41 / amd . Yb Rh2Al10 on the other hand forms in the serial Cmcm orthorhombic structure type. We discuss important similarities between the two types. At 5.310 Å the shortest Ce-Ce distance is, likewise to the situation in CeRu2Al10 and CeOs2Al10 , also well above the Hill limit of 3.40 Å. Despite the cage-like structure and large rare-earth separation distances, this study reveals the onset of long-range magnetic ordering in CeRh2Al10 at 3.9 K. The magnetic ordering develops out of an incoherent Kondo state that dominates the electrical resistivity below about 40 K.

  11. Magnetic properties of rare-earth intermetallics

    International Nuclear Information System (INIS)

    Kirchmayr, H.

    1978-01-01

    A review is given of the concepts at present used to explain the magnetic properties of rare-earth intermetallics which have been the subject of numerous investigations in recent years. Rare-earth intermetallics with the formula Rsub(a)Bsub(b) are divided according to the magnetic moment of the B atom(s). If there is no magnetic moment present at the B-site, the exchange is only between the magnetic moments at the R-sites, which can only be of indirect character. One possible model is still the RKKY model, although it usually gives in practice only a qualitative description of the magnetic properties. Typical R-B compounds with the B-moment equal to zero are (for instance) the RA1 2 compounds, and related compounds such as the RZn and RCd compounds as well as compounds of the general formula RB 2 (B = Ni, Os, Ir, Pd, Ru or Rh). Of all intermetallics with nonzero B-moment, the R-3d intermetallics are the most important. These intermetallics can be formed with Mn, Fe, Co and Ni. In these systems there exist in principle three interactions, namely between the R-R, R-3d and 3d-3d atoms. The most important is usually the latter interaction. After a short discussion of the crystal structures which occur with R-3d intermetallics, the basic magnetic properties of R-3d intermetallics are presented. These properties are discussed with respect to the formation of a magnetic moment at the 3d site in the framework of present band theories. Special emphasis is given to a discussion of the localized or itinerant character of 3d electrons. (author)

  12. Study of hyperfine interactions in intermetallic compounds Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In

    International Nuclear Information System (INIS)

    Lapolli, Andre Luis

    2006-01-01

    Systematic behavior of magnetic hyperfine field (B hf ) in the intermetallic compounds Gd(Ni,Pd,Cu)In Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In was studied by Perturbed Gamma-Gamma Angular Correlation spectroscopy. The measurements of B hf were carried out at the rare earth atom and in sites using the nuclear probes 140 Ce and 11 '1Cd respectively. The variation of hyperfine field with temperature, in most cases, follows the Brillouin function predicted from the molecular field theory. The hyperfine field values at rare earth atom sites obtained from 140 Ce probe as well as at in sites obtained from 111 Cd probe for each series of compounds were extrapolated to zero Kelvin B hf (T=0) from these curves. These values were compared with the values of the literature for other compounds containing the same rare earth element and all of them show a linear relationship with the ordering temperature. This indicates that the main contribution to B hf comes from the conduction electron polarization (CEP) through Fermi contact interaction and the principal mechanism of magnetic interaction in these compounds can be described by the RKKY type interaction. The values of B hf (T=0) for each family of intermetallic compounds RNiIn and RPdIn when plotted as a function of 4f spin projection of rare earth element also shows a linear relationship. Exceptions are the results for the compounds RNiIn obtained with 111 Cd probe where a small deviation from linearity is observed. The results of the measurements carried out with the 111 Cd probe were also analyzed to obtain the hyperfine parameters of the quadrupole interaction as a function of temperature for RPdln and GdNiIn compounds. The results show that for the compound GdPdIn there might be some Gd-In disorder at high temperature. (author)

  13. Magnetization and specific heat study of metamagnetism in Lu.sub.2./sub.Fe.sub.17./sub.-based intermetallic compounds

    Czech Academy of Sciences Publication Activity Database

    Tereshina, Evgeniya; Andreev, Alexander V.

    2010-01-01

    Roč. 18, č. 6 (2010), 1205-1210 ISSN 0966-9795 R&D Projects: GA ČR GA202/09/0339 Institutional research plan: CEZ:AV0Z10100520 Keywords : rare-earth intermetallics * magnetic properties * single crystal growth Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.327, year: 2010

  14. Interfacial reaction of Ni{sub 3}Sn{sub 4} intermetallic compound in Ni/SnAg solder/Ni system under thermomigration

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yi-Shan; Yang, Chia-Jung; Ouyang, Fan-Yi, E-mail: fyouyang@ess.nthu.edu.tw

    2016-07-25

    The growth of Ni{sub 3}Sn{sub 4} intermetallic compound (IMC) between liquid–solid interface in micro-scale Ni/SnAg/Ni system was investigated under a temperature gradient of 160 °C/cm at 260 °C on a hot plate. In contrast to a symmetrical growth of Ni{sub 3}Sn{sub 4} on both interfaces under isothermally annealed at 260 °C, the interfacial Ni{sub 3}Sn{sub 4} IMC exhibited asymmetric growth under a temperature gradient; the growth of Ni{sub 3}Sn{sub 4} at cold interface was faster than that at hot side because of temperature gradient induced mass migration of Ni atoms from the hot end toward the cold end. It was found that two-stage growth behavior of Ni{sub 3}Sn{sub 4} IMC under a temperature gradient. A growth model was established and growth kinetic analysis suggested that the chemical potential gradient controlled the growth of Ni{sub 3}Sn{sub 4} at stage I (0–120 min) whereas the dynamic equilibrium between chemical potential gradient and temperature gradient forces was attained at the hot end at stage II (120–210 min). When dynamic equilibrium was achieved at 260 °C, the critical length-temperature gradient product at the hot end was experimentally estimated to be 489.18 μm × °C/cm and the moving velocity of Ni{sub 3}Sn{sub 4} interface due to Ni consumption was calculated to be 0.134 μm/h. The molar heat of transport (Q*) of Ni atoms in molten SnAg solder was calculated to be +0.76 kJ/mol. - Highlights: • Interfacial reaction in Ni/SnAg solder/Ni system under thermal gradient. • Growth rate of Ni{sub 3}Sn{sub 4} at cold end is faster than that at hot end. • Critical length-temperature gradient product at hot end is 489.2 μm°C/cm at 260 °C. • Velocity of Ni{sub 3}Sn{sub 4} moving interface is 0.134 μm/h during dynamic equilibrium. • Molar heat of transport (Q*) of Ni in molten SnAg was +0.76 kJ/mol.

  15. Quantifying the dependence of Ni(P) thickness in ultrathin-ENEPIG metallization on the growth of Cu–Sn intermetallic compounds in soldering reaction

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Cheng-Ying; Duh, Jenq-Gong, E-mail: jgd@mx.nthu.edu.tw

    2014-11-14

    A new multilayer metallization, ENEPIG (Electroless Ni(P)/Electroless Pd/Immersion Au) with ultrathin Ni(P) deposit (ultrathin-ENEPIG), was designed to be used in high frequency electronic packaging in this study because of its ultra-low electrical impedance. Sequential interfacial microstructures of commercial Sn–3.0Ag–0.5Cu solders reflowed on ultarthin-ENEPIG with Ni(P) deposit thickness ranged from 4.79 μm to 0.05 μm were first investigated. Accelerated thermal aging test was then conducted to evaluate the long-term thermal stabilization of solder joints. The results showed that P-rich intermetallic compound (IMC) layer formed when the Ni(P) thickness was greater than a critical vale (about 0.18 μm). Besides, it is interesting to mention that the growth of (Cu,Ni){sub 6}Sn{sub 5} and (Cu,Ni){sub 3}Sn IMCs was suppressed with the formation of P-rich layer, i.e., Ni{sub 3}P and Ni{sub 2}Sn{sub 1+x}P{sub 1−x} phase, even though the electroless-plated Ni(P) layer was exhausted at initial stage of reflow process. The atomic Cu flux in solder joints without P-rich layer was calculated to be several times larger than that with P-rich layer formation after calculation, which implies that the P-rich layer and ultrathin Ni(P) deposit in ENEPIG served as diffusion barrier against rapid Cu diffusion. - Highlights: • Microstructures in ultrathin-ENEPIG with various Ni(P) thickness are investigated. • P-rich IMC layer formed when the Ni(P) thickness is greater than 0.18 μm. • Secondary (Cu,Ni){sub 6}Sn{sub 5} formed when the Ni(P) thickness is between 0.18 and 0.31 μm. • Cu diffusion flux without P-rich layer is larger than those with P-rich layer. • P-rich layer in ultrathin-ENEPIG exhibits good diffusion barrier characteristic.

  16. The Application of CPA to Calculations of the Mean Magnetic Moment in the Gd1-xNi, Gd1-xFe, Gd1xCox, and Y1-xCox Intermetallic Compounds

    DEFF Research Database (Denmark)

    Szpunar, B.; Kozarzewski, B.

    1977-01-01

    with a narrow d-band is considered. The magnetic moment of the alloy at zero temperature is calculated within the molecular field and Hartree-Fock approximations. Disorder is treated in the coherent potential approximation. Results are in good agreement with the experimental data obtained for the crystalline......Calculations are made of the mean magnetic moment per atom of the transition metal and the rare-earth metal in the intermetallic compounds, Gd1-x,Nix, Gd1-x Fex, Gd1-x Cox, and Y1-x Cox. A simple model of the disordered alloy consisting of spins localized on the rare-earth atoms and interacting...

  17. Valence instabilities in cerium intermetallics

    International Nuclear Information System (INIS)

    Dijkman, W.H.

    1982-01-01

    The primary purpose of this investigation was to study the magnetic behaviour of cerium in intermetallic compounds, that show an IV behaviour, e.g. CeSn 3 . In the progress of the investigations, it became of interest to study the effect of changes in the lattice of the IV compound by substituting La or Y for Ce, thus constituting the Cesub(1-x)Lasub(x)Sn 3 and Cesub(1-x)Ysub(x)Sn 3 quasibinary systems. A second purpose was to examine the possibility of introducing instabilities in the valency of a trivalent intermetallic cerium compound: CeIn 3 , also by La and Y-substitutions in the lattice. Measurements on the resulting Cesub(1-x)Lasub(x)In 3 and Cesub(1-x)Ysub(x)In 3 quasibinaries are described. A third purpose was to study the (gradual) transition from a trivalent cerium compound into an IV cerium compound. This was done by examining the magnetic properties of the CeInsub(x)Snsub(3-x) and CePbsub(x)Snsub(3-x) systems. Finally a new possibility was investigated: that of the occurrence of IV behaviour in CeSi 2 , CeSi, and in CeGa 2 . (Auth.)

  18. The intermetallic ThRh5: microstructure and enthalpy increments

    International Nuclear Information System (INIS)

    Banerjee, Aparna; Joshi, A.R.; Kaity, Santu; Mishra, R.; Roy, S.B.

    2013-01-01

    Actinide intermetallics are one of the most interesting and important series of compounds. Thermochemistry of these compounds play significant role in understand the nature of bonding in alloys and nuclear fuel performance. In the present paper we report synthesis and characterization of thorium based intermetallic compound ThRh 5 (s) by SEM/EDX technique. The mechanical properties and enthalpy increment as a function of temperature of the alloy has been measured. (author)

  19. FY 1997 report on the improvement of toughness of silicide system intermetallic compounds by complex texture; 1997 nendo chosa hokokusho (fukugo soshikika ni yoru silicide kei kinzokukan kagobutsu no kyojinsei kaizen)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    In order to develop new materials superior in both room- temperature ductility and high-temperature strength, the basic data on MoSi2 intermetallic compounds with complex texture were stored. Intermetallic compound is one of the promising candidates of new super heat-resistant materials superior to conventional super heat-resistant alloys, however, it is extremely poor in ductility at room temperature. Based on available information on isothermal sectional phase diagrams of ternary system (Mo-Si-X system) composed of Mo silicide and the third element (X), some alloy systems were selected in consideration of use of carbide and nitride stably existing as dispersed phase of deposits at high temperature. A knowledge on phase diagrams of ternary system specimens with various compositions was obtained through arc melting, X-ray diffraction and texture observation, and heat treatment conditions for obtaining target complex textures were also determined. Storage of the basic data suggested that improvement of the ductility is possible by forming fine texture through addition of the third element and teat treatment. 21 refs., 58 figs., 15 tabs.

  20. Single crystal growth of europium and ytterbium based intermetallic ...

    Indian Academy of Sciences (India)

    The difference between an intermetallic compound and a regular metal (e.g., ... intriguing properties, there have not been any reports of thorough investigations of .... scanning electron microscope (SEM) equipped with an energy dispersive ...

  1. The effect of pH on the corrosion behavior of intermetallic compounds Ni{sub 3}(Si,Ti) and Ni{sub 3}(Si,Ti) + 2Mo in sodium chloride solutions

    Energy Technology Data Exchange (ETDEWEB)

    Priyotomo, Gadang, E-mail: gada001@lipi.go.id; Nuraini, Lutviasari, E-mail: Lutviasari@gmail.com [Research Center for Metallurgy and Material, Indonesian Institute of Sciences, Kawasan PUSPIPTEK Gd.474, Setu, Tangerang Selatan, Banten 15314 (Indonesia); Kaneno, Yasuyuki, E-mail: kaneno@mtr.osakafu-u.ac.id [Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531 (Japan)

    2015-12-29

    The corrosion behavior of the intermetallic compounds, Ni{sub 3}(Si,Ti) (L1{sub 2}: single phase) and Ni{sub 3}(Si,Ti) + 2Mo (L1{sub 2} and (L12 + Ni{sub ss}) mixture region), has been investigated using an immersion test, electrochemical method and surface analytical method (SEM; scanning electron microscope and EDAX: Energy Dispersive X-ray) in 0.5 kmol/m{sup 3} NaCl solutions at various pH. The corrosion behavior of nickel alloy C-276 was studied under the same experimental conditions as a reference. It was found that the uniform attack was observed on Ni{sub 3}(Si,Ti) for the immersion test at lower pH, while the pitting attack was observed on this compound for this test at neutral solution. Furthermore, Ni{sub 3}(Si,Ti)+2Mo had the preferential dissolution of L1{sub 2} compared to (L1{sub 2} + Ni{sub ss}) mixture region at lower pH, while pitting attack occurred in (L1{sub 2} + Ni{sub ss}) mixture region at neutral solution. For both intermetallic compounds, the magnitude of pitting and uniform attack decrease with increasing pH of solutions. From the immersion test and polarization curves, the corrosion resistance of Ni{sub 3}(Si,Ti)+2Mo is lower than that of Ni{sub 3}(Si,Ti), while the nickel alloy C-276 is the highest one at various pH of solutions. On the other hand, in the lower pH of solutions, the corrosion resistance of tested materials decreased significantly compared to those in neutral and higher pH of solutions.

  2. The influence of pressure on diffusion leading to intermetallic compounds; Influence de la pression sur les diffusions donnant naissance a des composes intermetalliques

    Energy Technology Data Exchange (ETDEWEB)

    Adda, Y; Beyeler, M; Kirianenko, A; Pernot, B [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1961-07-01

    Some investigators A.D. LE CLAIRE, J.L. ZAMBROW, L. CASTLEMAN, have shown that the application of uniaxial pressure parallel to the direction of diffusion may notably modify the kinetics of growth of the intermediate phases which can be formed in this direction. The interpretation of this phenomenon being obscure, an attempt is made to explain it by detailed analysis of the experimental facts. The microscopic studies of the kinetics of growth of the zones formed shows particularly in the couples Uranium-Copper and Uranium-Nickel that it is influenced in a similar manner by a uniaxial pressure and a hydrostatic one. On the other hand the rate of growth of these zones increases as a function of the applied pressure in the systems Uranium-Copper, Uranium-Nickel and Uranium-Aluminium (this effect being particularly marked in Uranium-Aluminium). To determine with precision the limits of the range of stability of the intermetallic compounds, the curves of concentration penetration characteristics of the diffusion have been established by means of the CASTAING electronic microanalyser. The examination of the results indicates that when diffusion takes place without external pressure (couples U-Cu and U-Ni) or with a pressure less than 300 kg/cm{sup 2} (couple U-Al) the concentration varies notably in the compounds obtained, which theoretically are stoichiometric. Thus, when crossing the zone of diffusion of one base metal to another one notes a continual passage of: UCu{sub 4.70} to UCu{sub 5.25} in the couple U-Cu; UNi{sub 4.75} to UNi{sub 5.25} in the couple U-Ni; UAl{sub 2.2} to UAl{sub 3.3} in the couple U-Al. If an uniaxial or hydrostatic pressure above 500 kg/cm{sup 2} is applied to the couples U-Cu and U-Ni, or above 1000 kg/cm{sup 2} for the couple U-Al, the composition is then constant in the zones formed. It corresponds to: UCu{sub 5} in the couple U-Cu; UNi{sub 5} in the couple U-Ni; UAl{sub 3} in the couple U-Al. These results are confirmed by an X

  3. Formation of abrasion-resistant coatings of the AlSiFe{sub x}Mny intermetallic compound type on the AISI 304L alloy

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Peralez, L. G.; Flores-Valdes, A.; Salinas-Rodriguez, A.; Ochoa-Palacios, R. M.; Toscano-giles, J. A.; Torres-Torres, J.

    2016-05-01

    The α-Al{sub 9}FeMnSi and α-Al{sub 9}FeMn{sub 2}Si intermetallics formed by reactive sintering of Al, Si, Mn, Fe, Cr and Ni powders have been used in AISI 304L steels to enhance microhardness. Processing variables of the reactive sintering treatment were temperature (600, 650, 700, 750 and 800 degree centigrade), pressure (5, 10 y 20 MPa) and holding time (3600, 5400 y 7200 seconds). Experimental results show that temperature is the most important variable affecting the substrate/coating formation, while pressure does not appear to have a significant effect. The results show the optimum conditions of the reactive sintering that favor the substrate/coating formation are 800 degree centigrade, 20 MPa and 7200 seconds. Under these conditions, the reaction zone between the substrate and coating is more compacted and well-adhered, with a microhardness of 1300 Vickers. The results of SEM and X-Ray diffraction confirmed the formation of β-Al{sub 9}FeMnSi and β-Al{sub 9}FeMn{sub 2}Si intermetallics in the substrate/coating interface as well as the presence of Cr and Ni, indicating diffusion of these two elements from the substrate to the interface. (Author)

  4. Determination of slip systems and their relation to the high ductility and fracture toughness of the B2 DyCu intermetallic compound

    International Nuclear Information System (INIS)

    Cao, G.H.; Shechtman, D.; Wu, D.M.; Becker, A.T.; Chumbley, L.S.; Lograsso, T.A.; Russell, A.M.; Gschneidner, K.A.

    2007-01-01

    DyCu single crystals with CsCl-type B2 structure were tensile tested at room temperature. Slip trace analysis shows that the primary slip system in DyCu with a tensile axis orientation of is {1 1 0} and the critical resolved shear stress for {1 1 0} slip is 18 MPa. Slip traces were also observed from a secondary slip system, {1 1 0} , and this slip system appears to be a key contributor to the previously reported high ductility and high fracture toughness of polycrystalline DyCu. Transmission electron microscopy determinations of the Burgers vectors of dislocations in tensile tested specimens revealed and dislocations, with -type dislocations being more abundant. The implications of these findings for the understanding of the mechanical properties of DyCu and the large family of ductile rare earth B2 intermetallics are discussed

  5. Enthalpies of formation of Cd0.917Sr0.083, Cd0.857Sr0.143 and Cd0.667Sr0.333 intermetallic compounds

    International Nuclear Information System (INIS)

    Agarwal, Renu; Singh, Ziley

    2008-01-01

    Cadmium is expected to be the solvent for pyrochemical processing of the metallic nuclear fuel. Therefore, thermodynamic properties of cadmium with various fuel and clad elements are of interest. Enthalpies of formation of the intermetallic compounds of Cd-Sr system, Cd 0.917 Sr 0.083 , Cd 0.857 Sr 0.143 and Cd 0.667 Sr 0.333 were determined by precipitation using Calvet calorimeter. Enthalpies of formation of the compounds were found to be -3.05 ± 0.5 kJ mol -1 at 723 K, -14.2 ± 0.7 kJ mol -1 at 843 K and -28.4 ± 0.8 kJ mol -1 at 863 K, respectively. Enthalpies of formation of Cd 0.917 Sr 0.083 and Cd 0.857 Sr 0.143 were also determined by partial enthalpy of formation measurements and the values were found to be -3.9 ± 1.1 kJ mol -1 at 723 K and -13.42 ± 1.2 kJ mol -1 at 843 K, respectively. Miedema model was used to estimate the enthalpies of formation of these compounds and the estimated values were compared with the experimentally determined values

  6. Measurement of pressure effects on the magnetic and the magnetocaloric properties of the intermetallic compounds DyCo2 and Er(Co1-xSix)2

    International Nuclear Information System (INIS)

    Singh, Niraj K; Kumar, Pramod; Suresh, K G; Nigam, A K; Coelho, A A; Gama, S

    2007-01-01

    The effect of external pressure on the magnetic properties and magnetocaloric effect of polycrystalline compounds DyCo 2 and Er(Co 1-x Si x ) 2 (x = 0,0.025 and 0.05) has been studied. The ordering temperatures of both the parent and the Si-substituted compounds are found to decrease with pressure. In all the compounds, the critical field for metamagnetic transition increases with pressure. It is seen that the magnetocaloric effect in the parent compounds is almost insensitive to pressure, while there is considerable enhancement in the case of Si-substituted compounds. Spin fluctuations arising from the magnetovolume effect play a crucial role in determining the pressure dependence of the magnetocaloric effect in these compounds. The variation of the magnetocaloric effect is explained on the basis of the Landau theory of magnetic phase transitions

  7. Formation of abrasion-resistant coatings of the AlSiFexMny intermetallic compound type on the AISI 304L alloy

    Directory of Open Access Journals (Sweden)

    Martínez-Perales, Laura G.

    2016-03-01

    Full Text Available The α-Al9FeMnSi and β-Al9FeMn2Si intermetallics formed by reactive sintering of Al, Si, Mn, Fe, Cr and Ni powders have been used in AISI 304L steels to enhance microhardness. Processing variables of the reactive sintering treatment were temperature (600, 650, 700, 750 and 800 °C, pressure (5, 10 y 20 MPa and holding time (3600, 5400 y 7200 seconds. Experimental results show that temperature is the most important variable affecting the substrate/coating formation, while pressure does not appear to have a significant effect. The results show the optimum conditions of the reactive sintering that favor the substrate/coating formation are 800 °C, 20 MPa and 7200 seconds. Under these conditions, the reaction zone between the substrate and coating is more compacted and well-adhered, with a microhardness of 1300 Vickers. The results of SEM and X-Ray diffraction confirmed the formation of α-Al9FeMnSi and β-Al9FeMn2Si intermetallics in the substrate/coating interface as well as the presence of Cr and Ni, indicating diffusion of these two elements from the substrate to the interface.Los intermetálicos α-Al9FeMnSi y β-Al9FeMn2Si formados por sinterización reactiva de polvos Al, Si, Mn, Fe, Cr, Ni se han utilizado en aceros AISI 304L para mejorar la microdureza. Las variables de procesamiento de sinterización reactiva fueron temperatura (600, 650, 700, 750, y 800 °C, presión (5, 10 y 20 MPa y el tiempo de retención (3600, 5400 7200 segundos. Los resultados experimentales muestran que la temperatura es la variable más importante que afecta a la formación del sustrato/recubrimiento, mientras que la presión no parece tener un efecto significativo una influencia significativa. Los resultados muestran las condiciones óptimas de la sinterización reactiva que favorecen la formación del sustrato/recubrimiento a 800 °C, 20 MPa y 7200 segundos. En estas condiciones, la zona de reacción entre el sustrato y el recubrimiento es más compacta y bien

  8. Calculations of the magnetic properties of R{sub 2}M{sub 14}B intermetallic compounds (R=rare earth, M=Fe, Co)

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Masaaki, E-mail: masaaki.ito@neel.cnrs.fr [CNRS, Institut Néel, 25 rue des Martyrs, BP166, 38042 Grenoble (France); University Grenoble Alpes, Institut Néel, 38042 Grenoble (France); Advanced Material Engineering Division, Toyota Motor Corporation, Susono 410-1193 (Japan); Yano, Masao [Advanced Material Engineering Division, Toyota Motor Corporation, Susono 410-1193 (Japan); Dempsey, Nora M. [CNRS, Institut Néel, 25 rue des Martyrs, BP166, 38042 Grenoble (France); University Grenoble Alpes, Institut Néel, 38042 Grenoble (France); Givord, Dominique [CNRS, Institut Néel, 25 rue des Martyrs, BP166, 38042 Grenoble (France); University Grenoble Alpes, Institut Néel, 38042 Grenoble (France); Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil)

    2016-02-15

    The hard magnetic properties of “R–M–B” (R=rare earth, M=mainly Fe) magnets derive from the specific intrinsic magnetic properties encountered in Fe-rich R{sub 2}M{sub 14}B compounds. Exchange interactions are dominated by the 3d elements, Fe and Co, and may be modeled at the macroscopic scale with good accuracy. Based on classical formulae that relate the anisotropy coefficients to the crystalline electric field parameters and exchange interactions, a simple numerical approach is used to derive the temperature dependence of anisotropy in various R{sub 2}Fe{sub 14}B compounds (R=Pr, Nd, Dy). Remarkably, a unique set of crystal field parameters give fair agreement with the experimentally measured properties of all compounds. This implies reciprocally that the properties of compounds that incorporate a mixture of different rare-earth elements may be predicted accurately. This is of special interest for material optimization that often involves the partial replacement of Nd with another R element and also the substitution of Co for Fe. - Highlights: • Anisotropy constants derived from CEF parameters of R{sub 2}M{sub 14}B compounds (M=Fe, Co). • Anisotropy constants of all R{sub 2}Fe{sub 14}B compounds using unique set of CEF parameters. • Moment non-collinearity in magnetization processes under B{sub app} along hard axis.

  9. Calculations of the magnetic properties of R2M14B intermetallic compounds (R=rare earth, M=Fe, Co)

    International Nuclear Information System (INIS)

    Ito, Masaaki; Yano, Masao; Dempsey, Nora M.; Givord, Dominique

    2016-01-01

    The hard magnetic properties of “R–M–B” (R=rare earth, M=mainly Fe) magnets derive from the specific intrinsic magnetic properties encountered in Fe-rich R 2 M 14 B compounds. Exchange interactions are dominated by the 3d elements, Fe and Co, and may be modeled at the macroscopic scale with good accuracy. Based on classical formulae that relate the anisotropy coefficients to the crystalline electric field parameters and exchange interactions, a simple numerical approach is used to derive the temperature dependence of anisotropy in various R 2 Fe 14 B compounds (R=Pr, Nd, Dy). Remarkably, a unique set of crystal field parameters give fair agreement with the experimentally measured properties of all compounds. This implies reciprocally that the properties of compounds that incorporate a mixture of different rare-earth elements may be predicted accurately. This is of special interest for material optimization that often involves the partial replacement of Nd with another R element and also the substitution of Co for Fe. - Highlights: • Anisotropy constants derived from CEF parameters of R 2 M 14 B compounds (M=Fe, Co). • Anisotropy constants of all R 2 Fe 14 B compounds using unique set of CEF parameters. • Moment non-collinearity in magnetization processes under B app along hard axis.

  10. Magnetic domain structure and domain-wall energy in UFe8Ni2Si2 and UFe6Ni4Si2 intermetallic compounds

    International Nuclear Information System (INIS)

    Wyslocki, J.J.; Suski, W.; Wochowski, K.

    1994-01-01

    Magnetic domain structures in the UFe 8 Ni 2 Si 2 and UFe 6 Ni 4 Si 2 compounds were studied using the powder pattern method. The domain structure observed is typical for uniaxial materials. The domain-wall energy density γ was determined from the average surface domain width D s observed on surfaces perpendicular to the easy axis as equal to 16 erg/cm 2 for UFe 8 Ni 2 Si 2 and 10 erg/cm 2 for UFe 6 Ni 4 Si 2 . Moreover, the critical diameter for single domain particle D c was calculated for the studied compounds

  11. Cerium intermetallics CeTX. Review III

    Energy Technology Data Exchange (ETDEWEB)

    Poettgen, Rainer; Janka, Oliver [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Chevalier, Bernard [Bordeaux Univ., Pessac (France). Inst. de Chimie de la Matiere Condensee de Bordeaux

    2016-05-01

    The structure-property relationships of CeTX intermetallics with structures other than the ZrNiAl and TiNiSi type are systematically reviewed. These CeTX phases form with electron-poor and electron-rich transition metals (T) and X = Mg, Zn, Cd, Hg, Al, Ga, In, Tl, Si, Ge, Sn, Pb, P, As, Sb, and Bi. The review focusses on the crystal chemistry, the chemical bonding peculiarities, and the magnetic and transport properties. Furthermore {sup 119}Sn Moessbauer spectroscopic data, high-pressure studies, hydrogenation reactions and the formation of solid solutions are reviewed. This paper is the third of a series of four reviews on equiatomic intermetallic cerium compound [Part I: R. Poettgen, B. Chevalier, Z. Naturforsch. 2015, 70b, 289; Part II: R. Poettgen, B. Chevalier, Z. Naturforsch. 2015, 70b, 695].

  12. Fatigue of superalloys and intermetallics

    International Nuclear Information System (INIS)

    Stoloff, N.S.

    1993-01-01

    The fatigue behavior of intermetallic alloys and their composites is contrasted to that of nickel-base superalloys. The roles of microstructure and slip planarity are emphasized. Obstacles to use of intermetallics under cyclic loading conditions are described and future research directions are suggested

  13. Recent advances in ordered intermetallics

    International Nuclear Information System (INIS)

    Liu, C.T.

    1995-01-01

    Ordered intermetallic alloys based on aluminides and silicides offer many advantages for structural use at elevated temperatures in hostile environments. Their attractive properties include excellent oxidation and corrosion resistance, light weight, and superior strength at elevated temperatures. The major concern for structural use of intermetallics was their low ductility and poor fracture resistance at ambient temperatures. For the past ten years, considerable effort has been devoted to the research and development of ordered intermetallic alloys, and good progress has been made on understanding intrinsic and extrinsic factors controlling brittle fracture in intermetallic alloys based on aluminides and silicides. Parallel efforts on alloy design have led to the development of a number of ductile and strong intermetallic alloys based on Ni(3)Al, NiAl, Fe(3)Al, FeAl, Ti(3)Al and TiAl systems for structural applications. (orig.)

  14. Electron spin resonance of Gd3+ in the intermetallic Gd1-xYxNi3Ga9 (0 ≤ x ≤ 0.90) compounds

    Science.gov (United States)

    Mendonça, E. C.; Silva, L. S.; Mercena, S. G.; Meneses, C. T.; Jesus, C. B. R.; Duque, J. G. S.; Souza, J. C.; Pagliuso, P. G.; Lora-Serrano, R.; Teixeira-Neto, A. A.

    2017-10-01

    In this work, experiments of X-ray diffraction, magnetic susceptibility, heat capacitance, and Electron Spin Resonance (ESR) carried out in the Gd1-xYxNi3Ga9 (0 ≤ x ≤ 0.90) compounds grown through a Ga self flux method are reported. The X-ray diffraction data indicate that these compounds crystallize in a trigonal crystal structure with a space group R32. This crystal structure is unaffected by Y-substitution, which produces a monotonic decrease of the lattice parameters. For the x = 0 compound, an antiferromagnetic phase transition is observed at TN = 19.2 K, which is continuously suppressed as a function of the Y-doping and extrapolates to zero at x ≈ 0.85. The ESR data, taken in the temperature range 15 ≤ T ≤ 300 K, show a single Dysonian Gd3+ line with nearly temperature independent g-values. The linewidth follows a Korringa-like behavior as a function of temperature for all samples. The Korringa rates (b = ΔH /ΔT ) are Y-concentration-dependent indicating a "bottleneck" regime. For the most diluted sample (x = 0.90), when it is believed that the "bottleneck" effect is minimized, we have calculated the q-dependent effective exchange interactions between Gd3+ local moments and the c-e of 〈Jf-ce 2(q ) 〉 1 /2 = 18(2) meV and Jf -c e(q =0 ) = 90(10) meV.

  15. Phase transformations in intermetallic phases in zirconium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Filippov, V. P., E-mail: vpfilippov@mephi.ru [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) (Russian Federation); Kirichenko, V. G. [Kharkiv National Karazin University (Ukraine); Salomasov, V. A. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) (Russian Federation); Khasanov, A. M. [University of North Carolina – Asheville, Chemistry Department (United States)

    2017-11-15

    Phase change was analyzed in intermetallic compounds of zirconium alloys (Zr – 1.03 at.% Fe; Zr – 0.51 at.% Fe; Zr – 0.51 at.% Fe – M(M = Nb, Sn). Mössbauer spectroscopy on {sup 57}Fe nuclei in backscattering geometry with the registration of the internal conversion electrons and XRD were used. Four types of iron bearing intermetallic compounds with Nb were detected. A relationship was found between the growth process of intermetallic inclusions and segregation of these phases. The growth kinetics of inclusions possibly is not controlled by bulk diffusion, and a lower value of the iron atom’s activation energy of migration can be attributed to the existence of enhanced diffusion paths and interface boundaries.

  16. Calculation of the magnetic properties of pseudo-ternary R2M14B intermetallic compounds (R = rare earth, M = Fe, Co

    Directory of Open Access Journals (Sweden)

    Gabriel Gómez Eslava

    2016-06-01

    Full Text Available The extrinsic properties of NdFeB-based magnets can be tuned through partial substitution of Nd by another rare-earth element and Fe by Co, as such substitution leads to a modification in the intrinsic properties of the main phase. Optimisation of a magnet's composition through trial and error is time consuming and not straightforward, since the interplay existing between magnetocrystalline anisotropy and coercivity is not completely understood. In this paper we present a model to calculate the intrinsic magnetic properties of pseudo-ternary Nd2Fe14B-based compounds. As concrete examples, which are relevant for the optimisation of NdFeB-based high-performance magnets used in (hybrid electric vehicles and wind turbines, we consider partial substitution of Nd by Dy or Tb, and Fe by Co.

  17. Structure and magnetism of new rare-earth-free intermetallic compounds: Fe3+xCo3−xTi2 (0 ≤ x ≤ 3

    Directory of Open Access Journals (Sweden)

    Balamurugan Balasubramanian

    2016-11-01

    Full Text Available We report the fabrication of a set of new rare-earth-free magnetic compounds, which form the Fe3Co3Ti2-type hexagonal structure with P-6m2 symmetry. Neutron powder diffraction shows a significant Fe/Co anti-site mixing in the Fe3Co3Ti2 structure, which has a strong effect on the magnetocrystalline anisotropy as revealed by first-principle calculations. Increasing substitution of Fe atoms for Co in the Fe3Co3Ti2 lattice leads to the formation of Fe4Co2Ti2, Fe5CoTi, and Fe6Ti2 with significantly improved permanent-magnet properties. A high magnetic anisotropy (13.0 Mergs/cm3 and saturation magnetic polarization (11.4 kG are achieved at 10 K by altering the atomic arrangements and decreasing Fe/Co occupancy disorder.

  18. Ab initio study of the compound-energy modeling of multisublattice structures: The (hP6) Ni{sub 2}In-type intermetallics of the Ni–In–Sn system

    Energy Technology Data Exchange (ETDEWEB)

    Ramos de Debiaggi, S., E-mail: susana.ramos@fain.uncoma.edu.ar [Facultad de Ingeniería, Universidad Nacional del Comahue, Buenos Aires 1400, 8300 Neuquén (Argentina); Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas – CONICET-UNCo (Argentina); González Lemus, N.V. [Facultad de Ingeniería, Universidad Nacional del Comahue, Buenos Aires 1400, 8300 Neuquén (Argentina); Deluque Toro, C. [Grupo de Nuevos Materiales, Universidad de la Guajira, Riohacha (Colombia); Fernández Guillermet, A. [CONICET - Instituto Balseiro, Centro Atómico Bariloche, Avda. Bustillo 9500, 8400 Bariloche (Argentina)

    2015-01-15

    Highlights: • A DFT study of the compounds involved in CALPHAD modeling of the Ni–In–Sn (hP6) phase. • Several three-sublattice compounds of Ni, In, Sn and vacancies are studied ab initio. • Structural, cohesive and thermodynamic properties and the electronic DOS are reported. • Trends in calculated properties are correlated with changes in electronic structure. • A picture of the chemical bonding trends for these s-p/d type compounds is discussed. - Abstract: The thermodynamic modeling of non-stoichiometric, multisublattice intermetallic phases using the Compound-Energy Formalism (CEF) involves the determination of parameters representing the Gibbs energy (G{sub m}) of binary compounds, the so-called “end-member compounds” (EMCs), which are often metastable or hypothetical. In current CALPHAD (i.e., “Calculation of Phase Diagrams”) work, these quantities are treated as free parameters to be determined by searching for the best fit to the available information in the optimization procedure. The general purpose of this paper is to propose a theoretical approach to the study of the EMCs which makes use of density-functional-theory (DFT) ab initio calculations. The present method is applied to the EMCs involved in the CEF modeling of the non-stoichiometric (hP6) Ni{sub 2}In-structure type phase of the Ni–In and Ni–In–Sn systems using the three-sublattice models (Ni){sub 1}(Ni,Va){sub 1}(In,Ni){sub 1} and (Ni,Va){sub 1}(Ni,Va){sub 1}(In,Ni,Sn){sub 1}, respectively. By means of systematic ab initio projected augmented waves (PAW) calculations using the VASP code we study the EMCs involved in the CEF formulations of the G{sub m} for this phase in the binary and the ternary systems. Specifically, we study the twelve EMCs corresponding to the following sublattice occupations: (Ni){sub 1}(Ni){sub 1}(In){sub 1}, which is usually described as Ni:Ni:In (i.e., a compound with formula “Ni{sub 2}In”), Ni:Ni:Ni (i.e., “Ni{sub 3}”), Ni:Ni:Sn (

  19. Ab initio study of the compound-energy modeling of multisublattice structures: The (hP6) Ni2In-type intermetallics of the Ni–In–Sn system

    International Nuclear Information System (INIS)

    Ramos de Debiaggi, S.; González Lemus, N.V.; Deluque Toro, C.; Fernández Guillermet, A.

    2015-01-01

    Highlights: • A DFT study of the compounds involved in CALPHAD modeling of the Ni–In–Sn (hP6) phase. • Several three-sublattice compounds of Ni, In, Sn and vacancies are studied ab initio. • Structural, cohesive and thermodynamic properties and the electronic DOS are reported. • Trends in calculated properties are correlated with changes in electronic structure. • A picture of the chemical bonding trends for these s-p/d type compounds is discussed. - Abstract: The thermodynamic modeling of non-stoichiometric, multisublattice intermetallic phases using the Compound-Energy Formalism (CEF) involves the determination of parameters representing the Gibbs energy (G m ) of binary compounds, the so-called “end-member compounds” (EMCs), which are often metastable or hypothetical. In current CALPHAD (i.e., “Calculation of Phase Diagrams”) work, these quantities are treated as free parameters to be determined by searching for the best fit to the available information in the optimization procedure. The general purpose of this paper is to propose a theoretical approach to the study of the EMCs which makes use of density-functional-theory (DFT) ab initio calculations. The present method is applied to the EMCs involved in the CEF modeling of the non-stoichiometric (hP6) Ni 2 In-structure type phase of the Ni–In and Ni–In–Sn systems using the three-sublattice models (Ni) 1 (Ni,Va) 1 (In,Ni) 1 and (Ni,Va) 1 (Ni,Va) 1 (In,Ni,Sn) 1 , respectively. By means of systematic ab initio projected augmented waves (PAW) calculations using the VASP code we study the EMCs involved in the CEF formulations of the G m for this phase in the binary and the ternary systems. Specifically, we study the twelve EMCs corresponding to the following sublattice occupations: (Ni) 1 (Ni) 1 (In) 1 , which is usually described as Ni:Ni:In (i.e., a compound with formula “Ni 2 In”), Ni:Ni:Ni (i.e., “Ni 3 ”), Ni:Ni:Sn (“Ni 2 Sn”), Ni:Va:In (i.e., “NiIn”), Ni:Va:Ni (i

  20. Synthesis and characterization of Ge–Cr-based intermetallic compounds: GeCr3, GeCCr3, and GeNCr3

    International Nuclear Information System (INIS)

    Lin, S.; Tong, P.; Wang, B.S.; Huang, Y.N.; Song, W.H.; Sun, Y.P.

    2014-01-01

    Highlights: • Polycrystalline samples of GeCr 3 , GeCCr 3 , and GeNCr 3 are synthesized by using solid state reaction method. • A good quality of our samples is verified by the Rietveld refinement and electrical transport measurement. • We present a comprehensive understanding of physical properties of GeCr 3 , GeCCr 3 , and GeNCr 3 . -- Abstract: We report the synthesis of GeCr 3 , GeCCr 3 , and GeNCr 3 polycrystalline compounds, and present a systematic study of this series by the measurements of X-ray diffraction (XRD), magnetism, electrical/thermal transport, specific heat, and Hall coefficient. Good quality of our samples is verified by quite small value of residual resistivity and considerably large residual resistivity ratio. Based on the Rietveld refinement of XRD data, the crystallographic parameters are obtained, and, correspondingly, the sketches of crystal structure are plotted for all the samples. The ground states of GeCr 3 , GeCCr 3 , and GeNCr 3 are paramagnetic/antiferromagnetic metal, and even a Fermi-liquid behavior is observed in electrical transport at low temperatures. Furthermore, the analysis of the thermal conductivity data suggests the electron thermal conductivity plays a major role in total thermal conductivity for GeCr 3 at low temperatures, while the phonon thermal conductivity is dominant for GeCCr 3 and GeNCr 3 at high temperatures. The negative value of Seebeck coefficient and Hall coefficient indicate that the charge carriers are electron-type for GeCr 3 , GeCCr 3 , and GeNCr 3

  1. Nanoscale grain growth behaviour of CoAl intermetallic synthesized ...

    Indian Academy of Sciences (India)

    Grain growth behaviour of the nanocrystalline CoAl intermetallic compound synthesized by mechanical alloying has been studied by isothermal annealing at different temperatures and durations. X-ray diffraction method was employed to investigate structural evolutions during mechanical alloying and annealing processes.

