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Sample records for tini alloy matrix

  1. The martensitic transformation in Ti-rich TiNi shape memory alloys

    International Nuclear Information System (INIS)

    Lin, H.C.; Wu, S.K.; Lin, J.C.

    1994-01-01

    The martensitic (Ms) transformation temperatures and their ΔH values of Ti 51 Ni 49 and Ti 50.5 Ni 49.5 alloys are higher than those of equiatomic or Ni-rich TiNi alloys. The Ti-rich TiNi alloys exhibit good shape recovery in spite of a great deal of second phase Ti 2 Ni or Ti 4 Ni 2 O existing around B2 grain boundaries. The nearly identical transformation temperatures indicate that the absorbed oxygen in Ti-rich TiNi alloys may react with Ti 2 Ni particles, instead of the TiNi matrix, to form Ti 4 Ni 2 O. Martensite stabilization can be induced by cold rolling at room temperature. Thermal cycling can depress the transformation temperatures significantly, especially in the initial 20 cycles. The R-phase transformation can be promoted by both cold rolling and thermal cycling in Ti-rich TiNi alloys due to introduced dislocations depressing the Ms temperature. The strengthening effects of cold rolling and thermal cycling on the Ms temperature of Ti-rich TiNi alloys are found to follow the expression Ms = To - KΔσ y . The K values are affected by different strengthening processes and related to the as-annealed transformation temperatures. The higher the as-annealed Ms (or As), the larger the K value. (orig.)

  2. Stress transmission through Ti-Ni alloy, titanium and stainless steel in impact compression test.

    Science.gov (United States)

    Yoneyama, T; Doi, H; Kobayashi, E; Hamanaka, H; Tanabe, Y; Bonfield, W

    2000-06-01

    Impact stress transmission of Ti-Ni alloy was evaluated for biomedical stress shielding. Transformation temperatures of the alloy were investigated by means of DSC. An impact compression test was carried out with use of split-Hopkinson pressure-bar technique with cylindrical specimens of Ti-Ni alloy, titanium and stainless steel. As a result, the transmitted pulse through Ti-Ni alloy was considerably depressed as compared with those through titanium and stainless steel. The initial stress reduction was large through Ti-Ni alloy and titanium, but the stress reduction through Ti-Ni alloy was more continuous than titanium. The maximum value in the stress difference between incident and transmitted pulses through Ti-Ni alloy or titanium was higher than that through stainless steel, while the stress reduction in the maximum stress through Ti-Ni alloy was statistically larger than that through titanium or stainless steel. Ti-Ni alloy transmitted less impact stress than titanium or stainless steel, which suggested that the loading stress to adjacent tissues could be decreased with use of Ti-Ni alloy as a component material in an implant system. Copyright 2000 Kluwer Academic Publishers

  3. Prospect of Ti-Ni shape memory alloy applied in reactor structures

    International Nuclear Information System (INIS)

    Duan Yuangang

    1995-01-01

    Shape memory effect mechanism, physical property, composition, manufacturing process and application in mechanical structure of Ti-Ni shape memory alloy are introduced. Applications of Ti-Ni shape memory alloy in reactor structure are prospected and some necessary technical conditions of shape memory alloy applied in the reactor structure are put forward initially

  4. A study on the shape memory characteristics of Ti-Ni50-x-Pdx alloys

    International Nuclear Information System (INIS)

    Lee, H. W.; Chun, B. S.; Oh, S. J.; Kuk, I.H.

    1991-01-01

    The shape memory characteristics in TiNi alloys are greatly effected by the alloy composition and heat treatment condition. The present work was aimed to investigate the effect of Pd x (x=5,10,15,20) addition on the shape memory chracteristics of TiNi alloys by means of electrical resistance measurement. X-ray diffraction, differential scanning calorimetry and electron dispersive analysis X-ray measurement. The results obtained from this study are as follows; 1. The martensitic transformation start temperature, Ms of Ti-Ni 50-x -Pd x alloys decreased considerably with the increase of Pd content up to 10at%, whereas increased largely with the increase of Pd content in the alloys with Pd content more than 15at%. 2. The Ms temperature of Ti-Ni 50-x -Pd x alloys with cold working was significantly lower than that of the fully annealed alloys because high density dislocation has been introduced by the cold working which suppressed the martensitic transformation. (Author)

  5. Cavitation erosion of Ti-Ni shape memory alloy deposited coatings and Fe base shape memory alloy solid

    International Nuclear Information System (INIS)

    Hattori, Shuji; Fujisawa, Seiji; Owa, Tomonobu

    2007-01-01

    In this study, cavitation erosion tests were carried out by using thermal spraying and deposition of Ti-Ni shape memory alloy for the surface coating. The results show the test speciment of Ti-Ni thermal spraying has many initial defects, so that the erosion resistance is very low. The erosion resistance of Ti-Ni deposit is about 5-10 times higher than that of SUS 304, thus erosion resistance of Ti-Ni deposit is better than that of Ti-Ni thermal spraying. The cavitation erosion tests were carried out by using Fe-Mn-Si with shape memory and gunmetal with low elastic modulus. The erosion resistance of Fe-Mn-Si shape memory alloy solid is about 9 times higher than that of SUS 304. The erosion resistance of gunmetal is almost the same as SUS 304, because the test specimen of gunmetal has many small defects on the original surface. (author)

  6. Alloying process of sputter-deposited Ti/Ni multilayer thin films

    International Nuclear Information System (INIS)

    Cho, H.; Kim, H.Y.; Miyazaki, S.

    2006-01-01

    Alloying process of a Ti/Ni multilayer thin film was investigated in detail by differential scanning calorimetry (DSC), X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The Ti/Ni multilayer thin film was prepared by depositing Ti and Ni layers alternately on a SiO 2 /Si substrate. The number of each metal layer was 100, and the total thickness was 3 μm. The alloy composition was determined as Ti-51 at.%Ni by electron probe micro analysis (EPMA). The DSC curve exhibited three exothermic peaks at 621, 680 and 701 K during heating the as-sputtered multilayer thin film. In order to investigate the alloying process, XRD and TEM observation was carried out for the specimens heated up to various temperatures with the heating rate same as the DSC measurement. The XRD profile of the as-sputtered film revealed only diffraction peaks of Ti and Ni. But reaction layers of 3 nm in thickness were observed at the interfaces of Ti and Ni layers in cross-sectional TEM images. The reaction layer was confirmed as an amorphous phase by the nano beam diffraction analysis. The XRD profiles exhibited that the intensity of Ti diffraction peak decreased in the specimen heat-treated above 600 K. The peak from Ni became broad and shifted to lower diffraction angle. The amorphous layer thickened up to 6 nm in the specimen heated up to 640 K. The diffraction peak corresponding to Ti-Ni B2 phase appeared and the peak from Ni disappeared for the specimen heated up to 675 K. The Ti-Ni B2 crystallized from the amorphous reaction layer. After further heating above the third exothermic peak, the intensity of the peak from the Ti-Ni B2 phase increased, the peak from Ti disappeared and the peaks corresponding to Ti 2 Ni appeared. The Ti 2 Ni phase was formed by the reaction of the Ti-Ni B2 and Ti

  7. Laser welding of Ti-Ni type shape memory alloy

    International Nuclear Information System (INIS)

    Hirose, Akio; Araki, Takao; Uchihara, Masato; Honda, Keizoh; Kondoh, Mitsuaki.