  2. Nanoscale grain growth behaviour of CoAl intermetallic synthesized ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Grain growth behaviour of the nanocrystalline CoAl intermetallic compound synthesized by mechanical alloying has been studied by isothermal annealing at different temperatures and durations. X-ray diffraction method was employed to investigate structural evolutions during mechanical alloying and anneal-.

  3. Solid state diffusion in zirconium-copper and zirconium-nickel systems. Study of the intermetallic compounds formed; Diffusion a l'etat solide dans les systemes zirconium-cuivre et zirconium-nickel. Etude des composes intermetalliques formes

    Energy Technology Data Exchange (ETDEWEB)

    Meny, L; Champigny, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    Solid state diffusion has been provoked in pure Zr-Cu and Zr-Ni metal couples. The tests were carried out in the following experimental conditions : the samples were maintained at a mechanical pressure of 30 kg/cm{sup 2}; annealing was carried out in a secondary vacuum during 100 and 500 hours, at temperatures of between 650 C and 900 C. In all cases, a diffusion zone made up of several parallel layers was formed. The various intermetallic compounds have been studied by metallography (optical microscopy and micro-hardness) X-ray diffraction and micro-analysis with an electronic probe. In the Zr-Cu system, six compounds have been determined, Zr{sub 2}Cu, ZrCu, Zr{sub 2}Cu{sub 3}, ZrCu{sub 4} and ZrCu{sub 5}. These results confirm a recent publication mentioning for the first time the existence of ZrCu{sub 5} and demonstrating the formulae ZrCu{sub 3} and ZrCu{sub 4}. In a similar manner, we have found six compounds, stable at room temperature, in the Zr-Ni system: these are Zr{sub 2}Ni, ZrNi, Zr{sub 7}Ni{sub 10}, ZrNi{sub 3}, ZrNi{sub 4} and ZrNi{sub 5}; the results of American workers are confirmed for four of these compounds; however we identify as ZrNi{sub 3} and ZrNi{sub 4} the compounds for which they proposed the formulae Zr{sub 2}Ni{sub 5} and Zr{sub 2}Ni{sub 7}. A comparison of these results suggests that the two systems ZrCu and ZrNi have the same type of equilibrium diagrams. (authors) [French] Des diffusions a l'etat solide ont ete effectuees entre les couples de metaux purs Zr-Cu et Zr-Ni. Les essais ont eu lieu dans les conditions experimentales suivantes: les echantillons ont ete maintenus par une pression mecanique de 3O kg/cm{sup 2}; les recuits ont ete effectues sous vide secondaire pendant des temps de 100 et 500 heures, a des temperatures comprises entre 650 C et 900 C. Dans tous les cas, il y a eu formation d'une zone de diffusion formee de plusieurs couches paralleles. Les differents composes intermetalliques ont ete etudies par metallographie

  4. High temperature oxidation behavior of TiAl-based intermetallics

    International Nuclear Information System (INIS)

    Stroosnijder, M.F.; Sunderkoetter, J.D.; Haanappel, V.A.C.

    1996-01-01

    TiAl-based intermetallic compounds have attracted considerable interest as structural materials for high-temperature applications due to their low density and substantial mechanical strength at high temperatures. However, one major drawback hindering industrial application arises from the insufficient oxidation resistance at temperatures beyond 700 C. In the present contribution some general aspects of high temperature oxidation of TiAl-based intermetallics will be presented. This will be followed by a discussion of the influence of alloying elements, in particular niobium, and of the effect of nitrogen in the oxidizing environment on the high temperature oxidation behavior of such materials

  5. Pressure induced helimagnetism in Fe-based (Y.sub.2./sub.Fe.sub.17./sub., Lu.sub.2./sub.Fe.sub.17./sub.) intermetallic compounds

    Czech Academy of Sciences Publication Activity Database

    Kamarád, Jiří; Prokhnenko, Olexandr; Prokeš, K.; Arnold, Zdeněk; Andreev, Alexander V.

    2007-01-01

    Roč. 310, - (2007), s. 1801-1803 ISSN 0304-8853 R&D Projects: GA ČR GA202/06/0178 Institutional research plan: CEZ:AV0Z10100521 Keywords : magnetic structure * Fe-base intermetallics * Y 2 Fe 17 * pressure effects Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.704, year: 2007

  6. Solute-solute interactions in intermetallic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Debashis; Murray, Ryan; Collins, Gary S., E-mail: collins@wsu.edu [Washington State University, Department of Physics and Astronomy (United States); Zacate, Matthew O. [Northern Kentucky University, Department of Physics and Geology (United States)

    2017-11-15

    Experiments were carried out on highly ordered GdAl{sub 2} samples containing extremely dilute mole fractions of{sup 111}In/Cd probe-atom solutes (about 10{sup −11}), intrinsic antisite atoms Al{sub Gd} having mole fractions of order 0-10{sup −2}, and doped with Ag solutes at mole fractions of order 10{sup −2}. Three types of defect interactions were investigated. (1) Quadrupole interactions caused by Ag-solute atoms neighboring{sup 111}In/Cd solute probe atoms were detected using the method of perturbed angular correlation of gamma rays (PAC). Three complexes of pairs of In-probes and Ag-solutes occupying neighboring positions on Gd- and Al-sublattices were identified by comparing site fractions in Gd-poor and Gd-rich GdAl{sub 2}(Ag) samples and from the symmetry of the quadrupole interactions. Interaction enthalpies between solute-atom pairs were determined from temperature dependences of observed site fractions. Repulsive interactions were observed for close-neighbor complexes In{sub Gd}+Ag{sub Gd} and In{sub Gd}+Ag{sub Al} pairs, whereas a slightly attractive interaction was observed for In{sub Al}+Ag{sub Al}. Interaction enthalpies were all small, in the range ±0.15 eV. (2) Quadrupole interactions caused by intrinsic antisite atoms Al{sub Gd} neighboring In{sub Gd} probes were also detected and site fractions measured as a function of temperature, as in previous work on samples not doped with Ag-solutes [Temperature- and composition-driven changes in site occupation of solutes in Gd{sub 1+3x}Al{sub 2−3x}, Zacate and Collins (Phys. Rev. B69, 174202 (1))]. However, the effective binding enthalpy between In{sub Gd} probe and Al{sub Gd} antisite was found to change sign from -0.12 eV (attractive interaction) in undoped samples to + 0.24 eV (repulsive) in Ag-doped samples. This may be attributed to an attractive interaction between Al{sub Gd} antisite atoms and Ag-dopants that competes with the attractive interaction between In{sub Gd} and Al{sub Gd} defects observed in undoped samples. Alternatively, it may be attributed to competing flows of Ag and Al atoms that, in effect, change the numbers of available sites on the two sublattices (termed degeneracies). (3) The site preference of In-probes to occupy Gd- and Al-sublattices, without nearby defects, in Ag-doped samples was measured. Effective transfer enthalpies between the two sublattices were found in doped samples that were much smaller than the value 0.343(3) eV found in the previous study in undoped GdAl{sub 2}. Two approaches to understanding why the measured enthalpies in doped and undoped samples differ are discussed.

  7. Low temperature and surfactant-free synthesis of Pd2Sn intermetallic nanoparticles for ethanol electro-oxidation

    International Nuclear Information System (INIS)

    Wang, Congmin; Wu, Yurong; Wang, Xin; Zou, Liangliang; Zou, Zhiqing; Yang, Hui

    2016-01-01

    Many intermetallic compounds have a predictable structure, interesting electronic effects, and useful catalytic properties. In this work, a low temperature, surfactant-free, and one-pot method is used to synthesize carbon supported Pd 2 Sn intermetallic nanoparticles. The superlattice of the product was then characterized using X-ray diffraction and transmission electron microscopy. These synthesized intermetallic nanoparticles were found to exhibit a higher activity and stability for electrocatalysis of the ethanol oxidation reaction in an alkaline media than has been achieved using a traditional Pd/C catalyst, which could be attributed to the structural and compositional stabilities of ordered Pd 2 Sn intermetallic nanoparticles.

  8. Multi-component intermetallic electrodes for lithium batteries

    Science.gov (United States)

    Thackeray, Michael M; Trahey, Lynn; Vaughey, John T

    2015-03-10

    Multi-component intermetallic negative electrodes prepared by electrochemical deposition for non-aqueous lithium cells and batteries are disclosed. More specifically, the invention relates to composite intermetallic electrodes comprising two or more compounds containing metallic or metaloid elements, at least one element of which can react with lithium to form binary, ternary, quaternary or higher order compounds, these compounds being in combination with one or more other metals that are essentially inactive toward lithium and act predominantly, but not necessarily exclusively, to the electronic conductivity of, and as current collection agent for, the electrode. The invention relates more specifically to negative electrode materials that provide an operating potential between 0.05 and 2.0 V vs. metallic lithium.

  9. Thermodynamics and kinetics of the formation of rare earth intermetallics

    International Nuclear Information System (INIS)

    Deodhar, S.S.

    1975-01-01

    Heats of reaction of rare earth intermetallics with iron, cobalt and nickel were determined using Differential Thermal Analysis technique. The intermetallic compounds studied were of MgCu 2 type Laves phases and the rare earth elements studied were praseodymium, gadolinium, dyprosium and erbium. The reactions were exothermic and the heats of reaction were generally high. They varied from the low of -2.5 kcal/g mole for Fe 2 Gd to the high of -35.3 kcal/g mole for Ni 2 Er. The magnitudes of heats of reaction were always greater for the intermetallics of heavy rare earth elements. The rare earth intermetallics studied were either ferromagnetic or antiferromagnetic. The variations in the magnetic moments and the heats of reaction with respect to the atomic number of the rare earth elements followed certain trends. The similarities were observed in the trends of two properties. Electronic configuration for the MgCu 2 type rare earth intermetallics is proposed using Engel--Brewer correlation for metallic structures and the structural features of the Laves phase compounds. Kinetics of the reactions between the rare earth elements and iron, cobalt, and nickel was studied. The rate of reaction was diffusion controlled in each case. The Valensi--Carter equation for the diffusion mechanism satisfactorily described the kinetic behavior. The magnitudes of activation energies and frequency factors were determined. The reactions can be characterized by their reaction temperatures since they always begin at definite temperatures. It was observed that the reaction began at a higher temperature if the activation energy for the reaction was high

  10. Cerium intermetallics with TiNiSi-type structure

    Energy Technology Data Exchange (ETDEWEB)

    Janka, Oliver; Niehaus, Oliver; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Chevalier, Bernard [Bordeaux Univ. CNRS (UPR 9048), Pessac (France). Inst. de Chimie de la Matiere Condensee de Bordeaux (ICMCB)

    2016-08-01

    Intermetallic compounds with the equiatomic composition CeTX that crystallize with the orthorhombic TiNiSi-type structure can be synthesized with electron-rich transition metals (T) and X = Zn, Al, Ga, Si, Ge, Sn, As, Sb, and Bi. The present review focusses on the crystal chemistry and chemical bonding of these CeTX phases and on their physical properties, {sup 119}Sn and {sup 121}Sb Moessbauer spectra, high-pressure effects, hydrogenation reactions and the formation of solid solutions in order to elucidate structure-property relationships. This paper is the final one of a series of four reviews on equiatomic intermetallic cerium compounds [Part I: Z. Naturforsch. 2015, 70b, 289; Part II: Z. Naturforsch. 2015, 70b, 695; Part III: Z. Naturforsch. 2016, 71b, 165].

  11. Electronic structure and properties of rare earth and actinide intermetallics

    International Nuclear Information System (INIS)

    Kirchmayr, H.R.

    1984-01-01

    There are 188 contributions, experimental and theoretical, a few on rare earth and actinide elements but mostly on rare earth and actinide intermetallic compounds and alloys. The properties dealt with include 1) crystal structure, 2) magnetic properties and magnetic structure, 3) magnetic phase transformations and valence fluctuations, 4) electrical properties and superconductivity and their temperature, pressure and magnetic field dependence. A few papers deal with crystal growth and novel measuring methods. (G.Q.)

  12. Study of hyperfine interactions in intermetallic compounds Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In; Estudo de interacoes hiperfinas em compostos intermetalicos Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In e Ho(Ni,Pd)In

    Energy Technology Data Exchange (ETDEWEB)

    Lapolli, Andre Luis

    2006-07-01

    Systematic behavior of magnetic hyperfine field (B{sub hf}) in the intermetallic compounds Gd(Ni,Pd,Cu)In Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In was studied by Perturbed Gamma-Gamma Angular Correlation spectroscopy. The measurements of B{sub hf} were carried out at the rare earth atom and in sites using the nuclear probes {sup 140}Ce and {sup 11}'1Cd respectively. The variation of hyperfine field with temperature, in most cases, follows the Brillouin function predicted from the molecular field theory. The hyperfine field values at rare earth atom sites obtained from {sup 140}Ce probe as well as at in sites obtained from {sup 111}Cd probe for each series of compounds were extrapolated to zero Kelvin B{sub hf}(T=0) from these curves. These values were compared with the values of the literature for other compounds containing the same rare earth element and all of them show a linear relationship with the ordering temperature. This indicates that the main contribution to B{sub hf} comes from the conduction electron polarization (CEP) through Fermi contact interaction and the principal mechanism of magnetic interaction in these compounds can be described by the RKKY type interaction. The values of B{sub hf}(T=0) for each family of intermetallic compounds RNiIn and RPdIn when plotted as a function of 4f spin projection of rare earth element also shows a linear relationship. Exceptions are the results for the compounds RNiIn obtained with {sup 111}Cd probe where a small deviation from linearity is observed. The results of the measurements carried out with the {sup 111}Cd probe were also analyzed to obtain the hyperfine parameters of the quadrupole interaction as a function of temperature for RPdln and GdNiIn compounds. The results show that for the compound GdPdIn there might be some Gd-In disorder at high temperature. (author)

  13. Study of hyperfine interactions in intermetallic compounds Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In; Estudo de interacoes hiperfinas em compostos intermetalicos Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In e Ho(Ni,Pd)In

    Energy Technology Data Exchange (ETDEWEB)

    Lapolli, Andre Luis

    2006-07-01

    Systematic behavior of magnetic hyperfine field (B{sub hf}) in the intermetallic compounds Gd(Ni,Pd,Cu)In Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In was studied by Perturbed Gamma-Gamma Angular Correlation spectroscopy. The measurements of B{sub hf} were carried out at the rare earth atom and in sites using the nuclear probes {sup 140}Ce and {sup 11}'1Cd respectively. The variation of hyperfine field with temperature, in most cases, follows the Brillouin function predicted from the molecular field theory. The hyperfine field values at rare earth atom sites obtained from {sup 140}Ce probe as well as at in sites obtained from {sup 111}Cd probe for each series of compounds were extrapolated to zero Kelvin B{sub hf}(T=0) from these curves. These values were compared with the values of the literature for other compounds containing the same rare earth element and all of them show a linear relationship with the ordering temperature. This indicates that the main contribution to B{sub hf} comes from the conduction electron polarization (CEP) through Fermi contact interaction and the principal mechanism of magnetic interaction in these compounds can be described by the RKKY type interaction. The values of B{sub hf}(T=0) for each family of intermetallic compounds RNiIn and RPdIn when plotted as a function of 4f spin projection of rare earth element also shows a linear relationship. Exceptions are the results for the compounds RNiIn obtained with {sup 111}Cd probe where a small deviation from linearity is observed. The results of the measurements carried out with the {sup 111}Cd probe were also analyzed to obtain the hyperfine parameters of the quadrupole interaction as a function of temperature for RPdln and GdNiIn compounds. The results show that for the compound GdPdIn there might be some Gd-In disorder at high temperature. (author)

  14. Low-Temperature Synthesis Routes to Intermetallic Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Schaak, Raymond E

    2008-01-08

    Over the past few years, our group has gained expertise at developing low-temperature solution-based synthetic pathways to complex nanoscale solids, with particular emphasis on nanocrystalline intermetallic compounds. Our synthetic capabilities are providing tools to reproducibly generate intermetallic nanostructures with simultaneous control over crystal structure, composition, and morphology. This DOE-funded project aims to expand these capabilities to intermetallic superconductors. This could represent an important addition to the tools that are available for the synthesis and processing of intermetallic superconductors, which traditionally utilize high-temperature, high-pressure, thin film, or gas-phase vacuum deposition methods. Our current knowledge of intermetallic superconductors suggests that significant enhancements could result from the inherent benefits of low-temperature solution synthesis, e.g. metastable phase formation, control over nanoscale morphology to facilitate size-dependent property studies, robust and inexpensive processability, low-temperature annealing and consolidation, and impurity incorporation (for doping, stoichiometry control, flux pinning, and improving the critical fields). Our focus is on understanding the superconducting properties as a function of synthetic route, crystal structure, crystallite size, and morphology, and developing the synthetic tools necessary to accomplish this. This research program can currently be divided into two classes of superconducting materials: intermetallics (transition metal/post transition metal) and metal carbides/borides. Both involve the development and exploitation of low-temperature synthesis routes followed by detailed characterization of structures and properties, with the goal of understanding how the synthetic pathways influence key superconducting properties of selected target materials. Because of the low-temperature methods used to synthesize them and the nanocrystalline morphologies

  15. Intermetallic-Based High-Temperature Materials

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.

    1999-04-25

    The intermetallic-based alloys for high-temperature applications are introduced. General characteristics of intermetallics are followed by identification of nickel and iron aluminides as the most practical alloys for commercial applications. An overview of the alloy compositions, melting processes, and mechanical properties for nickel and iron aluminizes are presented. The current applications and commercial producers of nickel and iron aluminizes are given. A brief description of the future prospects of intermetallic-based alloys is also given.

  16. Rare earth-ruthenium-magnesium intermetallics

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Sebastian; Kersting, Marcel; Heletta, Lukas; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2017-07-01

    Eight new intermetallic rare earth-ruthenium-magnesium compounds have been synthesized from the elements in sealed niobium ampoules using different annealing sequences in muffle furnaces. The compounds have been characterized by powder and single crystal X-ray diffraction. Sm{sub 9.2}Ru{sub 6}Mg{sub 17.8} (a=939.6(2), c=1779(1) pm), Gd{sub 11}Ru{sub 6}Mg{sub 16} (a=951.9(2), c=1756.8(8) pm), and Tb{sub 10.5}Ru{sub 6}Mg{sub 16.5} (a=942.5(1), c=1758.3(4) pm) crystallize with the tetragonal Nd{sub 9.34}Ru{sub 6}Mg{sub 17.66} type structure, space group I4/mmm. This structure exhibits a complex condensation pattern of square-prisms and square-antiprisms around the magnesium and ruthenium atoms, respectively. Y{sub 2}RuMg{sub 2} (a=344.0(1), c=2019(1) pm) and Tb{sub 2}RuMg{sub 2} (a=341.43(6), c=2054.2(7) pm) adopt the Er{sub 2}RuMg{sub 2} structure and Tm{sub 3}Ru{sub 2}Mg (a=337.72(9), c=1129.8(4) pm) is isotypic with Sc{sub 3}Ru{sub 2}Mg. Tm{sub 3}Ru{sub 2}Mg{sub 2} (a=337.35(9), c=2671(1) pm) and Lu{sub 3}Ru{sub 2}Mg{sub 2} (a=335.83(5), c=2652.2(5) pm) are the first ternary ordered variants of the Ti{sub 3}Cu{sub 4} type, space group I4/mmm. These five compounds belong to a large family of intermetallics which are completely ordered superstructures of the bcc subcell. The group-subgroup scheme for Lu{sub 3}Ru{sub 2}Mg{sub 2} is presented. The common structural motif of all three structure types are ruthenium-centered rare earth cubes reminicent of the CsCl type. Magnetic susceptibility measurements of Y{sub 2}RuMg{sub 2} and Lu{sub 3}Ru{sub 2}Mg{sub 2} samples revealed Pauli paramagnetism of the conduction electrons.

  17. Method of production multifilamentary intermetallic superconductors

    International Nuclear Information System (INIS)

    Marancik, W.G.; Young, M.S.

    1980-01-01

    A method of making A-15 type intermetallic superconductors is disclosed which features elimination of numerous annealing steps. Nb or V filaments are embedded in Cu matrices; annular layers of Sn or Ga, respectively, separated from each other by Cu layers, provide the other component of the intermetallic superconductors Nb3Sn and V3Ga

  18. Intermetallic alloys: Deformation, mechanical and fracture behaviour

    International Nuclear Information System (INIS)

    Dogan, B.

    1988-01-01

    The state of the art in intermetallic alloys development with particular emphasis on deformation, mechanical and fracture behaviour is documented. This review paper is prepared to lay the ground stones for a future work on mechanical property characterization and fracture behaviour of intermetallic alloys at GKSS. (orig.)

  19. Intermetallics structures, properties, and statistics

    CERN Document Server

    Steurer, Walter

    2016-01-01

    The focus of this book is clearly on the statistics, topology, and geometry of crystal structures and crystal structure types. This allows one to uncover important structural relationships and to illustrate the relative simplicity of most of the general structural building principles. It also allows one to show that a large variety of actual structures can be related to a rather small number of aristotypes. It is important that this book is readable and beneficial in the one way or another for everyone interested in intermetallic phases, from graduate students to experts in solid-state chemistry/physics/materials science. For that purpose it avoids using an enigmatic abstract terminology for the classification of structures. The focus on the statistical analysis of structures and structure types should be seen as an attempt to draw the background of the big picture of intermetallics, and to point to the white spots in it, which could be worthwhile exploring. This book was not planned as a textbook; rather, it...

  20. Design and fabrication of a mechanical alloying system for preparing intermetallic, nanocrystalline, amorphous and quasicrystalline compounds; Diseno y fabricacion de un sistema de aleado mecanico para preparar compuestos intermetalicos, nanocristalinos, amorfos y cuasicristalinos

    Energy Technology Data Exchange (ETDEWEB)

    Bonifacio M, J.; Iturbe G, J.L.; Castaneda J, G. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2002-07-01

    In this work a grinding system was designed and fabricated which allowed to improve the operation conditions in time, frequency, temperature and selection of the grinding media and that allow the contamination decrease of the compounds. By means of this method of mechanical alloying new metallic compounds can be produced, starting from elemental powders, with fine and controlled microstructures. These compounds prepared by this method are going to be used as materials for the hydrogen storage. (Author)

  1. Irregular Homogeneity Domains in Ternary Intermetallic Systems

    Directory of Open Access Journals (Sweden)

    Jean-Marc Joubert

    2015-12-01

    Full Text Available Ternary intermetallic A–B–C systems sometimes have unexpected behaviors. The present paper examines situations in which there is a tendency to simultaneously form the compounds ABx, ACx and BCx with the same crystal structure. This causes irregular shapes of the phase homogeneity domains and, from a structural point of view, a complete reversal of site occupancies for the B atom when crossing the homogeneity domain. This work reviews previous studies done in the systems Fe–Nb–Zr, Hf–Mo–Re, Hf–Re–W, Mo–Re–Zr, Re–W–Zr, Cr–Mn–Si, Cr–Mo–Re, and Mo–Ni–Re, and involving the topologically close-packed Laves, χ and σ phases. These systems have been studied using ternary isothermal section determination, DFT calculations, site occupancy measurement using joint X-ray, and neutron diffraction Rietveld refinement. Conclusions are drawn concerning this phenomenon. The paper also reports new experimental or calculated data on Co–Cr–Re and Fe–Nb–Zr systems.

  2. Intermetallics: past, present and future

    Directory of Open Access Journals (Sweden)

    Morris, D. G.

    2005-12-01

    Full Text Available Intermetallics have seen extensive world-wide attention over the past decades. For the most part these studies have examined multi-phase aluminide based alloys, because of their high stiffness, combined with reasonable strength and ductility, good structural stability and oxidation resistance, and attempted to improve current Ni-base superalloys, Ti-base alloys, or Fe-base stainless steels for structural aerospace applications. The current status of development and application of such materials is briefly reviewed. Future developments are taking intermetallics from the realm of "improved high-temperature but low-ductility metallic alloys" into the realm of "improved aggressive-environment, high-toughness ceramic-like alloys". Such evolution will be outlined.

    Durante los últimos décadas ha habido un desarrollo de los intermetálicos, sobre todo por aplicaciones estructurales a alta temperatura en aplicaciones aeroespaciales, donde, por su rigidez alta, en combinación con una resistencia mecánica y ductilidad razonable, su buena estabilidad estructural y resistencia a la oxidación, han sido vistos como versiones avanzadas y mejoradas de las aleaciones metálicas como, por ejemplo, las superaleaciones a base de nitrógeno y las aleaciones de titanio. Se discute el desarrollo importante durante las últimas décadas, y también los nuevos desarrollos probables durante los próximos años. Se podrían ver los intermetálicos como versiones mejoradas de los cerámicos.

  3. Negative thermal expansion induced by intermetallic charge transfer.

    Science.gov (United States)

    Azuma, Masaki; Oka, Kengo; Nabetani, Koichiro

    2015-06-01

    Suppression of thermal expansion is of great importance for industry. Negative thermal expansion (NTE) materials which shrink on heating and expand on cooling are therefore attracting keen attention. Here we provide a brief overview of NTE induced by intermetallic charge transfer in A-site ordered double perovskites SaCu 3 Fe 4 O 12 and LaCu 3 Fe 4- x Mn x O 12 , as well as in Bi or Ni substituted BiNiO 3 . The last compound shows a colossal dilatometric linear thermal expansion coefficient exceeding -70 × 10 -6 K -1 near room temperature, in the temperature range which can be controlled by substitution.

  4. Plasticity enhancement mechanisms in refractory metals and intermetallics

    International Nuclear Information System (INIS)

    Gibala, R.; Chang, H.; Czarnik, C.M.; Edwards, K.M.; Misra, A.

    1993-01-01

    Plasticity enhancement associated with surface films and precipitates or dispersoids in bcc refractory metals is operative in ordered intermetallic compounds. Some results are given for NiAl and MoSi 2 -based materials. The monotonic and cyclic plasticity of NiAl at room temperature can be enhanced by surface films. Ductile second phases also enhance the plasticity of NiAl. MoSi 2 exhibits similar effects of surface films and dispersoids, but primarily at elevated temperatures. The plasticity enhancement is associated with enhanced dislocation generation from constrained deformation at the film-substrate or precipitate/dispersoid-matrix interface of the composite systems

  5. The chemical phenol extraction of intermetallic particles from casting AlSi5Cu1Mg alloy.

    Science.gov (United States)

    Mrówka-Nowotnik, G; Sieniawski, J; Nowotnik, A

    2010-03-01

    This paper presents a chemical extraction technique for determination of intermetallic phases formed in the casting AlSi5Cu1Mg aluminium alloy. Commercial aluminium alloys contain a wide range of intermetallic particles that are formed during casting, homogenization and thermomechanical processing. During solidification, particles of intermetallics are dispersed in interdendritic spaces as fine primary phases. Coarse intermetallic compounds that are formed in this aluminium alloy are characterized by unique atomic arrangement (crystallographic structure), morphology, stability, physical and mechanical properties. The volume fraction, chemistry and morphology of the intermetallics significantly affect properties and material behaviour during thermomechanical processing. Therefore, accurate determination of intermetallics is essential to understand and control microstructural evolution in Al alloys. Thus, in this paper it is shown that chemical phenol extraction method can be applied for precise qualitative evaluation. The results of optical light microscopy LOM, scanning electron microscopy SEM and X-ray diffraction XRD analysis reveal that as-cast AlSi5Cu1Mg alloy contains a wide range of intermetallic phases such as Al(4)Fe, gamma- Al(3)FeSi, alpha-Al(8)Fe(2)Si, beta-Al(5)FeSi, Al(12)FeMnSi.

  6. Mechanical properties of intermetallics formed during thermal aging of Cu-Al ball bonds

    NARCIS (Netherlands)

    Kouters, M.H.M.; Gubbels, G.H.M.; O'Halloran, O.; Rongen, R.; Weltevreden, E.R.

    2011-01-01

    In high power automotive electronics copper wire bonding is regarded as most promising alternative for gold wire bonding in 1st level interconnects and therefore subjected to severe functional requirements. In the Cu-Al ball bond interface the growth of intermetallic compounds may deteriorate the

  7. Intermetallics as innovative CRM-free materials

    Science.gov (United States)

    Novák, Pavel; Jaworska, Lucyna; Cabibbo, Marcello

    2018-03-01

    Many of currently used technical materials cannot be imagined without the use of critical raw materials. They require chromium (e.g. in stainless and tool steels), tungsten and cobalt (tool materials, heat resistant alloys), niobium (steels and modern biomaterials). Therefore there is a need to find substitutes to help the European economy. A promising solution can be the application of intermetallics. These materials offer wide variety of interesting properties, such as high hardness and wear resistance or high chemical resistance. In this paper, the overview of possible substitute materials among intermetallics is presented. Intermetallics based on aluminides and silicides are shown as corrosion resistant materials, composites composed of ceramics in intermetallic matrix as possible tool materials. The manufacturing processes are being developed to minimize the disadvantages of these materials, mainly the room-temperature brittleness.

  8. Sintered cobalt-rare earth intermetallic product

    International Nuclear Information System (INIS)

    Benz, M.G.

    1975-01-01

    This patent describes a sintered product having substantially stable permanent magnet properties in air at room temperature. It comprises compacted particulate cobalt--rare earth alloy consisting essentially of a Co 5 R intermetallic phase and a CoR intermetallic phase which is richer in rare earth metal content than the Co 5 R phase, where R is a rare earth metal. The Co 5 R intermetallic phase is present in an amount of at least 65 percent by weight of the sintered product and the CoR intermetallic phase which is richer in rare earth metal content than the Co 5 R phase is present in a positive amount having a value ranging up to about 35 percent by weight of the product. The sintered product has a density of at least 87 percent and has pores which are substantially noninterconnecting and wherein the component grains have an average size less than 30 microns

  9. Magnetic properties and magnetocaloric effect in the HoNi1−xCuxIn (x=0, 0.1, 0.3, 0.4) intermetallic compounds

    International Nuclear Information System (INIS)

    Mo, Zhao-Jun; Shen, Jun; Yan, Li-Qin; Tang, Cheng-Chun; He, Xiao-Nan; Zheng, Xinqi; Wu, Jian-Feng; Sun, Ji-Rong; Shen, Bao-Gen

    2014-01-01

    The magnetic properties and magnetocaloric effect (MCE) in HoNi 1−x Cu x In (x=0, 0.1, 0.3, 0.4) compounds have been investigated. With the substitution of Cu for Ni, the Ho magnetic moment will cant from the c-axis, and form a complicated magnetic structure. These compounds exhibit two successive magnetic transitions with the increase in temperature. The large reversible magnetocaloric effects have been observed in HoNi 1−x Cu x In compounds around T ord , with no thermal and magnetic hysteresis loss. The large reversible isothermal magnetic entropy change (−ΔS M ) is 20.2 J/kg K and the refrigeration capacity (RC) reaches 356.7 J/kg for field changes of 5 T for HoNi 0.7 Cu 0.3 In. Especially, the value of −ΔS M (12.5 J/kg K) and the large RC (132 J/kg) are observed for field changes of 2 T for HoNi 0.9 Cu 0.1 In. Additionally, the values of RC are improved to 149 J/K for the field changes of 2 T due to a wide temperature span for the mix of HoNi 0.9 Cu 0.1 In and HoNi 0.7 Cu 0.3 In compounds with the mass ratio of 1:1. These compounds with excellent MCE are expected to have effective applications in magnetic refrigeration around 20 K. - Highlights: • For magnetic-field changes of 2 T, the values of RC are improved to 149 J/K. • MCEs of these compounds show no thermal and magnetic hysteresis. • Compounds show two successive magnetic transitions with the increase in temperature. • With the substitution of Cu for Ni, compounds form a complicated magnetic structure

  10. Intermetallics Synthesis in the Fe–Al System via Layer by Layer 3D Laser Cladding

    Directory of Open Access Journals (Sweden)

    Floran Missemer

    2013-10-01

    Full Text Available Intermetallide phase formation was studied in a powdered Fe–Al system under layer by layer laser cladding with the aim of fabricating the gradient of properties by means of changing the Fe–Al concentration ratio in the powder mixture from layer to layer. The relationships between the laser cladding parameters and the intermetallic phase structures in the consecutively cladded layers were determined. In order to study the structure formation an optical microscopy, X-ray diffraction analysis, measurement of microhardness, scanning electron microscopy (SEM with energy dispersive X-ray (EDX spectroscopy analysis were used after the laser synthesis of intermetallic compounds.

  11. Chemistry and Properties of Complex Intermetallics from Metallic Fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Kanatzidis, Mercouri G. [Northwestern Univ., Evanston, IL (United States)

    2015-03-28

    This project investigated the reaction chemistry and synthesis of new intermetallic materials with complex compositions and structures using metallic fluxes as solvents. It was found that the metallic fluxes offer several key advantages in facilitating the formation and crystal growth of new materials. The fluxes mostly explored were liquid aluminum, gallium and indium. The main purpose of this project was to exploit the potential of metallic fluxes as high temperature solvent for materials discovery in the broad class of intermetallics. This work opened new paths to compound formation. We discovered many new Si (or Ge)-based compounds with novel structures, bonding and physicochemical properties. We created new insights about the reaction chemistry that is responsible for stabilizing the new materials. We also studied the structural and compositional relationships to understand their properties. We investigated the use of Group-13 metals Al, Ga and In as solvents and have generated a wide variety of new results including several new ternary and quaternary materials with fascinating structures and properties as well as new insights as to how these systems are stabilized in the fluxes. The project focused on reactions of metals from the rare earth element family in combination with transition metals with Si and Ge. For example molten gallium has serves both as a reactive and non-reactive solvent in the preparation and crystallization of intermetallics in the system RE/M/Ga/Ge(Si). Molten indium behaves similarly in that it too is an excellent reaction medium, but it gives compounds that are different from those obtained from gallium. Some of the new phase identified in the aluminide class are complex phases and may be present in many advanced Al-matrix alloys. Such phases play a key role in determining (either beneficially or detrimentally) the mechanical properties of advanced Al-matrix alloys. This project enhanced our basic knowledge of the solid state chemistry

  12. Annual research plan, 1983-84. [Organic compounds derived from fossil substances

    Energy Technology Data Exchange (ETDEWEB)

    None

    1984-05-01

    The National Institute for Petroleum and Energy Research (NIPER) resulted from efforts by the Department of Energy (DOE) to ensure the continuity of the unique energy research capabilities that had been developed at the Bartlesville Energy Technology Center (BETC) over the past 65 years. This was accomplished by a Cooperative Agreement between DOE and IIT Research Institute (IITRI). The agreement to operate NIPER for the five fiscal years 1984-88 became effective October 1, 1983. The NIPER Annual Research Plan for 1983-84 consists of eight projects in the Base Program and 13 projects in the Optional Program. A sampling of potential Work for Others projects is also presented. The Base Program consists of five EOR and three Fundamental Petroleum Chemistry projects. The Optional Program has three EOR projects, one Unconventional Gas Recovery project, five APT projects, and four Advanced Utilization Research projects.

  13. First principles electronic and thermal properties of some AlRE intermetallics

    International Nuclear Information System (INIS)

    Srivastava, Vipul; Sanyal, Sankar P.; Rajagopalan, M.

    2008-01-01

    A study on structural and electronic properties of non-magnetic cubic B 2 -type AlRE (RE=Sc, Y, La, Ce, Pr and Lu) intermetallics has been done theoretically. The self-consistent tight binding linear muffin tin orbital method is used to describe the electronic properties of these intermetallics at ambient and at high pressure. These compounds show metallic behavior under ambient conditions. The variation of density of states under compression indicates some possibility of structural phase transformation in AlLa, AlCe and AlPr. Thermal properties like Debye temperature and Grueneisen constant are calculated at T=0 K and at ambient pressure within the Debye-Grueneisen model and compared with the others' theoretical results. Our results are in good agreement. We have also performed a pressure-induced variation of Debye temperature and have found a decrease in Debye temperature around 40 kbar in AlRE (RE=La, Ce, Pr) intermetallics

  14. Microstructure and Tribological Properties of Mo-40Ni-13Si Multiphase Intermetallic Alloy.

    Science.gov (United States)

    Song, Chunyan; Wang, Shuhuan; Gui, Yongliang; Cheng, Zihao; Ni, Guolong

    2016-12-06

    Intermetallic compounds are increasingly being expected to be utilized in tribological environments, but to date their implementation is hindered by insufficient ductility at low and medium temperatures. This paper presents a novel multiphase intermetallic alloy with the chemical composition of Mo-40Ni-13Si (at %). Microstructure characterization reveals that a certain amount of ductile Mo phases formed during the solidification process of a ternary Mo-Ni-Si molten alloy, which is beneficial to the improvement of ductility of intermetallic alloys. Tribological properties of the designed alloy-including wear resistance, friction coefficient, and metallic tribological compatibility-were evaluated under dry sliding wear test conditions at room temperature. Results suggest that the multiphase alloy possesses an excellent tribological property, which is attributed to unique microstructural features and thereby a good combination in hardness and ductility. The corresponding wear mechanism is explained by observing the worn surface, subsurface, and wear debris of the alloy, which was found to be soft abrasive wear.

  15. Microstructure Characterization and Wear-Resistant Properties Evaluation of an Intermetallic Composite in Ni–Mo–Si System

    Directory of Open Access Journals (Sweden)

    Boyuan Huang

    2017-02-01

    Full Text Available Intermetallic compounds have been studied for their potential application as structural wear materials or coatings on engineering steels. In the present work, a newly designed intermetallic composite in a Ni–Mo–Si system was fabricated by arc-melting process with commercially pure metal powders as starting materials. The chemical composition of this intermetallic composite is 45Ni–40Mo–15Si (at %, selected according to the ternary alloy diagram. The microstructure was characterized using optical microscopy (OM, scanning electron microscopy (SEM, X-ray diffraction (XRD, and energy dispersive spectroscopy (EDS, and the wear-resistant properties at room temperature were evaluated under different wear test conditions. Microstructure characterization showed that the composite has a dense and uniform microstructure. XRD results showed that the intermetallic composite is constituted by a binary intermetallic compound NiMo and a ternary Mo2Ni3Si metal silicide phase. Wear test results indicated that the intermetallic composite has an excellent wear-resistance at room-temperature, which is attributed to the high hardness and strong atomic bonding of constituent phases NiMo and Mo2Ni3Si.

  16. Magnetocrystalline anisotropy constants, rotational hysteresis energy and magnetic domain structure in UFe6Al6, UFe9AlSi2 and ScFe10Si2 intermetallic compounds

    International Nuclear Information System (INIS)

    Wyslocki, J.J.; Pawlik, P.; Wochowski, K.; Kotur, B.; Bodak, O.I.

    1996-01-01

    The magnetic torque, T, was applied to determine the anisotropy constants K 1 and K 2 of the UFe 6 Al 6 , UFe 9 AlSi 2 and ScFe 10 Si 2 compounds. The mechanism of magnetization reversal processes in these compounds was investigated on the basis of the analysis of the rotational hysteresis energy, W r and rotational hysteresis integral, R, calculated from the magnetic torque curves. Applying the powder pattern method, magnetic domain structures were observed. Moreover, the fundamental parameters of the domain structure were determined. (orig.)

  17. Advanced ordered intermetallic alloy deployment

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.; Maziasz, P.J.; Easton, D.S. [Oak Ridge National Lab., TN (United States)

    1997-04-01

    The need for high-strength, high-temperature, and light-weight materials for structural applications has generated a great deal of interest in ordered intermetallic alloys, particularly in {gamma}-based titanium aluminides {gamma}-based TiAl alloys offer an attractive mix of low density ({approximately}4g/cm{sup 3}), good creep resistance, and high-temperature strength and oxidation resistance. For rotating or high-speed components. TiAl also has a high damping coefficient which minimizes vibrations and noise. These alloys generally contain two phases. {alpha}{sub 2} (DO{sub 19} structure) and {gamma} (L 1{sub 0}), at temperatures below 1120{degrees}C, the euticoid temperature. The mechanical properties of TiAl-based alloys are sensitive to both alloy compositions and microstructure. Depending on heat-treatment and thermomechanical processing, microstructures with near equiaxed {gamma}, a duplex structure (a mix of the {gamma} and {alpha}{sub 2} phases) can be developed in TiAl alloys containing 45 to 50 at. % Al. The major concern for structural use of TiAl alloys is their low ductility and poor fracture resistance at ambient temperatures. The purpose of this project is to improve the fracture toughness of TiAl-based alloys by controlling alloy composition, microstructure and thermomechanical treatment. This work is expected to lead to the development of TiAl alloys with significantly improved fracture toughness and tensile ductility for structural use.