    1990-01-01

    The present study was undertaken to apply the laser welding to the joining of a shape memory alloy. Butt welding of a Ti-Ni type shape memory alloy was performed using 10 kW CO 2 laser. The laser welded specimens showed successfully the shape memory effect and super elasticity. These properties were approximately identical with those of the base metal. The change in super elasticity of the welded specimen during tension cycling was investigated. Significant changes in stress-strain curves and residual strain were not observed in the laser welded specimen after the 50-time cyclic test. The weld metal exhibited the celler dendrite. It was revealed by electron diffraction analysis that the phase of the weld metal was the TiNi phase of B2 structure which is the same as the parent phase of base metal and oxide inclusions crystallized at the dendrite boundary. However, oxygen contamination in the weld metal by laser welding did not occur because there was almost no difference in oxygen content between the base metal and the weld metal. The transformation temperatures of the weld metal were almost the same as those of the base metal. From these results, laser welding is applicable to the joining of the Ti-Ni type shape memory alloy. As the application of laser welding to new shape memory devices, the multiplex shape memory device of welded Ti-50.5 at % Ni and Ti-51.0 at % Ni was produced. The device showed two-stage shape memory effects due to the difference in transformation temperature between the two shape memory alloys. (author)

  8. Limitations of constitutive relations for TiNi shape memory alloys

    International Nuclear Information System (INIS)

    Tang, W.; Sandstroem, R.

    1995-01-01

    Phase transformation tensor Ω in the constitutive equation proposed by Tanaka has been evaluated by employing experimental data of TiNi alloys in a constrained recovery process. It demonstrates that the absolute value of Ω for the constrained recovery process is typically about 0.6 ∼ 0.7 x 10 3 MPa, which is much smaller than that for the stress - induced martensitic transformation (typically 2.5 ∼ 3.5 x 10 3 ). Based on the evaluated results for Ω, predicted recovery stress - temperature relations by the constitutive equation are compared with the experimental data for TiNi rods under different strains. Big discrepancy exists for large strain conditions. Several transformation kinetic expressions are examined for the constitutive relation of the constrained recovery process. (orig.)

  9. Alloying effect on K shell X-ray fluorescence cross-sections and yields in Ti-Ni based shape memory alloys

    Directory of Open Access Journals (Sweden)

    Bünyamin Alım

    2018-04-01

    Full Text Available K shell X-ray fluorescence cross-sections (σKα, σKβ and σK, and K shell fluorescence yields (ωK of Ti, Ni both in pure metals and in different alloy compositions (TixNi1-x; x = 0.3, 0.4, 0.5, 0.6, 0.7 were measured by using energy dispersive X-ray fluorescence (EDXRF technique. The samples were excited by 22.69 keV X-rays from a 10 mCi Cd-109 radioactive point source and K X rays emitted by samples were counted by a high resolution Si(Li solid-state detector coupled to a 4 K multichannel analyzer (MCA. The alloying effects on the X-ray fluorescence (XRF parameters of Ti-Ni shape memory alloys (SMAs were investigated. It is clearly observed that alloying effect causes to change in K shell XRF parameter values in Ti-Ni based SMAs for different compositions of x. Also, the present investigation makes it possible to perform reliable interpretation of experimental σKα, σKβ and ωK values for Ti and Ni in SMAs and can also provide quantitative information about the changes of K shell X-ray fluorescence cross sections and fluorescence yields of these metals with alloy composition. Keywords: Alloying effect, XRF, K X-ray fluorescence cross-section, K shell fluorescence yield, Shape memory alloy

  10. Mechanical properties and related substructure of TiNi shape memory alloys

    International Nuclear Information System (INIS)

    Filip, P.; Kneissl, A.C.

    1995-01-01

    The mechanical properties of binary near equiatomic TiNi shape memory alloys were investigated after different types of mechanical and heat treatments. The changes of deformation behaviour are explained on the basis of substructure differences after work hardening. The ''elastic moduli'' of both the high-temperature phase B2 and the martensite B19' as well as the ''easy stage of deformation'' are dependent on the work hardening intensity and these changes are related to the mobility of B2/B19' interfaces. The martensite changes its morphology after work hardening. In contrast to a twinned martensite, typical for annealed alloys, the internally slipped martensite was detected after work hardening. (orig.)

  11. Interfacial characteristics and fracture behavior of spark-plasma-sintered TiNi fiber-reinforced 2024Al matrix composites

    International Nuclear Information System (INIS)

    Dong, Peng; Wang, Zhe; Wang, Wenxian; Chen, Shaoping; Zhou, Jun

    2017-01-01

    Embedding of shape memory alloy (SMA) fibers into materials to fabricate SMA composites has attracted considerable attention because of the potential applicability of these composites in smart systems and structures. In this study, 2024Al matrix composites reinforced by continuous TiNi SMA fibers were fabricated using spark plasma sintering (SPS). The interface between the fibers and matrix consisted of a bilayer. The layer close to the fiber consisted of a multiple phase mixture, and the other layer exhibited a periodic morphology resulting from the alternating phases of Al 3 Ti and Al 3 Ni. In addition, a small quantity of TiO 2 phases was also observed in the interface layer. Based on detailed interface studies of the orientation relationships between the Al 3 Ti, Al 3 Ni, and TiO 2 phases and the atomic correspondence at phase boundaries, the effects of the interface phases on the fracture behavior of the composites were demonstrated.

  12. Interfacial characteristics and fracture behavior of spark-plasma-sintered TiNi fiber-reinforced 2024Al matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Peng, E-mail: dongpeng@tyut.edu.cn [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Shanxi Key Laboratory of Advanced Magnesium-Based Materials, Taiyuan 030024 (China); Wang, Zhe [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Wenxian [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Shanxi Key Laboratory of Advanced Magnesium-Based Materials, Taiyuan 030024 (China); Chen, Shaoping [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Zhou, Jun [Department of Mechanical Engineering, Pennsylvania State University Erie, Erie, PA 16563 (United States)

    2017-04-13

    Embedding of shape memory alloy (SMA) fibers into materials to fabricate SMA composites has attracted considerable attention because of the potential applicability of these composites in smart systems and structures. In this study, 2024Al matrix composites reinforced by continuous TiNi SMA fibers were fabricated using spark plasma sintering (SPS). The interface between the fibers and matrix consisted of a bilayer. The layer close to the fiber consisted of a multiple phase mixture, and the other layer exhibited a periodic morphology resulting from the alternating phases of Al{sub 3}Ti and Al{sub 3}Ni. In addition, a small quantity of TiO{sub 2} phases was also observed in the interface layer. Based on detailed interface studies of the orientation relationships between the Al{sub 3}Ti, Al{sub 3}Ni, and TiO{sub 2} phases and the atomic correspondence at phase boundaries, the effects of the interface phases on the fracture behavior of the composites were demonstrated.

  13. Shape memory and pseudoelastic properties of Fe-Mn-Si and Ti-Ni based alloys

    International Nuclear Information System (INIS)

    Guenin, G.

    1997-01-01

    The aim of this presentation is to analyse and discuss some recent advances in shape memory and pseudoelastic properties of different alloys. Experimental work in connection with theoretical ones will be reviewed. The first part is devoted to the microstructural origin of shape memory properties of Fe-Mn-Si based alloys (γ-ε transformation); the second part is a synthetic analysis of the effects of thermomechanical treatments on shape memory and pseudoelastic effects in Ti-Ni alloys, with some focus on the behaviour of the R phase introduced. (orig.)

  14. Effect of hydrogen on transformation characteristics and deformation behavior in a Ti-Ni shape memory alloy

    International Nuclear Information System (INIS)

    Hoshiya, Taiji; Ando, Hiroei; Den, Shoji; Katsuta, Hiroshi.

    1992-01-01

    Transformation characteristics and deformation behavior of hydrogenated Ti-50.5 at% Ni alloys, which were occluded in a low pressure range of hydrogen between 1.1 and 78.5 kPa, have been studied by electrical resistivity measurement, tensile test, X-ray diffraction analysis and microstructural observation. M S temperature of the Ti-Ni alloys decreased with an increase in hydrogen content. This corresponds to the stabilization of the parent phase during cooling, which was confirmed by X-ray diffraction: The suppression effect of hydrogen takes place on the martensitic transformation. Critical stress for slip deformation of hydrogenated Ti-Ni alloys changed with hydrogen content and thus hydrogen had a major influence on deformation behavior of those alloys. With hydrogen contents above 0.032 mol%, hardening was distinguished from softening which was pronounced in the contents from 0 to 0.032 mol% H. Hydrides were formed in hydrogen contents over 1.9 mol%. The hydride formation results in the reorientation in variants of the R phase and increase in the lattice strains of the parent phase. (author)

  15. Effect of Substrate Roughness on Adhesion and Structural Properties of Ti-Ni Shape Memory Alloy Thin Film.

    Science.gov (United States)

    Kim, Donghwan; Lee, Hyunsuk; Bae, Joohyeon; Jeong, Hyomin; Choi, Byeongkeun; Nam, Taehyun; Noh, Jungpil

    2018-09-01

    Ti-Ni shape memory alloy (SMA) thin films are very attractive material for industrial and medical applications such as micro-actuator, micro-sensors, and stents for blood vessels. An important property besides shape memory effect in the application of SMA thin films is the adhesion between the film and the substrate. When using thin films as micro-actuators or micro-sensors in MEMS, the film must be strongly adhered to the substrate. On the other hand, when using SMA thin films in medical devices such as stents, the deposited alloy thin film must be easily separable from the substrate for efficient processing. In this study, we investigated the effect of substrate roughness on the adhesion of Ti-Ni SMA thin films, as well as the structural properties and phase-transformation behavior of the fabricated films. Ti-Ni SMA thin films were deposited onto etched glass substrates with magnetron sputtering. Radio frequency plasma was used for etching the substrate. The adhesion properties were investigated through progressive scratch test. Structural properties of the films were determined via Feld emission scanning electron microscopy, X-ray diffraction measurements (XRD) and Energy-dispersive X-ray spectroscopy analysis. Phase transformation behaviors were observed with differential scanning calorimetry and low temperature-XRD. Ti-Ni SMA thin film deposited onto rough substrate provides higher adhesive strength than smooth substrate. However the roughness of the substrate has no influence on the growth and crystallization of the Ti-Ni SMA thin films.

  16. An experimental study on the erosion behavior of pseudoelastic TiNi alloy in dry sand and in aggressive media

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, T.; Li, D.Y. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical Engineering

    2000-11-30

    The corrosive erosion behavior of Ti-51at.%Ni alloy under different erosion conditions was studied and compared to that of 304 stainless steel. Erosion tests were performed in a slurry-pot tester with dry sand, 3.5% NaCl slurry and 0.1 moll{sup -1} H{sub 2}SO{sub 4} slurry containing 30% silica sand, respectively. Synergistic effects of corrosion and erosion were studied in steady corrosion, polarization, dry sand erosion and micro-wear experiments. An electrochemical-scratching test characterized the failure and recovery of the passive film formed on TiNi alloy in 3.5% NaCl and 0.1 mol l{sup -1} H{sub 2}SO{sub 4} solutions, respectively. In both dry sand and the corrosive media, the TiNi alloy exhibited considerably greater erosion resistance than 304 stainless steel. (orig.)

  17. Evaluation on microscopic damage and fabrication process of shape memory alloy

    International Nuclear Information System (INIS)

    Lee, Jin Kyung; Choi, Il Kook; Park, Young Chul; Lee, Kyu Chang; Lee, Jun Hyun

    2002-01-01

    Shape memory alloy has been used to improve the tensile strength of composite by the occurrence of compressive residual stress in matrix using its shape memory effect. In order to fabricate shape memory alloy composite, TiNi alloy and Al6061 were used as reinforcing material and matrix, respectively. In this study, TiNi/Al6061 shape memory alloy composite was made by using hot press method. However, the specimen fabricated by this method had the bonding problem at tile boundary between TiNi fiber anti Al matrix when the load was applied to it. A cold rolling was imposed to the specimen to improve the bonding effort. It was found that tensile strength of specimen subjected to cold rolling was more increased than that of specimen which did not underwent cold rolling. In addition, acoustic emission technique was used to quantify the microscopic damage behavior of cold rolled TiNi/Al6061 shape memory alloy composite at high temperature.

  18. Fabrication Process and Reliability Evaluation of Shape Memory Alloy Composite

    International Nuclear Information System (INIS)

    Lee, Jin Kyung; Choi, Il Kook; Park, Young Chul; Lee, Kyu Chang; Lee, Joon Hyun

    2001-01-01

    Shape memory alloy has been used to improve the tensile strength of composite by the occurrence of compressive residual stress in matrix using its shape memory effect. In order to fabricate shape memory alloy composite, TiNi alloy and A16061 were used as reinforcing material and mix, respectively. In this study, TiNi/A16061 shape memory alloy composite was made by using hot press method. However, the specimen fabricated by this method had the bonding problem at the boundary between TiNi fiber and Al matrix when the load was applied to it. A cold rolling was imposed to the specimen to improve the bonding effect. It was found that tensile strength of specimen subjected to cold rolling was more increased than that of specimen which did not underwent cold rolling. In addition, acoustic emission technique was used to quantify the microscopic damage behavior of cold rolled TiNi/A16061 shape memory alloy composite at high temperature

  19. Electron irradiation effect on the reverse phase transformation temperatures in TiNi shape memory alloy thin films

    International Nuclear Information System (INIS)

    Wang, Z.G.; Zu, X.T.; Fu, Y.Q.; Zhu, S.; Wang, L.M.

    2005-01-01

    In this work, Ti-Ni shape memory alloy thin films were irradiated by 1.7 MeV electron with three types of fluences: 4 x 10 20 , 7 x 10 20 and 1 x 10 21 /m 2 . The influence of electron irradiation on the transformation behavior of the TiNi thin films were investigated by differential scanning calorimetry. The transformation temperatures A s and A f shifted to higher temperature after electron irradiation, the martensite was stabilized. The electron irradiation effect can be easily eliminated by one thermal cycle. The shifts of the transformation temperatures can be explained from the change of potential energy barrier and coherency energy between parent phase and martensite after irradiation

  20. Effects of post-irradiation annealing on the transformation behavior of Ti-Ni alloys

    International Nuclear Information System (INIS)

    Kimura, A.; Tsuruga, H.; Morimura, T.; Misawa, T.; Miyazaki, S.