  18. Investigation of local magnetism in RZn (R = Ce, Gd, Tb, Dy) and GdCu intermetallic compounds using perturbed angular correlation gamma-gamma spectroscopy; Investigacao do magnetismo local em compostos intermetalicos do tipo RZn (R = Ce, Gd, Tb, Dy) e GdCu pela espectroscopia de correlacao angular gama-gama perturbada

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Brianna Bosch dos

    2010-07-01

    This work presents, from a microscopic point of view, a systematic study of the local magnetism in RZn (R = Ce, Gd, Tb, Dy) and GdCu intermetallic compounds through measurements of hyperfine interactions using the Perturbed Angular Correlation Gamma- Gamma Spectroscopy technique with {sup 111}In {yields} {sup 111}Cd and {sup 140}La {yields} {sup 140}Ce as probe nuclei. As the magnetism in these compounds originates from the 4f electrons of the rare-earth elements it is interesting to observe in a systematic study of RZn compounds the behavior of the magnetic hyperfine field with the variation of the number of 4f electrons in the R element. The use of probe nuclei {sup 140}La {yields} {sup 140}Ce is interesting because Ce{sup +3} ion posses one 4f electron which may contribute to the total hyperfine field, and the results showed anomalous behavior. The results for {sup 111}Cd probe showed that the temperature dependence of the magnetic hyperfine field follows the Brillouin function, and the magnetic hyperfine field decreases linearly with increase of the atomic number of rare earth when plotted as a function of the rare-earth J spin projection, showing that the main contribution to the magnetic hyperfine field in RZn compounds comes from the polarization of the conduction electrons. The results for the electric field gradient measured with {sup 111}Cd for all compounds showed a strong decrease with the atomic number of the rare-earth element. We have therefore assumed that the major contribution to the electric field gradient originates from the 4f electrons of the rare-earths. The measurements of the electric field gradient for GdCu with {sup 111}Cd, after temperature decreases and increases again showed that two different structures, CsCl-type cubic and FeB-type orthorhombic structures co-exist. Finally, it is the first time that measurements of hyperfine parameters have been carried out with theses two probe nuclei in the studied RZn. (author)

  19. New intermetallic MIrP (M=Ti, Zr, Nb, Mo) and MgRuP compounds related with MoM'P (M'=Ni and Ru) superconductor

    Science.gov (United States)

    Kito, Hijiri; Iyo, Akira; Wada, Toshimi

    2011-01-01

    Using a cubic-anvil high-pressure apparatus, ternary iridium phosphides MIrP (M=Ti, Zr, Nb, Mo) and MgRuP have been prepared by reaction of stoichiometric amounts of each metal and phosphide powders at around 2 Gpa and above 1523 K for the first time. The structure of these compounds prepared at high-pressure has been characterized by X-ray powder diffraction. Diffraction lines of these compounds are assigned by the index of the Co2Si-type structure. The electrical resistivity and the d.c magnetic susceptibility of MIrP (M=Ti, Zr, Nb, Mo) have measured at low temperatures. Unfortunately, no superconducting transition for MIrP (M=Ti, Zr, Nb, Mo) and MgRuP are observed down to 2 K.

  20. New intermetallic MIrP (M=Ti, Zr, Nb, Mo) and MgRuP compounds related with MoM'P (M'=Ni and Ru) superconductor

    International Nuclear Information System (INIS)

    Kito, Hijiri; Iyo, Akira; Wada, Toshimi

    2011-01-01

    Using a cubic-anvil high-pressure apparatus, ternary iridium phosphides MIrP (M=Ti, Zr, Nb, Mo) and MgRuP have been prepared by reaction of stoichiometric amounts of each metal and phosphide powders at around 2 Gpa and above 1523 K for the first time. The structure of these compounds prepared at high-pressure has been characterized by X-ray powder diffraction. Diffraction lines of these compounds are assigned by the index of the Co 2 Si-type structure. The electrical resistivity and the d.c magnetic susceptibility of MIrP (M=Ti, Zr, Nb, Mo) have measured at low temperatures. Unfortunately, no superconducting transition for MIrP (M=Ti, Zr, Nb, Mo) and MgRuP are observed down to 2 K.

  1. Study of the hyperfine magnetic field acting on Ce probes substituting for the rare earth and the magnetic ordering in intermetallic compounds RAg (R=rare earth) by first principles calculations

    International Nuclear Information System (INIS)

    Pereira, Luciano Fabricio Dias

    2006-01-01

    In this work the magnetic hyperfine field acting on Ce atoms substituting the rare-earths in R Ag compounds (R = Gd e Nd) was studied by means of first-principles electronic structure calculations. The employed method was the Augmented Plane Waves plus local orbitals (APW+lo), embodied in the WIEN2k program, within the framework of the Density Functional Theory (DFT) and with the Generalized Gradient Approximation (GGA) for the exchange and correlation potential. The super-cell approach was utilized in order to simulate for the Ce atoms acting as impurities in the R Ag matrix. In order to improve for correlation effects within the 4f shells, a Hubbard term was added to the DFT Hamiltonian, within a procedure called GGA+U. It was found that the magnetic hyperfine field (MHF) generated by the Ce 4f electron is the main component of the total MHF and that the Ce 4f ground state level is probably a combination of the m l = -2 and m l = -1 sub-levels. In addition, the ground-state magnetic structure was determined for Ho Ag and Nd Ag by observing the behavior of the total energy as a function of the lattice volume for several possible magnetic ordering in these compounds, namely, ferromagnetic, and the (0,0,π), (π,π,0) and ((π,π,π) types of anti-ferromagnetic ordering of rare-earth atoms. It was found that the ground-state magnetic structure is anti-ferromagnetic of type (π,π,0) for both, the Ho Ag and Nd Ag compounds. The energy difference of the ferromagnetic and antiferromagnetic ordering is very small in the case of the Nd Ag compound. (author)

  2. Zirconium intermetallics and hydrogen uptake during corrosion

    International Nuclear Information System (INIS)

    Cox, B.

    1987-04-01

    The routes by which hydrogen can enter zirconium alloys containing second phase particles during corrosion are discussed. Both direct diffusion through the bulk of the oxide film, and migration through second phase particles that intersect the surface are considered. An examination of results for hydrogen uptake by zirconium alloys during the early stages of oxidation, when the oxide film is still coherent, suggests that for Zr, Zr-1%Cu and Zr-1%Fe the hydrogen enters by diffusing through the bulk ZrO 2 film, whereas for the Zircaloys the primary migration route may be through the intermetallics. The steps in the latter process are discussed and the evidence available on the properties of the intermetallics collated. A comparison of these data with results for hydrogen uptake by two series of ternary alloys (Zr-1%Nb - 1%X, Zr-1%Cu - 1%X) suggests that high hydrogen uptakes often correlate with intermetallics with high hydrogen solubilities and vice versa. The properties of Zr(Fe/Cr) 2+x intermetallics are examined in an attempt to understand the behaviour of the Zircaloys, and it is concluded that present data establishing composition and unit cell dimensions for such intermetallic particles are not of sufficient accuracy to permit a correlation

  3. Structural and functional intermetallics - an overview

    International Nuclear Information System (INIS)

    Varin, R.A.

    2000-01-01

    This overview presents the current status of the research and development of both structural and functional intermetallics. On the one hand, the discussion is focused on commercialization and existing industrial applications of intermetallics. Within this frame the applications of titanium aluminides (TiAl) for turbocharger rotors and exhaust valves in automotive industry are being discussed. Advances in the applications of TiAl alloys for the next generation of turbine blades in aerospace/aircraft segment are also presented. The entire spectrum of nickel and iron aluminide alloys developed commercially by the Oak Ridge national Laboratory (USA) and the examples of their application in various segments of industry are thoroughly discussed. Some inroads made in the application of directionally solidified (DS) multiphase niobium silicides (Nb 3 Si+Nb 5 Si 3 ) in situ intermetallic composites with the goal of pushing the service temperature envelope of turbine blades to ∼ 1200-1300 o C are also discussed. On the other hand, various topics in basic or curiosity driven research of titanium aluminides and trialuminides, iron aluminides and high temperature structural silicides are discussed. Some very recent findings on the improvements in fracture toughness and strength of titanium trialuminides and magnetic behaviour of unconventionally cold - worked iron aluminides are highlighted. The topic of functional intermetallics is limited to the systems must suitable for hydrogen storage applications. A perspective on the directions of future research and development of intermetallics is also provided. (author)

  4. Sintered cobalt-rare earth intermetallic product

    International Nuclear Information System (INIS)

    Benz, M.C.

    1975-01-01

    A process is described for preparing novel sintered cobalt--rare earth intermetallic products which can be magnetized to form permanent magnets having stable improved magnetic properties. A cobalt--rare earth metal alloy is formed having a composition which at sintering temperature falls outside the composition covered by the single Co 5 R intermetallic phase on the rare earth richer side. The alloy contains a major amount of the Co 5 R intermetallic phase and a second solid CoR phase which is richer in rare earth metal content than the Co 5 R phase. The specific cobalt and rare earth metal content of the alloy is substantially the same as that desired in the sintered product. The alloy, in particulate form, is pressed into compacts and sintered to the desired density. The sintered product is comprised of a major amount of the Co 5 R solid intermetallic phase and up to about 35 percent of the product of the second solid CoR intermetallic phase which is richer in rare earth metal content than the Co 5 R phase

  5. Photocatalytic and chemical oxidation of organic compounds in supercritical carbon dioxide. 1998 annual progress report

    International Nuclear Information System (INIS)

    Blake, D.M.

    1998-01-01

    'This report summarizes the results of work done during the first 1.3 years of a three year project. During the first nine months effort focussed on the design, construction and testing of a closed recirculating system that can be used to study photochemistry in supercritical carbon dioxide at pressures up to 5,000 psi and temperatures up to about 50 C. This was followed by a period of work in which the photocatalytic oxidation of benzene and acetone in supercritical, liquid, and gaseous carbon dioxide containing dissolved oxygen was demonstrated. The photocatalyst was titanium dioxide supported on glass spheres. This was the first time it was possible to observe photocatalytic oxidation in a supercritical fluid and to compare reaction in the three fluid phases of a solvent. This also demonstrated that it is possible to purify supercritical and liquid carbon dioxide using photochemical oxidation with no chemical additions other than oxygen. The oxidation of benzene produced no intermediates detectable using on line spectroscopic analysis or by gas chromatographic analysis of samples taken from the flow system. The catalyst surface did darken as the reaction proceeded indicating that oxidation products were accumulating on the surface. This is analogous to the behavior of aromatic compounds in air phase photocatalytic oxidation. The reaction of acetone under similar conditions resulted in the formation of low levels of by-products. Two were identified as products of the reaction of acetone with itself (4-methyl-3-penten-2-one and 4-hydroxy-4-methyl-2-pentanone) using gas chromatography with a mass spectrometer detector. Two other by-products also appear to be from the self-reaction of acetone. By-products of this type had not been observed in prior studies of the gas-phase photocatalytic oxidation of acetone. The by-products that have been observed can also be oxidized under the treatment conditions. The above results establish that photocatalytic oxidation of

  6. Contribution to the study of the amorphization mechanisms of intermetallic compounds by mechanical grinding; Contribution a l`etude des mecanismes d`amorphisation par sollicitation mecanique de composes intermetalliques

    Energy Technology Data Exchange (ETDEWEB)

    Galy, D

    1995-01-11

    This work aims at identifying the mechanisms responsible for amorphization of NiZr and NiZr{sub 2} compounds under ball-milling. In the first part, the effect of a localized deformation is studied: the deformation is produced by indentation on bulk samples, very high local strains can be achieved by this technique. The resulting microstructure is studied by transmission electron microscopy (TEM). No evidence for amorphization is found in these compounds, contrary to what is known to occur in silicon and germanium. Despite of their high brittleness, the NiZr and NiZr{sub 2} compounds accommodate the multiaxial localized stress by plastic deformation: dislocations multiplication and glide, micro-twinning. Dislocations (both perfect and imperfect) and micro-twins have been analysed into details for the first time. The twinning mechanism in NiZr{sub 2} has been elucidated. In the second part of this work, the microstructure of NiZr{sub 2} in the course of amorphization by ball-milling is studied by TEM observation are prepared by ultra-microtomy. The following evolution is observed: first, the material is fragmented and plastically deformed; the microstructure is refined by polygonation. Second, aggregates are formed by a fragmentation and sticking process, leading to a stationary size for the aggregates. The aggregates themselves are made of a mixture of nanocrystalline (about 10 nm) material and coarser crystallites. As milling proceeds, the latter disappear to the benefit of the former. Once aggregates are 100% nanocrystalline, the amorphous phase appears and develops to the expense of the nanocrystalline phase. At late stages, small crystallites embedded in an amorphous matrix are observed. No massive chemical disordering is observed but a small amount can not be ruled out. It is suggested that amorphization occurs by chemical disordering at interfaces, induced by shear waves. (Author). 76 refs., 57 figs., 12 tabs.

  7. Spark plasma sintering of titanium aluminide intermetallics and its composites

    Science.gov (United States)

    Aldoshan, Abdelhakim Ahmed

    Titanium aluminide intermetallics are a distinct class of engineering materials having unique properties over conventional titanium alloys. gamma-TiAl compound possesses competitive physical and mechanical properties at elevated temperature applications compared to Ni-based superalloys. gamma-TiAl composite materials exhibit high melting point, low density, high strength and excellent corrosion resistance. Spark plasma sintering (SPS) is one of the powder metallurgy techniques where powder mixture undergoes simultaneous application of uniaxial pressure and pulsed direct current. Unlike other sintering techniques such as hot iso-static pressing and hot pressing, SPS compacts the materials in shorter time (< 10 min) with a lower temperature and leads to highly dense products. Reactive synthesis of titanium aluminide intermetallics is carried out using SPS. Reactive sintering takes place between liquid aluminum and solid titanium. In this work, reactive sintering through SPS was used to fabricate fully densified gamma-TiAl and titanium aluminide composites starting from elemental powders at different sintering temperatures. It was observed that sintering temperature played significant role in the densification of titanium aluminide composites. gamma-TiAl was the predominate phase at different temperatures. The effect of increasing sintering temperature on microhardness, microstructure, yield strength and wear behavior of titanium aluminide was studied. Addition of graphene nanoplatelets to titanium aluminide matrix resulted in change in microhardness. In Ti-Al-graphene composites, a noticeable decrease in coefficient of friction was observed due to the influence of self-lubrication caused by graphene.

  8. Forecasting of superconducting compounds

    International Nuclear Information System (INIS)

    Savitskii, E.M.; Gribulya, V.G.; Kiseleva, N.N.

    1981-01-01

    In forecasting new superconducting intermetallic compounds of the A15 and Mo 3 Se types most promising from the viewpoint of high critical temperature Tsub(c), high critical magnetic fields Hsub(c), and high critical currents and in estimating their transition temperature it is proposed to apply cybernetic methods of computer learning

  9. Surfaces of Intermetallics: Quasicrystals and Beyond

    Energy Technology Data Exchange (ETDEWEB)

    Yuen, Chad [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    The goal of this work is to characterize surfaces of intermetallics, including quasicrystals. In this work, surface characterization is primarily focused on composition and structure using X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) performed under ultrahigh vacuum (UHV) conditions.

  10. Toughening and creep in multiphase intermetallics through ...

    Indian Academy of Sciences (India)

    It has however often been the case that the process of ductilisation or toughening has also led to a decrease in high temperature properties, especially creep. In this paper we describe approaches to the ductilisation of two different classes of intermetallic alloys through alloying to introduce beneficial, second phase effects.

  11. Vacancies and atomic processes in intermetallics - From crystals to quasicrystals and bulk metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Hans-Eckhardt [Institute of Theoretical and Applied Physics, Stuttgart University, Pfaffenwaldring 57, 70569 Stuttgart (Germany); Baier, Falko [Voith Turbo Comp., Alexanderstr. 2, 89552 Heidenheim (Germany); Mueller, Markus A. [GFT Technologies A. G., Filderhauptstr. 142, 70599 Stuttgart (Germany); Reichle, Klaus J. [Philipp-Matthaeus-Hahn School, Jakob-Beutter-Str. 15, 72336 Balingen (Germany); Reimann, Klaus [NXP Semiconductors, Central Research and Development, High Tech Campus 4, 5656 AE Eindhoven (Netherlands); Rempel, Andrey A. [Institute of Solid State Chemistry, Russian Academy of Sciences, Ul. Pervomaiskaya 91, 620041 Ekaterinburg (Russian Federation); Sato, Kiminori [Tokyo Gakugei University, Nukuikita 4-1-1, Koganei, Tokyo 184-8501 (Japan); Ye, Feng [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, 30 Xue Yuan Road, Beijing 100083 (China); Zhang, Xiangyi [Yanshan University, Qinhuangdao 066004 (China); Sprengel, Wolfgang [Institute of Materials Physics, Graz University of Technology, Petersgasse 16, 8010 Graz (Austria)

    2011-10-15

    A review is given on atomic vacancies in intermetallic compounds. The intermetallic compounds cover crystalline, quasicrystalline, and bulk metallic glass (BMG) structures. Vacancies can be specifically characterized by their positron lifetimes, by the coincident measurement of the Doppler broadening of the two quanta emitted by positron-electron annihilation, or by time-differential dilatometry. By these techniques, high concentrations and low mobilities of thermal vacancies were found in open-structured B2 intermetallics such as FeAl or NiAl, whereas the concentrations of vacancies are low and their mobilities high in close-packed structure as, e.g., L1{sub 2}-Ni{sub 3}Al. The activation volumes of vacancy formation and migration are determined by high-pressure experiments. The favorable sublattice for vacancy formation is found to be the majority sublattice in Fe{sub 61}Al{sub 39} and in MoSi{sub 2}. In the icosahedral quasicrystal Al{sub 70}Pd{sub 21}Mn{sub 9} the thermal vacancy concentration is low, whereas in the BMG Zr{sub 57}Cu{sub 15.4}Ni{sub 12.6}Nb{sub 3}Al{sub 10} thermal vacancies are found in high concentrations with low mobilities. This may determine the basic mechanisms of the glass transition. Making use of the experimentally determined vacancy data, the main features of atomic diffusion studies in crystalline intermetallics, in quasicrystals, and in BMGs can be understood. Manfred Faehnle and his group have substantially contributed to the theoretical understanding of vacancies and diffusion mechanisms in intermetallics. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. The Effects of Grain Refinement and Rare Earth Intermetallics on Mechanical Properties of As-Cast and Wrought Magnesium Alloys

    Science.gov (United States)

    Pourbahari, Bita; Mirzadeh, Hamed; Emamy, Massoud

    2018-03-01

    The effects of rare earth intermetallics and grain refinement by alloying and hot extrusion on the mechanical properties of Mg-Gd-Al-Zn alloys have been studied to elucidate some useful ways to enhance the mechanical properties of magnesium alloys. It was revealed that aluminum as an alloying element is a much better grain refining agent compared with gadolinium, but the simultaneous presence of Al and Gd can refine the as-cast grain size more efficiently. The presence of fine and widely dispersed rare earth intermetallics was found to be favorable to achieve finer recrystallized grains during hot deformation by extrusion. The presence of coarse dendritic structure in the GZ61 alloy, grain boundary eutectic containing Mg17Al12 phase in the AZ61 alloy, and rare earth intermetallics with unfavorable morphology in the Mg-4Gd-2Al-1Zn alloy was found to be detrimental to mechanical properties of the alloy in the as-cast condition. As a result, the microstructural refinement induced by hot extrusion process resulted in a significant enhancement in strength and ductility of the alloys. The presence of intermetallic compounds in the extruded Mg-4Gd-2Al-1Zn and Mg-2Gd-4Al-1Zn alloys deteriorated tensile properties, which was related to the fact that such intermetallic compounds act as stress risers and microvoid initiation sites.

  13. Quaternary borocarbides: New class of intermetallic superconductors

    Science.gov (United States)

    Nagarajan, R.; Gupta, L. C.; Dhar, S. K.; Mazumdar, Chandan; Hossain, Zakir; Godart, C.; Levy-Clement, C.; Padalia, B. D.; Vijayaraghavan, R.

    1995-01-01

    Our recent discovery of superconductivity (SC) in the four-element multiphase Y-Ni-B-C system at an elevated temperature (TC approximately 12 K) has opened up great possibilities of identifying new superconducting materials and generating new physics. Superconductivity with Tc (greater than 20 K) higher than that known so far in bulk intermetallics has been observed in multiphase Y-Pd-B-C and Th-Pd-B-C systems and a family of single phase materials RENi2B2C (RE= Y, rare earth) have been found. Our investigations show YNi2B2C to be a strong coupling hard type-II SC. HC2(T) exhibits an unconventional temperature dependence. Specific heat and magnetization studies reveal coexistence of SC and magnetism in RNi2B2C (R = Ho, Er, Tm) with magnetic ordering temperatures (Tc approximately 8 K, 10.5 K, 11 K and Tm approximately 5 K, approximately 7K, approximately 4 K respectively) that are remarkably higher than those in known magnetic superconductors . Mu-SR studies suggest the possibility of Ni atoms carrying a moment in TmNi2B2C. Resistivity results suggests a double re-entrant transition (SC-normal-SC) in HoNi2B2C. RENi2B2C (RE = Ce, Nd, Gd) do not show SC down to 4.2 K. The Nd- and Gd-compounds order magnetically at approximately 4.5 K and approximately 19.5 K, respectively. Two SC transitions are observed in Y-Pd-B-C (Tc approximately 22 K, approximately 10 K) and in Th-Pd-B-C (Tc approximately 20 K, approximately 14 K) systems, which indicate that there are at least two structures which support SC in these borocarbides. In our multiphase ThNi2B2C we observe SC at approximately 6 K. No SC was seen in multiphase UNi2B2C, UPd2B2C, UOs2Ge2C and UPd5B3C(0.35) down to 4.2 K. Tc in YNi2B2C is depressed by substitutions (Gd, Th and U at Y-sites and Fe, Co at Ni-sites).

  14. MD study of primary damage in L10 TiAl structural intermetallics

    International Nuclear Information System (INIS)

    Voskoboinikov, Roman E.

    2013-01-01

    Computer modelling by molecular dynamics has been applied to study the radiation damage created in collision cascades in L1 0 TiAl intermetallic compound. Either Al or Ti primary knock-on atoms (PKA) with energy 5 keV ⩽ E PKA ⩽ 20 keV were introduced in the intermetallic crystals at temperatures ranging from 100 K to 900 K. At least 24 different cascade for each (E PKA , T, PKA type) set were modelled in order to simulate a random spatial and temporal distribution of PKAs and provide statistical reliability of the results. The total yield of more than 760 simulated cascades is the largest yet reported for this binary intermetallic material. A comprehensive treatment of the modelling results has been carried out. The number of Frenkel pairs, fraction of Al and Ti vacancies, self-interstitial atoms and anti-sites as a function of (E PKA , T, PKA type) has been established. Preferred formation of Al self-interstitial atoms has been detected in L1 0 TiAl structural intermetallics exposed to irradiation

  15. Theory of Valence Transitions in Ytterbium and Europium Intermetallics

    International Nuclear Information System (INIS)

    Zlatic, V.; Freericks, J.K.

    2001-01-01

    The exact solution of the multi-component Falicov-Kimball model in infinite-dimensions is presented and used to discuss a new fixed point of valence fluctuating intermetallics with Yb and Eu ions. In these compounds, temperature, external magnetic field, pressure, or chemical pressure induce a transition between a metallic state with the f-ions in a mixed-valent (non-magnetic) configuration and a semi-metallic state with the f-ions in an integral-valence (paramagnetic) configuration. The zero-field transition occurs at the temperature T V , while the zero-temperature transition sets in at the critical field H c . We present the thermodynamic and dynamic properties of the model for an arbitrary concentration of d- and f -electrons. For large U, we find a MI transition, triggered by the temperature or field- induced change in the f-occupancy. (author)

  16. Electron-Poor Polar Intermetallics: Complex Structures, Novel Clusters, and Intriguing Bonding with Pronounced Electron Delocalization.

    Science.gov (United States)

    Lin, Qisheng; Miller, Gordon J

    2018-01-16

    Intermetallic compounds represent an extensive pool of candidates for energy related applications stemming from magnetic, electric, optic, caloric, and catalytic properties. The discovery of novel intermetallic compounds can enhance understanding of the chemical principles that govern structural stability and chemical bonding as well as finding new applications. Valence electron-poor polar intermetallics with valence electron concentrations (VECs) between 2.0 and 3.0 e - /atom show a plethora of unprecedented and fascinating structural motifs and bonding features. Therefore, establishing simple structure-bonding-property relationships is especially challenging for this compound class because commonly accepted valence electron counting rules are inappropriate. During our efforts to find quasicrystals and crystalline approximants by valence electron tuning near 2.0 e - /atom, we observed that compositions close to those of quasicrystals are exceptional sources for unprecedented valence electron-poor polar intermetallics, e.g., Ca 4 Au 10 In 3 containing (Au 10 In 3 ) wavy layers, Li 14.7 Mg 36.8 Cu 21.5 Ga 66 adopting a type IV clathrate framework, and Sc 4 Mg x Cu 15-x Ga 7.5 that is incommensurately modulated. In particular, exploratory syntheses of AAu 3 T (A = Ca, Sr, Ba and T = Ge, Sn) phases led to interesting bonding features for Au, such as columns, layers, and lonsdaleite-type tetrahedral frameworks. Overall, the breadth of Au-rich polar intermetallics originates, in part, from significant relativistics effect on the valence electrons of Au, effects which result in greater 6s/5d orbital mixing, a small effective metallic radius, and an enhanced Mulliken electronegativity, all leading to ultimate enhanced binding with nearly all metals including itself. Two other successful strategies to mine electron-poor polar intermetallics include lithiation and "cation-rich" phases. Along these lines, we have studied lithiated Zn-rich compounds in which structural

  17. Formation of Ni-Ti intermetallics during reactive sintering at 500-650 degrees C

    Czech Academy of Sciences Publication Activity Database

    Novák, P.; Pokorný, P.; Vojtěch, V.; Knaislová, A.; Školáková, A.; Čapek, J.; Karlík, M.; Kopeček, Jaromír

    2015-01-01

    Roč. 155, Apr (2015), s. 113-121 ISSN 0254-0584 R&D Projects: GA ČR(CZ) GA14-03044S Institutional support: RVO:68378271 Keywords : intermetallic compounds * powder metallurgy * electron microscopy * microstructure Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.101, year: 2015

  18. Mechanical and oxidation properties of some B2 rare earth–magnesium intermetallic

    Energy Technology Data Exchange (ETDEWEB)

    Stumphy, Brad [Iowa State Univ., Ames, IA (United States)

    2006-12-15

    The remainder of Chapter 1 provides background information on three main topics. First is a discussion about the basic structure and composition of binary B2 intermetallic compounds. Second, the mechanical properties of intermetallics are examined, starting with the cause for the typically inherent brittleness observed in B2 intermetallics. A number of B2 compounds have been found to possess an abnormal level of ductility compared to other intermetallics in this class, including a handful of other rare earth–non-rare earth (RM) B2 line compounds, and these findings are also discussed. Finally, oxidation studies of rare earth metals, focusing on yttrium and cerium, as well as magnesium and some B2 materials are discussed. Chapter 2 is an in-depth look into certain aspects of the laboratory work done during this study. The many challenges and difficulties encountered required that a variety of laboratory techniques be attempted in the making, processing, and testing of these two intermetallic materials. The results and ensuing discussion for the mechanical testing that was performed are found in Chapter 3. Tensile and compression testing results for YMg are shown first, followed by those for CeMg. Some samples were made using electrical discharge machining (EDM) while others were polished into the desired shape. A scanning electron microscope (SEM) was utilized to inspect surfaces of the tensile and compression samples. Hardness values and attempts to determine fracture toughness are also recorded before beginning the discussion. Chapter 4 follows the same basic format for the oxidation study portion of the research. Oxidation curves for CeMg are followed by a qualitative chemical analysis using energy dispersive spectroscopy (EDS). The YMg oxidation curves are shown next followed by an x-ray diffraction (XRD) analysis of the oxidation process for this material and a discussion of the results. Chapter 5 is a summary of the research performed in the mechanical and

  19. 55. Annual symposium of the Austrian Physical Society. Abstracts

    International Nuclear Information System (INIS)

    Vogl, G.; Sepiol, B.

    2005-01-01

    Full text: The 55 th Annual Symposium of the Austrian Physical Society was held from 27.-29. September 2005 at the University of Vienna (Austria), it consisted of a plenary session, oral and poster sessions devoted to: acoustics; women and physics; atomic-, molecular- and plasma physics; solid physics; nuclear and particle physics; medical-, bio-and environmental physics; neutrons and synchrotron radiation physics; surface and thin film analysis and quantum electronics, electrodynamics and optics. Topics such as graphs quantization, molecular interferometry, Brownian movement, ion beam diagnostics, electron emission, optical pumping, Bose-Einstein condensates, molecular matter waves, double-wall carbon nanotubes, quantum dots, ferromagnetic nanocomposites, nanowires, transmission electron microscopy analysis of nanostructures, nanocrystals studies, atomic defects in intermetallic compounds, electron energy loss spectroscopy of intermetallic compounds, CHIRALTEM project, covariance data, nuclear astrophysics, kaonic atoms, pionic hydrogen, geometric phase measurements with neutrons, International linear collider project, ATLAS muon spectrometer, ATLAS detector, LHC's protection system, baryon structure, QCD, lattice QCD, coherent tomography, light microscopy, high resolution magnetic resonance imaging, polymer gel dosimetry, radon microdosimetry, traffic air pollutants, BVOC seasonal variations, biogenic VOC emissions, ice dating, synchrotron small angle x-ray diffraction, small angle neutron scattering, stepped surfaces oxidation, grazing incidence synchrotron reflexion studies, magnetic thin films, atoms quantum dynamics, quantum entanglement, BEC and quantum gases experiments were discussed. This book of abstracts contains their summaries and those contributions which are in the INIS subject scope are indexed individually. (nevyjel)

  20. The μ3 model of acids and bases: extending the Lewis theory to intermetallics.

    Science.gov (United States)

    Stacey, Timothy E; Fredrickson, Daniel C

    2012-04-02

    A central challenge in the design of new metallic materials is the elucidation of the chemical factors underlying the structures of intermetallic compounds. Analogies to molecular bonding phenomena, such as the Zintl concept, have proven very productive in approaching this goal. In this Article, we extend a foundational concept of molecular chemistry to intermetallics: the Lewis theory of acids and bases. The connection is developed through the method of moments, as applied to DFT-calibrated Hückel calculations. We begin by illustrating that the third and fourth moments (μ(3) and μ(4)) of the electronic density of states (DOS) distribution tune the properties of a pseudogap. μ(3) controls the balance of states above and below the DOS minimum, with μ(4) then determining the minimum's depth. In this way, μ(3) predicts an ideal occupancy for the DOS distribution. The μ(3)-ideal electron count is used to forge a link between the reactivity of transition metals toward intermetallic phase formation, and that of Lewis acids and bases toward adduct formation. This is accomplished through a moments-based definition of acidity which classifies systems that are electron-poor relative to the μ(3)-ideal as μ(3)-acidic, and those that are electron-rich as μ(3)-basic. The reaction of μ(3) acids and bases, whether in the formation of a Lewis acid/base adduct or an intermetallic phase, tends to neutralize the μ(3) acidity or basicity of the reactants. This μ(3)-neutralization is traced to the influence of electronegativity differences at heteroatomic contacts on the projected DOS curves of the atoms involved. The role of μ(3)-acid/base interactions in intermetallic phases is demonstrated through the examination of 23 binary phases forming between 3d metals, the stability range of the CsCl type, and structural trends within the Ti-Ni system.

  1. Pressure-induced phenomena in U intermetallics

    Czech Academy of Sciences Publication Activity Database

    Sechovský, V.; Honda, F.; Prokeš, K.; Syshchenko, O.; Andreev, Alexander V.; Kamarád, Jiří

    2003-01-01

    Roč. 34, č. 2 (2003), s. 1377-1386 ISSN 0587-4254. [International Conference on Strongly Correlated Electron Systems (SCES 02). Cracow, 10.07.2002-13.07.2002] R&D Projects: GA ČR GA202/02/0739 Institutional research plan: CEZ:AV0Z1010914; CEZ:MSM 113200002 Keywords : pressure effect * intermetallics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.752, year: 2003

  2. Composites having an intermetallic containing matrix

    International Nuclear Information System (INIS)

    Nagle, D.C.; Brupbacher, J.M.; Christodoulou, L.

    1990-01-01

    This paper describes a composite material. It comprises: a dispersion of in-situ precipitated second phase particles selected from the group consisting of borides, carbides, nitrides, and sulfides, in an intermetallic containing matrix selected from the group consisting of the aluminides, silicides, and beryllides of nickel, copper, titanium, cobalt, iron, platinum, gold, silver, niobium, tantalum, zinc, molybdenum, hafnium, tin, tungsten, lithium, magnesium, thorium, chromium, vanadium, zirconium, and manganese

  3. Role of intermetallics on the mechanical fatigue behavior of Cu–Al ball bond interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lassnig, A., E-mail: alice.lassnig@univie.ac.at [University of Vienna, Faculty of Physics, Physics of Nanostructured Materials, Boltzmanngasse 5, 1090 Wien (Austria); Pelzer, R. [Infineon Technologies Austria AG, Siemensstrae 2, 9500 Villach (Austria); Gammer, C. [University of Vienna, Faculty of Physics, Physics of Nanostructured Materials, Boltzmanngasse 5, 1090 Wien (Austria); National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Khatibi, G. [Vienna University of Technology, Institute of Chemical Technology and Analytics, Getreidemarkt 9, 1060 Wien (Austria)

    2015-10-15

    The mechanical fatigue behavior of Cu–Al interfaces occurring in thermosonic ball bonds –typically used in microelectronic packages for automotive applications – is investigated by means of a specially designed fatigue test technique. Fully reversed cyclic shear stresses are induced at the bond interface, leading to subsequent fatigue lift off failure and revealing the weakest site of the bond. A special focus is set on the role of interfacial intermetallic compounds (IMC) on the fatigue performance of such interfaces. Therefore fatigue life curves were obtained for three representative microstructural states: The as-bonded state is compared to two annealed states at 200 °C for 200 h and at 200 °C for 2000 h respectively. In the moderately annealed state two IMC layers (Al{sub 2}Cu, Al{sub 4}Cu{sub 9}) could be identified, whereas in the highly aged state the original pad metallization was almost entirely consumed and AlCu is formed as a third IMC. Finally, the crack path is traced back as a function of interfacial microstructure by means of electron microscopy techniques. Whereas conventional static shear tests reveal no significant decrease of the bond shear force with increased IMC formation the fatigue tests prove a clear degradation in the cyclic mechanical performance. It can be concluded that during cycling the crack deflects easily into the formed intermetallics, leading to early failure of the ball bonds due to their brittle nature. - Highlights: • High cycle fatigue of various miniaturized Cu–Al interfaces is investigated. • Interfacial intermetallic compounds consist of Al2Cu, AlCu and Al4Cu9. • Static shear strength shows minor dependency on interfacial phase formation. • Fatigue tests prove significant degradation with intermetallic compound evolution. • Fatigue fracture surface analysis reveal microstructure dependent crack path.

  4. Role of intermetallics on the mechanical fatigue behavior of Cu–Al ball bond interfaces

    International Nuclear Information System (INIS)

    Lassnig, A.; Pelzer, R.; Gammer, C.; Khatibi, G.

    2015-01-01

    The mechanical fatigue behavior of Cu–Al interfaces occurring in thermosonic ball bonds –typically used in microelectronic packages for automotive applications – is investigated by means of a specially designed fatigue test technique. Fully reversed cyclic shear stresses are induced at the bond interface, leading to subsequent fatigue lift off failure and revealing the weakest site of the bond. A special focus is set on the role of interfacial intermetallic compounds (IMC) on the fatigue performance of such interfaces. Therefore fatigue life curves were obtained for three representative microstructural states: The as-bonded state is compared to two annealed states at 200 °C for 200 h and at 200 °C for 2000 h respectively. In the moderately annealed state two IMC layers (Al 2 Cu, Al 4 Cu 9 ) could be identified, whereas in the highly aged state the original pad metallization was almost entirely consumed and AlCu is formed as a third IMC. Finally, the crack path is traced back as a function of interfacial microstructure by means of electron microscopy techniques. Whereas conventional static shear tests reveal no significant decrease of the bond shear force with increased IMC formation the fatigue tests prove a clear degradation in the cyclic mechanical performance. It can be concluded that during cycling the crack deflects easily into the formed intermetallics, leading to early failure of the ball bonds due to their brittle nature. - Highlights: • High cycle fatigue of various miniaturized Cu–Al interfaces is investigated. • Interfacial intermetallic compounds consist of Al2Cu, AlCu and Al4Cu9. • Static shear strength shows minor dependency on interfacial phase formation. • Fatigue tests prove significant degradation with intermetallic compound evolution. • Fatigue fracture surface analysis reveal microstructure dependent crack path

  5. Addressing Machining Issues for the Intermetallic Compound 60-NITINOL

    Science.gov (United States)

    Stanford, Malcolm K.; Wozniak, Walter A.; McCue, Terry R.

    2012-01-01

    60-NITINOL (60 wt.% Ni - 40 wt.% Ti) is being studied as a material for advanced aerospace components. Frequent wire breakage during electrical-discharge machining of this material was investigated. The studied material was fabricated from hot isostatically pressed 60-NITINOL powder obtained through a commercial source. Bulk chemical analysis of the material showed that the composition was nominal but had relatively high levels of certain impurities, including Al and O. It was later determined that Al2O3 particles had contaminated the material during the hot isostatic pressing procedure and that these particles were the most likely cause of the wire breakage. The results of this investigation highlight the importance of material cleanliness to its further implementation.

  6. High Temperature Oxidation of Superalloys and Intermetallic Compounds

    Science.gov (United States)

    2010-02-28

    Oxid. Met. Vol.14, pp. 217-234. 1980. 20. T.A. Rannanarayanan, M. Raghavan and R. Petrovic-Luton. Metallic Yttrium Additions to High Temperatura ... Temperatura Alloys: Influence of AI2O3 Scale Properties. Oxid. Met. Vol.22, pp. 83-100. 1984. 21. High-temperature characterization of reactively

  7. The motion of hydrogen isotopes in metals and intermetallic compounds

    International Nuclear Information System (INIS)

    Drexel, W.; Murani, A.; Tocchetti, D.; Kley, W.

    1976-08-01

    The existence of local and band modes of hydrogen and deuterium impurities in α-palladium hydride was observed by inelastic scattering of thermal neutrons of 12.6 meV. The first and second harmonic of the hydrogen local mode could be observed at Esub(1)sup(H)=(66+-4)meV and Esub(2)sup(H)=(135+-15)meV. For deuterium the first harmonics appears at Esub(1)sup(D)=(48+-4)meV. The width of the hydrogen local mode Esub(1)sup(H) is changing from 30 to 20 meV and its position from 63 to 66meV if the hydrogen concentration is altered from 2.7 to 0.2 atom percent. The intensity of the Esub(1)sup(H) mode, integrated for scattering angles from 11 0 till 68 0 and a mean k-vector pointing in the [210]-direction, is decreasing by a factor of 5 with respect to harmonic oscillator while the intensity of the second harmonic Esub(2)sup(H) and of the band modes stays almost constant if the temperature is changed from 423 0 K till 673 0 K. The behavior of this intensity distributions with temperature indicates a partition of the proton motions in diffusive and localized motions and supports the assumption of an anharmonic periodic potential along the [110] direction. The frequency distribution function of the hydrogen band modes has a shape as expected from measured dispersion curves. For [Pdsub(0.018)sup(D)-Pd] a broad quasielastic line is observed that indicates the existence of overdamped phonons in the vicinity of the impurity atom

  8. New ternary intermetallics, based magnesium, for hydrogen storage

    International Nuclear Information System (INIS)

    Roquefere, J.G.

    2009-05-01

    The use of fossil fuels (non-renewable energy) is responsible for increasing the concentration of greenhouse gases in the atmosphere. Among the considered alternatives, hydrogen is seen as the most attractive energy vector. The storage in intermetallics makes it possible to obtain mass and volume capacities (e.g. 140 g/L) higher than those obtained by liquid form or under pressure (respectively 71 and 40 g/L). We have synthesised Mg and Rare Earth based compounds (RE = Y, Ce and Gd), derived from the cubic Laves phases AB2. Their physical and chemical properties have been studied (hydrogenation, electrochemistry, magnetism,...). The conditions of sorption (P and T) are particularly favorable (i.e. absorption at room temperature and atmospheric pressure). Besides, to improve the sorption kinetics of metallic magnesium, the compounds developed previously were used as catalysts. Thus, GdMgNi4 was milled with magnesium and the speeds of absorption and desorption of the mixture are found higher than those obtained for the composites Mg+Ni or Mg+V, which are reference systems. A theoretical approach (DFT) was used to model the electronic structure of the ternary compounds (i.e. REMgNi4) and thus to predict or confirm the experimental results. (authors)

  9. Annual Report, 1998

    International Nuclear Information System (INIS)

    Buettner, Herma G.; Leadbetter, Alan J.