    1993-01-01

    Recovery processes of martensitic transformation of neutron irradiated Ti-50.0, 50.5 and 51.0 at.%Ni alloys during post-irradiation annealing were investigated by means of differential scanning calorimetry (DSC), tensile tests and transmission electron microscope (TEM) observations. Neutron irradiation up to a fluence of 1.2x10 24 n/cm 2 at 333 K suppressed the martensitic transformation as well as the stress-induced martensitic transformation of these alloys above 150 K. The TEM observations revealed that the disordered zones containing small defect clusters in high density were formed in the neutron irradiated Ti-Ni alloys. The DSC measurements also showed that the post-irradiation annealing caused recovery of the transformation of which the progress depended on the annealing temperature and period. A significant retardation of the recovery was recognized in the Ti-51.0 at.%Ni alloy in comparison with the Ti-50.0 at.%Ni alloy. From the shifts in the transformation temperature upon isothermal annealing at various annealing temperatures, the activation energies of the recovery process of the transformation in the neutron irradiated Ti-50.0 and 51.0 at.%Ni alloys were evaluated by a cross-cut method to be 1.2 eV and 1.5 eV, respectively. The recovery of the transformation was ascribed to the re-ordering resulting from decomposition of vacancy clusters, and those obtained values of the activation energy were considered to be the sum of the migration energy of vacancy and the binding energy of vacancy-vacancy cluster. The retardation of the recovery in the Ti-51.0 at%Ni alloy was interpreted in terms of large binding energy in this alloy due to the off-stoichiometry. (author)

  1. The influence of the substrate on the adhesive strength of the micro-arc oxidation coating developed on TiNi shape memory alloy

    Science.gov (United States)

    Hsieh, Shy-Feng; Ou, Shih-Fu; Chou, Chia-Kai

    2017-01-01

    TiNi shape memory alloys (SMAs), used as long-term implant materials, have a disadvantage. Ni-ion release from the alloys may trigger allergies in the human body. Micro-arc oxidation has been utilized to modify the surface of the TiNi SMA for improving its corrosion resistance and biocompatibility. However, there are very few reports investigating the essential adhesive strength between the micro-arc oxidized film and TiNi SMA. Two primary goals were attained by this study. First, Ti50Ni48.5Mo1.5 SMA having a phase transformation temperature (Af) less than body temperature and good shape recovery were prepared. Next, the Ti50Ni50 and Ti50Ni48.5Mo1.5 SMA surfaces were modified by micro-arc oxidation in phosphoric acid by applying relatively low voltages to maintain the adhesive strength. The results indicated that the pore size, film thickness, and P content increased with applied voltage. The micro-arc oxidized film, comprising Ti oxides, Ni oxide, and phosphate compounds, exhibited a glassy amorphous structure. The outmost surface of the micro-arc oxidized film contained a large amount of P (>12 at%) but only a trace of Ni (micro-arc oxidized films exceeded the requirements of ISO 13779. Furthermore, Mo addition into TiNi SMAs was found to be favorable for improving the adhesive strength of the micro-arc oxidized film.

  2. Elastocaloric cooling of additive manufactured shape memory alloys with large latent heat

    International Nuclear Information System (INIS)

    Hou, Huilong; Stasak, Drew; Hasan, Naila Al; Takeuchi, Ichiro; Simsek, Emrah; Ott, Ryan; Cui, Jun; Qian, Suxin

    2017-01-01

    The stress-induced martensitic phase transformation of shape memory alloys (SMAs) is the basis for elastocaloric cooling. Here we employ additive manufacturing to fabricate TiNi SMAs, and demonstrate compressive elastocaloric cooling in the TiNi rods with transformation latent heat as large as 20 J g −1 . Adiabatic compression on as-fabricated TiNi displays cooling Δ T as high as  −7.5 °C with recoverable superelastic strain up to 5%. Unlike conventional SMAs, additive manufactured TiNi SMAs exhibit linear superelasticity with narrow hysteresis in stress–strain curves under both adiabatic and isothermal conditions. Microstructurally, we find that there are Ti 2 Ni precipitates typically one micron in size with a large aspect ratio enclosing the TiNi matrix. A stress transfer mechanism between reversible phase transformation in the TiNi matrix and mechanical deformation in Ti 2 Ni precipitates is believed to be the origin of the unique superelasticity behavior. (paper)

  3. Solid-state reaction in Ti/Ni multilayered films studied by using magneto-optical spectroscopy

    CERN Document Server

    Lee, Y P; Kim, K W; Kim, C G; Kudryavtsev, Y V; Nemoshkalenko, V V; Szymanski, B

    2000-01-01

    A comparative study of the solid-state reaction (SSR) in a series of Ti/Ni multilayered films (MLDs) with bilayer periods of 0.65-22.2 nm and a constant Ti to Ni sublayer thickness ratio was performed by using experimental and computer-simulated magneto-optical (MO) spectroscopy based on different models of MLFs, as well as x-ray diffraction (XRD). The spectral and sublayer thickness dependences of the MO properties of the Ti/Ni MLFs were explained on the basis of the electromagnetic theory. The existence of a threshold nominal Ni-sublayer thickness of about 3 nm for the as-deposited Ti/Ni MLF to observe of the equatorial Kerr effect was explained by a solid-state reaction which formed nonmagnetic alloyed regions between pure components during the MLF deposition. The SSR in the Ti/Ni MLFs, which was caused by the low temperature annealing, led to the formation of an amorphous Ti-Ni alloy and took place mainly in the Ti/Ni MLFs with ''thick'' sublayers. For the caes of Ti/Ni MLFs, the MO approach turned out to...

  4. Corrosion behavior of HPT-deformed TiNi alloys in cell culture medium

    Science.gov (United States)

    Shri, D. N. Awang; Tsuchiya, K.; Yamamoto, A.

    2017-09-01

    In recent years there are growing interest in fabrication of bulk nanostructured metals and alloys by using severe plastic deformation (SPD) techniques as new alternative in producing bulk nanocrystalline materials. These techniques allows for processing of bulk, fully dense workpiece with ultrafine grains. Metal undergoes SPD processing in certain techniques such as high pressure torsion (HPT), equal-channel angular pressing (ECAP) or multi-directional forging (MDF) are subjected to extensive hydrostatic pressure that may be used to impart a very high strain to the bulk solid without the introduction of any significant change in overall dimension of the sample. The change in the structure (small grain size and high-volume fraction of grain boundaries) of the material may result in the corrosion behavior different from that of the coarse-grained material. Electrochemical measurements were done to understand the corrosion behavior of TiNi alloys before and after HPT deformation. The experiment was carried out using standard three electrode setup (a sample as working electrode; a platinum wire as a counter electrode and a saturated calomel electrode in saturated KCl as a reference electrode) with the surface area of 26.42 mm2 exposed to the EMEM+10% FBS cell culture medium. The measurements were performed in an incubator with controlled environment at 37 °C and 5% CO2, simulating the cell culture condition. The potential of the specimen was monitored over 1 hour, and the stabilized potential was used as the open-circuit potential (EOCP). Potentiodynamic curves were scanned in the potential range from -0.5 V to 1.5 V relative to the EOCP, at a rate of 0.5 mV/s. The result of OCP-time measurement done in the cell culture medium shows that the OCP of HPT-deformed samples shifts towards to the more positive rather than that of BHPT samples. The OCP of deformed samples were ennobled to more than +70 mV for Ti-50mol%. The shift of OCP towards the nobler direction

  5. Determination of local constitutive properties of titanium alloy matrix in boron-modified titanium alloys using spherical indentation

    International Nuclear Information System (INIS)

    Sreeranganathan, A.; Gokhale, A.; Tamirisakandala, S.