    1999-01-01

    In this Annual Report a selection of about 30 scientific achievements are highlighted. These are intended to represent the huge range of high quality research carried out at ILL. In 1998 about 750 experiments were performed in the 225 days of reactor operation. The fields of magnetism and strongly correlated electron systems continue to be fertile and to throw up strong new growth. Remarkable new advances are coming from the applications of both existing and new neutron techniques and the development of new materials. These highlights concern superconductors, nano-magnetic particles, colossal magneto-resistance, magnetic-nuclear correlations, quantum spin systems and more. Novel magnetic measurements are also reported for a quasicrystal and on thin films of both normal and superconducting materials. Thanks to special abilities of neutrons to penetrate matter new results were obtained: following the production of novel intermetallic compounds, pressure dependence of phonon frequencies, the structure of glasses, solutions (in both bulk and thin films) and adsorbed phases; dynamics and relaxation in liquids; the confirmation of reptant motion in linear polymers, self-assembly and shear phenomena in liquid crystals. Three important results from nuclear physics are also included. These involve: fission-produced neutron-rich nuclei, weighing gamma photons in connection with the determination of fundamental constants and the determination of interatomic potentials from the slowing down process of atoms recoiling from gamma-ray emission - a direct link between nuclear and solid-state physics. The neutron experiments of importance for particle physics and biology will be reported next year

  10. Annual Report, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Buettner, Herma G; Leadbetter, Alan J [eds.; Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1999-11-01

    In this Annual Report a selection of about 30 scientific achievements are highlighted. These are intended to represent the huge range of high quality research carried out at ILL. In 1998 about 750 experiments were performed in the 225 days of reactor operation. The fields of magnetism and strongly correlated electron systems continue to be fertile and to throw up strong new growth. Remarkable new advances are coming from the applications of both existing and new neutron techniques and the development of new materials. These highlights concern superconductors, nano-magnetic particles, colossal magneto-resistance, magnetic-nuclear correlations, quantum spin systems and more. Novel magnetic measurements are also reported for a quasicrystal and on thin films of both normal and superconducting materials. Thanks to special abilities of neutrons to penetrate matter new results were obtained: following the production of novel intermetallic compounds, pressure dependence of phonon frequencies, the structure of glasses, solutions (in both bulk and thin films) and adsorbed phases; dynamics and relaxation in liquids; the confirmation of reptant motion in linear polymers, self-assembly and shear phenomena in liquid crystals. Three important results from nuclear physics are also included. These involve: fission-produced neutron-rich nuclei, weighing gamma photons in connection with the determination of fundamental constants and the determination of interatomic potentials from the slowing down process of atoms recoiling from gamma-ray emission - a direct link between nuclear and solid-state physics. The neutron experiments of importance for particle physics and biology will be reported next year

  11. Microstructure and Tribological Properties of Mo–40Ni–13Si Multiphase Intermetallic Alloy

    Science.gov (United States)

    Song, Chunyan; Wang, Shuhuan; Gui, Yongliang; Cheng, Zihao; Ni, Guolong

    2016-01-01

    Intermetallic compounds are increasingly being expected to be utilized in tribological environments, but to date their implementation is hindered by insufficient ductility at low and medium temperatures. This paper presents a novel multiphase intermetallic alloy with the chemical composition of Mo–40Ni–13Si (at %). Microstructure characterization reveals that a certain amount of ductile Mo phases formed during the solidification process of a ternary Mo–Ni–Si molten alloy, which is beneficial to the improvement of ductility of intermetallic alloys. Tribological properties of the designed alloy—including wear resistance, friction coefficient, and metallic tribological compatibility—were evaluated under dry sliding wear test conditions at room temperature. Results suggest that the multiphase alloy possesses an excellent tribological property, which is attributed to unique microstructural features and thereby a good combination in hardness and ductility. The corresponding wear mechanism is explained by observing the worn surface, subsurface, and wear debris of the alloy, which was found to be soft abrasive wear. PMID:28774106

  12. Limitation of critical current density by intermetallic formation in fine filament Nb-Ti superconductors

    International Nuclear Information System (INIS)

    Larbalestier, D.C.; Chengren, L.; Starch, W.; Lee, P.J.

    1985-01-01

    Two experiments have been performed to investigate the role that the intermetallic reaction between the copper matrix and the Nb-Ti filaments plays in limiting the critical current density (J/sub c/) of Nb 45.6 wt% Ti composites. The first experiment involved composites which were industrially extruded. It was found that as the number of heat treatments increased, the J/sub c/ declined, the resistive transition broadened and the filaments sausaged. The filament sausaging was initiated by intermetallic particles at the filament matrix interface. A series of many heat treatment procedures were then applied to composites fabricated in the authors own laboratories without extrusion. Very high J/sub c/ values were obtained at filament sizes of 20 μm. When the same heat treatment procedures were applied to 4 - 5 μm conductors, extensive sausaging and degraded J/sub c/ values resulted. This degradation was also found to be due to the formation of Cu-Nb-Ti intermetallic compounds. It is concluded that a reliable filament diffusion barrier technology is necessary to permit full flexibility in the heat treatment of 2 - 5 μ filament Nb-Ti composites

  13. Limitation of critical current density by intermetallic formation in fine filament Nb-Ti superconductors

    International Nuclear Information System (INIS)

    Larbalestier, D.C.; Chengren, Li; Lee, P.J.; Starch, W.

    1985-01-01

    Two experiments have been performed to investigate the role that the intermetallic reaction between the copper matrix and the Nb-Ti filaments plays in limiting the critical current density (J /SUB c/ ) of Nb 46.5 wt% Ti composites. The first experiment involved composites which were industrially extruded. It was found that as the number of heat treatments increased, the J /SUB c/ declined, the resistive transition broadened and the filaments sausaged. The filament sausaging was initiated by intermetallic particles at the filament matrix interface. A series of many heat treatment procedures were then applied to composites fabricated in our own laboratories without extrusion. Very high J /SUB c/ values were obtained at filament sizes of 20 μm. When the same heat treatment procedures were applied to 4 - 5 μm conductors, extensive sausaging and degraded J /SUB c/ values resulted. This degradation was also found to be due to the formation of Cu-Nb-Ti intermetallic compounds. It is concluded that a reliable filament diffusion barrier technology is necessary to permit full flexibility in the heat treatment of 2 - 5 μm filament Nb-Ti composites

  14. First principles electronic and thermal properties of some AlRE intermetallics

    Science.gov (United States)

    Srivastava, Vipul; Sanyal, Sankar P.; Rajagopalan, M.

    2008-10-01

    A study on structural and electronic properties of non-magnetic cubic B 2-type AlRE (RE=Sc, Y, La, Ce, Pr and Lu) intermetallics has been done theoretically. The self-consistent tight binding linear muffin tin orbital method is used to describe the electronic properties of these intermetallics at ambient and at high pressure. These compounds show metallic behavior under ambient conditions. The variation of density of states under compression indicates some possibility of structural phase transformation in AlLa, AlCe and AlPr. Thermal properties like Debye temperature and Grüneisen constant are calculated at T=0 K and at ambient pressure within the Debye-Grüneisen model and compared with the others’ theoretical results. Our results are in good agreement. We have also performed a pressure-induced variation of Debye temperature and have found a decrease in Debye temperature around 40 kbar in AlRE (RE=La, Ce, Pr) intermetallics.

  15. First principles electronic and thermal properties of some AlRE intermetallics

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Vipul [Department of Physics, Barkatullah University, Hoshangabad Road, Bhopal, Madhya Pradesh 462 026 (India)], E-mail: vips73@yahoo.com; Sanyal, Sankar P. [Department of Physics, Barkatullah University, Hoshangabad Road, Bhopal, Madhya Pradesh 462 026 (India); Rajagopalan, M. [Department of Physics, Anna University, Chennai-600 025 (India)

    2008-10-01

    A study on structural and electronic properties of non-magnetic cubic B{sub 2}-type AlRE (RE=Sc, Y, La, Ce, Pr and Lu) intermetallics has been done theoretically. The self-consistent tight binding linear muffin tin orbital method is used to describe the electronic properties of these intermetallics at ambient and at high pressure. These compounds show metallic behavior under ambient conditions. The variation of density of states under compression indicates some possibility of structural phase transformation in AlLa, AlCe and AlPr. Thermal properties like Debye temperature and Grueneisen constant are calculated at T=0 K and at ambient pressure within the Debye-Grueneisen model and compared with the others' theoretical results. Our results are in good agreement. We have also performed a pressure-induced variation of Debye temperature and have found a decrease in Debye temperature around 40 kbar in AlRE (RE=La, Ce, Pr) intermetallics.

  16. Intermetallic Growth and Interfacial Properties of the Grain Refiners in Al Alloys

    Science.gov (United States)

    Li, Chunmei; Cheng, Nanpu; Chen, Zhiqian; Xie, Zhongjing; Hui, Liangliang

    2018-01-01

    Al3TM(TM = Ti, Zr, Hf, Sc) particles acting as effective grain refiners for Al alloys have been receiving extensive attention these days. In order to judge their nucleation behaviors, first-principles calculations are used to investigate their intermetallic and interfacial properties. Based on energy analysis, Al3Zr and Al3Sc are more suitable for use as grain refiners than the other two intermetallic compounds. Interfacial properties show that Al/Al3TM(TM = Ti, Zr, Hf, Sc) interfaces in I-ter interfacial mode exhibit better interface wetting effects due to larger Griffith rupture work and a smaller interface energy. Among these, Al/Al3Sc achieves the lowest interfacial energy, which shows that Sc atoms should get priority for occupying interfacial sites. Additionally, Sc-doped Al/Al3(Zr, Sc) interfacial properties show that Sc can effectively improve the Al/Al3(Zr, Sc) binding strength with the Al matrix. By combining the characteristics of interfaces with the properties of intermetallics, the core-shell structure with Al3Zr-core or Al3Zr(Sc1-1)-core encircled with an Sc-rich shell forms. PMID:29677155

  17. Microstructure and Tribological Properties of Mo–40Ni–13Si Multiphase Intermetallic Alloy

    Directory of Open Access Journals (Sweden)

    Chunyan Song

    2016-12-01

    Full Text Available Intermetallic compounds are increasingly being expected to be utilized in tribological environments, but to date their implementation is hindered by insufficient ductility at low and medium temperatures. This paper presents a novel multiphase intermetallic alloy with the chemical composition of Mo–40Ni–13Si (at %. Microstructure characterization reveals that a certain amount of ductile Mo phases formed during the solidification process of a ternary Mo–Ni–Si molten alloy, which is beneficial to the improvement of ductility of intermetallic alloys. Tribological properties of the designed alloy—including wear resistance, friction coefficient, and metallic tribological compatibility—were evaluated under dry sliding wear test conditions at room temperature. Results suggest that the multiphase alloy possesses an excellent tribological property, which is attributed to unique microstructural features and thereby a good combination in hardness and ductility. The corresponding wear mechanism is explained by observing the worn surface, subsurface, and wear debris of the alloy, which was found to be soft abrasive wear.

  18. Strong, ductile, and thermally stable Cu-based metal-intermetallic nanostructured composites.

    Science.gov (United States)

    Dusoe, Keith J; Vijayan, Sriram; Bissell, Thomas R; Chen, Jie; Morley, Jack E; Valencia, Leopolodo; Dongare, Avinash M; Aindow, Mark; Lee, Seok-Woo

    2017-01-09

    Bulk metallic glasses (BMGs) and nanocrystalline metals (NMs) have been extensively investigated due to their superior strengths and elastic limits. Despite these excellent mechanical properties, low ductility at room temperature and poor microstructural stability at elevated temperatures often limit their practical applications. Thus, there is a need for a metallic material system that can overcome these performance limits of BMGs and NMs. Here, we present novel Cu-based metal-intermetallic nanostructured composites (MINCs), which exhibit high ultimate compressive strengths (over 2 GPa), high compressive failure strain (over 20%), and superior microstructural stability even at temperatures above the glass transition temperature of Cu-based BMGs. Rapid solidification produces a unique ultra-fine microstructure that contains a large volume fraction of Cu 5 Zr superlattice intermetallic compound; this contributes to the high strength and superior thermal stability. Mechanical and microstructural characterizations reveal that substantial accumulation of phase boundary sliding at metal/intermetallic interfaces accounts for the extensive ductility observed.

  19. Lattice anisotropy in uranium ternary compounds

    DEFF Research Database (Denmark)

    Maskova, S.; Adamska, A.M.; Havela, L.

    2012-01-01

    Several U-based intermetallic compounds (UCoGe, UNiGe with the TiNiSi structure type and UNiAl with the ZrNiAl structure type) and their hydrides were studied from the point of view of compressibility and thermal expansion. Confronted with existing data for the compounds with the ZrNiAl structure...

  20. Lattice disorder in strongly correlated lanthanide and actinide intermetallics

    International Nuclear Information System (INIS)

    Booth, C.H.; Bauer, E.D.; Maple, M.B.; Lawrence, J.M.; Kwei, G.H.; Sarrao, J.L.

    2001-01-01

    Lanthanide and actinide intermetallic compounds display a wide range of correlated-electron behavior, including ferromagnetism, antiferromagnetism, nonmagnetic (Kondo) ground states, and so-called 'non-Fermi liquid' (NFL) behavior. The interaction between f electrons and the conduction band is a dominant factor in determining the ground state of a given system. However, lattice disorder can create a distribution of interactions, generating unusual physical properties. These properties may include NFL behavior in many materials. In addition, lattice disorder can cause deviations from standard Kondo behavior that is less severe than NFL behavior. A review of the lattice disorder mechanism within a tight-binding model is presented, along with measurements of the YbBCu 4 and UPd x Cu 5-x systems, demonstrating the applicability of the model. These measurements indicate that while the YbBCu 4 system appears to be well ordered, both site interchange and continuous bond-length disorder occur in the UPd x Cu 5-x series. Nevertheless, the measured bond-length disorder in UPdCu 4 does not appear to be enough to explain the NFL properties simply with the Kondo disorder model. (au)

  1. Diffusion in substitutionally disordered B2 intermetallics

    International Nuclear Information System (INIS)

    Belova, I.V.; Murch, G.E.

    2002-01-01

    In this paper, a comprehensive diffusion kinetics theory is formulated to describe seamlessly tracer and chemical diffusion in antistructurally disordered B2 intermetallics showing positive and negative deviations from stoichiometry. The theory is based around unit processes consisting of six-jump cycles that can be assisted by intrinsic and extrinsic antistructural atoms of either atomic species. The Ising alloy model is used to illustrate the formalism, but the formalism can be adapted to other models. Expressions are developed for the tracer diffusion coefficients, the phenomenological coefficients, the intrinsic diffusion coefficients, the interdiffusion coefficient and the various correlation factor components. Results for the tracer and collective correlation factors and the vacancy wind factor (in interdiffusion) are in excellent agreement with results from Monte Carlo computer simulations based around single vacancy jumps. (author)

  2. Thermomechanical processing of plasma sprayed intermetallic sheets

    Science.gov (United States)

    Hajaligol, Mohammad R.; Scorey, Clive; Sikka, Vinod K.; Deevi, Seetharama C.; Fleischhauer, Grier; Lilly, Jr., A. Clifton; German, Randall M.

    2001-01-01

    A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3% Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

  3. Persistent local chemical bonds in intermetallic phase formation

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Yanwen [Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Bian, Xiufang, E-mail: xfbian@sdu.edu.cn [Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Qin, Xubo [Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Zhang, Shuo; Huang, Yuying [Shanghai Synchrotron Radiation Facilities, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China)

    2014-05-01

    We found a direct evidence for the existence of the local chemical Bi–In bonds in the BiIn{sub 2} melt. These bonds are strong and prevail, dominating the structure evolution of the intermetallic clusters. From the local structure of the melt-quenched BiIn{sub 2} ribbon, the chemical Bi–In bonds strengthen compared with those in the equilibrium solidified alloy. The chemical bonds in BiIn{sub 2} melt retain to solid during a rapid quenching process. The results suggest that the intermetallic clusters in the melt evolve into the as-quenched intermetallic phase, and the intermetallic phase originates from the chemical bonds between unlike atoms in the melt. The chemical bonds preserve the chemical ordered clusters and dominate the clusters evolution.

  4. Magnetocaloric effect in rare-earth intermetallics: Recent trends

    Indian Academy of Sciences (India)

    ... intermetallic hydrides, manganite oxides, Ni–Mn–Sb-type shape memory ... With the help of temperature-dependent heat capacity information in various applied .... for relative cooling power and a wide working temperature range of about ...

  5. Predicting the stability of ternary intermetallics with density functional theory and machine learning

    Science.gov (United States)

    Schmidt, Jonathan; Chen, Liming; Botti, Silvana; Marques, Miguel A. L.

    2018-06-01

    We use a combination of machine learning techniques and high-throughput density-functional theory calculations to explore ternary compounds with the AB2C2 composition. We chose the two most common intermetallic prototypes for this composition, namely, the tI10-CeAl2Ga2 and the tP10-FeMo2B2 structures. Our results suggest that there may be ˜10 times more stable compounds in these phases than previously known. These are mostly metallic and non-magnetic. While the use of machine learning reduces the overall calculation cost by around 75%, some limitations of its predictive power still exist, in particular, for compounds involving the second-row of the periodic table or magnetic elements.

  6. The adsorption and reaction of halogenated volatile organic compounds (VOC's) on metal oxides. 1998 annual progress report

    International Nuclear Information System (INIS)

    Goodman, D.W.; Haw, J.F.; Lunsford, J.

    1998-01-01

    'The goal of the research is to elucidate the properties of the materials responsible for the activation of halocarbons and the nature of the intermediates formed in the dissociative adsorption of this class of compounds. This information is essential for interpreting and predicting stoichiometric and catalytic pathways for the safe destruction of halocarbon pollutants. The specific objectives are: (1) to study the adsorption and reactivity of chloromethanes and chloroethanes on metal oxides; (2) to identify the reaction intermediates using spectroscopic methods; and (3) to develop kinetic models for the reaction of these halocarbons with oxide surfaces. This report summarizes work after 20 months of a 36-month project. Emphasis has been placed understanding the surfaces phases, as well as the bulk phases that are present during the reactions of chlorinated hydrocarbons with strongly basic metal oxides. Most of the research has been carried out with carbon tetrachloride.'

  7. The influence of the surface distribution of Al6(MnFe) intermetallic on the electrochemical response of AA5083 aluminium alloy in NaCl solutions

    International Nuclear Information System (INIS)

    Bethencourt, M.; Botana, F.J.; Calvino, J.J.; Perez, J.; Rodriguez, M.A.; Marcos, M.

    1998-01-01

    In this paper the behaviour against pitting corrosion of different samples of AA5083 aluminium alloy has been studied. A correlation between the microstructure of the samples and their susceptibility to pitting has been established. Metallographic analysis combined with SEM and EDS techniques have allowed us to detect three intermetallic compounds in the samples. The particle size distribution and surface density of each intermetallic phase have been evaluated for the three AA5083 alloy samples coming from different suppliers. Significant differences in the microstructure of the three samples have been found. Full immersion test carried out in 3.5% aerated aqueous solutions showed that pitting starts at the locations of the Al 6 (MnFe) intermetallic particles. As a consequence of this, the samples with higher Al 6 (MnFe) content showed a higher pit density on its surface. The results of cyclic polarisation tests showed also a good correlation with the microstructural parameters. (orig.)

  8. Ground state searches in fcc intermetallics

    International Nuclear Information System (INIS)

    Wolverton, C.; de Fontaine, D.; Ceder, G.; Dreysse, H.

    1991-12-01

    A cluster expansion is used to predict the fcc ground states, i.e., the stable phases at zero Kelvin as a function of composition, for alloy systems. The intermetallic structures are not assumed, but derived regorously by minimizing the configurational energy subject to linear constraints. This ground state search includes pair and multiplet interactions which spatially extend to fourth nearest neighbor. A large number of these concentration-independent interactions are computed by the method of direct configurational averaging using a linearized-muffin-tin orbital Hamiltonian cast into tight binding form (TB-LMTO). The interactions, derived without the use of any adjustable or experimentally obtained parameters, are compared to those calculated via the generalized perturbation method extention of the coherent potential approximation within the context of a KKR Hamiltonian (KKR-CPA-GPM). Agreement with the KKR-CPA-GPM results is quite excellent, as is the comparison of the ground state results with the fcc-based portions of the experimentally-determined phase diagrams under consideration

  9. Thermal stress effects in intermetallic matrix composites

    Science.gov (United States)

    Wright, P. K.; Sensmeier, M. D.; Kupperman, D. S.; Wadley, H. N. G.

    1993-01-01

    Intermetallic matrix composites develop residual stresses from the large thermal expansion mismatch (delta-alpha) between the fibers and matrix. This work was undertaken to: establish improved techniques to measure these thermal stresses in IMC's; determine residual stresses in a variety of IMC systems by experiments and modeling; and, determine the effect of residual stresses on selected mechanical properties of an IMC. X ray diffraction (XRD), neutron diffraction (ND), synchrotron XRD (SXRD), and ultrasonics (US) techniques for measuring thermal stresses in IMC were examined and ND was selected as the most promising technique. ND was demonstrated on a variety of IMC systems encompassing Ti- and Ni-base matrices, SiC, W, and Al2O3 fibers, and different fiber fractions (Vf). Experimental results on these systems agreed with predictions of a concentric cylinder model. In SiC/Ti-base systems, little yielding was found and stresses were controlled primarily by delta-alpha and Vf. In Ni-base matrix systems, yield strength of the matrix and Vf controlled stress levels. The longitudinal residual stresses in SCS-6/Ti-24Al-llNb composite were modified by thermomechanical processing. Increasing residual stress decreased ultimate tensile strength in agreement with model predictions. Fiber pushout strength showed an unexpected inverse correlation with residual stress. In-plane shear yield strength showed no dependence on residual stress. Higher levels of residual tension led to higher fatigue crack growth rates, as suggested by matrix mean stress effects.

  10. Effect of intermetallic precipitation on the properties of multi passed duplex stainless steel weldment

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Seong Han [Technology research institute, Ulsan (Korea, Republic of); Lee, Hae Woo [Dong-A University, Busan (Korea, Republic of)

    2014-01-15

    This study investigated the effect of the aging time of weldment of 24Cr-3.5Mo duplex stainless steel on the microstructure and corrosion behavior. After performing FCAW, we carried out heat treatments at varying times at 850 ℃ and performed observation of microstructure, potentio dynamic test, SEM-EDS analysis, and X-ray diffraction analysis. As the aging time increased, the fraction of δ-ferrite decreased sharply, but the fraction of γ slightly increased. The σ phase was generated at a non-metallic inclusion along the grain boundaries of δ-ferrite and γ, while the χ phase was generated in the structure of δ-ferrite. As the intermetallic compounds increased, the critical pitting potential fell sharply, and PREN of the surrounding structure decreased by 5 due to precipitation of the σ phase in 3.5% NaCl at 60 ℃. Pitting occurred intensively under a multi-pass line which relatively had more intermetallic compounds, and the precipitation of the σ phase caused the formation of Cr carbide.

  11. Effect of intermetallic precipitation on the properties of multi passed duplex stainless steel weldment

    International Nuclear Information System (INIS)

    Bae, Seong Han; Lee, Hae Woo

    2014-01-01

    This study investigated the effect of the aging time of weldment of 24Cr-3.5Mo duplex stainless steel on the microstructure and corrosion behavior. After performing FCAW, we carried out heat treatments at varying times at 850 ℃ and performed observation of microstructure, potentio dynamic test, SEM-EDS analysis, and X-ray diffraction analysis. As the aging time increased, the fraction of δ-ferrite decreased sharply, but the fraction of γ slightly increased. The σ phase was generated at a non-metallic inclusion along the grain boundaries of δ-ferrite and γ, while the χ phase was generated in the structure of δ-ferrite. As the intermetallic compounds increased, the critical pitting potential fell sharply, and PREN of the surrounding structure decreased by 5 due to precipitation of the σ phase in 3.5% NaCl at 60 ℃. Pitting occurred intensively under a multi-pass line which relatively had more intermetallic compounds, and the precipitation of the σ phase caused the formation of Cr carbide.

  12. Dynamic modeling of a solar ORC with compound parabolic collectors: Annual production and comparison with steady-state simulation

    International Nuclear Information System (INIS)

    Baccioli, A.; Antonelli, M.; Desideri, U.

    2017-01-01

    Highlights: • A small scale solar ORC was investigated during a year-long simulation. • The system was operated without a thermal storage. • High flexibility thanks to a sliding-velocity control and volumetric expander. • Influence of ORC and solar field parameters considered. • Strong influence of concentration factor and system inertia. - Abstract: In this paper the dynamic behavior of a small low-concentration solar plant with static Compound Parabolic Collectors (CPC) and an ORC power unit with rotary volumetric expander has been analyzed. The plant has been simulated in transient conditions for a year-long operation and for three different sites respectively located in northern, central and southern Italy, in order to evaluate the influence of the latitude on the production. Hourly discretized data for solar radiation and for ambient temperature have been used. The adoption of a sliding-velocity control strategy, has allowed to operate without any storage system with a solar multiple (S.M.) of 1, reducing the amplitude of the solar field and simplifying the control system. Different collectors tilt angles and concentration factors, as well as thermodynamic parameters of the cycle have been tested, to evaluate the optimal working conditions for each locality. Results highlighted that specific production increased with the concentration ratio, and with the decrease of latitude. The comparison with the steady-state analysis showed that this type of control strategy is suited for those configurations having a smaller number of collectors, since the thermal inertia of the solar field is not recovered at all during the plant shut-down phase.

  13. Studies of hydrogen absorption and desorption processes in advanced intermetallic hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Masashi

    2005-07-01

    This work is a part of the research program performed in the Department of Energy Systems, Institute for Energy Technology (Kjeller, Norway), which is focused on the development of the advanced hydrogen storage materials. The activities are aimed on studies of the mechanisms of hydrogen interactions with intermetallic alloys with focus on establishing an interrelation between the crystal structure, thermodynamics and kinetics of the processes in the metal-hydrogen systems, on the one hand, and hydrogen storage properties (capacity, rates of desorption, hysteresis). Many of the materials under investigation have potential to be applied in applications, whereas some already have been commercialised in the world market. A number of metals take up considerable amounts of hydrogen and form chemical compounds with H, metal hydrides. Unfortunately, binary hydrides are either very stable (e.g. for the rare earth metals [RE], Zr, Ti, Mg: metal R) or are formed at very high applied pressures of hydrogen gas (e.g. for the transition metals, Ni, Co, Fe, etc.: Metal T). However, hydrogenation process becomes easily reversible at very convenient from practical point of view conditions, around room temperature and at H2 pressures below 1 MPa for the two-component intermetallic alloys R{sub x}T{sub y}. This raised and maintains further interest to the intermetallic hydrides as solid H storage materials. Materials science research of this thesis is focused on studies of the reasons staying behind the beneficial effect of two non-transition elements M(i.e., In and Sn) contributing to the formation of the ternary intermetallic alloys R{sub x}T{sub y}M{sub 2}., on the hydrogen storage behaviours. Particular focus is on two aspects where the remarkable improvement of ordinary metal hydrides is achieved via introduction of In and Sn: a) Increase of the volume density of stored hydrogen in solid materials to the record high level. b) Improvement of the kinetics of hydrogen charge and

  14. Magnetic properties of the LaCu5-xCox compounds

    International Nuclear Information System (INIS)

    Crisan, V.; Popescu, V.; Vernes, A.; Andreica, D.; Cristea, S.; Koepe, B.

    1996-01-01

    Magnetic moments and Curie temperatures of the intermetallic compounds LaCu 5-x Co x (x = 5) are calculated using a recursion method in the framework of the spin-fluctuation theory of Mohn and Wohlfarth. (orig.)

  15. Microstructure and electrode performance of AB5-type hydride-forming compounds

    NARCIS (Netherlands)

    Notten, P.H.L.

    1998-01-01

    A interesting experimental technique is proposed to investigate the hydrideformation/ decomposition reaction of intermetallic compounds. This X-ray diffraction (XRD) technique combines hydrogen absorptionldesorption measure ments with in situ XRD measurements. A high pressure XRD cell allows gas

  16. Mechanical properties of aluminium matrix composites reinforced with intermetallics

    International Nuclear Information System (INIS)

    Torres, B.; Garcia-Escorial, A.; Ibanez, J.; Lieblich, M.

    2001-01-01

    In this work 2124 aluminium matrix composites reinforced with Ni 3 Al, NiAl, MoSi 2 and Cr 3 Si intermetallic powder particles have been investigated. For comparison purposes, un reinforced 2124 and reinforced with SiC have also been studied. In all cases, the same powder metallurgy route was used, i. e. the 2124 alloy was obtained by rapid solidification and the intermetallic particles by self-propagating high-temperature synthesis (SHS). The matrix and the intermetallics were mechanically blended, cold compacted and finally hot extruded. Tensile tests were carried out in T1 and T4 treatments. Results indicate that mechanical properties depend strongly on the tendency to form new phases at the matrix-intermetallic interface during processing and/or further thermal treatments. The materials which present better properties are those that present less reaction between matrix and intermetallic reinforcement, i. e. MoSi 2 and SiC reinforced composites. (Author) 9 refs

  17. Electronic structure, elasticity, bonding features and mechanical behaviour of zinc intermetallics: A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Fatima, Bushra, E-mail: bushrafatima25@gmail.com; Acharya, Nikita; Sanyal, Sankar P. [Department of Physics, Barkatullah University, Bhopal, 462026 (India)

    2016-05-06

    The structural stability, electronic structure, elastic and mechanical properties of TiZn and ZrZn intermetallics have been studied using ab-initio full potential linearized augmented plane wave (FP-LAPW) method within generalized gradient approximation for exchange and correlation potentials. The various structural parameters, such as lattice constant (a{sub 0}), bulk modulus (B), and its pressure derivative (B’) are analysed and compared. The investigation of elastic constants affirm that both TiZn and ZrZn are elastically stable in CsCl (B{sub 2} phase) structure. The electronic structures have been analysed quantitatively from the band structure which reveals the metallic nature of these compounds. To better illustrate the nature of bonding and charge transfer, we have also studied the Fermi surfaces. The three well known criterion of ductility namely Pugh’s rule, Cauchy’s pressure and Frantsevich rule elucidate the ductile nature of these compounds.

  18. Hybridization and pressure effects in UTX compounds

    Czech Academy of Sciences Publication Activity Database

    Alsmadi, A. M.; Sechovský, V.; Lacerda, A. H.; Prokes, K.; Kamarád, Jiří; Chang, S.; Jung, M. H.; Nakotte, H.

    2002-01-01

    Roč. 91, - (2002), s. 8123-8125 ISSN 0021-8979 Institutional research plan: CEZ:AV0Z1010914 Keywords : UTX intermetallic compounds * pressure effects magnetoresistance Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.281, year: 2002

  19. Superplastic ceramics and intermetallics and their potential applications

    International Nuclear Information System (INIS)

    Wadsworth, J.; Nieh, T.G.

    1994-11-01

    Recent advances in the basic understanding of superplasticity and superplastic forming of ceramics and intermetallics are reviewed. Fine-grained superplastic ceramics, including yttria-stabilized tetragonal zirconia polycrystal, Y- or MgO-doped Al 2 O 3 Hydroxyapatite, β-spodumene glass ceramics, Al 2 0 3 -YTZP two-phase composites, SiC-Si 3 N 4 and Fe-Fe 3 C composites, are discussed. Superplasticity in the nickel-base (e.g., Ni 3 Al and Ni 3 Si) and titanium-base intermetallics (TiAl and T1 3 Al), is described. Deformation mechanisms as well as microstructural requirements and effects such as grain size, grain growth, and grain-boundary phases, on the superplastic deformation behavior am addressed. Factors that control the superplastic tensile elongation of ceramics are discussed. Superplastic forming, and particularly biaxial gas-pressure forming, of several ceramics and intermetallics are presented with comments on the likelihood of commercial application

  20. X-ray diffraction study of the phase purity, order and texture of ductile B2 intermetallics

    Energy Technology Data Exchange (ETDEWEB)

    Mulay, R.P.; Wollmershauser, J.A.; Heisel, M.A. [Materials Science and Engineering, University of Virginia, Charlottesville, VA 22904-4745 (United States); Bei, H. [Oak Ridge National Laboratory, Material Science and Technology Division, Oak Ridge, TN 37831 (United States); Russell, A.M. [Iowa State University, Department of Materials Science and Engineering, Ames, IA 50011 (United States); Agnew, S.R., E-mail: sra4p@virginia.edu [Materials Science and Engineering, University of Virginia, Charlottesville, VA 22904-4745 (United States)

    2010-04-15

    Representatives (AgY, CuY, AgEr, CuDy, MgY and MgCe) of the newly discovered family of ductile stoichiometric B2 intermetallic (metal-rare-earth element, MR) compounds were characterized by X-ray diffraction, to determine if their anomalous ductility is related to an exceptional level of phase purity, lack of chemical ordering or a strong crystallographic texture. Brittle NiAl served as an anti-type in this study. We found that all of the rare-earth compounds, except MgY, have a significant volume fraction ({approx}5-20 vol.%) of second phases (M{sub 2}R intermetallics and R{sub 2}O{sub 3} oxides), which has not been reported in previous studies of these materials. The most ductile of observed MR compounds, AgY, is highly ordered. A moderate texture was observed in AgY, which may explain its higher ductility (using polycrystal modeling) as compared to other MR compounds. However, the intrinsic polycrystalline ductility of these compounds in the randomly textured state (like that observed in CuY) still has no specific, definitive explanation.

  1. X-ray diffraction study of the phase purity, order and texture of ductile B2 intermetallics

    International Nuclear Information System (INIS)

    Mulay, R.P.; Wollmershauser, J.A.; Heisel, M.A.; Bei, H.; Russell, A.M.; Agnew, S.R.

    2010-01-01

    Representatives (AgY, CuY, AgEr, CuDy, MgY and MgCe) of the newly discovered family of ductile stoichiometric B2 intermetallic (metal-rare-earth element, MR) compounds were characterized by X-ray diffraction, to determine if their anomalous ductility is related to an exceptional level of phase purity, lack of chemical ordering or a strong crystallographic texture. Brittle NiAl served as an anti-type in this study. We found that all of the rare-earth compounds, except MgY, have a significant volume fraction (∼5-20 vol.%) of second phases (M 2 R intermetallics and R 2 O 3 oxides), which has not been reported in previous studies of these materials. The most ductile of observed MR compounds, AgY, is highly ordered. A moderate texture was observed in AgY, which may explain its higher ductility (using polycrystal modeling) as compared to other MR compounds. However, the intrinsic polycrystalline ductility of these compounds in the randomly textured state (like that observed in CuY) still has no specific, definitive explanation.

  2. Transformation of iron containing constituent intermetallic particles during hydrothermal treatment

    DEFF Research Database (Denmark)

    Borgaonkar, Shruti; Din, Rameez Ud; Kasama, Takeshi

    2018-01-01

    in the alloys. Furthermore, electron energy loss spectroscopy analysis revealed that the during the steam treatment, the Fe enriched areas of the Al (Fe-Si) Mn type intermetallic particles were transformed into Fe2O3 and Fe3O4 phases, while energy-dispersive X-ray spectroscopy line profile measurements...... by scanning transmission electron microscope showed that Mn and Si were leached out and incorporated into the surrounding oxide layer. Further, the part of intermetallic phase was transformed into polycrystalline material....

  3. Characterization of intermetallics in aluminum to zinc coated interstitial free steel joining by pulsed MIG brazing for automotive application

    Energy Technology Data Exchange (ETDEWEB)

    Basak, Sushovan, E-mail: sushovanbasak@gmail.com [Metallurgical and Material Engineering Department, Jadavpur University, Kolkata–700032 (India); Das, Hrishikesh, E-mail: hrishichem@gmail.com [Metallurgical and Material Engineering Department, Jadavpur University, Kolkata–700032 (India); Pal, Tapan Kumar, E-mail: tkpal.ju@gmail.com [Metallurgical and Material Engineering Department, Jadavpur University, Kolkata–700032 (India); Shome, Mahadev, E-mail: mshome@tatasteel.com [Material Characterization & Joining Group, R & D, Tata Steel, Jamshedpur–831007 (India)

    2016-02-15

    In order to meet the demand for lighter and more fuel efficient vehicles, a significant attempt is currently being focused toward the substitution of aluminum for steel in the car body structure. It generates vital challenge with respect to the methods of joining to be used for fabrication. However, the conventional fusion joining has its own difficulty owing to formation of the brittle intermetallic phases. In this present study AA6061-T6 of 2 mm and HIF-GA steel sheet of 1 mm thick are metal inert gas (MIG) brazed with 0.8 mm Al–5Si filler wire under three different heat inputs. The effect of the heat inputs on bead geometry, microstructure and joint properties of MIG brazed Al-steel joints were exclusively studied and characterized by X-ray diffraction, field emission scanning electron microscopy (FESEM), electron probe micro analyzer (EPMA) and high resolution transmission electron microscopy (HRTEM) assisted X-ray spectroscopy (EDS) and selective area diffraction pattern. Finally microstructures were correlated with the performance of the joint. Diffusion induced intermetallic thickness measured by FESEM image and concentration profile agreed well with the numerically calculated one. HRTEM assisted EDS study was used to identify the large size FeAl{sub 3} and small size Fe{sub 2}Al{sub 5} type intermetallic compounds at the interface. The growth of these two phases in A2 (heat input: 182 J mm{sup −1}) is attributed to the slower cooling rate with higher diffusion time (~ 61 s) along the interface in comparison to the same for A1 (heat input: 155 J mm{sup −1}) with faster cooling rate and shorter diffusion time (~ 24 s). The joint efficiency as high as 65% of steel base metal is achieved for A2 which is the optimized parameter in the present study. - Highlights: • AA 6061 and HIF-GA could be successfully joined by MIG brazing. • Intermetallics are exclusively studied and characterized by XRD, FESEM and EPMA. • Intermetallic formation by diffusion is

  4. Influence of the ion implantation on the nanoscale intermetallic phases formation in Ni-Ti system

    International Nuclear Information System (INIS)

    Kalashnikov, M.P.; Kurzina, I.A.; Bozhko, I.A.; Kozlov, E.V.; Fortuna, S.V.; Sivin, D.O.; Stepanov, I.B.; Sharkeev, Yu.P.

    2005-01-01

    Full text: The ion implantation at a high intensity mode is an effective method for modification of the surface properties of metals and alloys. Improvement of mechanical and tribological properties of irradiated materials using the high intensity implantation is connected with an element composition and microstructure modification of the surface and subsurface layers. One shows a great interest in intermetallic phase's synthesis by ion implantation, because of unique physical-mechanical properties of the intermetallic compounds. The influence of the irradiation conditions on the structural state and surface properties of implanted materials is not clear enough. The study of the factors influencing on the formation of the surface ion - alloyed layers of metal targets having the high tribological and mechanical properties by high intensity ion implantation is actual. The aim of the present work is a study of the microstructure, phase composition, physical and mechanical properties of the ion-alloyed Ni surfaces formed at high intensity implantation of Ti ions. The implantation Ti ions into Ni samples at high intensity mode was realized using ion source 'Raduga - 5'. The implantation Ti ions into Ni was carried out at accelerating voltage 20 kV for 2 h. The regimes were differed in the samples temperature (580 - 700 K), the distance from the ion implanted samples to the ion source (0.43-0.93 m) and the dose of irradiated ions (0.3·10 18 -2.9·10 18 ion/cm -2 ). The element composition of the implanted samples was analyzed by the electron spectroscopy. The structural-phase state of the Ni ion-modified layers was investigated by the transmission electron microscopy and X-ray diffraction methods. Additionally, the investigation of mechanical and tribological properties of the implanted Ni samples was carried out. It was established that the maximum thickness of the ion-alloyed nickel layers at high intensity mode allows forming the nanoscale intermetallic phases (Ni

  5. Stability of ZrBe17, and NiBe intermetallics during intermediate temperature oxidation

    International Nuclear Information System (INIS)

    Chou, T.C.; Nieh, T.G.; Wadsworth, J.

    1992-01-01

    This paper reports that since the finding of MoSi 2 pest by Fitzer in 1955, a number of intermetallic compounds, e.g., ZrBe 13 , WSi 2 , and NiAl have also been reported to exhibit similar behavior during oxidation in air. For example, Lewis reported that catastrophic failure (total disintegration into powders) occurred in ZrBe 13 when oxidized at 700 degrees C in air. X-ray diffraction analyses revealed that the powders were composed of BeO, ZrO 2 (cubic), Zr 2 Be 17 , and unreacted ZrBe 13 . Regardless of numerous cited incidents of pest in intermetallics, fundamental understanding of pest is very limited. Recently, MoSi 2 pest has been studied in a great detail and fundamental insights to the mechanism of pest have been established. It is found that both single- and ply- crystalline MoSi 2 are susceptible to pest, which leads to the disintegration of test samples into powder consisting of MoO 3 whiskers, SiP 2 clusters, and residual MoSi 2 crystals. Pest is also noted to associate with substantial volume expansion of the samples. Most important, the occurrence of pest is contingent upon the formation of blisters, resulting from volume expansion by oxidation and the evaporation of MoO 3 on the surfaces and grain boundary interfaces

  6. Preparation of Fe-Al Intermetallic / TiC-Al2O3 Ceramic Composites from Ilmenite by SHS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Fe-Al intermetallic/TiC-Al2O3 ceramic composites were successfully prepared by self-propagating high-temperature synthesis (SHS) from natural ilmenite, aluminium and carbon as the raw materials. The effects of carbon sources, preheating time and heat treatment temperature on synthesis process and products were investigated in detail, and the reaction process of the FeTiO3-Al-C system was also discussed.It is shown that the temperature and velocity of the combustion wave are higher when graphite is used as the carbon source, which can reflect the effect of the carbon source structure on the combustion synthesis;Prolonging the preheating time or heat treatment temperature is beneficial to the formation of the ordered intermetallics; The temperature and velocity of the combustion wave arc improved, but the disordered alloys are difficult to eliminate with the preheating time prolonged. The compound powders mainly containing ordered Fe3Al intermetallic can be prepared through heat treatment at 750 ℃.

  7. Structural plasticity: how intermetallics deform themselves in response to chemical pressure, and the complex structures that result.

    Science.gov (United States)

    Berns, Veronica M; Fredrickson, Daniel C

    2014-10-06

    Interfaces between periodic domains play a crucial role in the properties of metallic materials, as is vividly illustrated by the way in which the familiar malleability of many metals arises from the formation and migration of dislocations. In complex intermetallics, such interfaces can occur as an integral part of the ground-state crystal structure, rather than as defects, resulting in such marvels as the NaCd2 structure (whose giant cubic unit cell contains more than 1000 atoms). However, the sources of the periodic interfaces in intermetallics remain mysterious, unlike the dislocations in simple metals, which can be associated with the exertion of physical stresses. In this Article, we propose and explore the concept of structural plasticity, the hypothesis that interfaces in complex intermetallic structures similarly result from stresses, but ones that are inherent in a defect-free parent structure, rather than being externally applied. Using DFT-chemical pressure analysis, we show how the complex structures of Ca2Ag7 (Yb2Ag7 type), Ca14Cd51 (Gd14Ag51 type), and the 1/1 Tsai-type quasicrystal approximant CaCd6 (YCd6 type) can all be traced to large negative pressures around the Ca atoms of a common progenitor structure, the CaCu5 type with its simple hexagonal 6-atom unit cell. Two structural paths are found by which the compounds provide relief to the Ca atoms' negative pressures: a Ca-rich pathway, where lower coordination numbers are achieved through defects eliminating transition metal (TM) atoms from the structure; and a TM-rich path, along which the addition of spacer Cd atoms provides the Ca coordination environments greater independence from each other as they contract. The common origins of these structures in the presence of stresses within a single parent structure highlights the diverse paths by which intermetallics can cope with competing interactions, and the role that structural plasticity may play in navigating this diversity.