    2008-01-01

    The constitutive properties of the titanium alloy matrix in boron-modified titanium alloys are different from those of the corresponding unreinforced alloy due to the microstructural changes resulting from the addition of boron. Experimental and finite-element analyses of spherical indentation with a large penetration depth to indenter radius ratio are used to compute the local constitutive properties of the matrix alloy. The results are compared with that of the corresponding alloy without boron, processed in the same manner

  6. Solidification processing of monotectic alloy matrix composites

    Science.gov (United States)

    Frier, Nancy L.; Shiohara, Yuh; Russell, Kenneth C.

    1989-01-01

    Directionally solidified aluminum-indium alloys of the monotectic composition were found to form an in situ rod composite which obeys a lambda exp 2 R = constant relation. The experimental data shows good agreement with previously reported results. A theoretical boundary between cellular and dendritic growth conditions was derived and compared with experiments. The unique wetting characteristics of the monotectic alloys can be utilized to tailor the interface structure in metal matrix composites. Metal matrix composites with monotectic and hypermonotectic Al-In matrices were made by pressure infiltration, remelted and directionally solidified to observe the wetting characteristics of the alloys as well as the effect on structure of solidification in the constrained field of the fiber interstices. Models for monotectic growth are modified to take into account solidification in these constrained fields.

  7. Effect of phase formation on valence band photoemission and photoresonance study of Ti/Ni multilayers using synchrotron radiation

    International Nuclear Information System (INIS)

    Bhatt, Pramod; Chaudhari, S.M.

    2006-01-01

    This paper presents investigation of Ti-Ni alloy phase formation and its effect on valence band (VB) photoemission and photoresonance study of as-deposited as well as annealed Ti/Ni multilayers (MLs) up to 600 deg. C using synchrotron radiation. For this purpose [Ti (50 A)/Ni (50 A)]X 10 ML structures were deposited by using electron-beam evaporation technique under ultra-high vacuum (UHV) conditions. Formation of different phases of Ti-Ni alloy due to annealing treatment has been confirmed by the X-ray diffraction (XRD) technique. The XRD pattern corresponding as-deposited ML sample shows crystalline nature of both Ti and Ni deposited layers, whereas 300 deg. C annealed ML sample show solid-state reaction (SSR) leading to amorphization and subsequent recrystallisation at higher temperatures of annealing (≥400 deg. C) with the formation of TiNi, TiNi 3 and Ti 2 Ni alloy phases. The survey scans corresponding to 400, 500 and 600 deg. C annealed ML sample shows interdiffusion and intermixing of Ni atoms into Ti layers leading to chemical Ti-Ni alloys phase formation at interface. The corresponding recorded VB spectra using synchrotron radiation at 134 eV on as-deposited ML sample with successive sputtering shows alternately photoemission bands due to Ti 3d and Ni 3d, respectively, indicating there is no mixing of the consequent layers and any phase formation at the interface during deposition. However, ML samples annealed at higher temperatures of annealing, particularly at 400, 500 and 600 deg. C show a clear shift in Ni 3d band and its satellite peak position to higher BE side indicates Ti-Ni alloy phase formation. In addition to this, reduction of satellite peak intensity and Ni 3d density of states (DOS) near Fermi level is also observed due to Ti-Ni phase formation with higher annealing temperatures. The variable photon energy VB measurements on as-deposited and ML samples annealed at 400 deg. C confirms existence and BE position of observed Ni 3d satellite

  8. Fracture of Shape Memory Alloys

    OpenAIRE

    Miyazaki, Shuichi; Otsuka, Kazuhiro

    1981-01-01

    The initiation and the propagation of cracks during both quenching and deformation in polycrystalline Cu-Al-Ni alloys have been investigated under various conditions. The fracture surfaces of Ti-Ni and Cu-Al-Ni alloys were also observed by a scanning electron microscope. From these results, it was concluded that the brittleness of Cu-Al-Ni alloy and other β phase alloys are due to large elastic anisotropy and large grain sizes, while that the large ductility in Ti-Ni alloy being due to the sm...

  9. Anisotropic Negative Thermal Expansion Behavior of the As-Fabricated Ti-Rich and Equiatomic Ti-Ni Alloys Induced by Preferential Grain Orientation

    Science.gov (United States)

    Zhao, Zhong-Xun; Ma, Xiao; Cao, Shan-Shan; Ke, Chang-Bo; Zhang, Xin-Ping

    2018-03-01

    The present study focuses on the anisotropic negative thermal expansion (NTE) behaviors of Ti-rich (Ti54Ni46) and equiatomic Ti-Ni (Ti50Ni50) alloys fabricated by vacuum arc melting and without subsequent plastic deformation. Both alloys exhibit NTE responses in vertical and horizontal directions, and the total strains and CTEs of the NTE stage along the two mutually perpendicular measuring directions are obviously different, indicating obvious anisotropic NTE behavior of the alloys. Besides, the numerical differences between the starting temperature of NTE and austenitic transformation and between the finishing temperature of NTE and austenitic transformation are very small, which indicates that an apparent relationship exists between the NTE behavior and the phase transformation. The microstructure in the vertical cross sections shows obviously preferential orientation characteristics: Ti2Ni phases of both alloys grow along the vertical direction, and B19' martensite of Ti50Ni50 alloy has distinct preferential orientation, which results from a large temperature gradient between the top and the bottom of the button ingots during solidification. The microstructure with preferential orientation induces the anisotropic NTE behavior of the samples.

  10. Change of texture, microdeformation and hardness in surface layer of TiNi alloy depending on the number of pulses of electron beam effects

    International Nuclear Information System (INIS)

    Meisner, L. L.; Meisner, S. N.; Markov, A. B.; Yakovlev, E. V.; Ozur, G. E.; Rotshtein, V. P.; Mironov, Yu. P.