  8. High-pressure structural stability of the ductile intermetallic ...

    Indian Academy of Sciences (India)

    Administrator

    Murnaghan equation of state fit to the pressure, volume data yielded a bulk modulus of 67∙6 GPa with the pressure derivative of bulk modulus fixed at 4. Keywords. Intermetallics; X-ray ... ners of the unit cell cube occupied by the 'M' element and cube centre occupied by the 'R' element. Although some ductility has been ...

  9. Magnetic properties of RNi5-xCux intermetallics

    International Nuclear Information System (INIS)

    Kuchin, A.G.; Ermolenko, A.S.; Kulikov, Yu.A.; Khrabrov, V.I.; Rosenfeld, E.V.; Makarova, G.M.; Lapina, T.P.; Belozerov, Ye.V.

    2006-01-01

    The magnetic properties have been studied for the series of RNi 5-x Cu x intermetallics with R=Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu; x= 5-x Cu x but GdNi 5-x Cu x . These results are explained in the frame of band magnetism, random local crystal field, and domain wall pinning theories

  10. Investigation on thixojoining to produce hybrid components with intermetallic phase

    Science.gov (United States)

    Seyboldt, Christoph; Liewald, Mathias

    2018-05-01

    Current research activities at the Institute for Metal Forming Technology of the University of Stuttgart are focusing on the manufacturing of hybrid components using semi-solid forming strategies. One process investigated is the joining of different materials in the semi-solid state and is so called "thixojoining". In this process, metallic inlays are inserted into the semi-solid forming die before the actual forming process and are then joined with a material which was heated up to its semi-solid state. Earlier investigations have shown that using this process a very well-shaped form closure can be produced. Furthermore, it was found that sometimes intermetallic phases are built between the different materials, which decisively influence the part properties of such hybrid components for its future application. Within the framework presented in this paper, inlays made of aluminum, brass and steel were joined with aluminum in the semi-solid state. The aim of the investigations was to create an intermetallic bond between the different materials. For this investigations the liquid phase fraction of the aluminum and the temperature of the inlay were varied in order to determine the influence on the formation of the intermetallic phase. Forming trials were performed using a semi-solid forming die with a disk shaped design. Furthermore, the intermetallic phase built was investigated using microsections.

  11. Studies in group IV organometallic chemistry XXX. Synthesis of compounds containing tin---titanium and tin---zirconium bonds

    NARCIS (Netherlands)

    Creemers, H.M.J.C.; Verbeek, F.; Noltes, J.G.

    1968-01-01

    Starting from the tetrakis(diethylamino) derivatives of titanium and zirconium and pheyltin hydrides six intermetalic compounds contianing up to nine tin and titanium(or zirconium) atoms have been obtained by hydrostannolysis type reactions.

  12. Post-heat treatment of arc-sprayed coating prepared by the wires combination of Mg-cathode and Al-anode to form protective intermetallic layers

    International Nuclear Information System (INIS)

    Xu Rongzheng; Song Gang

    2011-01-01

    A Mg-Al intermetallic compounds coating was prepared on the surface of Mg-steel lap joint by arc-sprayed Al-Mg composite coating (Mg-cathode and Al-anode) and its post-heat treatment (PHT). The effect of PHT temperature on the phase transition, microstructure and mechanical properties of the coating was investigated by X-ray diffraction, scanning electron microscope, energy dispersive X-ray spectroscopy, optical microscope and microhardness test. The result shows that the intermetallic compounds layer that is mainly composed of Al 3 Mg 2 and Mg 17 Al 12 is formed by the self-diffusion reaction of Mg and Al splats in the coating after PHT for 4 h at 430 deg. C.

  13. Advances in processing of NiAl intermetallic alloys and composites for high temperature aerospace applications

    Science.gov (United States)

    Bochenek, Kamil; Basista, Michal

    2015-11-01

    Over the last few decades intermetallic compounds such as NiAl have been considered as potential high temperature structural materials for aerospace industry. A large number of investigations have been reported describing complex fabrication routes, introducing various reinforcing/alloying elements along with theoretical analyses. These research works were mainly focused on the overcoming of main disadvantage of nickel aluminides that still restricts their application range, i.e. brittleness at room temperature. In this paper we present an overview of research on NiAl processing and indicate methods that are promising in solving the low fracture toughness issue at room temperature. Other material properties relevant for high temperature applications are also addressed. The analysis is primarily done from the perspective of NiAl application in aero engines in temperature regimes from room up to the operating temperature (over 1150 °C) of turbine blades.

  14. Effects of Nb content on the Zr{sub 2}Fe intermetallic stability

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, C. E-mail: ciramos@cnea.gov.ar; Saragovi, C.; Granovsky, M.; Arias, D

    2003-02-01

    With the aim of studying the stability range of the Zr{sub 2}Fe intermetallic when adding Nb, the range of existence of the cubic ternary phase ({lambda}{sub 1}) and the corresponding two-phase field between them, four samples were analyzed, each one containing 35 at.% Fe and different at.% Nb: 0.5, 4 10 and 15. Optical and scanning electron metallographies, X-ray diffraction, microprobe analysis and Moessbauer spectroscopy were performed to determine and characterize the phases present in the samples. Results show that the Zr{sub 2}Fe compound accepts up to nearly 0.5 at.% Nb in solution, since the Zr{sub 2}Fe+{lambda}{sub 1} region is stable in the (0.5-3.5) at.% Nb range. To summarize these results an 800 deg. C section of the ternary Zr-Nb-Fe diagram, in the studied zone, was proposed.

  15. Effects of Nb content on the Zr2Fe intermetallic stability

    International Nuclear Information System (INIS)

    Ramos, C.; Saragovi, C.; Granovsky, M.; Arias, D.

    2003-01-01

    With the aim of studying the stability range of the Zr 2 Fe intermetallic when adding Nb, the range of existence of the cubic ternary phase (λ 1 ) and the corresponding two-phase field between them, four samples were analyzed, each one containing 35 at.% Fe and different at.% Nb: 0.5, 4 10 and 15. Optical and scanning electron metallographies, X-ray diffraction, microprobe analysis and Moessbauer spectroscopy were performed to determine and characterize the phases present in the samples. Results show that the Zr 2 Fe compound accepts up to nearly 0.5 at.% Nb in solution, since the Zr 2 Fe+λ 1 region is stable in the (0.5-3.5) at.% Nb range. To summarize these results an 800 deg. C section of the ternary Zr-Nb-Fe diagram, in the studied zone, was proposed

  16. Size and surface AREA analysis of some metallic and intermetallic powders

    International Nuclear Information System (INIS)

    Elmasry, M.A.A.; Elsayed, A.A.; Abadir, M.F.

    1988-01-01

    The powder characterization of three intermetallic compounds ( Cr B, B 4 c and S ib 4 ) and three metallic powders (Fe, Co, and Ni) has been performed. This included the determination of powder density, chemical analysis, impurity analysis, shape factor, particle size analysis and specific surface area. The particle size analysis for the six powders was carried out using three techniques, namely; the 0-23, the microtrac and the fisher sub sieve and size. It was found that the analysis of the two powders and deviates from the log-normal probability distribution and the deviation was corrected. The specific surface area of the powders was measured using the high speed surface area analysis (BET method), and it was also calculated from surface area analysis findings, the BET technique was found to give the highest specific surface area values, and was attributed to the inclusion of internal porosity in the measurement. 8 fig., 10 tab

  17. The possibility to use TiAl intermetallics for high temperature applications

    International Nuclear Information System (INIS)

    Molotkov, A.V.

    1993-01-01

    Titanium aluminide TiAl is the promising heat resisting structural material with operation temperature up to 850-900 deg C. This intermetallic compound is characterized by low density and high specific values of elasticity moduli and heat resistance properties in wide temperature range, as compared to known heat resisting titanium, iron and nickel base alloys. Test batch of pressed blades was manufactured of TiAl with the use of powder technology. Results of testing showed, that endurance strength of blades exceeded by 30% the strength, required for operation. The calculations showed, that the use of such blades in gas-turbine cagines could provide 30-40% decrease of mass of compressor blading

  18. Reliable and cost effective design of intermetallic Ni2Si nanowires and direct characterization of its mechanical properties

    OpenAIRE

    Seung Zeon Han; Joonhee Kang; Sung-Dae Kim; Si-Young Choi; Hyung Giun Kim; Jehyun Lee; Kwangho Kim; Sung Hwan Lim; Byungchan Han

    2015-01-01

    We report that a single crystal Ni2Si nanowire (NW) of intermetallic compound can be reliably designed using simple three-step processes: casting a ternary Cu-Ni-Si alloy, nucleate and growth of Ni2Si NWs as embedded in the alloy matrix via designing discontinuous precipitation (DP) of Ni2Si nanoparticles and thermal aging, and finally chemical etching to decouple the Ni2Si NWs from the alloy matrix. By direct application of uniaxial tensile tests to the Ni2Si NW we characterize its mechanica...

  19. Crystal Growth and Characterization of MT2Si2 Ternary Intermetallics (M = U, RE and T = 3d, 4d, 5d Transition Metals)

    NARCIS (Netherlands)

    Menovsky, A.A.; Moleman, A.C.; Snel, G.E.; Gortenmulder, T.J.; Palstra, T.T.M.

    1986-01-01

    Bulk single crystals of the ternary intermetallic compounds UT2Si2 (T = Ni, Pd, Pt and Ru), LaT2Si2 (T = Pd and Rh) and LuPd2Si2 have been grown from the melt with a modified “tri-arc” Czochralski method. The as-grown crystals were characterized by X-ray, microprobe and chemical analyses. The

  20. Magnetic propertiesof Lu.sub.2./sub.Fe.sub.16./sub.X (X = Fe, Ni, Cr, Si) intermetallics under high hydrostatic pressure

    Czech Academy of Sciences Publication Activity Database

    Kamarád, Jiří; Andreev, Alexander V.; Machátová, Zuzana; Arnold, Zdeněk

    408-412, - (2006), s. 151-154 ISSN 0925-8388 R&D Projects: GA ČR(CZ) GA202/02/0739; GA MŠk(CZ) ME 495 Institutional research plan: CEZ:AV0Z10100521 Keywords : intermetallic compounds * Lu 2 Fe 17 * magnetic properties * high pressure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.250, year: 2006

  1. Antiferromagnetism, structural instability and frustration in intermetallic AFe4X2 systems

    Science.gov (United States)

    Rosner, Helge; Bergmann, Christoph; Weber, Katharina; Kraft, Inga; Mufti, N.; Klauss, Hans-Henning; Dellmann, T.; Woike, T.; Geibel, Christoph

    2013-03-01

    Magnetic systems with reduced dimensionality or frustration attract strong interest because these features lead to an increase of quantum fluctuations and often result in unusual properties. Here, we present a detailed study of the magnetic, thermodynamic, and structural properties of the intermetallic AFe4X2 compounds (A=Sc,Y,Lu,Zr; X=Si,Ge) crystallizing in the ZrFe4Si2 structure type. Our results evidence that these compounds cover the whole regime from frustrated AFM order up to an AFM quantum critical point. Susceptibility χ(T), specific heat, resistivity, and T-dependent XRD measurements were performed on polycrystalline samples. In all compounds we observed a Curie-Weiss behavior in χ(T) at high T indicating a paramagnetic moment of about 3μB/Fe. Magnetic and structural transitions as previously reported for YFe4Ge2 occur in all compounds with trivalent A. However, transition temperatures, nature of the transition as well as the relation between structural and magnetic transitions change significantly with the A element. Low TN's and large θCW /TN ratios confirm the relevance of frustration. The results are analyzed and discussed with respect to electronic, structural and magnetic instabilities applying DFT calculations. Financial support from the DFG (GRK 1621) is acknowledged

  2. Investigation of AA2024-T3 surfaces modified by cerium compounds: A localized approach

    International Nuclear Information System (INIS)

    Paussa, L.; Andreatta, F.; De Felicis, D.; Bemporad, E.; Fedrizzi, L.

    2014-01-01

    Highlights: •The precipitation of cerium compounds occurs on the entire AA2024-T3 surface. •The matrix is less involved in the cerium precipitation. •Cerium intensely precipitates on Mg-rich IM particles. •The electrochemical behavior of Mg-rich IM particles influences the mechanism of cerium precipitation. -- Abstract: The precipitation of cerium compounds on polished AA2024-T3 surfaces was investigated following an electrochemical and microstructural localized approach. It was found that cerium precipitation occurs on the entire surface covering intermetallic particles and the matrix as well. The matrix is the region where the precipitation of cerium is less favoured. The highest amount of cerium was observed on magnesium-rich intermetallic particles. The localized analyses suggest that precipitation of cerium on magnesium-rich intermetallic particles could happen following two mechanisms: the former based on a potential reversal of the intermetallic particles and the latter due to a partial magnesium dissolution

  3. Electronic and optical properties of RESn{sub 3} (RE=Pr & Nd) intermetallics: A first principles study

    Energy Technology Data Exchange (ETDEWEB)

    Pagare, G., E-mail: gita-pagare@yahoo.co.in [Department of Physics, Government M. L. B. Girls P. G. Autonomous College, Bhopal-462002 (India); Abraham, Jisha A. [Department of Physics, Government M. L. B. Girls P. G. Autonomous College, Bhopal-462002 (India); Department of Physics, National Defence Academy, Pune-411023 (India); Sanyal, S. P. [Department of Physics, Barkatullah University, Bhopal-462026 (India)

    2015-06-24

    A theoretical study of structural, electronic and optical properties of RESn{sub 3} (RE = Pr & Nd) intermetallics have been investigated systematically using first principles density functional theory. The calculations are carried out within the PBE-GGA and LSDA for the exchange correlation potential. The ground state properties such as lattice parameter (a{sub 0}), bulk modulus (B) and its pressure derivative (B′) are calculated and the calculated lattice parameters show well agreement with the experimental results. We first time predict elastic constants for these compounds. From energy dispersion curves, it is found that these compounds are metallic in nature. The linear optical response of these compounds are also studied and the higher value of static dielectric constant shows the possibility to use them as good dielectric materials.

  4. f-band narrowing in uranium intermetallics

    International Nuclear Information System (INIS)

    Dunlap, B.D.; Litterst, F.J.; Malik, S.K.; Kierstead, H.A.; Crabtree, G.W.; Kwok, W.; Lam, D.J.; Mitchell, A.W.

    1987-01-01

    Although the discovery of heavy fermion behavior in uranium compounds has attracted a great deal of attention, relatively little work has been done which is sufficiently systematic to allow an assessment of the relationship of such behavior to more common phenomena, such as mixed valence, narrow-band effects, etc. In this paper we report bulk property measurements for a number of alloys which form a part of such a systematic study. The approach has been to take relatively simple and well-understood materials and alter their behavior by alloying to produce heavy fermion or Kondo behavior in a controlled way

  5. Rare-earth transition-metal intermetallics: Structure-bonding-property relationships

    Energy Technology Data Exchange (ETDEWEB)

    Han, M. K. [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    The explorations of rare-earth, transition metal intermetallics have resulted in the synthesis and characterization, and electronic structure investigation, as well as understanding the structure-bonding property relationships. The work has presented the following results: (1) Understanding the relationship between compositions and properties in LaFe13-xSix system: A detailed structural and theoretical investigation provided the understanding of the role of a third element on stabilizing the structure and controlling the transformation of cubic NaZn{sub 13}-type structures to the tetragonal derivative, as well as the relationship between the structures and properties. (2) Synthesis of new ternary rare-earth iron silicides Re2-xFe4Si14-y and proposed superstructure: This compound offers complex structural challenges such as fractional occupancies and their ordering in superstructure. (3) Electronic structure calculation of FeSi2: This shows that the metal-semiconductor phase transition depends on the structure. The mechanism of band gap opening is described in terms of bonding and structural distortion. This result shows that the electronic structure calculations are an essential tool for understanding the relationship between structure and chemical bonding in these compounds. (4) Synthesis of new ternary rare-earth Zinc aluminides Tb3Zn3.6Al7.4: Partially ordered structure of Tb3Zn3.6Al7.4 compound provides new insights into the formation, composition and structure of rare-earth transition-metal intermetallics. Electronic structure calculations attribute the observed composition to optimizing metal-metal bonding in the electronegative (Zn, Al) framework, while the specific ordering is strongly influenced by specific orbital interactions. (5) Synthesis of new structure type of Zn39(CrxAl1-x)81

  6. Rare-Earth Transition-Metal Intermetallics: Structure-bonding-Property Relationships

    Energy Technology Data Exchange (ETDEWEB)

    Han, Mi-Kyung [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    Our explorations of rare-earth, transition metal intermetallics have resulted in the synthesis and characterization, and electronic structure investigation, as well as understanding the structure-bonding-property relationships. Our work has presented the following results: (1) Understanding the relationship between compositions and properties in LaFe13-xSix system: A detailed structural and theoretical investigation provided the understanding of the role of a third element on stabilizing the structure and controlling the transformation of cubic NaZn13-type structures to the tetragonal derivative, as well as the relationship between the structures and properties. (2) Synthesis of new ternary rare-earth iron silicides RE2-xFe4Si14-y and proposed superstructure: This compound offers complex structural challenges such as fractional occupancies and their ordering in superstructure. (3) Electronic structure calculation of FeSi2: This shows that the metal-semiconductor phase transition depends on the structure. The mechanism of band gap opening is described in terms of bonding and structural distortion. This result shows that the electronic structure calculations are an essential tool for understanding the relationship between structure and chemical bonding in these compounds. (4) Synthesis of new ternary rare-earth Zinc aluminides Tb3Zn3.6Al7.4: Partially ordered structure of Tb3.6Zn13-xAl7.4 compound provides new insights into the formation, composition and structure of rare-earth transition-metal intermetallics. Electronic structure calculations attribute the observed composition to optimizing metal-metal bonding in the electronegative (Zn, Al) framework, while the specific ordering is strongly influenced by specific orbital interactions. (5) Synthesis of new structure type of Zn39(CrxAl1-x

  7. Discontinuously reinforced intermetallic matrix composites via XD synthesis. [exothermal dispersion

    Science.gov (United States)

    Kumar, K. S.; Whittenberger, J. D.

    1992-01-01

    A review is given of recent results obtained for discontinuously reinforced intermetallic matrix composites produced using the XD process. Intermetallic matrices investigated include NiAl, multiphase NiAl + Ni2AlTi, CoAl, near-gamma titanium aluminides, and Ll2 trialuminides containing minor amounts of second phase. Such mechanical properties as low and high temperature strength, compressive and tensile creep, elastic modulus, ambient ductility, and fracture toughness are discussed as functions of reinforcement size, shape, and volume fraction. Microstructures before and after deformation are examined and correlated with measured properties. An observation of interest in many of the systems examined is 'dispersion weakening' at high temperatures and high strain rates. This behavior is not specific to the XD process; rather similar observations have been reported in other discontinuous composites. Proposed mechanisms for this behavior are presented.

  8. Theoretical energy release of thermites, intermetallics, and combustible metals

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, S.H.; Grubelich, M.C.

    1998-06-01

    Thermite (metal oxide) mixtures, intermetallic reactants, and metal fuels have long been used in pyrotechnic applications. Advantages of these systems typically include high energy density, impact insensitivity, high combustion temperature, and a wide range of gas production. They generally exhibit high temperature stability, and possess insensitive ignition properties. In this paper, the authors review the applications, benefits, and characteristics of thermite mixtures, intermetallic reactants, and metal fuels. Calculated values for reactant density, heat of reaction (per unit mass and per unit volume), and reaction temperature (without and with consideration of phase changes and the variation of specific heat values) are tabulated. These data are ranked in several ways, according to density, heat of reaction, reaction temperature, and gas production.

  9. Production of nanograined intermetallics using high-pressure torsion

    Energy Technology Data Exchange (ETDEWEB)

    Alhamidi, Ali; Edalati, Kaveh; Horita, Zenji, E-mail: horita@zaiko.kyushu-u.ac.jp [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka (Japan)

    2013-11-01

    Formation of intermetallics is generally feasible at high temperatures when the lattice diffusion is fast enough to form the ordered phases. This study shows that nanograined intermetallics are formed at a low temperature as 573 K in Al- 25 mol% Ni, Al- 50 mol.% Ni and Al- 50 mol% Ti powder mixtures through powder consolidation using high-pressure torsion (HPT). For the three compositions, the hardness gradually increases with straining but saturates to the levels as high as 550-920 Hv. In addition to the high hardness, the TiAl material exhibits high yield strength as {approx}3 GPa with good ductility as {approx}23%, when they are examined by micropillar compression tests. X-ray diffraction analysis and high-resolution transmission electron microscopy reveal that the significant increase in hardness and strength is due to the formation of nanograined intermetallics such as Al{sub 3}Ni, Al{sub 3}Ni{sub 2}, TiAl{sub 3}, TiAl{sub 2} and TiAl with average grain sizes of 20-40 nm (author)

  10. First principles study of halogens adsorption on intermetallic surfaces

    International Nuclear Information System (INIS)

    Zhu, Quanxi; Wang, Shao-qing

    2016-01-01

    Graphical abstract: - Highlights: • The linear relation between adsorbates induced work function change and dipole moment change also exists for intermetallic surfaces. • It is just a common linear relationship rather than a directly proportion. • A new weight parameter β is proposed to describe different factors effect on work function shift. - Abstract: Halides are often present at electrochemical environment, they can directly influence the electrode potential or zero charge potential through the induced work-function change. In this work, we focused in particular on the halogen-induced work function change as a function of the coverage of fluorine, chlorine, bromine and iodine on Al_2Au and Al_2Pt (110) surfaces. Results show that the real relation between work function change and dipole moment change for halogens adsorption on intermetallic surfaces is just a common linear relationship rather than a directly proportion. Besides, the different slopes between fitted lines and the theoretical slope employed in pure metal surfaces demonstrating that the halogens adsorption on intermetallic surfaces are more complicated. We also present a weight parameter β to describe different factors effect on work function shift and finally qualify which factor dominates the shift direction.

  11. The role of intermetallic precipitates in Ti-62222S

    Energy Technology Data Exchange (ETDEWEB)

    Evans, D J [US Air Force Mater. Directorate Wright Lab., Wright Patterson AFB, OH (United States); Broderick, T F [US Air Force Mater. Directorate Wright Lab., Wright Patterson AFB, OH (United States); Woodhouse, J B [UES Inc, Dayton, OH (United States); Hoenigman, J R [Wright State Univ., Dayton, OH (United States). Research Inst.

    1996-08-15

    Samples of Ti-62222-0.23wt.%Si were heat treated and aged at temperatures ranging from 1150 F to 1500 F with the view of effecting selective precipitation of {alpha}{sub 2} precipitates and silicides (i.e. Ti{sub x}Zr{sub 5-x}Si{sub 3}). The effect of these intermetallic precipitates on the mechanical properties and fracture morphology was assessed via three separate microstructural conditions: Ti-62222S with {alpha}{sub 2} precipitates, Ti-62222S with {alpha}{sub 2} and silicide precipitates, and Ti-62222S with silicide precipitates. Both types of intermetallic precipitate appear to lower the fracture toughness, however {alpha}{sub 2} promotes intergranular fracture while silicides lead to transgranular failure and dimpling. The combined presence of the {alpha}{sub 2} and silicides leads to mixed mode failure. Further, since {alpha}{sub 2} is present in the {alpha} phase and silicides precipitate out in the {beta} phase, it appears that the effect of each of these intermetallics in Ti-62222S is additive rather than synergistic. (orig.)

  12. The nucleation and growth of intermetallic Al-Pt phases

    International Nuclear Information System (INIS)

    Kovacs, A.; Barna, P.B.; Labar, J. l.

    2002-01-01

    The nucleation and growth of intermetallic Al-Pt phases on amorphous carbon was investigated by half shadow technique in co-deposited thin films. In such experimental condition, the composition of the deposited films varied in the range of Al x Pt 1-x (0≤x≤0.6). The coexistence of Al 5 Pt, Al 2 Pt, Al 3 Pt 2 intermetallic phases have been found in the whole range with varying ratio. Vapour depositions were performed in an UHV system. The Al and Pt components were evaporated simultaneously onto amorphous carbon layer supported by TEM micro-grids. Deposition rates were controlled separately by quartz crystal monitors. Substrate temperature during deposition was 350 grad C. A special evaporation arrangement made possible to create a half shadow area on the substrate in which the quantity one of the components increased from zero to the wanted composition of the sample. The composition of the zones was determined by energy dispersive X-ray spectroscopy (EDS) in TEM. The intermetallic phases developed in the sample were investigated by analytical TEM (Philips CM20) and high resolution TEM (JEOL 3010 UHR). The electron diffraction patterns have been evaluated by ProcessDiffraction program. (Authors)

  13. Laves intermetallics in stainless steel-zirconium alloys

    International Nuclear Information System (INIS)

    Abraham, D.P.; McDeavitt, S.M.; Richardson, J.W. Jr.

    1997-01-01

    Laves intermetallics have a significant effect on properties of metal waste forms being developed at Argonne National Laboratory. These waste forms are stainless steel-zirconium alloys that will contain radioactive metal isotopes isolated from spent nuclear fuel by electrometallurgical treatment. The baseline waste form composition for stainless steel-clad fuels is stainless steel-15 wt.% zirconium (SS-15Zr). This article presents results of neutron diffraction measurements, heat-treatment studies and mechanical testing on SS-15Zr alloys. The Laves intermetallics in these alloys, labeled Zr(Fe,Cr,Ni) 2+x , have both C36 and C15 crystal structures. A fraction of these intermetallics transform into (Fe,Cr,Ni) 23 Zr 6 during high-temperature annealing; the authors have proposed a mechanism for this transformation. The SS-15Zr alloys show virtually no elongation in uniaxial tension, but exhibit good strength and ductility in compression tests. This article also presents neutron diffraction and microstructural data for a stainless steel-42 wt.% zirconium (SS-42Zr) alloy

  14. First principle studies of electronic and magnetic properties of Lanthanide-Gold (RAu) binary intermetallics

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Sardar [Center for Computational Materials Science, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Department of Chemistry, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Ahmad, Rashid, E-mail: rashmad@gmail.com [Center for Computational Materials Science, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Department of Chemistry, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Jalali-Asadabadi, S. [Department of Physics, Faculty of Sciences, University of Isfahan (UI), Hezar Gerib Avenue, Isfahan 81746-73441 (Iran, Islamic Republic of); Ali, Zahid [Center for Computational Materials Science, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Department of Physics, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Ahmad, Iftikhar [Center for Computational Materials Science, University of Malakand, Chakdara, 18800 Pakistan (Pakistan); Vice Chancellor, Abbott Abad University of Science and Technology, Abbott Abad (Pakistan)

    2017-01-15

    In this article we explore the electronic and magnetic properties of RAu intermetallics (R=Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) for the first time. These properties are calculated by using GGA, GGA+U and hybrid density functional theory (HF) approaches. Our calculations show that HF provides superior results, consistent to the experimentally reported data. The chemical bonding between rare-earth and gold atoms within these compounds are explained on the basis of spin dependent electronic clouds in different planes, which shows predominantly ionic and metallic nature between Au and R atoms. The Cohesive energies of RAu compounds show direct relation with the melting points. Spin-dependent electronic band structure demonstrates that all these compounds are metallic in nature. The magnetic studies show that HoAu and LuAu are stable in non-magnetic structure, PrAu is stable in ferromagnetic phase and CeAu, NdAu, SmAu, GdAu, TbAu, DyAu, ErAu, TmAu, YbAu are anti-ferromagnetic materials.

  15. A diffraction based study of the deformation mechanisms in anomalously ductile B2 intermetallics

    Science.gov (United States)

    Mulay, Rupalee Prashant

    For many decades, the brittle nature of most intermetallic compounds (e.g. NiAl) has been the limiting factor in their practical application. Many B2 (CsCl prototypical structure) intermetallics are known to exhibit slip on the {110} slip mode, which provides only 3 independent slip systems and, hence, is unable to satisfy the von Mises (a.k.a. Taylor) criterion for polycrystalline ductility. As a result, inherent polycrystalline ductility is unexpected. Recent discovery of a number of ductile B2 intermetallics has raised questions about possible violation of the von Mises criterion by these alloys. These ductile intermetallic compounds are MR (metal (M) combined with a rare earth metal or group IV refractory metal (R)) alloys and are stoichiometric, ordered compounds. Single crystal slip trace analyses have only identified the presence of {011} or {010} slip systems. More than 100 other B2 MR compounds are known to exist and many of them have already been shown to be ductile (e.g., CuY, AgY, CuDy, CoZr, CoTi, etc.). Furthermore, these alloys exhibit a large Bauschinger effect. The present work uses several diffraction based techniques including electron back scattered diffraction (EBSD), X-ray diffraction (XRD) and in-situ neutron diffraction; in conjunction with scanning electron microscopy (SEM), transmission electron microscopy (TEM), mechanical testing, and crystal plasticity modeling, to elucidate the reason for ductility in select B2 alloys, explore the spread of this ductility over the B2 family, and understand the Bauschinger effect in these alloys. Several possible explanations (e.g., slip of dislocations, strong texture, phase transformations and twinning) for the anomalous ductility were explored. An X-ray diffraction based analysis ruled out texture, phase purity and departure from order as explanations for the anomalous ductility in MR alloys. In-situ neutron diffraction and post deformation SEM, EBSD, and TEM were unable to detect any evidence for

  16. Phase transition of intermetallic TbPt at high temperature and high pressure

    Science.gov (United States)

    Qin, Fei; Wu, Xiang; Yang, Ke; Qin, Shan

    2018-04-01

    Here we present synchrotron-based x-ray diffraction experiments combined with diamond anvil cell and laser heating techniques on the intermetallic rare earth compound TbPt (Pnma and Z  =  4) up to 32.5 GPa and ~1800 K. The lattice parameters of TbPt exhibit continuous compression behavior up to 18.2 GPa without any evidence of phase transformation. Pressure-volume data were fitted to a third-order Birch-Murnaghan equation of state with V 0  =  175.5(2) Å3, {{K}{{T0}}}   =  110(5) GPa and K{{T0}}\\prime   =  3.8(7). TbPt exhibits anisotropic compression with β a   >  β b   >  β c and the ratio of axial compressibility is 2.50:1.26:1.00. A new monoclinic phase of TbPt assigned to the Pc or P2/c space group was observed at 32.5 GPa after laser heating at ~1800 K. This new phase is stable at high pressure and presented a quenchable property on decompression to ambient conditions. The pressure-volume relationship is well described by the second-order Birch-Murnaghan equation of state, which yields V 0  =  672(4) Å3, {{K}{{T0}}}   =  123(6) GPa, which is about ~14% more compressible than the orthorhombic TbPt. Our results provide more information on the structure and elastic property view, and thus a better understanding of the physical properties related to magnetic structure in some intermetallic rare earth alloys.

  17. Femtosecond laser ablation and nanoparticle formation in intermetallic NiAl

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, David J., E-mail: davidjjorgensen@engr.ucsb.edu; Titus, Michael S.; Pollock, Tresa M.

    2015-10-30

    Highlights: • The single-pulse fs laser ablation threshold of NiAl is 83 mJ/cm{sup 2}. • The transition between low- and high-fluence ablation regimes is 2.8 J/cm{sup 2}. • A bimodal size distribution of nanoparticles is formed with fs laser ablation. • Smaller nanoparticles are enriched in Al during pulsed fs laser ablation. • The target surface is depleted in Al during pulsed fs laser ablation. - Abstract: The ablation behavior of a stoichiometric intermetallic compound β-NiAl subjected to femtosecond laser pulsing in air has been investigated. The single-pulse ablation threshold for NiAl was determined to be 83 ± 4 mJ/cm{sup 2} and the transition to the high-fluence ablation regime occurred at 2.8 ± 0.3 J/cm{sup 2}. Two sizes of nanoparticles consisting of Al, NiAl, Ni{sub 3}Al and NiO were formed and ejected from the target during high-fluence ablation. Chemical analysis revealed that smaller nanoparticles (1–30 nm) tended to be rich in Al while larger nanoparticles (>100 nm) were lean in Al. Ablation in the low-fluence regime maintained this trend. Redeposited material and nanoparticles remaining on the surface after a single 3.7 J/cm{sup 2} pulse, one hundred 1.7 J/cm{sup 2} pulses, or one thousand 250 mJ/cm{sup 2} pulses were enriched in Al relative to the bulk target composition. Further, the surface of the irradiated high-fluence region was depleted in Al indicating that the fs laser ablation removal rate of the intermetallic constituents in this regime does not scale with the individual pure element ablation thresholds.

  18. Study of the hyperfine magnetic field acting on Ce probes substituting for the rare earth and the magnetic ordering in intermetallic compounds RAg (R=rare earth) by first principles calculations; Estudo do campo hiperfino magnetico na sonda de Ce colocada nos compostos intermetalicos do tipo RAg (R=terra rara) e do ordenamento magnetico desses compostos usando calculos de primeiros principios

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Luciano Fabricio Dias

    2006-07-01

    In this work the magnetic hyperfine field acting on Ce atoms substituting the rare-earths in R Ag compounds (R = Gd e Nd) was studied by means of first-principles electronic structure calculations. The employed method was the Augmented Plane Waves plus local orbitals (APW+lo), embodied in the WIEN2k program, within the framework of the Density Functional Theory (DFT) and with the Generalized Gradient Approximation (GGA) for the exchange and correlation potential. The super-cell approach was utilized in order to simulate for the Ce atoms acting as impurities in the R Ag matrix. In order to improve for correlation effects within the 4f shells, a Hubbard term was added to the DFT Hamiltonian, within a procedure called GGA+U. It was found that the magnetic hyperfine field (MHF) generated by the Ce 4f electron is the main component of the total MHF and that the Ce 4f ground state level is probably a combination of the m{sub l} = -2 and m{sub l} = -1 sub-levels. In addition, the ground-state magnetic structure was determined for Ho Ag and Nd Ag by observing the behavior of the total energy as a function of the lattice volume for several possible magnetic ordering in these compounds, namely, ferromagnetic, and the (0,0,{pi}), ({pi},{pi},0) and (({pi},{pi},{pi}) types of anti-ferromagnetic ordering of rare-earth atoms. It was found that the ground-state magnetic structure is anti-ferromagnetic of type ({pi},{pi},0) for both, the Ho Ag and Nd Ag compounds. The energy difference of the ferromagnetic and antiferromagnetic ordering is very small in the case of the Nd Ag compound. (author)

  19. Electrocatalytic hydride-forming compounds for rechageable batteries

    NARCIS (Netherlands)

    Notten, P.H.L.; Einerhand, R.E.F.

    1991-01-01

    Non-toxic intermetallic hydride-forming compounds are attractive alternatives to cadmium as the negative electrode materials in the new generation of Ni/metal hydride rechargeable batteries. High exchange currents and discharge efficiencies even at low temperatures can be achieved using highly

  20. FP-LAPW study of structural, electronic, elastic, mechanical and thermal properties of AlFe intermetallic

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Ekta, E-mail: jainekta05@gmail.com [Department of Physics, Government M. L. B. Girls P. G. Autonomous College, Bhopal-462002 (India); Pagare, Gitanjali, E-mail: gita-pagare@yahoo.co.in [Department of Physics, Sarojini Naidu Government Girls P. G. Autonomous College, Bhopal-462016 (India); Sanyal, S. P., E-mail: sps.physicsbu@gmail.com [Department of Physics, Barkatullah University, Bhopal-462026 (India)

    2016-05-06

    The structural, electronic, elastic, mechanical and thermal properties of AlFe intermetallic compound in B{sub 2}-type (CsCl) structure have been investigated using first-principles calculations. The exchange-correlation term was treated within generalized gradient approximation. Ground state properties i.e. lattice constants (a{sub 0}), bulk modulus (B) and first-order pressure derivative of bulk modulus (B’) are presented. The density of states are derived which show the metallic character of present compound. Our results for C{sub 11}, C{sub 12} and C{sub 44} agree well with previous theoretical data. Using Pugh’s criteria (B/G{sub H} < 1.75), brittle character of AlFe is satisfied. In addition shear modulus (G{sub H}), Young’s modulus (E), sound wave velocities and Debye temperature (θ{sub D}) have also been estimated.

  1. Investigation of electronic structure and chemical bonding of intermetallic Pd2HfIn: An ab-initio study

    Science.gov (United States)

    Bano, Amreen; Gaur, N. K.

    2018-05-01

    Ab-initio calculations are carried out to study the electronic and chemical bonding properties of Intermetallic full Heusler compound Pd2HfIn which crystallizes in F-43m structure. All calculations are performed by using density functional theory (DFT) based code Quantum Espresso. Generalized gradient approximations (GGA) of Perdew- Burke- Ernzerhof (PBE) have been adopted for exchange-correlation potential. Calculated electronic band structure reveals the metallic character of the compound. From partial density of states (PDoS), we found the presence of relatively high intensity electronic states of 4d-Pd atom at Fermi level. We have found a pseudo-gap just abouve the Fermi level and N(E) at Fermi level is observed to be 0.8 states/eV, these finding indicates the existence of superconducting character in Pd2HfIn.

  2. Microstructure study of the rare-earth intermetallic compounds R5(SixGe1-x)4 and R5(SixGe1-x)3

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Qing [Iowa State Univ., Ames, IA (United States)

    2012-01-01

    The unique combination of magnetic properties and structural transitions exhibited by many members of the R5(SixGe1-x)4 family (R = rare earths, 0 ≤ x ≤ 1) presents numerous opportunities for these materials in advanced energy transformation applications. Past research has proven that the crystal structure and magnetic ordering of the R5(SixGe1-x)4 compounds can be altered by temperature, magnetic field, pressure and the Si/Ge ratio. Results of this thesis study on the crystal structure of the Er5Si4 compound have for the first time shown that the application of mechanical forces (i.e. shear stress introduced during the mechanical grinding) can also result in a structural transition from Gd5Si4-type orthorhombic to Gd5Si2Ge2-type monoclinic. This structural transition is reversible, moving in the opposite direction when the material is subjected to low-temperature annealing at 500 °C.

  3. Development of intermetallic coatings for fusion power applications

    International Nuclear Information System (INIS)

    Park, J.H.; Domenico, T.; Dragel, G.; Clark, R.

    1994-03-01

    In the design of liquid-metal cooling systems, corrosion resistance of structural materials and magnetohydrodynamic (MHD) force and its subsequent influence on thermal hydraulics and corrosion are major concerns. The objective of this study is to develop stable corrosion-resistant electrical insulator coatings at the liquid-metal/structural-material interface, with emphasis on electrically insulating coatings that prevent adverse MHD-generated currents from passing through the structural walls. Vanadium and V-base alloys are potential materials for structural applications in a fusion reactor. Insulator coatings inside the tubing are required when the system is cooled by liquid metals. Various intermetallic films were produced on V, V-t, and V-20 Ti, V-5Cr-t and V-15Cr-t, and Ti, and Types 304 and 316 stainless steel. The intermetallic layers were developed by exposure of the materials to liquid lithium of 3--5 at.% and containing dissolved metallic solutes at temperatures of 416--880 degrees C. Subsequently, electrical insulator coatings were produced by reaction of the reactive layers with dissolved nitrogen in liquid lithium or by air oxidation under controlled conditions at 600--1000 degrees C. These reactions converted the intermetallic layers to electrically insulating oxide/nitride or oxy-nitride layers. This coating method could be applied to a commercial product. The liquid metal can be used over and over because only the solutes are consumed within the liquid metal. The technique can be applied to various shapes because the coating is formed by liquid-phase reaction. This paper will discuss initial results on the nature of the coatings and their in-situ electrical resistivity characteristics in liquid lithium at high temperatures

  4. Electromagnetic generation of volume waves in RFe2 intermetallics

    International Nuclear Information System (INIS)

    Il'yasov, R.S.; Borovkova, M.A.

    1996-01-01

    Experimental results are presented on the phenomenon of electromagneto-acoustic transformation of longitudinal and cross waves in RFe 2 intermetallics. It is shown that in the range from the room temperature to Curie point the generation of ultrasound occurs only at the expense of one-ion anisotropic magnetostriction. In the vicinity of Curie point the contribution of isotropic magnetostriction of paraprocess is not observed. The quantitative interpretation is given to temperature and field dependences of electromagneto-acoustic transformation parameters. A noticeable temperature hysteresis of the above-mentioned transformation is revealed in ErFe 2 near the point of compensation. 7 refs.; 5 figs

  5. Study of Intermetallic Nanostructures for Light-Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Niels Grobech [Univ. of California, Davis, CA (United States); Asta, Mark D. [Univ. of California, Berkeley, CA (United States); Hosemann, Peter [Univ. of California, Berkeley, CA (United States); Maloy, Stuart [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-30

    High temperature mechanical measurements were conducted to study the effect of the dynamic precipitation process of PH 13-8 Mo maraging steel. Yield stress, ultimate tensile strength, total elongation, hardness, strain rate sensitivity and activation volume were evaluated as a function of the temperature. The dynamic changes in the mechanical properties at different temperatures were evaluated and a balance between precipitation hardening and annealed softening is discussed. A comparison between hardness and yield stress and ultimate tensile strength over a temperature range from 300 to 600 °C is made. The behavior of the strain rate sensitivity was correlated with the intermetallic precipitates formed during the experiments.

  6. A novel method to fabricate TiAl intermetallic alloy 3D parts using additive manufacturing

    Directory of Open Access Journals (Sweden)

    J.J.S. Dilip

    2017-04-01

    Full Text Available The present work explores the feasibility of fabricating porous 3D parts in TiAl intermetallic alloy directly from Ti–6Al–4V and Al powders. This approach uses a binder jetting additive manufacturing process followed by reactive sintering. The results demonstrate that the present approach is successful for realizing parts in TiAl intermetallic alloy.

  7. A survey of combustible metals, thermites, and intermetallics for pyrotechnic applications

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, S.H.; Grubelich, M.C.