    2015-01-01

    This work comprises a study of the influence of the pulse number of low-energy high-current electron beam (LEHCEB) exposure on the value and character of distribution of residual elastic stresses, texturing effects and the relationship between structural-phase states and physical and mechanical properties of the modified surface layers of TiNi alloy. LEHCEB processing of the surface of TiNi samples was carried out using a RITM-SP [3] installation. Energy density of electron beam was constant at E s = 3.9 ± 0.5 J/cm 2 ; pulse duration was 2.8 ± 0.3 μs. The number of pulses in the series was changeable, (n = 2–128). It was shown that as the result of multiple LEHCEB processing of TiNi samples, hierarchically organized multilayer structure is formed in the surface layer. The residual stress field of planar type is formed in the modified surface layer as following: in the direction of the normal to the surface the strain component ε ⊥ < 0 (compressing strain), and in a direction parallel to the surface, the strain component ε || > 0 (tensile deformation). Texturing effects and the level of residual stresses after LEHCEB processing of TiNi samples with equal energy density of electron beam (∼3.8 J/cm 2 ) depend on the number of pulses and increase with the rise of n > 10

  11. Transformation-Induced Relaxation and Stress Recovery of TiNi Shape Memory Alloy

    Directory of Open Access Journals (Sweden)

    Kohei Takeda

    2014-03-01

    Full Text Available The transformation-induced stress relaxation and stress recovery of TiNi shape memory alloy (SMA in stress-controlled subloop loading were investigated based on the local variation in temperature and transformation band on the surface of the tape in the tension test. The results obtained are summarized as follows. (1 In the loading process, temperature increases due to the exothermic martensitic transformation (MT until the holding strain and thereafter temperature decreases while holding the strain constant, resulting in stress relaxation due to the MT; (2 In the unloading process, temperature decreases due to the endothermic reverse transformation until the holding strain and thereafter temperature increases while holding the strain constant, resulting in stress recovery due to the reverse transformation; (3 Stress varies markedly in the initial stage followed by gradual change while holding the strain constant; (4 If the stress rate is high until the holding strain in the loading and unloading processes, both stress relaxation and stress recovery are large; (5 It is important to take into account this behavior in the design of SMA elements, since the force of SMA elements varies even if the atmospheric temperature is kept constant.

  12. Fabrication, microstructure and stress effects in sputtered TiNi thin films

    International Nuclear Information System (INIS)

    Grummon, D.S.

    2000-01-01

    Sputtered thin films of equiatomic TiNi and TiNiX ternary alloys have excellent mechanical properties and exhibit robust shape-memory and transformational superelasticity. Furthermore, the energetic nature of the sputter deposition process allows the creation of highly refined microstructures that are difficult to achieve by melt-solidification. The present paper will present recent work on the relationship between processing, microstructure and properties of binary TiNi thin films, focusing primarily on residual stresses, kinetics of stress-relaxation and crystallization, and fine grain sizes achievable using hot-substrate direct crystallization. (orig.)

  13. High Porosity Alumina as Matrix Material for Composites of Al-Mg Alloys

    International Nuclear Information System (INIS)

    Gömze, L A; Egész, Á; Gömze, L N; Ojima, F

    2013-01-01

    The sophisticated industry and technologies require higher and higher assumptions against mechanical strength and surface hardness of ceramic reinforced metal alloys and metal matrix composites. Applying the well-known alumina powders by dry pressing technology and some special pore-forming additives and sintering technology the authors have successfully developed a new, high porosity alumina matrix material for composites of advenced Al-Mg alloys. The developed new matrix material have higher than 30% porosity, with homogenous porous structure and pore sizes from few nano up to 2–3 mm depending on the alloys containments. Thanks to the used materials and the sintering conditions the authors could decrease the wetting angles less than 90° between the high porosity alumina matrix and the Al-Mg alloys. Applied analytical methods in this research were laser granulometry, scanning electron microscopy, and X-ray diffraction. Digital image analysis was applied to microscopy results, to enhance the results of transformation

  14. Advances in developing TiNi nanoparticles

    International Nuclear Information System (INIS)

    Castro, A. Torres; Cuellar, E. Lopez; Mendez, U. Ortiz; Yacaman, M. Jose

    2006-01-01

    The elaboration of nanoparticles has become a field of great interest for many scientists. Nanoparticles possess different properties than those ones shown in bulk materials. Shape memory alloys have the exceptional ability to recuperate its original shape by simple heating after being 'plastically' deformed. When this process is originated, important changes in properties, as mechanical and electrical, are developed in bulk material. If there is possible to obtain nanoparticles with shape memory effects, these nanoparticles could be used in the elaboration of nanofluids with the ability to change their electrical and thermal conductivity with temperature changes, i.e., smart nanofluids. In this work, some recent results and discussion of TiNi nanoparticles obtained by ion beam milling directly from a TiNi wire with shape memory are presented. The nanoparticles obtained by this process are about 2 nm of diameter with a composition of Ti-41.0 at.% Ni. Synthesized nanoparticles elaborated by this method have an ordered structure

  15. Fabrication of TiNi/CFRP smart composite using cold drawn TiNi wires

    Science.gov (United States)

    Xu, Ya; Otsuka, Kazuhiro; Toyama, Nobuyuki; Yoshida, Hitoshi; Jang, Byung-Koog; Nagai, Hideki; Oishi, Ryutaro; Kishi, Teruo

    2002-07-01

    In recent years, pre-strained TiNi shape memory alloys (SMA) have been used for fabricating smart structure with carbon fibers reinforced plastics (CFRP) in order to suppress microscopic mechanical damages. However, since the cure temperature of CFRP is higher than the reverse transformation temperatures of TiNi SMA, special fixture jigs have to be used for keeping the pre-strain during fabrication, which restricted its practical application. In order to overcome this difficulty, we developed a new method to fabricate SMA/CFRP smart composites without using special fixture jigs by controlling the transformation temperatures of SMA during fabrication. This method consists of using heavily cold-worked wires to increase the reverse transformation temperatures, and of using flash electrical heating of the wires after fabrication in order to decrease the reverse transformation temperatures to a lower temperature range again without damaging the epoxy resin around SMA wires. By choosing proper cold-working rate and composition of TiNi alloys, the reverse transformation temperatures were well controlled, and the TiNi/CFRP hybrid smart composite was fabricated without using special fixture jigs. The damage suppressing effect of cold drawn wires embedded in CFRP was confirmed.

  16. Application of ceramic short fiber reinforced Al alloy matrix composite on piston for internal combustion engines

    Directory of Open Access Journals (Sweden)

    Wu Shenqing

    2010-11-01

    Full Text Available The preparation and properties of ceramic short fiber reinforced Al-Si alloy matrix composite and it’s application on the piston for internal combustion engines are presented. Alumina or aluminosilicate fibers reinforced Al-Si alloy matrix composite has more excellent synthetical properties at elevated temperature than the matrix alloys. A partially reinforced Al-Si alloy matrix composite piston produced by squeeze casting technique has a firm interface between reinforced and unreinforced areas, low reject rate and good technical tolerance. As a new kind of piston material, it has been used for mass production of about 400,000 pieces of automobile engines piston. China has become one of a few countries in which aluminum alloy matrix composite materials have been used in automobile industry and attained industrialization.

  17. Surface of Ti-Ni alloys after their preparation

    International Nuclear Information System (INIS)

    Saldan, I.; Frenzel, J.; Shekhah, O.; Chelmowski, R.; Birkner, A.; Woell, Ch.