    1996-08-01

    Thermite mixtures, intermetallic reactants, and metal fuels have long been used in pyrotechnics. Advantages include high energy density, impact insensitivity, high combustion temperature, and a wide range of gas production. They generally exhibit high temperature stability and possess insensitive ignition properties. This paper reviews the applications, benefits, and characteristics of thermite mixtures, intermetallic reactants, and metal fuels. 50 refs, tables.

  8. Intermetallic nickel silicide nanocatalyst-A non-noble metal-based general hydrogenation catalyst.

    Science.gov (United States)

    Ryabchuk, Pavel; Agostini, Giovanni; Pohl, Marga-Martina; Lund, Henrik; Agapova, Anastasiya; Junge, Henrik; Junge, Kathrin; Beller, Matthias

    2018-06-01

    Hydrogenation reactions are essential processes in the chemical industry, giving access to a variety of valuable compounds including fine chemicals, agrochemicals, and pharmachemicals. On an industrial scale, hydrogenations are typically performed with precious metal catalysts or with base metal catalysts, such as Raney nickel, which requires special handling due to its pyrophoric nature. We report a stable and highly active intermetallic nickel silicide catalyst that can be used for hydrogenations of a wide range of unsaturated compounds. The catalyst is prepared via a straightforward procedure using SiO 2 as the silicon atom source. The process involves thermal reduction of Si-O bonds in the presence of Ni nanoparticles at temperatures below 1000°C. The presence of silicon as a secondary component in the nickel metal lattice plays the key role in its properties and is of crucial importance for improved catalytic activity. This novel catalyst allows for efficient reduction of nitroarenes, carbonyls, nitriles, N-containing heterocycles, and unsaturated carbon-carbon bonds. Moreover, the reported catalyst can be used for oxidation reactions in the presence of molecular oxygen and is capable of promoting acceptorless dehydrogenation of unsaturated N-containing heterocycles, opening avenues for H 2 storage in organic compounds. The generality of the nickel silicide catalyst is demonstrated in the hydrogenation of over a hundred of structurally diverse unsaturated compounds. The wide application scope and high catalytic activity of this novel catalyst make it a nice alternative to known general hydrogenation catalysts, such as Raney nickel and noble metal-based catalysts.

  9. Morphology of intermetallic phases in Al-Si cast alloys and their fracture behaviour

    Directory of Open Access Journals (Sweden)

    Lenka Hurtalová

    2015-03-01

    Full Text Available Applications of Al-Si cast alloys in recent years have increased especially in the automotive industry (dynamic exposed cast, en-gine parts, cylinder heads, pistons and so on. Controlling the microstructure of secondary aluminium cast alloys is very important, because these alloys contain more additional elements that form various intermetallic phases in the structure. Therefore, the contribution is dealing with the valuation type of intermetallic phases and their identification with using optical and scanning microscopy. Some of the intermetallic phases could be identified on the basis of morphology but some of them must be identified according EDX analysis. The properties of alu-minium alloy are affected by morphology of intermetallic phases and therefore it is necessary to study morphology and its fracture behav-iour. The present work shows morphology and typical fracture behaviour as the most common intermetallic phases forming in Al-Si alloys.

  10. Uranium magnetism in UGa2 and U(Gasub(1-x)Alsub(x))2 compounds

    International Nuclear Information System (INIS)

    Ballou, R.

    1983-01-01

    Magnetism of intermetallic compounds of uranium is studied. A monocrystal of the highly anisotropic ferromagnetic material UGa 2 is studied by polarized neutron diffraction. Localisation of 5f electrons is evidenced. Magnetic structure of uranium in UGa 2 is determined. The pseudobinary compound U(Gasub(1-x)Alsub(x)) 2 is studied for crystal structure, ferromagnetism, paramagnetism, specific heat and resistivity [fr

  11. Influence of Al grain boundaries segregations and La-doping on embrittlement of intermetallic NiAl

    Energy Technology Data Exchange (ETDEWEB)

    Kovalev, Anatoly I., E-mail: a_kovalev@sprg.ru; Wainstein, Dmitry L.; Rashkovskiy, Alexander Yu.

    2015-11-01

    Highlights: • We investigated Al grain boundaries segregations in ordered pure and La-doped NiAl. • Structural segregation of Al decreases critical strain for brittle cracks nucleation. • La alloying sharply improves plasticity of NiAl intermetallic. • Metallicity of interatomic bonds on grain boundaries increases at La alloying. • We have experimentally measured by EELFS that La atoms are located in Al sublattice. - Abstract: The microscopic nature of intergranular fracture of NiAl was experimentally investigated by the set of electron spectroscopy techniques. The paper demonstrates that embrittlement of NiAl intermetallic compound is caused by ordering of atomic structure that leads to formation of structural aluminum segregations at grain boundaries (GB). Such segregations contain high number of brittle covalent interatomic bonds. The alloying by La increases the ductility of material avoiding Al GB enrichment and disordering GB atomic structure. The influence of La alloying on NiAl mechanical properties was investigated. GB chemical composition, atomic and electronic structure transformations after La doping were investigated by AES, XPS and EELFS techniques. To qualify the interatomic bonds metallicity the Fermi level (E{sub F}) position and electrons density (n{sub eff}) in conduction band were determined in both undoped and doped NiAl. Basing on experimental results the physical model of GB brittleness formation was proposed.

  12. Tracing crystal-field splittings in the rare-earth-based intermetallic CeIrIn5

    Science.gov (United States)

    Chen, Q. Y.; Wen, C. H. P.; Yao, Q.; Huang, K.; Ding, Z. F.; Shu, L.; Niu, X. H.; Zhang, Y.; Lai, X. C.; Huang, Y. B.; Zhang, G. B.; Kirchner, S.; Feng, D. L.

    2018-02-01

    Crystal electric field states in rare earth intermetallics show an intricate entanglement with the many-body physics that occurs in these systems and that is known to lead to a plethora of electronic phases. Here we attempt to trace different contributions to the crystal electric field (CEF) splittings in CeIrIn5, a heavy-fermion compound and member of the Ce M In5 (M = Co, Rh, Ir) family. To this end, we utilize high-resolution resonant angle-resolved photoemission spectroscopy (ARPES) and present a spectroscopic study of the electronic structure of this unconventional superconductor over a wide temperature range. As a result, we show how ARPES can be used in combination with thermodynamic measurements or neutron scattering to disentangle different contributions to the CEF splitting in rare earth intermetallics. We also find that the hybridization is stronger in CeIrIn5 than CeCoIn5 and the effects of the hybridization on the Fermi volume increase is much smaller than predicted. By providing experimental evidence for 4 f7/2 1 splittings which, in CeIrIn5, split the octet into four doublets, we clearly demonstrate the many-body origin of the so-called 4 f7/2 1 state.

  13. Intermetallic superconductors - The state of development in 1991

    International Nuclear Information System (INIS)

    Forsyth, E.

    1991-01-01

    The commercial fabrication of intermetallic superconductors has reached a high degree of maturity in the past thirty years. The only significant, commercial requirement for superconducting wire is the construction of magnetic resonance imaging (MRI) devices for medical diagnosis. In addition to this demand there are one-time projects such as a high energy particle accelerators which often need considerable quantities of superconducting material over the few years of construction. R and D projects also provide a fluctuating market for superconducting materials, in the past the projects have included power apparatus such as generators, motors, energy storage and transmission cables, and magnets for experimental fusion reactors. Superconducting magnetically levitated trains have undergone full scale trials in Japan and Germany. This is by no means a comprehensive list of all the possible applications. Virtually all the devices requiring a magnetic field to be produced by superconducting windings have used NbTi wire, but a few experimental Nb 3 Sn high field magnets have been constructed. In the case of these materials commercial vendors can provide a high degree of quality assurance on such characteristics as critical current, coupling effects and mechanical tolerances. This paper discusses the market for intermetallic and ceramic superconductors, their fabrication properties, applications, and cost

  14. Theoretical Energy Release of Thermites, Intermetallics, and Combustible Metals

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, S.H.; Grubelich, M.C.

    1999-05-14

    Thermite mixtures, intermetallic reactants, and metal fuels have long been used in pyrotechnic applications. Advantages of these systems typically include high energy density, high combustion temperature, and a wide range of gas production. They generally exhibit high temperature stability and possess insensitive ignition properties. For the specific applications of humanitarian demining and disposal of unexploded ordnance, these pyrotechnic formulations offer additional benefits. The combination of high thermal input with low brisance can be used to neutralize the energetic materials in mines and other ordnance without the "explosive" high-blast-pressure events that can cause extensive collateral damage to personnel, facilities, and the environment. In this paper, we review the applications, benefits, and characteristics of thermite mixtures, intermetallic reactants, and metal fuels. Calculated values for reactant density, heat of reaction (per unit mass and per unit volume), and reaction temperature (without and with consideration of phase changes and the variation of specific heat values) are tabulated. These data are ranked in several ways, according to density, heat of reaction, reaction temperature, and gas production.

  15. The Effect of CuSn Intermetallics on the Interstrand Contact Resistance in Superconducting Cables for the Large Hadron Collider (LHC)

    CERN Document Server

    Scheuerlein, C; Jacob, P; Leroy, D; Oberli, L R; Taborelli, M

    2005-01-01

    The LHC superconducting cables are submitted to a 200°C heat-treatment in air in order to increase the resistance between the crossing strands (RC) within the cable. During this treatment the as-applied Sn-Ag alloy strand coating is transformed into a CuSn intermetallic compound layer. The microstructure, the surface topography and the surface chemistry of the non-reacted and reacted coatings have been characterised by different techniques, notably focused ion beam (FIB), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Based on the results obtained by these techniques the different influences that the intermetallics have on RC are discussed. The desired RC is obtained only when a continuous Cu3Sn layer is formed, i.e. a sufficient wetting of the Cu substrate by the tinning alloy is crucial. Among other effects the formation of the comparatively hard intermetallics roughens the surface and, thus, reduces the true contact area and i...

  16. Antiferromagnetic ordering of Er2NiSi3 compound

    International Nuclear Information System (INIS)

    Pakhira, Santanu; Mazumdar, Chandan; Ranganathan, R.

    2014-01-01

    Ternary intermetallics of the stoichiometric composition R 2 TX 3 , where, R = rare earth element, T = d-electron transition metal and X= p-electron element, crystallizes in hexagonal A1B 2 type crystal structure with space group P6/mmm. We report here the synthesis and basic magnetic properties of the compound Er 2 NiSi 3 . Paramagnetic to antiferromagnetic phase change occurs below 5.4 K for this compound. (author)

  17. Investigation of passivity and its breakdown on Fe3Al–Si and Fe3Al–Ge intermetallics in chloride-containing solution

    International Nuclear Information System (INIS)

    Rosalbino, F.; Carlini, R.; Parodi, R.; Zanicchi, G.; Scavino, G.

    2014-01-01

    Highlights: • Passivity and its breakdown on Fe 3 Al–Si and Fe 3 Al–Ge iron aluminides was investigated. • Investigation was performed in borate buffer solution with and without 100 mM KCl. • Polarization, potentiostatic transients and impedance measurements have been employed. • Results have been compared with those obtained on Fe 3 Al intermetallic. • Si and Ge improve the resistance to localized corrosion of Fe 3 Al. - Abstract: The passivity and passivity breakdown of Fe 3 Al–Si and Fe 3 Al–Ge iron aluminides were studied in borate buffer solution (pH 8.4) in the absence and presence of 100 mM KCl, performing potentiodynamic polarization, potentiostatic transients and electrochemical impedance spectroscopy (EIS) measurements complemented with scanning electron microscopy (SEM). In the absence of chloride ions Si and Ge exercise a beneficial role in the passivating characteristics of Fe 3 Al intermetallic. Addition of Si or Ge significantly modifies the electrochemical response of iron aluminide Fe 3 Al resulting in a more stable passive film. In the presence of chloride ions all the intermetallic compounds experience localized corrosion (pitting). However, Si and Ge alloying additions increase the breakdown potential and the extent of passivation domain, indicating improved resistance to initiation of pitting corrosion. Furthermore, EIS measurements performed at the breakdown state evidenced higher R ct and lower depression angle values for Fe 3 Al–Si and Fe 3 Al–Ge iron aluminides compared to Fe 3 Al intermetallic, confirming their better localized corrosion behavior. The improved resistance to pitting corrosion results from the enhanced protective function of passive film due to the presence of Si or Ge that inhibit pit initiation by hindering the adsorption of Cl − ions at the metal surface

  18. Study and development of NiAl intermetallic coating on hypo-eutectoid steel using highly activated composite granules of the Ni-Al system

    Energy Technology Data Exchange (ETDEWEB)

    Shahzad, Aamir; Zadorozhnyy, Vladislav Yu.; Pavlov, Mikhail D.; Semenov, Dmitri V.; Kaloshkin, Sergey D. [National Univ. of Science and Technology (MISIS), Moscow (Russian Federation)

    2018-01-15

    NiAl intermetallic coating thickness of about 50 μm was fabricated on hypo-eutectoid steel by mechanical alloying using pre-activated Ni-Al composite granules as coating material. First, Ni and Al powders were mixed with the composition of Ni-50 at.% Al and mechanically activated in a planetary ball mill, until the composite granules of this powder mixture, having maximum activity (9 cm sec{sup -1}), were formed after 120 min of milling at 200 rpm. The composite granules were then taken out from the planetary ball mill just before the critical time, i. e. the time at which these granules synthesize and convert to an intermetallic NiAl compound. The highly activated composite granules of Ni-Al were then put into the vial of a vibratory ball mill with the substrate on top of the chamber. After mechanical alloying for 60 min in the vibratory ball mill, the composite granules were synthesized fully and heat was produced during the synthesis which helped producing a thick and strong adhesive coating of NiAl intermetallic on the steel substrate. The main advantage of this technique is that not only is time saved but also there is no need for any post mechanical alloying process such as annealing or laser treatment etc. to get homogeneous, strongly bonded intermetallic coatings. X-ray diffraction analysis clearly indicates the formation of NiAl phase. Micro-hardness of the coating and substrate was also measured. The cross-sectional microstructure of the composite granules and the final coating were studied by scanning electron microscopy.

  19. Analytical chemical system for the determination of heavy metals and organic compounds. Annual progress report, December 1, 1978-November 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Siggia, S.; Barnes, R.M.

    1979-10-24

    Progress has been made in the synthesis and characterization of new resins for sequestering inorganic and organic compounds. The capabilities of the poly(dithiocarbamate) resin have been extended, a new poly(acrylamidoxime) resin prepared and characterized, and a series of resins for organic compounds prepared and tested. Limited actual sample analyses have been performed with these resins. A new inductively coupled plasma source, spectrometer, and computer system have been received and they are undergoing tests and installation. With this system in place, the multielement analysis of metals during the forthcoming period will insure the application of sequestering resins to practical analysis of energy-related materials. An automated sample handling and data system has been designed, some components purchased, and construction is scheduled for 1980.

  20. Analytical chemical system for the determination of heavy metals and organic compounds. Annual progress report, December 1, 1978-November 30, 1979

    International Nuclear Information System (INIS)

    Siggia, S.; Barnes, R.M.

    1979-01-01

    Progress has been made in the synthesis and characterization of new resins for sequestering inorganic and organic compounds. The capabilities of the poly(dithiocarbamate) resin have been extended, a new poly(acrylamidoxime) resin prepared and characterized, and a series of resins for organic compounds prepared and tested. Limited actual sample analyses have been performed with these resins. A new inductively coupled plasma source, spectrometer, and computer system have been received and they are undergoing tests and installation. With this system in place, the multielement analysis of metals during the forthcoming period will insure the application of sequestering resins to practical analysis of energy-related materials. An automated sample handling and data system has been designed, some components purchased, and construction is scheduled for 1980

  1. Formation of nickel-tantalum compounds in tantalum fluoride halide melts

    International Nuclear Information System (INIS)

    Matychenko, Eh.S.; Zalkind, O.A.; Kuznetsov, B.Ya.; Orlov, V.M.; Sukhorzhevskaya, S.L.

    2001-01-01

    Interaction of nickel with NaCl-K 2 TaF 7 melt (14 mol.%) at 750 deg C was studied, the composition of intermetallic compounds formed in Ni-Ta system being analyzed, using the methods of chemical and X-ray phase analyses, IR spectroscopy. It was ascertained that composition of intermetallic compounds (Ni 3 Ta, Ni 2 Ta) depends on K 2 TaF 7 concentration in the melt, metallic tantalum additions, nickel substrate thickness and experiment duration. The mechanism of currentless deposition of tantalum on nickel was considered and the assumption was made that disproportionation reaction lies in the basis of the process [ru

  2. Incorporation of Interfacial Intermetallic Morphology in Fracture Mechanism Map for Sn-Ag-Cu Solder Joints

    Science.gov (United States)

    Huang, Z.; Kumar, P.; Dutta, I.; Sidhu, R.; Renavikar, M.; Mahajan, R.

    2014-01-01

    A fracture mechanism map (FMM) is a powerful tool which correlates the fracture behavior of a material to its microstructural characteristics in an explicit and convenient way. In the FMM for solder joints, an effective thickness of the interfacial intermetallic compound (IMC) layer ( t eff) and the solder yield strength ( σ ys,eff) are used as abscissa and ordinate axes, respectively, as these two predominantly affect the fracture behavior of solder joints. Earlier, a definition of t eff, based on the uniform thickness of IMC ( t u) and the average height of the IMC scallops ( t s), was proposed and shown to aptly explain the fracture behavior of solder joints on Cu. This paper presents a more general definition of t eff that is more widely applicable to a range of metallizations, including Cu and electroless nickel immersion gold (ENIG). Using this new definition of t eff, mode I FMM for SAC387/Cu joints has been updated and its validity was confirmed. A preliminary FMM for SAC387/Cu joints with ENIG metallization is also presented.

  3. DFT modeling of the electronic and magnetic structures and chemical bonding properties of intermetallic hydrides

    International Nuclear Information System (INIS)

    Al Alam, A.F.

    2009-06-01

    This thesis presents an ab initio study of several classes of intermetallics and their hydrides. These compounds are interesting from both a fundamental and an applied points of view. To achieve this aim two complementary methods, constructed within the DFT, were chosen: (i) pseudo potential based VASP for geometry optimization, structural investigations and electron localization mapping (ELF), and (ii) all-electrons ASW method for a detailed description of the electronic structure, chemical bonding properties following different schemes as well as quantities depending on core electrons such as the hyperfine field. A special interest is given with respect to the interplay between magneto-volume and chemical interactions (metal-H) effects within the following hydrided systems: binary Laves (e.g. ScFe 2 ) and Haucke (e.g. LaNi 5 ) phases on one hand, and ternary cerium based (e.g. CeRhSn) and uranium based (e.g. U 2 Ni 2 Sn) alloys on the other hand. (author)

  4. Physical properties of the GaPd2 intermetallic catalyst in bulk and nanoparticle morphology

    DEFF Research Database (Denmark)

    Wencka, M.; Schwerin, J.; Klanjšek, M.

    2015-01-01

    Intermetallic compound GaPd2 is a highly selective catalyst material for the semi-hydrogenation of acetylene. We have determined anisotropic electronic, thermal and magnetic properties of a GaPd2 monocrystal along three orthogonal orthorhombic directions of the structure. By using 69Ga and 71Ga NMR...... properties of the GaPd2 phase on going from the bulk material to the nanoparticles morphology, we have synthesized GaPd2/SiO2 supported nanoparticles and determined their electronic DOS at εF from the 71Ga NMR spin-lattice relaxation rate. The electronic DOS of the GaPd2 was also studied theoretically from...... spectroscopy, we have determined the electric-field-gradient tensor at the Ga site in the unit cell and the Knight shift, which yields the electronic density of states (DOS) at the Fermi energy εF. The DOS at εF was determined independently also from the specific heat. To see the change of electronic...

  5. Behavior of aluminum oxide, intermetallics and voids in Cu-Al wire bonds

    International Nuclear Information System (INIS)

    Xu, H.; Liu, C.; Silberschmidt, V.V.; Pramana, S.S.; White, T.J.; Chen, Z.; Acoff, V.L.

    2011-01-01

    Nanoscale interfacial evolution in Cu-Al wire bonds during isothermal annealing from 175 deg. C to 250 deg. C was investigated by high resolution transmission electron microscopy (HRTEM). The native aluminum oxide film (∼5 nm thick) of the Al pad migrates towards the Cu ball during annealing. The formation of intermetallic compounds (IMC) is controlled by Cu diffusion, where the kinetics obey a parabolic growth law until complete consumption of the Al pad. The activation energies to initiate crystallization of CuAl 2 and Cu 9 Al 4 are 60.66 kJ mol -1 and 75.61 kJ mol -1 , respectively. During IMC development, Cu 9 Al 4 emerges as a second layer and grows together with the initial CuAl 2 . When Al is completely consumed, CuAl 2 transforms to Cu 9 Al 4 , which is the terminal product. Unlike the excessive void growth in Au-Al bonds, only a few voids nucleate in Cu-Al bonds after long-term annealing at high temperatures (e.g., 250 o C for 25 h), and their diameters are usually in the range of tens of nanometers. This is due to the lower oxidation rate and volumetric shrinkage of Cu-Al IMC compared with Au-Al IMC.

  6. Phase equilibria of Al3(Ti,V,Zr) intermetallic system

    International Nuclear Information System (INIS)

    Park, S.I.; Han, S.Z.; Choi, S.K.; Lee, H.M.

    1996-01-01

    Trialuminides such as DO 22 -structured Al 3 Ti are promising candidates as potential materials for elevated temperature applications because of their attractive high temperature strength and excellent oxidation resistance along with their low density. However, in the tetragonal structure, slip systems are restricted due to low symmetry and the primary deformation mode is twinning. And, therefore, monolithic trialuminide compounds have been very impractical to be used as structural materials. When transition elements such as Ti, V and Zr which constitute trialuminides are alloyed in aluminum, they have low solubilities and low diffusion coefficients in the Al matrix. If precipitated as trialuminide intermetallics, they maintain a small lattice mismatch with the Al matrix, which reduces the interfacial energy between matrix and precipitates. As a result, these precipitates would have a large coarsening resistance in the matrix. As most of the previous works have been concentrated on the microstructural stability and mechanical properties, thermochemical properties will be treated in this work. In this study, phase equilibria and diagrams of Al 3 (Ti,V,Zr) systems will be experimentally determined and then thermodynamically analyzed with a hope to extend to the Al-Al 3 (Ti,V,Zr) composite system. This approach will then be used as a guide for alloy design of Al-Al 3 (Ti,V,Zr) composite system

  7. Joining of Ni-TiC FGM and Ni-Al Intermetallics by Centrifugal Combustion Synthesis

    International Nuclear Information System (INIS)

    Ohmi, Tatsuya; Matsuura, Kiyotaka; Iguchi, Manabu; Mizuma, Kiminori

    2008-01-01

    A centrifugal combustion synthesis (CCS) process has been investigated to join a Ni-Al intermetallic compound and a Ni-TiC cermet. The cermet, a tubular graphite mold, and a green compact of reactants consisting of Al, Ni and NiO were set in a centrifugal caster. When the combustion synthesis reaction was induced in the centrifugal force field, a synthesized molten Ni-Al alloy flowed into the graphite mold and joined to the cermet. The soundness of the joint interface depended on the volume percentage of TiC phase in the cermet. A lot of defects were formed near the interface between the Ni-TiC cermet and the cast Ni-Al alloy when the volume percentage of TiC was 50% or higher. For this kind of cermet system, using a functionally graded cermet such as Ni-10 vol.%TiC/Ni-25 vol.%TiC/Ni-50 vol.%TiC overcame this difficulty. The four-point bending strength of the joined specimen consisting of the three-layered FGM cermet and cast Ni-29 mol%Al alloy was 1010 MPa which is close to the result for a Ni-29 mol%Al alloy specimen

  8. Microstructure evolution and hardness change in ordered Ni3V intermetallic alloy by energetic ion irradiation

    International Nuclear Information System (INIS)

    Hashimoto, A.; Kaneno, Y.; Semboshi, S.; Yoshizaki, H.; Saitoh, Y.; Okamoto, Y.; Iwase, A.

    2014-01-01

    Ni 3 V bulk intermetallic compounds with ordered D0 22 structure were irradiated with 16 MeV Au ions at room temperature. The irradiation induced phase transformation was examined by means of the transmission electron microscope (TEM), the extended X-ray absorption fine structure measurement (EXAFS) and the X-ray diffraction (XRD). We also measured the Vickers hardness for unirradiated and irradiated specimens. The TEM observation shows that by the Au irradiation, the lamellar microstructures and the super lattice spot in diffraction pattern for the unirradiated specimen disappeared. This TEM result as well as the result of XRD and EXAFS measurements means that the intrinsic D0 22 structure of Ni 3 V changes into the A1 (fcc) structure which is the lattice structure just below the melting point in the thermal equilibrium phase diagram. The lattice structure change from D0 22 to A1 (fcc) accompanies a remarkable decrease in Vickers microhardness. The change in crystal structure was discussed in terms of the thermal spike and the sequential atomic displacements induced by the energetic heavy ion irradiation

  9. Characterization of ceramics and intermetallics fabricated by self-propagating high-temperature synthesis

    International Nuclear Information System (INIS)

    Hurst, J.B.

    1989-05-01

    Three efforts aimed at investigating the process of self-propagating high temperature synthesis (SHS) for the fabrication of structural ceramics and intermetallics are summarized. Of special interest was the influence of processing variables such as exothermic dopants, gravity, and green state morphology in materials produced by SHS. In the first effort directed toward the fabrication of SiC, exothermic dopants of yttrium and zirconium were added to SiO2 or SiO2 + NiO plus carbon powder mix and processed by SHS. This approach was unsuccessful since it did not produce the desired product of crystalline SiC. In the second effort, the influence of gravity was investigated by examining Ni-Al microstructures which were produced by SHS combustion waves traveling with and opposite the gravity direction. Although final composition and total porosities of the combusted Ni-Al compounds were found to be gravity independent, larger pores were created in those specimens which were combusted opposite to the gravity force direction. Finally, it was found that green microstructure has a significant effect on the appearance of the combusted piece. Severe pressing laminations were observed to arrest the combustion front for TiC samples

  10. Mechanical alloying of TiFe intermetallic for hydrogen storage

    International Nuclear Information System (INIS)

    Vega, L.E.R.; Leiva, D.R.; Silva, W.B.; Ishikawa, T.T.; Botta, W.J.; Leal Neto, R.M.

    2016-01-01

    Elementary powders of Ti and Fe in the stoichiometric ratio 50:50 were submitted to mechanical alloying for 2, 6, 10 and 20 h in a planetary ball mill. The synthesis of TiFe intermetallic with high yield was achieved for all milling times. The structural characterization of the samples revealed the trend of the particles to form agglomerates and the formation of cracks. H-absorption capacities of 0,74; 0,90; 0,97 and 0,95 wt. % (at room temperature and 20 bar of H2) were obtained for processing times of 2, 6, 10 and 20 h, respectively, without using a thermal activation process after milling. (author)

  11. A tem investigation on intermetallic particles in zircaloy-2

    International Nuclear Information System (INIS)

    Sudarminto, Harini Sosiati; Kuwano, Noriyuki; Oki, Kensuke

    1996-01-01

    Tem investigation were conducted on the heat treated zircaloy-2 having the composition of Zr containing 1.6% Sn, 0.2% Fe, 0.1% Cr and 0.05% Ni (%wt) in order tostudy the characteristics of intermetallic particles related to the microstructural basis on the corrosion effect. Forged zircaloy-2 was annealed in the β-phase at 1050 C degrees for various isothermally in the α-phase region at 650 and 750 C degrees, followed by water quenching. The size precipates, the lower became their number. By increasing the annealing temperature, the growth of precipitates formed in this zircaloy-2 were of the Zr(Cr,Fe) 2 and Zr 2 (Fe,Cr,Ni) types. These kinds of precipitates and the ratios of Fe/Cr were independent of size and shape of precipitates and annealing time and temperature. (author), 16 refs, 2 tabs, 5 figs

  12. Influence of Al grain boundaries segregations and La-doping on embrittlement of intermetallic NiAl

    Science.gov (United States)

    Kovalev, Anatoly I.; Wainstein, Dmitry L.; Rashkovskiy, Alexander Yu.

    2015-11-01

    The microscopic nature of intergranular fracture of NiAl was experimentally investigated by the set of electron spectroscopy techniques. The paper demonstrates that embrittlement of NiAl intermetallic compound is caused by ordering of atomic structure that leads to formation of structural aluminum segregations at grain boundaries (GB). Such segregations contain high number of brittle covalent interatomic bonds. The alloying by La increases the ductility of material avoiding Al GB enrichment and disordering GB atomic structure. The influence of La alloying on NiAl mechanical properties was investigated. GB chemical composition, atomic and electronic structure transformations after La doping were investigated by AES, XPS and EELFS techniques. To qualify the interatomic bonds metallicity the Fermi level (EF) position and electrons density (neff) in conduction band were determined in both undoped and doped NiAl. Basing on experimental results the physical model of GB brittleness formation was proposed.

  13. Structural and magnetic order of ThMn12-type rare earth-iron-aluminium intermetallics studied by neutron diffraction

    International Nuclear Information System (INIS)

    Schaefer, W.; Halevy, I.; Gal, J.

    2000-01-01

    neutron powder diffraction data of ThMn 12 -type compounds RFe 4 Al 8 , RFe 5 Al 7 , and RFe 6 Al 6 (R = heavy rare earth) are compared to work out the structural variations and the different magnetic properties of these ternary intermetallics as a function of increasing iron concentrations. The variations of unit cell metric, of atomic coordinations and of interatomic distances are discussed. A magnetic phase diagram is presented showing the increase of the magnetic ordering temperatures from 120 K to 340 K and the change of the magnetic order from two separate magnetic phase transitions of rare earth and iron sublattices to one common ferrimagnetic transition of both sublattices, when changing the ratio of Fe/Al atoms from 4/8 to 6/6, respectively. Long range order is hampered by frozen spins. Magnetically ordered rare earth and iron moments are given. (orig.)

  14. The Ni3Al and NiAl alloys: a class of intermetallics which can replace the Ni-base superalloys for the aerospace high temperature structural applications

    International Nuclear Information System (INIS)

    Lucaci, M.; Vidu, C.D.; Vasile, E.

    2001-01-01

    The paper presents the results obtained in synthesizing Ni-base refractory intermetallics from elemental powder mixes. In view of this, four mixes were made for the Ni 3 Al intermetallics and five mixes for the NiAl ones. The compound synthesis was made at T = 660 o C under vacuum by the SHS method, in the thermo-explosion mode. The variable parameters were the compacting pressure and the aluminum amount in the mixes. The obtained materials were then characterized by the microstructure and by the physical properties. The product synthesis degree was followed as well as their influence on the types of microstructures obtained. The reaction products were evidenced by x-ray diffraction and by quantitative chemical microanalysis. The obtained results revealed the formation of the Ni 3 Al compound having a primitive cubic crystal lattice with a 0 = 3,564 Aa and the formation of the NiAl compound, of a bcc lattice having a 0 = 2,86 Aa. Those obtained prove the ample influences of the powder homogeneity degree and of the powder purity on the possibility to produce an adequate synthesis, as well as the influence of the amount liquid appeared in the system on the synthesis degree, on the reaction rate and on the porosity of materials obtained. (author)

  15. Annual Report 1985

    International Nuclear Information System (INIS)

    Muenze, R.

    1986-06-01

    This annual report covers the work carried out at the Radioisotope Department, ZfK Rossendorf, during the year 1985. It contains 12 contributions related to the development of processes for generating radioisotopes, 23 contributions related to the synthesis of radioactive compounds, and 26 contributions related to the characterization of radioactive compounds. All contributions are published in summary form only and are individually processed for the INIS database. Additionally, a list is given of publications and lectures issued between January and December 1985

  16. 3D study of intermetallics and their effect on the corrosion morphology of rheocast aluminium alloy

    International Nuclear Information System (INIS)

    Mingo, B.; Arrabal, R.; Pardo, A.; Matykina, E.; Skeldon, P.

    2016-01-01

    In the present study, the effect of heat treatment T6.1 on the microstructure and corrosion behaviour of rheocast aluminium alloy A356 is investigated on the basis of 2D/3D characterization techniques and electrochemical and SKPFM measurements. Heat treatment strengthens the α-Al matrix, modifies the intermetallic particles and spheroidizes eutectic Si. These changes do not modify significantly the corrosion behaviour of the alloy. 3D SEM-Tomography clearly shows that the corrosion advances in the shape of narrow paths between closely spaced intermetallics without a major influence of eutectic Si. - Highlights: • T6.1 spheroidizes Si, strengthens the matrix and modifies the intermetallics. • Electrochemical behaviour of untreated and heat-treated alloys is similar. • 3D SEM-Tomography provides additional information on the corrosion morphology. • Corrosion advances as paths between intermetallics with little influence of Si.

  17. First principles study of electronic, elastic and thermal properties of lutetium intermetallics

    International Nuclear Information System (INIS)

    Pagare, Gitanjali; Chouhan, Sunil Singh; Soni, Pooja; Sanyal, S.P.; Rajagopalan, M.

    2011-01-01

    In the present work, the electronic, elastic and thermal properties of lutetium intermetallics LuX have been studied theoretically by using first principles calculations based on density functional theory (DFT) with the generalized gradient approximation (GCA)

  18. Intermetallic matrix composites; Proceedings of the MRS Symposium, San Francisco, CA, Apr. 18-20, 1990

    International Nuclear Information System (INIS)

    Anton, D.L.; Martin, P.L.; Miracle, D.B.; Mcmeeking, R.

    1990-01-01

    The present volume on intermetallic matrix composites discusses the modeling, processing, microstructure/property relationships, and compatibility of intermetallic matrix composites. Attention is given to models for the strength of ductile matrix composites, innovative processing techniques for intermetallic matrix composites, ductile phase toughening of brittle intermetallics, and reactive synthesis of NbAl3 matrix composites. Topics addressed include solidification processing of NbCr2 alloys, Ta and Nb reinforced MoSi2, the microstructure and mechanical behavior of Ni3Al-matrix composites, and ductile-phase toughening of Cr3Si with chromium. Also discussed are dislocation morphologies in TiB2/NiAl, the development of highly impact resistant NiAl matrix composites, the effect of notches on the fatigue life of the SCS-6Ti3Al composite, and the chemical stability of fiber-metal matrix composites

  19. Reaction kinetics of the formation of intermetallic Fe – Zn during hot - dip galvanizing of steel

    Directory of Open Access Journals (Sweden)

    P. Pokorny

    2016-01-01

    Full Text Available This review article mainly describes the composition of intermetallic Fe - Zn, i.e. zeta (ζ, delta (δ1k + δ1p, gamma1 (Γ1 and gamma (Γ on galvanized steel during low temperature galvanization (t ~ 450 °C. It gives detailed the formation, growth of individual phases during galvanization and their interaction. In terms of the kinetics, the formation of the coating is defined by a parabolic kinetic equation of the growth of different intermetallic phases under ideal conditions. From the available literature the rate constants of the formation of individual intermetallic phases and also for the total coating are cited. The composition of the intermetallic phases, iron content, crystal structure, and group symmetry in which the surface of galvanized steel forms.

  20. Elemental analysis of the Al-Fe intermetallic prepared by fast solidification

    International Nuclear Information System (INIS)

    Sandoval J, R.A.; Lopez M, J.; Ramirez T, J.J.; Aspiazu F, J.; Villasenor S, P.

    2003-01-01

    Applying the PIXE technique samples of the Al-Fe intermetallic prepared by fast solidification, obtained starting from Al recycled were analyzed. The concentrations of the found elements are given. (Author)

  1. Micromechanisms of fracture and fatigue in Ti3Al based and TiAl based intermetallics

    International Nuclear Information System (INIS)

    James, A.W.; Chave, R.A.; Hippsley, C.A.; Bowen, P.

    1993-01-01

    Micromechanisms of fracture and fatigue crack growth resistance in specific Ti 3 Al based and TiAl based intermetallics are reviewed. Effects of test temperature, environment and microstructure on crack growth resistance are considered in detail for several Ti 3 Al and Ti'Al based intermetallic systems under development. The implications of these studies for the structural reliability of these materials is also addressed briefly. (orig.)

  2. Study on the Mechanical Properties and Corrosion Behaviors of Fe-(20, 45) wt%Gd Intermetallics

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Bo Kyeong; Baik, Youl; Choi, Yong [Dankook University, Chungnam (Korea, Republic of); Moon, Byung Moon [Korea Institute of Industrial Technology, Incheon (Korea, Republic of)

    2017-02-15

    Fe-(20, 45 wt%) Gd intermetallics were vacuum arc melted as the mother alloy of a neutron shielding and absorbing material. The structure of the cast Fe-20 wt%Gd intermetallics had primary dendrites with a short width of about 2 μm, which became coarse with increasing Gd content. The final compositions of the Fe-20 wt%Gd and Fe-45 wt%Gd intermetallics determined by Rietveld refinement were mainly Fe{sub 3}Gd with 26.6 at%Fe{sub 2}Gd, and Fe{sub 3}Gd with various intermetallics like 13.9 at%Fe{sub 2}Gd, 7.3 at%Fe{sub 9}Gd and 3.9 at%Fe{sub 17}Gd{sub 2}, respectively. The micro-hardnesses, yield strength, ultimate compressive strength and elongation of the Fe-20 wt%Gd intermetallics were 629±12 Hv, 753 MPa, 785 MPa and 4%, respectively, and those of the Fe-45 wt%Gd intermetallics were 741±13 Hv, 772 MPa, 823 MPa and 3%. Passivity was not present in artificial sea water at room temperature. The corrosion potentials and the corrosion rates of the Fe-20 wt%Gd and Fe-45 wt%Gd intermetallics were –624 mV{sub SHE}, 2.771 mA/cm{sup 2} , and –804 mV{sub SHE}, 3.397 mA/cm{sup 2} , respectively. The corroded surface of the Fe-Gd intermetallics contained corrosion products like gadolinium with iron, which detached to leave a trail of pits.

  3. Pitting Corrosion of Ni3(Si,Ti+2Cr Intermetallic Compound at Various Chloride Concentrations

    Directory of Open Access Journals (Sweden)

    Gadang Priyotomo

    2014-05-01

    Full Text Available The pitting corrosion of Ni3(Si,Ti with 2 at% Cr containing two regions of a Ni3(Si,Ti single-phase of L12 structure and a mixture phase of of (L12 +Niss was investigated as function of chloride concentrations by using a polarization method, scanning electron microscope and energy dispersive X-Ray spectroscopy in neutral sodium chloride solutions at 293 K.  The pitting corrosion of Ni3(Si,Ti with and without the addition of aluminium and type C276 alloy were also studied under the same experimental condition for the comparison.  The pitting potential obtained for the Ni3(Si,Ti with 2 at% Cr decreased with increasing chloride concentration.  The specific pitting potentials and the pitting potentials were decreased in the order of C276 alloy > Ni3(Si,Ti > Ni3(Si,Ti + 2Cr > Ni3(Si,Ti + 4Al, which means that the pitting corrosion resistance of Ni3(Si,Ti with 2 at% Cr was higher than Ni3(Si,Ti with 4 at% Al, but lower than that of Ni3(Si,Ti.  A critical chloride concentration of Ni3(Si,Ti with 2 at% Cr was found to be higher than that of Ni3(Si,Ti with at% Al. In addition, the presence of high concentration for oxygen indicates the occurrence of pit formation.

  4. Studies of Modified Hydrogen Storage Intermetallic Compounds Used as Fuel Cell Anodes

    Directory of Open Access Journals (Sweden)

    Rui F. M. Lobo

    2011-12-01

    Full Text Available The possibility of substituting Pt/C with the hydrogen storage alloy MlNi3.6Co0.85Al0.3Mn0.3 as the anode active material of a proton exchange membrane fuel cell system has been analyzed. The electrochemical properties indicate that a much more electrochemically active anode is obtained by impregnating the active material loaded anode in a Nafion proton conducting polymer. Such performance improvement might result from the increase of three-phase boundary sites or length in the gas diffusion electrode where the electrochemical reaction occurs. The experimental data revealed that the membrane electrode assembly (MEA shows better results when the anode active material, MlNi3.6Co0.85Al0.3Mn0.3, is treated with a hot alkaline KBH4 solution, and then chemically coated with 3 wt.% Pd. The MEA with the aforesaid modification presents an enhanced surface capability for hydrogen adsorption, and has been studied by molecular beam-thermal desorption spectrometry.

  5. Electroerosion of Zr3Al and ZrAl3 intermetallic compounds

    International Nuclear Information System (INIS)

    Asanov, U.A.; Sakavov, I.E.; Denisov, A.S.

    1974-01-01

    The results of an investigation of the mechanochemical processes initiated in polymers (polypropylene and polystyrene in contact with Br 2 , I 2 and CBr 4 ) owing to simultaneous effect of mechanical action and u.v. irradiation are presented. The treatment results in the formation of a large number of active radicals and broken chemical bonds. It was shown that u.v. irradiation facilitates mechanoactivation and mechanodestruction of the polymers

  6. NMR studies on magnetic properties of intermetallic compounds Er1-xYxCo3

    International Nuclear Information System (INIS)

    Niki, H.; Kinjo, T.; Yogi, M.; Pieper, M.W.; Gratz, E.; Markosyan, A.S.