    2009-01-01

    The Ti 3.87 Ni 1.73 Fe 0.7 O 0.3, Ti 3.87 Ni 1.73 Fe 0.4 N 0.3 and Ti 3.87 Ni 1.73 Fe 0.4 C 0.3 alloys were investigated regarding their surface characteristics. The scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) was used for phase characterization. The X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical composition of alloy surface. The atomic force microscopy (AFM) to observe alloy surface topography after cutting and electrochemical polishing separately has been done. The transmission electron microscopy (TEM) with X-ray diffraction was carried out to get a high contrast images and the diffraction pattern from alloy surface. The results clearly shown, that all alloys were multiphase, and their surface was totally oxidized with no pure metals

  18. TiNi shape memory alloys: effects of the fabrication route, the oxygen content and the zirconium or hafnium additions on the metallurgical characteristics and the thermomechanical properties

    International Nuclear Information System (INIS)

    Olier, P.

    1996-01-01

    In order to promote the development of Ti-Ni shape memory alloys, we have studied the correlation between the fabrication route, the chemical composition (O 2 content, Zr or Hf additions), the metallurgical characteristics and the thermomechanical properties. A conventional sintering does not allow to obtain a homogeneous compound of pure Ti 50 Ni 50 alloy because of the occurrence of Kirkendall porosities which act as a diffusion barrier. An original process including combustion synthesis and hot-extrusion was successfully developed. Resulting products exhibit a smaller grain size (15-20μm) and an enhanced workability in comparison with products obtained by arc-melting and subsequent hot rolling. The presence of oxygen in equiatomic Ti-Ni alloy induces the oxide precipitation of Ti 4 Ni 2 O x type (with x ≤ 1). The precipitated particle fraction is proportional to the oxygen nominal content of the alloy. We show that the decrease of the transformation temperatures is correlated with the decrease of Ti in solid solution due to Ti 4 Ni 2 O precipitation. Moreover, we find that a fine and homogenous oxide dispersion is suitable to decrease the grain size during hot rolling and to enhance to the one way shape memory properties. An increase of the typical transformation temperatures is obtained through of Zr or Hf (in substitution to Ti). But, an increase of the hardness is measured, and consequently the workability of the ternary alloys becomes reduced. However, it is worthwhile to point out that a Ti 38 Ni 50 Hf 12 product obtained by arc melting and hot extrusion is able to fully recover an apparent plastic strain of more than 4% during tensile tests performed under special loading conditions. Such as behaviour is of great interest with respect to potential applications in a temperature range higher that 100 deg. C. (author)

  19. Matrix Transformation in Boron Containing High-Temperature Co-Re-Cr Alloys

    Science.gov (United States)

    Strunz, Pavel; Mukherji, Debashis; Beran, Přemysl; Gilles, Ralph; Karge, Lukas; Hofmann, Michael; Hoelzel, Markus; Rösler, Joachim; Farkas, Gergely

    2018-03-01

    An addition of boron largely increases the ductility in polycrystalline high-temperature Co-Re alloys. Therefore, the effect of boron on the alloy structural characteristics is of high importance for the stability of the matrix at operational temperatures. Volume fractions of ɛ (hexagonal close-packed—hcp), γ (face-centered cubic—fcc) and σ (Cr2Re3 type) phases were measured at ambient and high temperatures (up to 1500 °C) for a boron-containing Co-17Re-23Cr alloy using neutron diffraction. The matrix phase undergoes an allotropic transformation from ɛ to γ structure at high temperatures, similar to pure cobalt and to the previously investigated, more complex Co-17Re-23Cr-1.2Ta-2.6C alloy. It was determined in this study that the transformation temperature depends on the boron content (0-1000 wt. ppm). Nevertheless, the transformation temperature did not change monotonically with the increase in the boron content but reached a minimum at approximately 200 ppm of boron. A probable reason is the interplay between the amount of boron in the matrix and the amount of σ phase, which binds hcp-stabilizing elements (Cr and Re). Moreover, borides were identified in alloys with high boron content.

  20. Laser Surface Treatment and Modification of Aluminum Alloy Matrix Composites

    Science.gov (United States)

    Abbass, Muna Khethier

    2018-02-01

    The present work aimed to study the laser surface treatment and modification of Al-4.0%Cu-1.0%Mg alloy matrix composite reinforced with 10%SiC particles produced by stir casting. The specimens of the base alloy and composite were irradiated with an Nd:YAG laser of 1000 mJ, 1064 nm and 3 Hz . Dry wear test using the pin-on -disc technique at different sliding times (5-30 min) at a constant applied load and sliding speed were performed before and after laser treatment. Micro hardness and wear resistance were increased for all samples after laser hardening treatment. The improvement of these properties is explained by microstructural homogenization and grain refinement of the laser treated surface. Modification and refinement of SiC particles and grain refinement in the microstructure of the aluminum alloy matrix (α-Al) were observed by optical and SEM micrographs. The highest increase in hardness was 21.4% and 26.2% for the base alloy and composite sample respectively.

  1. Heat treatments and thermomechanical cycling influences on the R-phase in Ti-Ni shape memory alloys

    Directory of Open Access Journals (Sweden)

    Cezar Henrique Gonzalez

    2010-09-01

    Full Text Available This article studies changes observed on the R-phase thermoelastic behavior in a near-equiatomic Ti-Ni shape memory alloy. Three kinds of procedures have been performed: different treatments, thermomechanical cycling under constant loading in shape memory helical springs and thermal cycling in as-treated and trained samples. Several heat treatments were carried out to investigate evolution of the R-phase by differential scanning calorimetry (DSC. A heat treatment was chosen on which R-phase is absent. Shape memory springs were produced and submitted to a training process in an apparatus by tensioning the springs under constant loading. Thermal cycling in DSC was realized in as-treated and trained samples. Several aspects of one-step (B2→B19' and two-steps (B2→R→B19' martensitic transformations and R-phase formation and their evolution during tests were observed and discussed.

  2. TinyDebug

    DEFF Research Database (Denmark)

    Hansen, Morten Tranberg

    2011-01-01

    Debugging embedded wireless systems can be cumbersome due to low visibility. To ease the task of debugging this paper present TinyDebug which is a multi-purpose passive debugging framework for developing embedded wireless sys- tems. TinyDebug is designed to be used throughout the entire system...... logging to extraction and show how the frame- work improves upon existing message based and event log- ging debugging techniques while enabling distributed event processing. We also present a number of optional event anal- ysis tools demonstrating the generality of the TinyDebug debug messages....

  3. METMET fuel with Zirconium matrix alloys

    International Nuclear Information System (INIS)

    Savchenko, A.; Konovalov, I.; Totev, T.

    2008-01-01

    The novel type of WWER-1000 fuel has been designed at A.A. Bochvar Institute. Instead of WWER-1000 UO 2 pelletized fuel rod we apply dispersion type fuel element with uniformly distributed high uranium content granules of U9Mo, U5Nb5Zr, U3Si alloys metallurgically bonded between themselves and to cladding by a specially developed Zr-base matrix alloy. The fuel meat retains a controllable porosity to accommodate fuel swelling. The optimal volume ratios between the components are: 64% fuel, 18% matrix, 18% pores. Properties of novel materials as well as fuel compositions on their base have been investigated. Method of fuel elements fabrication by capillary impregnation has been developed. The primary advantages of novel fuel are high uranium content (more than 15% in comparison with the standard UO 2 pelletized fuel rod), low temperature of fuel ( * d/tU) and serviceability under transient conditions. The use of the novel fuel might lead to natural uranium saving and reduced amounts of spent fuel as well as to optimization of Nuclear Plant operation conditions and improvements of their operation reliability and safety. As a result the economic efficiency shall increase and the cost of electric power shall decrease. (authors)

  4. Fabrication of Ti-Ni-Cu shape memory alloy powders by ball milling method

    International Nuclear Information System (INIS)

    Kang, S.; Nam, T.