    2007-01-01

    Field dependence of 59 Co NMR in ferrimagnetic Er 1-x Y x Co 3 was measured up to 8T at 4.2K using aligned powdered samples. For pure ErCo 3 in fields perpendicular to the c axis the resonance frequencies change discontinuously between 2 and 3T due to a field induced metamagnetic transition. The easy axis is found to be along the c axis for x=0 and 0.1. An average angle for the Co moments of 45+/-5 o from the c axis is obtained from field dependence of 59 Co NMR at x=0.3. Directions of Co moments are also found to be inclined from the c axis for x=0.5

  7. Atomic site occupancies and magnetic properties of Ni-doped FeAl intermetallic compounds

    CERN Document Server

    Ko, K Y; Yoon, S

    1999-01-01

    Neutron and X-ray powder diffraction revealed FeAl sub 1 sub - sub x Ni sub x alloys to have the B2(CsCl) structure with a virtually constant lattice parameter of 2.91 A and with the Ni atoms preferring the Fe sites. The annealed specimens showed paramagnetism for x 0.25 whereas the rapidly solidified specimens showed superparamagnetism for x = 0.25. The magnetization increased as the Ni concentration (x) increased. The rapidly solidified specimens, in general, showed stronger magnetic properties than the annealed ones. The magnetic properties were explained in terms of the local environmental model for magnetic atoms.

  8. Magnetic properties of intermetallic compounds La(Ni,Co,Cu)3

    International Nuclear Information System (INIS)

    Tazuke, Y.; Tanikawa, H.; Okano, A.; Miyaji, T.

    2006-01-01

    LaNi 3 exhibited a metallic antiferromagnetic property with T N =30 K. La(Ni 1-x Co x ) 3 with x=0.01, 0.03 and 0.05 exhibited ferromagnetic properties, T C increasing linearly with increasing x. La(Ni 1-2z Co z Cu z ) 3 with z=0.015 exhibited a ferromagnetic property with a small T C . A La(Ni 1-y Cu y ) 3 sample with y=0.01 exhibited a Pauli-paramagnetic property; those with y=0.02, 0.03 and 0.04 exhibited gradual metamagnetic behavior and that with y=0.05 exhibited a ferromagnetic property. The gradual metamagnetic M-H variations are numerically simulated by using Landau-type free energies. The results suggest that the gradual metamagnetic behavior occurs from an antiferromagnetic state to a ferromagnetic one. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  9. High Temperature Advanced Structural Composites. Book 1: Executive Summary and Intermetallic Compounds

    Science.gov (United States)

    1993-04-02

    modulus begins to grow rapidly above 1200 c. An algorithm has been developed for the determination of isothermal gage length data from the parabolic...show a fully duue mi• cstr =ctre. Therefore, it appears the HIP process has effectively closed the reaining poromity preet in the as-sintered material

  10. Moessbauer effect measurements on the intermetallic compounds Ni3Al and Ni3Ge

    International Nuclear Information System (INIS)

    Drijver, J.W.; Woude, F. van der

    1975-01-01

    Moessbauer parameters obtained from room temperature emission and absorption spectra of Ni 3 Al and Ni 3 Ga processed by a computer assuming a singlet and a doublet are given. The doublet is due to iron or cobalt atoms at the nickel site. Quadrupole splitting at 57 Fe nuclei in Ni 3 Ga is larger than in Ni 3 Al, viz. 0.52 and 0.37 mm/sec, respectively. Isomer shift at the Al/Ga position is very close to -0.02 mm/sec found in metallic nickel. Also given are the hyperfine magnetic fields at 4.2 K. Considering the preference of 57 Co and 57 Fe atoms in the lattice, the field intensities at the nickel and aluminium sites are found to be 227 +- 1 and 238 +- 1 kOe, respectively. (Z.S.)

  11. Electronic and Spectral Properties of RRhSn (R = Gd, Tb) Intermetallic Compounds

    Science.gov (United States)

    Knyazev, Yu. V.; Lukoyanov, A. V.; Kuz'min, Yu. I.; Gupta, S.; Suresh, K. G.

    2018-02-01

    The investigations of electronic structure and optical properties of GdRhSn and TbRhSn were carried out. The calculations of band spectrum, taking into account the spin polarization, were performed in a local electron density approximation with a correction for strong correlation effects in 4f shell of rare earth metal (LSDA + U method). The optical studies were done by ellipsometry in a wide range of wavelengths, and the set of spectral and electronic characteristics was determined. It was shown that optical absorption in a region of interband transitions has a satisfactory explanation within a scope of calculations of density of electronic states carried out.

  12. Spin reorientation transition and hard magnetic properties of MnBi intermetallic compound

    Science.gov (United States)

    Suzuki, K.; Wu, X.; Ly, V.; Shoji, T.; Kato, A.; Manabe, A.

    2012-04-01

    The effects of mechanical grinding (MG) on the crystallite size, the spin reorientation transition temperature (TSR) and the hard magnetic properties in melt-spun low temperature phase (LTP) MnBi have been investigated in order to understand the origin of magnetic hardening induced by MG. The room-temperature coercive field (μ0Hcj) is enhanced dramatically from 0.08 T before MG to 1.5 T after MG for 43.2 ks while TSR is concurrently suppressed from 110 to 38 K. The coercive force exhibits positive temperature dependence approximately 50-60 K above TSR and the lowered TSR after MG could result in magnetic hardening at room temperature. The room-temperature coercive force of LTP-MnBi is highly dependent on the crystallite size (D) and is found to be described phenomenologically by the following relationship: μ0Hcj = μ0Ha(δ/D)n, where μ0Ha is ˜ 4 T, the Bloch wall width δ is 7 nm, and the exponent n is approximately 0.7. Our results suggest that the grain refinement is the primary origin of the hardening effect induced by MG with a possible minor hardening effect due to the suppression of the spin reorientation transition temperature.

  13. Pitting Corrosion of Ni3(Si,Ti+4Al Intermetallic Compound at Various Chloride Concentrations

    Directory of Open Access Journals (Sweden)

    Gadang Priyotomo

    2014-04-01

    Full Text Available The pitting corrosion of Ni3(Si,Ti with 4 at% Al consisting of two regions of a Ni3(Si,Ti single-phase of L12 structure and two phases of L12 and fcc Niss was investigated as function of chloride concentrations by using electrochemical method, scanning electron microscope and energy dispersive X-Ray spectroscopy in neutral sodium chloride solutions at 293 K.  In addition, the pitting corrosion of Ni3(Si,Ti and  type C276 alloy were also studied under the same experimental condition for comparison.  The pitting potential obtained for the Ni3(Si,Ti with 4 at%Al decreased with increasing chloride concentration.  The specific pitting potential and pitting potential of Ni3(Si,Ti with 4at%, Ni3(Si,Ti and C276 were the lowest, the moderate and the highest, respectively, which means that the pitting corrosion resistance of Ni3(Si,Ti was higher than Ni3(Si,Ti with 4at% Al, but lower than that of C276.  A critical chloride concentration of Ni3(Si,Ti with 4at% Al was found to be lower than that of Ni3(Si,Ti.  The Pitting corrosion of Ni3(Si,Ti with 4at% Al occurred in the two phase mixture (L12 + Niss.

  14. Magnetic properties of intermetallic compounds La(Ni,Co,Cu)3

    Science.gov (United States)

    Tazuke, Y.; Tanikawa, H.; Okano, A.; Miyaji, T.

    2006-09-01

    LaNi3 exhibited a metallic antiferromagnetic property with T N = 30 K. La(Ni1-x Cox )3 with x = 0.01, 0.03 and 0.05 exhibited ferromagnetic properties, T C increasing linearly with increasing x . La(Ni1-2z Coz Cuz )3 with z = 0.015 exhibited a ferromagnetic property with a small T C. A La(Ni1-y Cuy )3 sample with y = 0.01 exhibited a Pauli-paramagnetic property; those with y = 0.02, 0.03 and 0.04 exhibited gradual metamagnetic behavior and that with y = 0.05 exhibited a ferromagnetic property. The gradual metamagnetic M -H variations are numerically simulated by using Landau-type free energies. The results suggest that the gradual metamagnetic behavior occurs from an antiferromagnetic state to a ferromagnetic one.

  15. Hydrogen diffusion in Mg2NiH4 intermetallic compound

    Czech Academy of Sciences Publication Activity Database

    Čermák, Jiří; Král, Lubomír; David, Bohumil

    2008-01-01

    Roč. 16, č. 4 (2008), s. 508-517 ISSN 0966-9795 R&D Projects: GA ČR GA106/07/0010 Institutional research plan: CEZ:AV0Z20410507 Keywords : diffusion * hydrogen storage * phase transformations Subject RIV: BJ - Thermodynamics Impact factor: 2.034, year: 2008

  16. Continuous 25-yr aerosol records at coastal Antarctica - I: inter-annual variability of ionic compounds and links to climate indices

    Energy Technology Data Exchange (ETDEWEB)

    Weller, Rolf; Koenig-Langlo, Gert (Alfred Wegener Inst. for Polar and Marine Research, Bremerhaven (Germany)), e-mail: Rolf.Weller@awi.de; Wagenbach, Dietmar; Elsaesser, Christoph (Institut fur Umweltphysik, Univ. of Heidelberg, Heidelberg (Germany)); Legrand, Michel (Laboratoire de Glaciologie et Geophysique de l' Environnement du Centre National de la Recherche Scientifique, St Martin d' Heres (France)); Tian-Kunze, Xiangshan (Institut fur Meereskunde, Univ. of Hamburg, Hamburg (Germany))

    2011-11-15

    The aerosol climatology at the coastal Antarctic Neumayer Station (NM) was investigated based on continuous, 25-yr long observations of biogenic sulphur components (methanesulfonate and non-sea salt sulphate), sea salt and nitrate. Although significant long-term trends could only be detected for nitrate (-3.6 +- 2.5% per year between 1983 and 1993 and +4.0 +- 3.2% per year from 1993-2007), non-harmonic periodicities between 2 and 5 yr were typical for all species. Dedicated time series analyses revealed that relations to sea ice extent and various circulation indices are weak at best or not significant. In particular, no consistent link between sea ice extent and sea salt loadings was evident suggesting only a rather local relevance of the NM sea salt record. Nevertheless, a higher Southern Annular Mode index tended to entail a lower biogenic sulphur signal. In examining the spatial uniformity of the NM findings we contrasted them to respective 17 yr records from the coastal Dumont d'Urville Station. We found similar long-term trends for nitrate, indicating an Antarctic-wide but not identifiable atmospheric signal, although any significant impact of solar activity or pollution could be ruled out. No inter-site variability on the multiannual scale was evident for the other ionic compounds

  17. Codeformation processing of mechanically-dissimilar metal/intermetallic composites

    Science.gov (United States)

    Marte, Judson Sloan

    A systematic and scientific approach has been applied to the study of codeformation processing. A series of composites having mechanically-dissimilar phases were developed in which the high temperature flow behavior of the reinforcement material could be varied independent of the matrix. This was accomplished through the use of a series of intermetallic matrix composites (IMCs) as discontinuous reinforcements in an otherwise conventional metal matrix composite. The IMCs are produced using an in-situ reaction synthesis technique, called the XD(TM) process. The temperature of the exothermic synthesis reaction, called the adiabatic temperature, has been calculated and shown to increase with increasing volume percentage of TiB2 reinforcement. Further, this temperature has been shown to effect the size and spacing of the TiB2, microstructural features which are often used in discontinuous composite strength models. Study of the high temperature flow behavior of the components of the metal/IMC composite is critical to the development of an understanding of codeformation. A series of compression tests performed at 1000° to 1200°C and strain-rates of 10-3 and 10-4 sec-1. Peak flow stresses were used to evaluate the influence of material properties and process conditions. These data were incorporated into phenomenologically-based constitutive equations that have been used to predict the flow behavior. It has been determined that plastic deformation of the IMCs occurs readily, and is largely TiB2 independent, at temperatures approaching the melting point of the intermetallic matrices. Ti-6Al-4V/IMC powder blends were extruded at high temperatures to achieve commensurately deformed microstructures. The results of codeformation processing were analyzed in terms of the plastic strain of the IMC particulates. IMC particle deformation was shown to increase with increasing IMC particle size, volume percentage of IMC, extrusion temperature, homologous temperature, extrusion

  18. EFFECT OF INTERMETALLIC PHASES ON CORROSION BEHAVIOR AND MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL AND SUPER-DUPLEX STAINLESS STEEL

    OpenAIRE

    Prabhu Paulraj; Rajnish Garg

    2015-01-01

    Duplex Stainless Steels (DSS) and Super Duplex Stainless Steel (SDSS) have excellent integration of mechanical and corrosion properties. However, the formation of intermetallic phases is a major problem in their usage. The mechanical and corrosion properties are deteriorated due to the presence of intermetallic phases. These phases are induced during welding, prolonged exposure to high temperatures, and improper heat treatments. The main emphasis of this review article is on intermetallic pha...

  19. Fracture toughness of intermetallics using a micro-mechanical probe

    International Nuclear Information System (INIS)

    Gerberich, W.W.; Venkataraman, S.K.; Hoehn, J.W.; Marsh, P.G.

    1993-01-01

    A novel technique for determining the fracture toughness of brittle intermetallics is presented, wherein very small samples are used and multiple tests are easily conducted on a flat polished surface. The fracture toughness of single crystal NiAl and polycrystalline Al 3 Sc are evaluated with this continuous microscratch technique at scratch rates ranging from 0.5 to greater than 100 μm s - . For comparison, small compact tension samples of (100) NiAl are evaluated at applied stress intensity rates ranging from 1.5 to 5,400 MPa-m 1/2 s -1 . Good comparison of microscratch toughness to compact tension K Ic values are obtained in this study for (001) NiAl, 10.6 vs. 10.0 MPa-m 1/2 , from the literature for (001) , 13.5 vs. 12.2 MPa-m 1/2 , and from the literature for polycrystalline Al 3 Sc, 3.5 vs. 3.1 MPa-m 1/2 . Also, the fracture toughness of both NiAl and Al 3 Sc are found to be strongly dependent on strain rate at room temperature with toughness dropping by an order of magnitude over a decade increase in rate. Possible reasons and implications to improving low temperature brittleness are discussed

  20. Calorimetric investigations of UPb{sub 3} compound

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Renu, E-mail: arenu@barc.gov.in; Samui, Pradeep; Mukerjee, S.K.

    2016-08-10

    Highlights: • First time reporting of enthalpy increment and heat capacity data of UPb{sub 3} compound. • First time reporting of high temperature calorimetric determination of enthalpy of formation of UPb{sub 3} compound. • Miedema model was used to calculate enthalpies of formation of UPb{sub 3} and UPb. • Thermodynamic table of the compound UPb{sub 3} was generated. - Abstract: Interaction of uranium based metallic fuels and lead coolant can lead to formation of intermetallic compounds of U-Pb system. To understand U-Pb interactions, it is important to know thermodynamic properties of intermetallic compounds present in this system, UPb{sub 3} and UPb. In the present work, enthalpy increment, heat capacity and enthalpy of formation of UPb{sub 3} intermetallic compound were determined. The enthalpy increment was determined by high temperature Calvet calorimeter and heat capacity was determined using DSC. The heat capacity data was used to calculate thermodynamic parameters of the compound as a function of temperature. The enthalpy of formation at 843 K was determined using successive precipitation method, by direct reaction calorimetry. The enthalpy of formation at 843 K, from Pb(l) and U(l), was −28.9 kJ at-mol{sup −1} and after adjusting enthalpy increments of pure elements and compound, the enthalpy of formation of the compound at 298 K, from Pb(s) and U(α) was found to be −20.0 kJ at-mol{sup −1}.

  1. Ab initio study of antiphase boundaries and stacking faults in L12 and DO22 compounds

    DEFF Research Database (Denmark)

    Rosengaard, N. M.; Skriver, Hans Lomholt

    1994-01-01

    We have performed ab initio calculations of the energies of antiphase boundaries as well as complex and superlattice intrinsic stacking faults in nine intermetallic compounds observed in the face-centered-cubic L1(2) and DO22 structures. The calculations were performed by means of a Green...

  2. Investigation of Y6Mn23 and YMn12 intermetallic alloys under high hydrogen pressure

    Science.gov (United States)

    Filipek, S. M.; Sato, R.; Kuriyama, N.; Tanaka, H.; Takeichi, N.

    2010-03-01

    Among three intermetallic compounds existing in Y-Mn system the YMn2 and Y6Mn23 can easily form interstitial hydrides while for YMn12 existence of hydride has never been reported. At moderate hydrogen pressure YMn2 and Y6Mn23 transform into YMn2H4.5 and Y6Mn23H25 respectively. At high hydrogen pressure the YMn2 (C15 or C14 parent structure) forms a unique YMn2H6 (s.g. Fm3m) complex hydride of fluorite structure in which one Mn atom Mn(1) and Y randomly occupy the 8c sites while second manganese (Mn2) in position 4a forms complex anion with 6 hydrogen atoms located in positions 24e. Formation of YMn2H6 independently of the structure of parent phase (C14 or C15) as well as occupation of the same site (8c) by Y and Mn(1) atoms suggested that also Y6Mn23 and YMn12 could transform into YMn2H6 - type hydride in which suitable number of Y atoms will be substituted by Mn(1) in the 8c positions. This assumption was confirmed by exposing R6Mn23 and RMn12 to 1 GPa of hydrogen pressure at 1000C. Formation of (RxMn2-x)MnH6 (where x = 18/29 or 3/13 for R6Mn23 and RMn12 hydrides respectively) was confirmed by XRD. Hydrogen concentration in both R6Mn23 and RMn12 based hydrides reached H/Me = 2 thus value two times higher than in R6Mn23H25.

  3. Investigation of Y6Mn23 and YMn12 intermetallic alloys under high hydrogen pressure

    International Nuclear Information System (INIS)

    Filipek, S M; Sato, R; Kuriyama, N; Tanaka, H; Takeichi, N

    2010-01-01

    Among three intermetallic compounds existing in Y-Mn system the YMn 2 and Y 6 Mn 23 can easily form interstitial hydrides while for YMn 12 existence of hydride has never been reported. At moderate hydrogen pressure YMn 2 and Y 6 Mn 23 transform into YMn 2 H 4.5 and Y 6 Mn 23 H 25 respectively. At high hydrogen pressure the YMn 2 (C15 or C14 parent structure) forms a unique YMn 2 H 6 (s.g. Fm3m) complex hydride of fluorite structure in which one Mn atom Mn(1) and Y randomly occupy the 8c sites while second manganese (Mn2) in position 4a forms complex anion with 6 hydrogen atoms located in positions 24e. Formation of YMn 2 H 6 independently of the structure of parent phase (C14 or C15) as well as occupation of the same site (8c) by Y and Mn(1) atoms suggested that also Y 6 Mn 23 and YMn 12 could transform into YMn 2 H 6 - type hydride in which suitable number of Y atoms will be substituted by Mn(1) in the 8c positions. This assumption was confirmed by exposing R 6 Mn 23 and RMn 12 to 1 GPa of hydrogen pressure at 100 0 C. Formation of (R x Mn 2-x )MnH 6 (where x = 18/29 or 3/13 for R 6 Mn 23 and RMn 12 hydrides respectively) was confirmed by XRD. Hydrogen concentration in both R 6 Mn 23 and RMn 12 based hydrides reached H/Me = 2 thus value two times higher than in R 6 Mn 23 H 25 .

  4. Annual report 1979/1980

    International Nuclear Information System (INIS)

    Muenze, R.

    1981-11-01

    The annual report concentrates result of investigations in the field of the production of radioisotopes, the synthesis of radioactive compounds and their characterization. Main topics are the production of 99 Mo and the application of radioactive compounds in nuclear medicine especially as radiopharmaceuticals. A list of publications and lectures is enclosed. (author)

  5. Electrochemical properties of the passive film on bulk Zr–Fe–Cr intermetallic fabricated by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Yakui [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Ling, Yunhan, E-mail: yhling@mail.tsinghua.edu.cn [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Lai, Wensheng [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Xing, Shupei; Ma, Wen [School of Materials Science and Engineering, Inner Mongolia University of Technology, Huhhot 010051 (China)

    2016-12-01

    Highlights: • SPS was employed to prepare Zr-based intermetallics which were commonly existed in zircaloy. • Zr-based intermetallics act as cathode when they embedded in zirconium matrix. • The passive films on surface of intermetallics behaved as n-type semiconductors. • Carrier concentration of Zr(Fe{sub 3}Cr){sub 2} was much lower than that of other intermetallics. - Abstract: Although Zr-based second phase particles (SPPs) are important factors influencing corrosion resistance of zircaloy cladding materials, the corrosion behavior of SPPs has not been investigated by means of electrochemical method so far. In order to clarify the role of SPPs commonly existed in zircaloy, bulk Zr-based intermetallics were firstly fabricated by spark plasma sintering (SPS) at temperatures 1373 K and an applied pressure of 60 MPa in this work. Both the natural passive film on surface and oxidation behavior of intermetallic has been investigated in this work. X-ray diffraction (XRD) pattern showed that as-prepared intermetallic of crystal structure belongs to Laves phase with AB{sub 2} type. Electrochemical measurement of passive film on surface of bulk Zr-based intermetallic exhibited significant difference with that of zirconium. Potentiodynamic measurements results revealed that intermetallic exhibited higher corrosion potential and lower corrosion current density than that of pure zirconium, implying that Zr-based second phase will act as cathode when they are included in zirconium matrix. Meanwhile, significant improvement of Zr–Fe–Cr intermetallic on the water chemistry corrosion resistance was demonstrated comparing with Zr–Fe and Zr–Cr binary intermetallics.

  6. Kinetics of intermetallic phase formation at the interface of Sn-Ag-Cu-X (X = Bi, In) solders with Cu substrate

    International Nuclear Information System (INIS)

    Hodulova, Erika; Palcut, Marian; Lechovic, Emil; Simekova, Beata; Ulrich, Koloman

    2011-01-01

    Highlights: → In substitutes Sn in intermetallic compounds formed at the Cu-solder interface. → Bi and In decrease the parabolic rate constant of Cu 3 Sn layer growth. → In increases the parabolic rate constant of Cu 6 Sn 5 layer growth. → High In concentrations should be avoided since they may lead to a pre-mature solder joint degradation. - Abstract: The effects of Bi and In additions on intermetallic phase formation in lead-free solder joints of Sn-3.7Ag-0.7Cu; Sn-1.0Ag-0.5Cu-1.0Bi and Sn-1.5Ag-0.7Cu-9.5In (composition given in weight %) with copper substrate are studied. Soldering of copper plate was conducted at 250 deg. C for 5 s. The joints were subsequently aged at temperatures of 130-170 deg. C for 2-16 days in a convection oven. The aged interfaces were analyzed by optical microscopy and energy dispersive X-ray spectroscopy (EDX) microanalysis. Two intermetallic layers are observed at the interface - Cu 3 Sn and Cu 6 Sn 5 . Cu 6 Sn 5 is formed during soldering. Cu 3 Sn is formed during solid state ageing. Bi and In decrease the growth rate of Cu 3 Sn since they appear to inhibit tin diffusion through the grain boundaries. Furthermore, indium was found to produce a new phase - Cu 6 (Sn,In) 5 instead of Cu 6 Sn 5 , with a higher rate constant. The mechanism of the Cu 6 (Sn,In) 5 layer growth is discussed and the conclusions for the optimal solder chemical composition are presented.

  7. An MHD heat source based on intermetallic reactions

    Energy Technology Data Exchange (ETDEWEB)

    Sadjian, H.; Zavitsanos, P. (General Sciences, Inc., Souderton, PA (United States)); Marston, C.H. (Villanova Univ., PA (United States))

    1991-05-06

    The main objective of this program was the development of an MHD heat source of potential use in Space - Based Multi Megawatt, MHD Power Systems. The approach is based on extension of high temperature chemical/ion release technology developed by the General Sciences, Incorporated (GSI) team and successfully applied in other Space Applications. Solid state reactions have been identified which can deliver energy densities and electrons in excess of those from high energy explosives as well as other conventional fuels. The use of intermetallic reactions can be used to generate hot hydrogen plasma from the reaction, to create a high level of seedant ionization, can be packaged as a cartridge type fuels for discrete pulses. The estimated weight for energizing a (100 MW - 1000 sec) Pulsed MHD Power System can range from 12 to 25 {times} 10{sup 3} kg depending on reaction system and strength of the magnetic field. The program consisted of two major tasks with eight subtasks designed to systematically evaluate these concepts in order to reduce fuel weight requirements. Laboratory measurements on energy release, reaction product identification and levels of ionization were conducted in the first task to screen candidate fuels. The second task addressed the development of a reaction chamber in which conductivity, temperature and pressure were measured. Instrumentation was developed to measure these parameters under high temperature pulsed conditions in addition to computer programs to reduce the raw data. Measurements were conducted at GSI laboratories for fuel weights of up to 120 grams and at the Franklin Research Center* for fuel weights up to 1 kilogram. The results indicate that fuel weight can be scaled using modular packaging. Estimates are presented for fuel weight requirements. 15 refs.

  8. A Review on the Properties of Iron Aluminide Intermetallics

    Directory of Open Access Journals (Sweden)

    Mohammad Zamanzade

    2016-01-01

    Full Text Available Iron aluminides have been among the most studied intermetallics since the 1930s, when their excellent oxidation resistance was first noticed. Their low cost of production, low density, high strength-to-weight ratios, good wear resistance, ease of fabrication and resistance to high temperature oxidation and sulfurization make them very attractive as a substitute for routine stainless steel in industrial applications. Furthermore, iron aluminides allow for the conservation of less accessible and expensive elements such as nickel and molybdenum. These advantages have led to the consideration of many applications, such as brake disks for windmills and trucks, filtration systems in refineries and fossil power plants, transfer rolls for hot-rolled steel strips, and ethylene crackers and air deflectors for burning high-sulfur coal. A wide application for iron aluminides in industry strictly depends on the fundamental understanding of the influence of (i alloy composition; (ii microstructure; and (iii number (type of defects on the thermo-mechanical properties. Additionally, environmental degradation of the alloys, consisting of hydrogen embrittlement, anodic or cathodic dissolution, localized corrosion and oxidation resistance, in different environments should be well known. Recently, some progress in the development of new micro- and nano-mechanical testing methods in addition to the fabrication techniques of micro- and nano-scaled samples has enabled scientists to resolve more clearly the effects of alloying elements, environmental items and crystal structure on the deformation behavior of alloys. In this paper, we will review the extensive work which has been done during the last decades to address each of the points mentioned above.

  9. Influence of severe plastic deformation on intermetallic particles in Mg-12 wt.%Zn alloy investigated using transmission electron microscopy

    International Nuclear Information System (INIS)

    Němec, M.; Gärtnerová, V.; Jäger, A.

    2016-01-01

    -crystalline form of the parent Mg 21 Zn 25 microparticles. The Mg 21 Zn 25 + Mg 51 Zn 20 eutectic compound was confirmed for both forms of the parent Mg 21 Zn 25 microparticles, and the growth of Mg 51 Zn 20 nanoparticles is discussed. - Highlights: •Comprehensive microstructure characterization of Mg-12 wt.%Zn alloy after ECAP-BP •TEM analysis of changes of intermetallic phases caused by SPD •Mg 21 Zn 25 particles exhibit nano-crystalline regions with grain size below 100 nm. •MgZn 2 preserved its orientation relationship toward highly deformed α-Mg after SPD. •Existence of Mg 21 Zn 25 + Mg 51 Zn 20 eutectic remained for each Mg 21 Zn 25 particle form.

  10. The thermal expansion and Co magnetic state in light RCo3 intermetallics (R=Pr, Nd, Sm)

    International Nuclear Information System (INIS)

    Gaidukova, I.Yu.; Granovsky, S.A.; Markosyan, A.S.; Rodimin, V.E.

    2006-01-01

    The temperature variation of the lattice parameters of three light RCo 3 intermetallic compounds with R=Pr, Nd, Sm and the Nd 1- x Y x Co 3 system was studied by X-ray diffraction in a wide temperature range 10-550 K. From the magnetovolume effect arising considerably below the Curie temperature it has been concluded that in the Nd 1- x Y x Co 3 system a temperature-induced change of the Co magnetic state from a low to a high magnetic moment one occurs, whereas in the case of R=Pr and Sm the internal magnetic field acting on the Co sublattice is not high enough and the Co sublattice remains in the low magnetic moment state down to at least 10 K. The results are compared with those of heavy RCo 3 compounds. In SmCo 3 an orthorhombic distortion of the rhombohedral crystal lattice was observed below 125 K. This is accounted for a spin reorientation of the magnetization vector from the c-axis (high temperatures) to the basal plane (low temperatures)

  11. The thermal expansion and Co magnetic state in light RCo{sub 3} intermetallics (R=Pr, Nd, Sm)

    Energy Technology Data Exchange (ETDEWEB)

    Gaidukova, I.Yu. [Faculty of Physics, M.V. Lomonosov Moscow State University 119992 Moscow, GSP-2 (Russian Federation); Granovsky, S.A. [Faculty of Physics, M.V. Lomonosov Moscow State University 119992 Moscow, GSP-2 (Russian Federation); Markosyan, A.S. [Faculty of Physics, M.V. Lomonosov Moscow State University 119992 Moscow, GSP-2 (Russian Federation)]. E-mail: ashot_markosyan@yahoo.com; Rodimin, V.E. [Faculty of Physics, M.V. Lomonosov Moscow State University 119992 Moscow, GSP-2 (Russian Federation)

    2006-06-15

    The temperature variation of the lattice parameters of three light RCo{sub 3} intermetallic compounds with R=Pr, Nd, Sm and the Nd{sub 1-} {sub x} Y {sub x} Co{sub 3} system was studied by X-ray diffraction in a wide temperature range 10-550 K. From the magnetovolume effect arising considerably below the Curie temperature it has been concluded that in the Nd{sub 1-} {sub x} Y {sub x} Co{sub 3} system a temperature-induced change of the Co magnetic state from a low to a high magnetic moment one occurs, whereas in the case of R=Pr and Sm the internal magnetic field acting on the Co sublattice is not high enough and the Co sublattice remains in the low magnetic moment state down to at least 10 K. The results are compared with those of heavy RCo{sub 3} compounds. In SmCo{sub 3} an orthorhombic distortion of the rhombohedral crystal lattice was observed below 125 K. This is accounted for a spin reorientation of the magnetization vector from the c-axis (high temperatures) to the basal plane (low temperatures)

  12. Effect of intermetallic phases on the anodic oxidation and corrosion of 5A06 aluminum alloy

    Science.gov (United States)

    Li, Song-mei; Li, Ying-dong; Zhang, You; Liu, Jian-hua; Yu, Mei

    2015-02-01

    Intermetallic phases were found to influence the anodic oxidation and corrosion behavior of 5A06 aluminum alloy. Scattered intermetallic particles were examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) after pretreatment. The anodic film was investigated by transmission electron microscopy (TEM), and its corrosion resistance was analyzed by electrochemical impedance spectroscopy (EIS) and Tafel polarization in NaCl solution. The results show that the size of Al-Fe-Mg-Mn particles gradually decreases with the iron content. During anodizing, these intermetallic particles are gradually dissolved, leading to the complex porosity in the anodic film beneath the particles. After anodizing, the residual particles are mainly silicon-containing phases, which are embedded in the anodic film. Electrochemical measurements indicate that the porous anodic film layer is easily penetrated, and the barrier plays a dominant role in the overall protection. Meanwhile, self-healing behavior is observed during the long immersion time.

  13. Mechanical properties and electronic structures of Fe-Al intermetallic

    Energy Technology Data Exchange (ETDEWEB)

    Liu, YaHui; Chong, XiaoYu; Jiang, YeHua, E-mail: jiangyehua@kmust.edu.cn; Zhou, Rong; Feng, Jing, E-mail: jingfeng@kmust.edu.cn

    2017-02-01

    Using the first-principles calculations, the elastic properties, anisotropy properties, electronic structures, Debye temperature and stability of Fe-Al (Fe{sub 3}Al, FeAl, FeAl{sub 2}, Fe{sub 2}Al{sub 5} and FeAl{sub 3}) binary compounds were calculated. The formation enthalpy and cohesive energy of these Fe-Al compounds are negative, and show they are thermodynamically stable structures. Fe{sub 2}Al{sub 5} has the lowest formation enthalpy, which shows the Fe{sub 2}Al{sub 5} is the most stable of Fe-Al binary compounds. These Fe-Al compounds display disparate anisotropy due to the calculated different shape of the 3D curved surface of the Young’s modulus and anisotropic index. Fe{sub 3}Al has the biggest bulk modulus with the value 233.2 GPa. FeAl has the biggest Yong’s modulus and shear modulus with the value 296.2 GPa and 119.8 GPa, respectively. The partial density of states, total density of states and electron density distribution maps of the binary Fe-Al binary compounds are analyzed. The bonding characteristics of these Fe-Al binary compounds are mainly combination by covalent bond and metallic bonds. Meanwhile, also exist anti-bond effect. Moreover, the Debye temperatures and sound velocity of these Fe-Al compounds are explored.

  14. EFFECT OF INTERMETALLIC PHASES ON CORROSION BEHAVIOR AND MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL AND SUPER-DUPLEX STAINLESS STEEL

    Directory of Open Access Journals (Sweden)

    Prabhu Paulraj

    2015-08-01

    Full Text Available Duplex Stainless Steels (DSS and Super Duplex Stainless Steel (SDSS have excellent integration of mechanical and corrosion properties. However, the formation of intermetallic phases is a major problem in their usage. The mechanical and corrosion properties are deteriorated due to the presence of intermetallic phases. These phases are induced during welding, prolonged exposure to high temperatures, and improper heat treatments. The main emphasis of this review article is on intermetallic phases and their effects on corrosion and mechanical properties. First the effect of various alloying elements on DSS and SDSS has been discussed followed by formation of various intermetallic phases. The intermetallic phases affect impact toughness and corrosion resistance significantly. Their deleterious effect on weldments has also been reviewed.

  15. Atom probe tomography of intermetallic phases and interfaces formed in dissimilar joining between Al alloys and steel

    International Nuclear Information System (INIS)

    Lemmens, B.; Springer, H.; Duarte, M.J.; De Graeve, I.; De Strycker, J.; Raabe, D.; Verbeken, K.

    2016-01-01

    While Si additions to Al are widely used to reduce the thickness of the brittle intermetallic seam formed at the interface during joining of Al alloys to steel, the underlying mechanisms are not clarified yet. The developed approach for the site specific atom probe tomography analysis revealed Si enrichments at grain and phase boundaries between the θ (Fe 4 Al 13 ) and η (Fe 2 Al 5 ) phase, up to about ten times that of the concentration in Al. The increase in Si concentration could play an important role for the growth kinetics of the intermetallic phases formed for example in hot-dip aluminizing of steel. - Highlights: •Si additions to Al reduce thickness of intermetallic seam in joining with steel. •Approach developed for the site specific APT analysis of the intermetallic seam •Si enrichment at grain and phase boundaries possibly affects growth of intermetallics.

  16. A Self-Propagating Foaming Process of Porous Al-Ni Intermetallics Assisted by Combustion Reactions

    Directory of Open Access Journals (Sweden)

    Makoto Kobashi

    2009-12-01

    Full Text Available The self-propagating foaming process of porous Al-Ni intermetallics was investigated. Aluminum and nickel powders were blended, and titanium and boron carbide powders were added as reactive exothermic agents. The blended powder was extruded to make a rod-shape precursor. Only one end of the rod precursor was heated to ignite the reaction. The reaction propagated spontaneously throughout the precursor. Pore formation took place at the same time as the reaction occurred. Adding the exothermic agent was effective to increase the porosity. Preheating the precursor before the ignition was also very effective to produce porous Al-Ni intermetallics with high porosity.

  17. Influence of annealing time and temperature on the Fe3Al intermetallic alloys microstructure modification

    Directory of Open Access Journals (Sweden)

    K. Garbala

    2011-04-01

    Full Text Available There is an industry interesting in intermetallic alloys in recent years. There are widely possibilities to adopt this kind of materials for structural units. More expensive materials can be replaced by them. A property which limits their wider application is the low plasticity at environment and elevated temperatures. In paper the results of the thermal microstructure modification are shown. To this end, the influence of annealing time and temperature on the intermetallic phase Fe3Al grain size was investigated. The impact of these factors on micro-hardness was examined as well. It was found that these operations cause the grain size reduction and the micro-hardness decrease.

  18. Intermetallic Strengthened Alumina-Forming Austenitic Steels for Energy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Bin [Dartmouth College, Hanover, NH (United States); Baker, Ian [Dartmouth College, Hanover, NH (United States)

    2016-03-31

    In order to achieve energy conversion efficiencies of >50 % for steam turbines/boilers in power generation systems, the materials required must be strong, corrosion-resistant at high temperatures (>700°C), and economically viable. Austenitic steels strengthened with Laves phase and L12 precipitates, and alloyed with aluminum to improve oxidation resistance, are potential candidate materials for these applications. The creep resistance of these alloys is significantly improved through intermetallic strengthening (Laves-Fe2Nb + L12-Ni3Al precipitates) without harmful effects on oxidation resistance. Microstructural and microchemical analyses of the recently developed alumina-forming austenitic (AFA) steels (Fe-14Cr-32Ni-3Nb-3Al-2Ti-based) indicated they are strengthened by Ni3Al(Ti) L12, NiAl B2, Fe2Nb Laves phase and MC carbide precipitates. Different thermomechanical treatments (TMTs) were performed on these stainless steels in an attempt to further improve their mechanical properties. The thermo-mechanical processing produced nanocrystalline grains in AFA alloys and dramatically increased their yield strength at room temperature. Unfortunately, the TMTs didn’t increase the yield strengths of AFA alloys at ≥700ºC. At these temperatures, dislocation climb is the dominant mechanism for deformation of TMT alloys according to strain rate jump tests. After the characterization of aged AFA alloys, we found that the largest strengthening effect from L12 precipitates can be obtained by aging for less than 24 h. The coarsening behavior of the L12 precipitates was not influenced by carbon and boron additions. Failure analysis and post-mortem TEM analysis were performed to study the creep failure mechanisms of these AFA steels after creep tests. Though the Laves and B2-NiAl phase precipitated along the boundaries can improve the creep properties, cracks were

  19. Growth of intermetallics between Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layered structures

    International Nuclear Information System (INIS)

    Horváth, Barbara; Illés, Balázs; Shinohara, Tadashi

    2014-01-01

    Intermetallic growth mechanisms and rates are investigated in Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layer systems. An 8–10 μm thick Sn surface finish layer was electroplated onto a Cu substrate with a 1.5–2 μm thick Ni or Ag barrier layer. In order to induce intermetallic layer growth, the samples were aged in elevated temperatures: 50 °C and 125 °C. Intermetallic layer growth was checked by focused ion beam–scanning ion microscope. The microstructures and chemical compositions of the intermetallic layers were observed with a transmission electron microscope. It has been found that Ni barrier layers can effectively block the development of Cu 6 Sn 5 intermetallics. The intermetallic growth characteristics in the Sn/Cu and Sn/Ni/Cu systems are very similar. The intermetallic layer grows towards the Sn layer and forms a discrete layer. Differences were observed only in the growth gradients and surface roughness of the intermetallic layer which may explain the different tin whiskering properties. It was observed that the intermetallic layer growth mechanisms are completely different in the Ag barrier layers compared to the Ni layers. In the case of Sn/Ag/Cu systems, the Sn and Cu diffused through the Ag layer, formed Cu 6 Sn 5 intermetallics mainly at the Sn/Ag interface and consumed the Ag barrier layer. - Highlights: • Intermetallic growth was characterised in Sn/Ni/Cu, Sn/Ag/Cu and Sn/Cu layer systems. • Intermetallic growth rates and roughness are similar in the Sn/Cu and Sn/Ni/Cu systems. • Sn/Ni/Cu system contains the following intermetallic layer structure Sn–Ni3Sn4–Ni3Sn2–Ni3Sn–Ni. • In the case of Sn/Ag/Cu systems the Sn and Cu diffusion consumes the Ag barrier layer. • When Cu reaches the Sn/Ag interface a large amount of Cu 6 Sn 5 forms above the Ag layer

  20. Corrosion Study and Intermetallics Formation in Gold and Copper Wire Bonding in Microelectronics Packaging

    Directory of Open Access Journals (Sweden)

    Christopher Breach

    2013-07-01

    Full Text Available A comparison study on the reliability of gold (Au and copper (Cu wire bonding is conducted to determine their corrosion and oxidation behavior in different environmental conditions. The corrosion and oxidation behaviors of Au and Cu wire bonding are determined through soaking in sodium chloride (NaCl solution and high temperature storage (HTS at 175 °C, 200 °C and 225 °C. Galvanic corrosion is more intense in Cu wire bonding as compared to Au wire bonding in NaCl solution due to the minimal formation of intermetallics in the former. At all three HTS annealing temperatures, the rate of Cu-Al intermetallic formation is found to be three to five times slower than Au-Al intermetallics. The faster intermetallic growth rate and lower activation energy found in this work for both Au/Al and Cu/Al as compared to literature could be due to the thicker Al pad metallization which removed the rate-determining step in previous studies due to deficit in Al material.

  1. Al/Ni metal intermetallic composite produced by accumulative roll bonding and reaction annealing

    International Nuclear Information System (INIS)

    Mozaffari, A.; Hosseini, M.; Manesh, H. Danesh

    2011-01-01

    Highlights: → Al/Ni metallic composites produced by accumulative roll bonding were heat treated at different temperatures and periods, to investigate the effect of reaction annealing on the structure and mechanical properties. → Based on the annealing conditions, various intermetallic phases were formed. The structure and composition of the composites were detected by SEM and XRD techniques. → The strength of the initial metallic composite can be improved due to the formation of the hard intermetallic phases, by the heat treatment process. - Abstract: In this research, Al/Ni multilayers composites were produced by accumulative roll bonding and then annealed at different temperatures and durations. The structure and mechanical properties of the fabricated metal intermetallic composites (MICs) were investigated. Scanning electron microscopy and X-ray diffraction analyses were used to evaluate the structure and composition of the composite. The Al 3 Ni intermetallic phase is formed in the Al/Ni interface of the samples annealed at 300 and 400 deg. C. When the temperature increased to 500 deg. C, the Al 3 Ni 2 phase was formed in the composite structure and grew, while the Al 3 Ni and Al phases were simultaneously dissociated. At these conditions, the strength of MIC reached the highest content and was enhanced by increasing time. At 600 deg. C, the AlNi phase was formed and the mechanical properties of MIC were intensively degraded due to the formation of structural porosities.

  2. Ni.sub.3 Al-based intermetallic alloys having improved strength above 850.degree. C.

    Science.gov (United States)

    Liu, Chain T.

    2000-01-01

    Intermetallic alloys composed essentially of: 15.5% to 17.0% Al, 3.5% to 5.5% Mo, 4% to 8% Cr, 0.04% to 0.2% Zr, 0.04% to 1.5% B, balance Ni, are characterized by melting points above 1200.degree. C. and superior strengths at temperatures above 1000.degree. C.

  3. Fe-Zn intermetallic phases prepared by diffusion annealing and spark-plasma sintering

    Czech Academy of Sciences Publication Activity Database

    Pokorný, P.; Cinert, Jakub; Pala, Zdeněk

    2016-01-01

    Roč. 50, č. 2 (2016), s. 253-256 ISSN 1580-2949 R&D Projects: GA ČR GB14-36566G Institutional support: RVO:61389021 Keywords : Fe-Zn intermetallics * spark-plasma sintering * diffusion annealing * phase composition * hardness Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 0.436, year: 2016

  4. Atomic interaction of the MEAM type for the study of intermetallics in the Al–U alloy

    Energy Technology Data Exchange (ETDEWEB)

    Pascuet, M.I. [CONICET, Avda. Rivadavia 1917, 1033 Buenos Aires (Argentina); Fernández, J.R., E-mail: julrfern@cnea.gov.ar [CONICET, Avda. Rivadavia 1917, 1033 Buenos Aires (Argentina); CAC-CNEA, Avda. Gral Paz 1499, 1650 Buenos Aires (Argentina); UNSAM, Avda. Gral Paz 1499, 1650 Buenos Aires (Argentina)

    2015-12-15

    Interaction for both pure Al and Al–U alloys of the MEAM type are developed. The obtained Al interatomic potential assures its compatibility with the details of the framework presently adopted. The Al–U interaction fits various properties of the Al{sub 2}U, Al{sub 3}U and Al{sub 4}U intermetallics. The potential verifies the stability of the intermetallic structures in a temperature range compatible with that observed in the phase diagram, and also takes into account the greater stability of these structures relative to others that are competitive in energy. The intermetallics are characterized by calculating elastic and thermal properties and point defect parameters. Molecular dynamics simulations show a growth of the Al{sub 3}U intermetallic in the Al/U interface in agreement with experimental evidence. - Highlights: • Potential parameters for Al and Al–U systems are obtained. • Intermetallics are characterized by calculating elastic and thermal properties. • Point defect diffusivities are calculated for the three intermetallics. • Growth of the Al{sub 3}U intermetallic is shown to occur in the Al/U interface as in the real alloy.

  5. Atomic interaction of the MEAM type for the study of intermetallics in the Al–U alloy

    International Nuclear Information System (INIS)

    Pascuet, M.I.; Fernández, J.R.

    2015-01-01

    Interaction for both pure Al and Al–U alloys of the MEAM type are developed. The obtained Al interatomic potential assures its compatibility with the details of the framework presently adopted. The Al–U interaction fits various properties of the Al_2U, Al_3U and Al_4U intermetallics. The potential verifies the stability of the intermetallic structures in a temperature range compatible with that observed in the phase diagram, and also takes into account the greater stability of these structures relative to others that are competitive in energy. The intermetallics are characterized by calculating elastic and thermal properties and point defect parameters. Molecular dynamics simulations show a growth of the Al_3U intermetallic in the Al/U interface in agreement with experimental evidence. - Highlights: • Potential parameters for Al and Al–U systems are obtained. • Intermetallics are characterized by calculating elastic and thermal properties. • Point defect diffusivities are calculated for the three intermetallics. • Growth of the Al_3U intermetallic is shown to occur in the Al/U interface as in the real alloy.

  6. Intermetallic and metal-rich phases in the system Li-Ba-In-N

    International Nuclear Information System (INIS)

    Smetana, Volodymyr; Vajenine, Grigori V.; Kienle, Lorenz; Duppel, Viola; Simon, Arndt

    2010-01-01

    Three new intermetallic phases, BaLi 2.1 In 1.9 , BaLi 1.12 In 0.98 , and BaLi 1.06 In 1.16 and two subnitrides Li 35 In 45 Ba 39 N 9 and LiIn 2 Ba 3 N 0.83 have been synthesized and their crystal structures have been determined. According to single crystal X-ray diffraction data BaLi 2.1 In 1.9 and BaLi 1.12 In 0.98 crystallize with hexagonal symmetry (BaLi 2.1 In 1.9 : P6 3 /mmc, a=10.410(2), c=8.364(2) A, Z=6, V=785.0(2) A 3 ) and BaLi 1.12 In 0.98 : P6/mmm, a=17.469(1), c=10.6409(7) A, Z=30, V=2813.5(8) A 3 ), while BaLi 1.06 In 1.16 has a rhombohedral structure (R-3c, a=18.894(3), c=85.289(17) A, Z=276, V=26368(8) A 3 ). BaLi 2.1 In 1.9 is isostructural with the known phase BaLi 4 . The phase BaLi 1.12 In 0.98 is structurally related to Na 8 K 23 Cd 12 In 48 , while BaLi 1.06 In 1.16 is isostructural with Li 33.3 Ba 13.1 Ca 3 . A sample containing structurally similar BaLi 1.12 In 0.98 and BaLi 1.02 In 1.16 was also investigated by transmission electron microscopy. Li 35 In 45 Ba 39 N 9 and LiIn 2 Ba 3 N 0.83 crystallize with tetragonal (I-42m, a=15.299(2), c=30.682(6) A, Z=2, V=7182(2) A 3 ) and cubic (Fd-3m, a=14.913(2) A, Z=8, V=3316.7(7) A 3 ) symmetry, respectively. While the first-mentioned subnitride belongs to the Li 80 Ba 39 N 9 structure type, the second extends the structural family of Ba 6 In 4.78 N 2.72 . The structural features of the new compounds are discussed in comparison to the known phases and the results of total energy calculations. - Graphical abstract: One-dimensional chain of face-sharing centered icosahedra in BaLi 2.1 In 1.9

  7. Structural and electronic properties of non-magnetic intermetallic ...

    Indian Academy of Sciences (India)

    LAPW) method based on the density functional theory (DFT), within the generalized gradient approximation. (GGA). ... A class of compounds that has attracted a great attention in recent years is RETX, .... states (DOS) was determined by the tetrahedral integration ... The features of the occupied densities of states for both ...

  8. Thermodynamic properties and solidification kinetics of intermetallic Ni7Zr2 alloy investigated by electrostatic levitation technique and theoretical calculations

    International Nuclear Information System (INIS)

    Li, L. H.; Hu, L.; Yang, S. J.; Wang, W. L.; Wei, B.

    2016-01-01

    The thermodynamic properties, including the density, volume expansion coefficient, ratio of specific heat to emissivity of intermetallic Ni 7 Zr 2 alloy, have been measured using the non-contact electrostatic levitation technique. These properties vary linearly with temperature at solid and liquid states, even down to the obtained maximum undercooling of 317 K. The enthalpy, glass transition, diffusion coefficient, shear viscosity, and surface tension were obtained by using molecular dynamics simulations. Ni 7 Zr 2 has a relatively poor glass forming ability, and the glass transition temperature is determined as 1026 K. The inter-diffusivity of Ni 7 Zr 2 alloy fitted by Vogel–Fulcher–Tammann law yields a fragility parameter of 8.49, which indicates the fragile nature of this alloy. Due to the competition of increased thermodynamic driving force and decreased atomic diffusion, the dendrite growth velocity of Ni 7 Zr 2 compound exhibits double-exponential relationship to the undercooling. The maximum growth velocity is predicted to be 0.45 m s −1 at the undercooling of 335 K. Theoretical analysis reveals that the dendrite growth is a diffusion-controlled process and the atomic diffusion speed is only 2.0 m s −1

  9. Reliable and cost effective design of intermetallic Ni2Si nanowires and direct characterization of its mechanical properties.

    Science.gov (United States)

    Han, Seung Zeon; Kang, Joonhee; Kim, Sung-Dae; Choi, Si-Young; Kim, Hyung Giun; Lee, Jehyun; Kim, Kwangho; Lim, Sung Hwan; Han, Byungchan

    2015-10-12

    We report that a single crystal Ni2Si nanowire (NW) of intermetallic compound can be reliably designed using simple three-step processes: casting a ternary Cu-Ni-Si alloy, nucleate and growth of Ni2Si NWs as embedded in the alloy matrix via designing discontinuous precipitation (DP) of Ni2Si nanoparticles and thermal aging, and finally chemical etching to decouple the Ni2Si NWs from the alloy matrix. By direct application of uniaxial tensile tests to the Ni2Si NW we characterize its mechanical properties, which were rarely reported in previous literatures. Using integrated studies of first principles density functional theory (DFT) calculations, high-resolution transmission electron microscopy (HRTEM), and energy-dispersive X-ray spectroscopy (EDX) we accurately validate the experimental measurements. Our results indicate that our simple three-step method enables to design brittle Ni2Si NW with high tensile strength of 3.0 GPa and elastic modulus of 60.6 GPa. We propose that the systematic methodology pursued in this paper significantly contributes to opening innovative processes to design various kinds of low dimensional nanomaterials leading to advancement of frontiers in nanotechnology and related industry sectors.

  10. Structure and magnetic transport properties of GdIn{sub 3−x}Mn{sub x} intermetallics

    Energy Technology Data Exchange (ETDEWEB)

    He, Qiang; Guo, Yongquan, E-mail: yqguo@ncepu.edu.cn; Liu, Hanyuan

    2016-03-01

    The crystal structures and magneto-transport properties of GdIn{sub 3−x}Mn{sub x} have been investigated using X-ray diffraction and magnetic and electric measurements. GdIn{sub 3−x}Mn{sub x} crystallize in cubic structure, and their lattice parameters tend to decrease with increasing Mn content due to the size effect at In site by Mn substitution for In. Mn doped GdIn{sub 3−x}Mn{sub x} order antiferromagnetically at low temperature. However, Mn doping into GdIn{sub 3} causes the decrease of Néel temperature due to the distortion of Gd(In,Mn){sub 3} tetrahedron formed by Gd at corners and (In,Mn) at face centers in unit cell. The resistivities of GdIn{sub 3−x}Mn{sub x} are going up with increasing Mn content. The electric phase transition is associated with the magnetic transition, and the magneto-transport follows electron–magnon scattering model in low temperature region and the Stoner spin fluctuation model in high temperature region, respectively. - Highlights: • Novel GdIn{sub 3−x}Mn{sub x} intermetallic compounds have been successfully prepared. • The lattice parameters tend to decrease with increasing Mn content. • GdIn{sub 3−x}Mn{sub x} orders antiferromagnetically at low temperature. • The strong correlation between the electric transport and magnetic state is observed.

  11. Characterization and hardness of TiCu–Ti2Cu3 intermetallic material fabricated by mechanical alloying and subsequent annealing

    International Nuclear Information System (INIS)

    Akbarpour, Mohammad Reza; Hesari, Feridoun Alikhani

    2016-01-01

    In this research, the microstructural and phase evolutions during mechanical alloying (MA) and subsequent heat treatment of Cu–Ti powder mixture are investigated through x-ray diffraction, scanning electron microscopy, transmission electron microscopy and micro-hardness measurements. The obtained experimental results demonstrated that after an optimum MA time of 30 h, TiCu intermetallic compound was achieved with a mean grain size of ≈8 nm and a high micro-hardness value of ≈634 Hv. Annealing the milled powder at different temperatures resulted in formation of major TiCu and Ti 2 Cu 3 , and minor Ti 2 Cu and Cu 4 Ti nanocrystalline phases, release of internal strain, and coarsening of grains. The amount of TiCu phase and the grain size increased with increase of the annealing temperature. Micro-hardness value of ≈765 Hv was recorded when the milled TiCu powder was annealed at 850 °C. This superior high micro-hardness value can be attributed to formation of higher amount of TiCu phase. (paper)

  12. Effect of Intermetallic on Electromigration and Atomic Diffusion in Cu/SnAg3.0Cu0.5/Cu Joints: Experimental and First-Principles Study

    Science.gov (United States)

    Zhou, Wei; Liu, Lijuan; Li, Baoling; Wu, Ping

    2009-06-01

    Electromigration phenomena in a one-dimensional Cu/SnAg3.0Cu0.5/Cu joint were investigated with current stressing. The special effect of intermetallic compound (IMC) layers on the formation of serious electromigration damage induced by nonuniform current density distribution was discussed based on experimental results. Meanwhile, hillocks were observed both at the anode and near the cathode of the joint, and they were described as the result of diffusion of atoms and compressive stress released along grain boundaries to the relatively free surface. Moreover, the diffusion behavior of Cu at the cathode was analyzed with the electromigration equation, and the stability of Ag atoms in the solder during electromigration was evaluated with a first-principles method.

  13. Obtaining and characterizing the binary compound Zr3Pt

    International Nuclear Information System (INIS)

    Tanoni, Diego; Arico, Sergio F; Alonso, Paula R

    2006-01-01

    The equilibrium phases in the Zr - Pt binary system are not fully defined. Experiences carried out from 0% to 50% at. Pt in the equilibrium diagram of Zr-Pt phases in 2001 revealed the presence of the intermetallic compounds Zr 2 Pt, Zr 5 Pt 3 , ZrPt (already previously identified by other authors) and a compound of 25% composition at Pt with an unidentified crystalline structure. This experimental work aims to fill out the information on this compound by characterizing its crystallography. An alloy was produced in the binary system Zr-Pt with a composition close to the stoichiometry by casting in an arc furnace, and was studied by optic and electronic metallography. The identification and crystallographic characterization of the phase is based on measurements of composition in electronic microwave and on analysis of spectrums obtained by X-ray diffraction. The results are presented, showing the presence in the cast structure of the solid solution zircon phases (hexagonal) and of the inter-metallic compound Zr 5 Pt 3 . These two phases were identified in the X-ray diffraction diagrams as well as the presence of other reflections that are associated with the inter-metallic Zr 3 Pt. The measurements of composition consistently reveal the presence of a phase of 25%at Pt composition. The structure's morphology shown in metallographies reveals the occurrence of a eutectic type transformation during cooling. We conclude that the formation of the phase sought in a composition 25 % at Pt should occur at temperatures below the eutectic transformation, and could be a peritectoid formation as was previously proposed. Therefore, the sample needs to be homogenized with thermal treatments that favor the formation and stabilization of the compound (CW)

  14. Superconducting transition temperature and the formation of closed electron shells in the atoms of superconducting compounds

    International Nuclear Information System (INIS)

    Chapnik, I.M.

    1985-01-01

    The relationship between the regularities in the tansition temperature (T/sub c/) values in analogous compounds (having the same structure and stoichiometry) and the formation of the closed electron shells outside inert gas shells in the atoms of the variable component of the 158 intermetallic superconducting compounds has been discussed. The T/sub c/ data for compounds of the elements from the first long period of the Periodic Table (K to Se) are compared with the T/sub c/ data for the analogous compounds of the elements from the second long period (Rb to Te)

  15. The sequence of intermetallic formation and solidification pathway of an Al–13Mg–7Si–2Cu in-situ composite

    Energy Technology Data Exchange (ETDEWEB)

    Farahany, Saeed, E-mail: saeedfarahany@gmail.com [Department of Materials, Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia (UTM), 81310 Johor Bahru (Malaysia); Nordin, Nur Azmah; Ourdjini, Ali; Abu Bakar, TutyAsma; Hamzah, Esah; Idris, Mohd Hasbullah [Department of Materials, Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia (UTM), 81310 Johor Bahru (Malaysia); Hekmat-Ardakan, Alireza [École Polytechnique de Montréal, Dép. de Génie Chimique, P.O. Box 6079, Centre-ville, Montreal, Quebec H3C 3A7 (Canada)

    2014-12-15

    The phase transformation sequence and solidification behaviour of an Al–13Mg–7Si–2Cu in-situ composite was examined using a combination of computer-aided cooling curve thermal analysis and interrupted quenching techniques. Five different phases were identified by analysing the derivative cooling curves, the X-ray diffraction profile, optical and scanning electron microscopy images and the corresponding energy dispersive spectroscopy. It has been found that the solidification of this alloy begins with primary Mg{sub 2}Si precipitation and continues with the formation of eutectic Al–Mg{sub 2}Si, followed by Al{sub 5}FeSi and simultaneous precipitation of Al{sub 5}Cu{sub 2}Mg{sub 8}Si{sub 6} and Al{sub 2}Cu complex intermetallic phases. The formation of the last three intermetallic compounds changes the solidification behaviour of these composites remarkably due to their complex eutectic formation reactions. The solidification of the alloy, calculated using the Factsage thermochemical analysis software, has demonstrated a good agreement with the experiments in terms of compound prediction, their weight fractions and reaction temperatures. - Highlights: • Solidification path of a commercial Al-13Mg-7Si-2Cu composite was characterized. • Five different phases were identified and then confirmed with EDS and XRD results. • Mg{sub 2}Si, Al-Mg{sub 2}Si,Al{sub 5}FeSi (β),Al{sub 5}Cu{sub 2}Mg{sub 8}Si{sub 6} (Q) and Al{sub 2}Cu(θ) precipitated respectively. • Solidification was predicted using the Factsage thermochemical analysis software.

  16. Magnetic and superconducting order in some random pseudobinary compounds

    International Nuclear Information System (INIS)

    Dongen, J.C.M. van.

    1982-01-01

    This thesis presents the results of a study on the magnetic and superconducting ordering phenomena in some random pseudobinary compounds. In the investigations ternary systems are utilised in which two of the elements form a binary intermetallic compound, e.g. PdH, GdCu and YCo 2 . A third element is then randomly substituted into one of the sublattices without changing the basic intermetallic compound structure. In chapter II a study is presented on the Kondo effect and spin-glass freezing of the magnetic impurities Cr, Mn, and Fe in superconducting palladium hydride. Chapter III contains a study on crystal structure transformations and magnetic ordering phenomena in GdCusub(1-x)Gasub(x) and related pseudobinary compounds. In Chapter IV experiments on the magnetic properties and the electrical resistivity of the transition metal Laves phase compounds Y(Cosub(1-x)Fesub(x)) 2 , Y(Irsub(1-x)Fesub(x)) 2 and Hf(Cosub(1-x)Fesub(x)) 2 are described. (Auth.)

  17. The energetics of ordered intermetallic alloys (of the transition metals)

    International Nuclear Information System (INIS)

    Watson, R.E.; Weinert, M.; Davenport, J.W.; Fernando, G.W.; Bennett, L.H.

    1992-01-01

    The atomically ordered phases in ordered transition metal alloys are discussed. This chapter is divided into: physical parameters controlling phase stability (Hume-Rothery, structural maps, Miedema Hamiltonian), wave functions ampersand band theory, comment on entropy terms, cohesive energies (electron promotion energies, Hund's rule on orbital effects), structural energies/stabilities of elemental solids, total energies and atomic positions, charge transfer (Au alloys, charge tailing), heats of formation of ordered compounds

  18. Chemical Frustration. A Design Principle for the Discovery of New Complex Alloy and Intermetallic Phases, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Fredrickson, Daniel C [Univ. of Wisconsin, Madison, WI (United States)

    2015-06-23

    Final technical report for "Chemical Frustration: A Design Principle for the Discovery of New Complex Alloy and Intermetallic Phases" funded by the Office of Science through the Materials Chemistry Program of the Office of Basic Energy Sciences.

  19. An Investigation of the Microstructure of an Intermetallic Layer in Welding Aluminum Alloys to Steel by MIG Process.

    Science.gov (United States)

    Nguyen, Quoc Manh; Huang, Shyh-Chour

    2015-12-02

    Butt joints of A5052 aluminum alloy and SS400 steel, with a new type of chamfered edge, are welded by means of metal inert gas welding and ER4043 Al-Si filler metal. The microhardness and microstructure of the joint are investigated. An intermetallic layer is found on the surface of the welding seam and SS400 steel sheet. The hardness of the intermetallic layer is examined using the Vickers hardness test. The average hardness values at the Intermetallic (IMC) layer zone and without the IMC layer zone were higher than that of the welding wire ER4043. The tensile strength test showed a fracture at the intermetallic layer when the tensile strength is 225.9 MPa. The tensile value test indicated the average of welds was equivalent to the 85% tensile strength of the A5052 aluminum alloy. The thickness of the intermetallic layers is non-uniform at different positions with the ranges from 1.95 to 5 μm. The quality of the butt joint is better if the intermetallic layer is minimized. The Si crystals which appeared at the welding seam, indicating that this element participated actively during the welding process, also contributed to the IMC layer's formation.

  20. Isothermal analysis of intermetallic MmNi5-xAlx in air decomposition processes

    International Nuclear Information System (INIS)

    Obregon, S.A.; Andrade Gamboa, J.J.; Esquivel, M.R.

    2012-01-01

    In this paper, it is analyzed the behavior of the degree of reaction as function of time α (t) of a sample of MmNi 4.3 Al 0.7 (Mm mischmetal = La 0.25 Ce 0.52 Nd 0.17 Pr 0.06 ) at different temperatures. The curves were obtained by isothermal calorimetric techniques. As a result of this study, it was observed that the kinetics of intermetallic can be separated into two main stages. At temperatures below 350 o C, the first stage is the oxidation of Mm and Al. At temperatures over 400 o C, the oxidation of Ni is also produced parallel to the above mentioned reactions. But the kinetics of the last one is at least three orders of magnitude slower. It was also observed that no thermal event occurs below 180 o C. It indicates that the intermetallic do not react at temperatures below this temperature value (author)

  1. An application of Pettifor structure maps for the identification of pseudo-binary quasicrystalline intermetallics

    International Nuclear Information System (INIS)

    Ranganathan, S.; Inoue, A.

    2006-01-01

    Quasicrystal-forming ability is considered from the viewpoint of Pettifor maps, where a single phenomenological coordinate, the Mendeleev number, captures the bonding characteristics of elements in forming intermetallics. By considering the largest sized atom as the most important constituent, it is shown that most known ternary and quaternary quasicrystals can be treated as pseudo-binary intermetallics. This also results in a classification of quasicrystals into four structural classes based on the nature of the bond orbital - s, p, d or f - of the large atom with four associated related crystal structures. A colour scheme is introduced to indicate preferences for two types of sites. We propose a new classification of quasicrystals as centred on Li, Mg, Al, Ga, Ca, Sc, Y, Ti, Zr, Hf and rare earth elements, as they are the largest atoms in the constituent quasicrystals in contrast to the conventional classification based on majority species

  2. An application of Pettifor structure maps for the identification of pseudo-binary quasicrystalline intermetallics

    Energy Technology Data Exchange (ETDEWEB)

    Ranganathan, S. [Department of Metallurgy, Indian Institute of Science, CV Raman Avenue, Bangalore 560012, Karnataka (India) and Institute for Materials Research, Tohoku University, Sendai 9808577 (Japan)]. E-mail: rangu@met.iisc.ernet.in; Inoue, A. [Institute for Materials Research, Tohoku University, Sendai 9808577 (Japan)

    2006-08-15

    Quasicrystal-forming ability is considered from the viewpoint of Pettifor maps, where a single phenomenological coordinate, the Mendeleev number, captures the bonding characteristics of elements in forming intermetallics. By considering the largest sized atom as the most important constituent, it is shown that most known ternary and quaternary quasicrystals can be treated as pseudo-binary intermetallics. This also results in a classification of quasicrystals into four structural classes based on the nature of the bond orbital - s, p, d or f - of the large atom with four associated related crystal structures. A colour scheme is introduced to indicate preferences for two types of sites. We propose a new classification of quasicrystals as centred on Li, Mg, Al, Ga, Ca, Sc, Y, Ti, Zr, Hf and rare earth elements, as they are the largest atoms in the constituent quasicrystals in contrast to the conventional classification based on majority species.

  3. Intermetallic alloys - overview on new materials developments for structural applications in West Germany

    International Nuclear Information System (INIS)

    Sauthoff, G.

    1990-01-01

    As a result of recent research on intermetallics for high-temperature applications several alloy systems which are based on intermetallics are regarded as promising for new materials developments, and respective developments have been initiated in West Germany. The present work is aimed a lightweight materials on one hand and at high-temperature high-strength materials on the other hand. The overview surveys the work in West Germany on γ-TiAl, Ti 5 Si 3 -based alloys, Mg 2 Si-Al, NiAl-Cr, Al 3 Nb-NiAl and Laves phase-based alloys, and the mechanical properties - strength, ductility and/or toughness - are described. (orig.) [de

  4. Novel Nanocrystalline Intermetallic Coatings for Metal Alloys in Coal-fired Environments

    Energy Technology Data Exchange (ETDEWEB)

    Z. Zak Fang; H. Y. Sohn

    2009-08-31

    Intermetallic coatings (iron aluminide and nickel aluminide) were prepared by a novel reaction process. In the process, the aluminide coating is formed by an in-situ reaction between the aluminum powder fed through a plasma transferred arc (PTA) torch and the metal substrate (steel or Ni-base alloy). Subjected to the high temperature within an argon plasma zone, aluminum powder and the surface of the substrate melt and react to form the aluminide coatings. The prepared coatings were found to be aluminide phases that are porosity-free and metallurgically bonded to the substrate. The coatings also exhibit excellent high-temperature corrosion resistance under the conditions which simulate the steam-side and fire-side environments in coal-fired boilers. It is expected that the principle demonstrated in this process can be applied to the preparation of other intermetallic and alloy coatings.

  5. FIB-SEM investigation of trapped intermetallic particles in anodic oxide films on AA1050 aluminium

    DEFF Research Database (Denmark)

    Jariyaboon, Manthana; Møller, Per; Dunin-Borkowski, Rafal E.

    2011-01-01

    -containing intermetallic particles incorporated into the anodic oxide films on industrially pure aluminium (AA1050, 99.5 per cent) has been investigated. AA1050 aluminium was anodized in a 100?ml/l sulphuric acid bath with an applied voltage of 14?V at 20°C ±2°C for 10 or 120?min. The anodic film subsequently was analyzed......Purpose - The purpose of this investigation is to understand the structure of trapped intermetallics particles and localized composition changes in the anodized anodic oxide film on AA1050 aluminium substrates. Design/methodology/approach - The morphology and composition of Fe......-shaped particles were embedded in the anodic oxide film as a thin strip structure and located near the top surface of the film, whereas the round-shaped particles were trapped in the film with a spherical structure, but partially dissolved and were located throughout the thickness of the anodic film. The Fe...

  6. Electronic structure and phase stability during martensitic transformation in Al-doped ZrCu intermetallics

    International Nuclear Information System (INIS)

    Qiu Feng; Shen Ping; Liu Tao; Lin Qiaoli; Jiang Qichuan

    2010-01-01

    Martensitic transformation, phase stability and electronic structure of Al-doped ZrCu intermetallics were investigated by experiments and first-principles calculations using the pseudopotentials plane wave method. The formation energy calculations indicate that the stability of the ZrCu phase increases with the increasing Al content. Al plays a decisive role in controlling the formation and microstructures of the martensite phases in Zr-Cu-Al alloys. The total energy difference between ZrCu (B2) austenite and ZrCu martensite plays an important role in the martensitic transformation. The phase stability is dependent on its electronic structure. The densities of states (DOS) of the intermetallics were discussed in detail.

  7. The shock Hugoniot of the intermetallic alloy Ti-46.5Al-2Nb-2Cr

    International Nuclear Information System (INIS)

    Millett, Jeremy; Gray, George T. Rusty III; Bourne, Neil

    2000-01-01

    Plate impact experiments were conducted on a γ-titanium aluminide (TiAl) based ordered intermetallic alloy. Stress measurements were recorded using manganin stress gauges supported on the back of TiAl targets using polymethylmethacrylate windows. The Hugoniot in stress-particle velocity space for this TiAl alloy was deduced using impedance matching techniques. The results in this study are compared to the known Hugoniot data of the common alpha-beta engineering Ti-based alloy Ti-6Al-4V. The results of the current study on the intermetallic alloy TiAl support that TiAl possesses a significantly higher stress for a given particle velocity than the two-phase Ti-6Al-4V alloy. (c) 2000 American Institute of Physics

  8. Fracture and fatigue considerations in the development of ductile-phase reinforced intermetallic-matrix composites

    International Nuclear Information System (INIS)

    Venkateswara Rao, K.T.; Ritchie, R.O.

    1994-01-01

    The salient microstructural factors influencing fracture and fatigue-crack growth resistance of ductile-particle reinforced intermetallic-matrix composites at ambient temperature are reviewed through examples from the Nb/MoSi 2 , TiNb/TiAl, Nb/TiAl and Nb/Nb 3 Al systems; specific emphasis is placed on properties and morphology of the reinforcement and its interfacial properties with the matrix. It is shown that composites must be fabricated with a high aspect ratio ductile-reinforcement morphology in order to promote crack-particle interception and resultant crack bridging for improved fracture and fatigue properties. Concurrently, however, the ductile phases have contrasting effects on crack growth under monotonic vs. cyclic loading suggesting that composite microstructures tailored for optimal toughness may not necessarily yield optimal fatigue resistance. Perspectives for the future development of damage-tolerant intermetallic-composite microstructures are discussed

  9. Sn and Ti influences on intermetallic phases damage in hot dip galvanizing

    Directory of Open Access Journals (Sweden)

    V. Di Cocco

    2012-10-01

    Full Text Available Protection against metallic materials corrosion is one of the most important means to reduce both maintenance costs and environmental impact. In the last years new studies on chemical baths compositions and fluxes have been performed in order to improve processes, corrosion resistance and mechanical behavior of Zn based coatings. Chemical bath composition is often improved by the Sn addition which increases the fluidity of the melt. Ti addition makes the coatings to change color under appropriate heat treatment. In this work a comparative microstructural analysis, in Zn-Sn and Zn-Ti coatings, is performed to evaluate intermetallic phases formation kinetics and the influence of intermetallic microstructure on coating damage under constant bending deformation.

  10. Vanadium Influence on Iron Based Intermetallic Phases in AlSi6Cu4 Alloy

    Directory of Open Access Journals (Sweden)

    Bolibruchová D.

    2014-10-01

    Full Text Available Negative effect of iron in Al-Si alloys mostly refers with iron based intermetallic phases, especially Al5FeSi phases. These phases are present in platelet-like forms, which sharp edges are considered as main cracks initiators and also as contributors of porosity formation. In recent times, addition of some elements, for example Mn, Co, Cr, Ni, V, is used to reduce influence of iron. Influence of vanadium in aluminium AlSi6Cu4 alloy with intentionally increased iron content is presented in this article. Vanadium amount has been graduated and chemical composition of alloy has been analysed by spectral analysis. Vanadium influence on microstructural changes was evaluated by microstructural analysis and some of intermetallic particles were reviewed by EDX analysis.

  11. Effect of Iron-Containing Intermetallic Particles on the Corrosion Behaviour of Aluminium

    DEFF Research Database (Denmark)

    Ambat, Rajan

    2006-01-01

    The effect of heat treatment on the corrosion behaviour of binary Al-Fe alloys containing iron at levels between 0.04 and 0.42 wt.% was investigated by electrochemical measurements in both acidic and alkaline chloride solutions. Comparing solution heat-treated and quenched materials with samples...... with {100} facets, and are observed to contain numerous intermetallic particles. Fine facetted filaments also radiate out from the periphery of pits. The results demonstrate that the corrosion of "pure" 99.96% Al is thus dominated by the role of iron, which is the main impurity, and its electrochemical...... that had been subsequently annealed to promote precipitation of Al3Fe intermetallic particles, it was found that annealing increases both the cathodic and anodic reactivity. The increased cathodic reactivity is believed to be directly related to the increased available surface area of the iron...

  12. The Role of Second Phase Intermetallic Particles on the Spall Failure of 5083 Aluminum

    Science.gov (United States)

    2016-12-01

    Bradley Survice Engineering Company, Aberdeen, MD A reprint from Journal of Dynamic Behavior of Materials. 2016;2:476–483...Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MD, USA 2 Survice Engineering Company, Aberdeen Proving Ground, Aberdeen, MD, USA 123 J...2016) 2:476–483 479 123 ligaments between cracks and a second phase intermetallic particle (identified by black arrow) above the crack with an average

  13. Magnetic-field induced phase transitions in intermetallic rare-earth ferrimagnets with a compensation point

    Czech Academy of Sciences Publication Activity Database

    Sabdenov, Ch.K.; Davydova, M.D.; Zvezdin, K.A.; Gorbunov, Denis; Tereshina, I. S.; Andreev, Alexander V.; Zvezdin, A. K.

    2017-01-01

    Roč. 43, č. 5 (2017), s. 551-558 ISSN 1063-777X R&D Projects: GA ČR GA16-03593S Institutional support: RVO:68378271 Keywords : rare-earth intermetallics * phase diagram * field-induced transition * magnetic anisotropy * high magnetic fields Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 0.804, year: 2016

  14. PAC and μSr investigations of light interstitial diffusion in intermetallic hydrides

    International Nuclear Information System (INIS)

    Boyer, P.; Baudry, A.

    1988-01-01

    Specific aspects of the Perturbed Angular Correlation (PAC) of gamma rays concerning its application to the study of atomic diffusion in solids are presented. PAC results recently obtained on the 181 Ta probe in several crystalline and amorphous phases of Zr 2 Ni hydrides are briefly summarized. Preliminary μSR results relative to these intermetallic hydrides are presented and compared to the PAC data

  15. Gas-Solid Reaction Route toward the Production of Intermetallics from Their Corresponding Oxide Mixtures

    Directory of Open Access Journals (Sweden)

    Hesham Ahmed

    2016-08-01

    Full Text Available Near-net shape forming of metallic components from metallic powders produced in situ from reduction of corresponding pure metal oxides has not been explored to a large extent. Such a process can be probably termed in short as the “Reduction-Sintering” process. This methodology can be especially effective in producing components containing refractory metals. Additionally, in situ production of metallic powder from complex oxides containing more than one metallic element may result in in situ alloying during reduction, possibly at lower temperatures. With this motivation, in situ reduction of complex oxides mixtures containing more than one metallic element has been investigated intensively over a period of years in the department of materials science, KTH, Sweden. This review highlights the most important features of that investigation. The investigation includes not only synthesis of intermetallics and refractory metals using the gas solid reaction route but also study the reaction kinetics and mechanism. Environmentally friendly gases like H2, CH4 and N2 were used for simultaneous reduction, carburization and nitridation, respectively. Different techniques have been utilized. A thermogravimetric analyzer was used to accurately control the process conditions and obtain reaction kinetics. The fluidized bed technique has been utilized to study the possibility of bulk production of intermetallics compared to milligrams in TGA. Carburization and nitridation of nascent formed intermetallics were successfully carried out. A novel method based on material thermal property was explored to track the reaction progress and estimate the reaction kinetics. This method implies the dynamic measure of thermal diffusivity using laser flash method. These efforts end up with a successful preparation of nanograined intermetallics like Fe-Mo and Ni-W. In addition, it ends up with simultaneous reduction and synthesis of Ni-WN and Ni-WC from their oxide mixtures

  16. Metals and Ceramics Division Materials Science Program. Annual progress report for period ending June 30, 1984

    International Nuclear Information System (INIS)

    McHargue, C.J.

    1984-11-01

    This report summarizes the activities of the Materials Sciences Program in the Metals and Ceramics Division for the period January 1, 1983, to June 30, 1984. These activities constitute about one-fourth of the research and development conducted by the division. The emphasis of the program can be described as the scientific design of materials. The efforts are directed toward three classes of materials: high-temperature metallic alloys based on intermetallic compounds, structural ceramics, and radiation-resistant alloys

  17. Metals and Ceramics Division Materials Science Program. Annual progress report for period ending June 30, 1984

    Energy Technology Data Exchange (ETDEWEB)

    McHargue, C.J. (comp.)

    1984-11-01

    This report summarizes the activities of the Materials Sciences Program in the Metals and Ceramics Division for the period January 1, 1983, to June 30, 1984. These activities constitute about one-fourth of the research and development conducted by the division. The emphasis of the program can be described as the scientific design of materials. The efforts are directed toward three classes of materials: high-temperature metallic alloys based on intermetallic compounds, structural ceramics, and radiation-resistant alloys.

  18. Modification of NiAl intermetallic coatings processed by PTA with chromium carbides

    International Nuclear Information System (INIS)

    Yano, Diogo Henrique Sepel; Brunetti, Cristiano; Pintaude, Giuseppe; Oliveira, Ana Sofia Climaco Monteiro d'

    2010-01-01

    Equipment that operate under high-temperatures can be protected with NiAl intermetallic coatings mainly because of their metallurgical stability. This study as it evaluates the effect of chromium carbide added to Ni-Al intermetallic coatings processed by PTA. Three Ni-Al-Cr23C6 powder mixtures with different carbide fractions (15, 30 and 45 wt%) and another without carbides were deposited by PTA on an AISI 304 stainless steel plate, using two different current intensities (100 and 150A). Coatings were evaluated regarding the presence of welding defects, and resultant microstructures were characterized by X-ray diffraction and scanning electron microscopy. Vickers microhardness and EDS chemical composition were also determined. NiAl and Cr_7C_3 development was confirmed by X-ray diffraction analysis. A combination of NiAl/Cr-Fe-Ni phases was identified. The hardness was strongly related to the formed phases and their amounts. Besides presenting advances toward the development of coatings which can withstand severe operation conditions, the present study shows that PTA hardfacing is able to produce reinforced intermetallic coatings for high-temperature applications. (author)

  19. Preparation, microstructural evolution and properties of Ni–Zr intermetallic/Zr–Si ceramic reinforced composite coatings on zirconium alloy by laser cladding

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Kun; Li, Yajiang, E-mail: yajli@sdu.edu.cn; Wang, Juan; Ma, Qunshuang; Li, Jishuai; Li, Xinyue

    2015-10-25

    NiZr{sub 2}–ZrSi–Zr{sub 5}(Si{sub x}Ni{sub 1−x}){sub 4}-ZrC intermetallic/ceramic reinforced composite coatings were in situ synthesized by laser cladding the pre-placed Ni–Cr–B–Si powder on zirconium substrate. Microstructure and phase constituents were investigated by X-ray diffraction (XRD), optical microscope (OM), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). Microhardness tester and block-on-ring wear tester were employed to measure the hardness distribution and wear resistance of the intermetallic/ceramic reinforced composite coating. Results indicated that the multiphase of reinforcements includes Ni–Zr intermetallic compounds (e.g., NiZr and NiZr{sub 2}) and Zr–Si(C) ceramic phases (e.g., ZiSi, Zr{sub 5}Si{sub 4} and ZrC). Ni–Si clusters transforming to Zr–Si–Ni clusters at high temperature facilitated the forming of Zr{sub 5}(Si{sub x}Ni{sub 1−x}){sub 4} and during the growth of Zr{sub 5}(Si{sub x}Ni{sub 1−x}){sub 4}, the consumption of Zr atoms at the lateral interface of liquid/Zr{sub 5}(Si{sub x}Ni{sub 1−x}){sub 4} resulted into developing Zr-poor zone near Zr{sub 5}(Si{sub x}Ni{sub 1−x}){sub 4}. The microhardness and wear resistance of the coating were significantly improved by various reinforced phases in comparison to zirconium substrate. - Highlights: • NiZr{sub 2}–ZrSi–Zr{sub 5}(Si{sub x}Ni{sub 1−x}){sub 4}-ZrC compostie coating was in-situ synthesized. • Ni–Si clusters transforming resulted into developing Zr-poor zone near Zr{sub 5}(Si{sub x}Ni{sub 1−x}){sub 4}. • Reinforced phases significantly improve wear resistance of the coating.

  20. Isothermal section of the ternary phase diagram U–Fe–Ge at 900 °C and its new intermetallic phases

    Energy Technology Data Exchange (ETDEWEB)

    Henriques, M.S., E-mail: mish@itn.pt [Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague (Czech Republic); CCTN, IST/CFMCUL, University of Lisbon, Nuclear and Technological Campus, P-2695-066 Bobadela (Portugal); Berthebaud, D.; Lignie, A.; El Sayah, Z.; Moussa, C.; Tougait, O. [Institut des Sciences Chimiques de Rennes, Chimie du Solide et Matériaux, Université Rennes 1, UMR CNRS 6226, 263 Avenue du Général Leclerc, 35042 Rennes (France); Havela, L. [Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague (Czech Republic); Gonçalves, A.P. [CCTN, IST/CFMCUL, University of Lisbon, Nuclear and Technological Campus, P-2695-066 Bobadela (Portugal)

    2015-08-05

    Highlights: • Isothermal section of the U–Fe–Ge at 900 °C was investigated. • Ten ternary compounds and four significant solubility ranges were found. • Three new compounds and a solid solution were discovered. - Abstract: The isothermal section at 900 °C of the U–Fe–Ge ternary system was assessed using experimental results from X-ray diffraction and observations by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy chemical analysis. The phase diagram at this temperature is characterized by the formation of fourteen stable phases: four homogeneity ranges and ten intermetallic compounds. Among these, there is an extension of the binary compound UFe{sub 2} into the ternary system (UFe{sub 2−x}Ge{sub x,}x < 0.15), three ternary line compounds, U{sub 2}Fe{sub 17−x}Ge{sub x} (2 < x < 3.7), UFe{sub 1−x}Ge{sub 2} (0.58 < x < 0.78), UFe{sub 6+x}Ge{sub 6−x} (x < 0.7), and ten ternary stoichiometric compounds, U{sub 2}Fe{sub 3}Ge, U{sub 6}Fe{sub 16}Ge{sub 7}, UFe{sub 4}Ge{sub 2}, U{sub 6}Fe{sub 22}Ge{sub 13}, UFeGe, U{sub 3}Fe{sub 4}Ge{sub 4}, UFe{sub 2}Ge{sub 2}, U{sub 34}Fe{sub 3.32}Ge{sub 33}, U{sub 3}Fe{sub 2}Ge{sub 7}, and U{sub 9}Fe{sub 7}Ge{sub 24}.