    2001-01-01

    Ti-Ni and Ti-Ni-Cu shape memory alloy powders have been fabricated by ball milling method, and then alloying behavior and transformation behavior were investigated by means of optical microscopy, electron microscopy, X-ray diffraction and differential scanning calorimetry. As milled Ti-Ni powders fabricated with milling time less than 20 hrs was a mixture of pure elemental Ti and Ni, and therefore it was unable to obtain alloy powders because the combustion reaction between Ti and Ni occurred during heat treatment. Since those fabricated with milling time more than 20 hrs was a mixture of Ti-rich and Ni-rich Ti-Ni solid solution, however, it was possible to obtain alloy powders without the combustion reaction during heat treatment. Clear exothermic and endothermic peaks appeared in the cooling and heating curves, respectively in DSC curves of 20 hrs and 30 hrs milled Ti-Ni powders. On the other hand, in DSC curves of 1 hr, 10 hrs, 50 hrs and 100 hrs, the thermal peaks were almost discernible. The most optimum ball milling time for fabricating Ti-Ni alloy powders was 30 hrs. Ti-40Ni-10Cu(at%) alloy powders were fabricated successfully by ball milling conditions with rotating speed of 100 rpm and milling time of 30 hrs. (author)

  5. Titanium-nickel shape memory alloys development in Taiwan

    International Nuclear Information System (INIS)

    Wu, S. K.; Lin, H. C.

    1997-01-01

    In Taiwan, many groups engage in the development of TiNi SMAs. The two-stage martensitic transformations of B2 R-phase B19' and B2 B19 B19' have been clarified for both TiNi binary and ternary alloys. The deformation behaviours have been investigated by cold-rolling, hot-rolling and wire drawing. Both shape memory effect and pseudoelasticity can be improved by some thermo-mechanical treatments. The damping characteristics of TiNi and TiNiX SMAs have also been systematically studied. Both B19'/B19 martensite (M) and R-phase (R) have high damping capacities due to stress induced movement of twin boundaries. Meanwhile, the addition of third elements, Fe and Cu, can largely increase the damping capacity. Recently, some high temperature shape memory alloys of TiNiPd and TiNiAu SMAs and thin films of TiNi and TiNiX alloys have also been intensively studied in Taiwan. All these potential investigations on the TiNi SMAs in Taiwan have attracted much attention and their important characteristics will be applied widely in the near future. (author)

  6. The studies of the martensite transformations in a Ti36.5Ni48.5Hf15 alloy

    International Nuclear Information System (INIS)

    Han, S.; Jin, S.; Chinese Academy of Sciences, Beijing; Zou, W.; Zhang, Z.; Yang, D.

    1995-01-01

    In recent years, high temperature shape memory alloy (SMA) has attracted much interest by many groups of researchers. Many kinds of alloys, such as TiNiPd and NiAL alloys were reported to have shape memory effect in high temperatures. But for different kinds of reasons, these alloys were not put to practical use. TiNi alloys have been considered the best shape memory materials until now. Adding a third element whose characteristics are similar to Ti or Ni in TiNi binary alloys can produce a new style SMA, which has been done in many cases. In most circumstances, Ni was substituted and only a few investigations on the TiNi alloys was Ti replaced. But in recent years, many investigators have given more attention to this subject. In 1976, Eckelmeyer showed that Zr was one of the element that can raise the phase transformation temperatures of TiNi alloys. In 1990, Krupp obtained a patent on TiNiZr SMA with high transformation temperatures for TiNi alloys. J.H. Mulder also published his work on TiNiZr alloys in 1992. In their previous work, a new type of high temperature SMA Ti 36.5 Ni 48.5 Hf 15 alloy were investigated in more detail by DSC measurement, TEM and high-resolution observations

  7. Effect of electrothermal annealing on the transformation behavior of TiNi shape memory alloy and two-way shape memory spring actuated by direct electrical current

    International Nuclear Information System (INIS)

    Wang, Z.G.; Zu, X.T.; Feng, X.D.; Zhu, S.; Deng, J.; Wang, L.M.

    2004-01-01

    In this work, the effect of electrothermal annealing on the transformation characterization of TiNi shape memory alloy and the electrothermal actuating characteristics of a two-way shape memory effect (TWSME) extension spring were investigated with direct electrical current. The results showed that with increasing direct electrical current density, the B2→R-phase transformation shifts to a lower temperature and R-phase→B19' shifts to a higher temperature in the cooling process. When annealing electrical current density reached 12.2 A/mm 2 , the R-phase disappeared and austenite transformed into martensite directly. The electrothermal annealing was an effective method of heat treatment in a selected part of shape memory alloy device. The electrothermal actuating characteristics of a TWSME spring showed that the time response and the maximum elongation greatly depended on the magnitude of the electrical current

  8. Production of NbC reinforced aluminum matrix composites by mechanical alloying

    International Nuclear Information System (INIS)

    Silva, Marina Judice; Cardoso, Katia Regina; Travessa, Dilermando Nagle

    2014-01-01

    Aluminum and their alloys are key materials for the automotive and aerospace industries. The dispersion of hard ceramic particles in the Al soft matrix produces lightweight composites with interesting properties, as environmental resistance, high specific strength and stiffness, high thermal and electrical conductivity, and good wear resistance, encouraging their technological use. Powder metallurgy techniques like mechanical alloying (MA) are very attractive to design metal matrix composites, as they are able to achieve a homogeneous distribution of well dispersed particles inside the metal matrix. In this work, pure aluminum has been reinforced with particles of Niobium carbide (NbC), an extremely hard and stable refractory ceramic. NbC is frequently used as a grain growth inhibitor in micro-alloyed steel due to their low solubility in austenite. In the present work, NbC is expected to act as a reinforcing phase by its fine dispersion into the aluminum matrix, produced by MA. Composite powders produced after different milling times (up to 50h), with 10 and 20% (volume) of NbC were characterized by diffraction laser particle size analysis, scanning electron microscopy (SEM) and by X-ray diffraction (DRX), in order to establish a relationship between the milling time and the characteristics of the powder produced, as size and morphology, crystallite size and reinforcement distribution. This characterization is important in defining the MA process for production of composites for further consolidation by hot extrusion process. (author)

  9. Production of NbC reinforced aluminum matrix composites by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marina Judice; Cardoso, Katia Regina; Travessa, Dilermando Nagle, E-mail: dilermando.travessa@unifesp.br [Universidade Federal de Sao Paulo (UNIFESP), Sao Jose dos Campos, SP (Brazil). Instituto de Ciencia e Tecnologia

    2014-07-01

    Aluminum and their alloys are key materials for the automotive and aerospace industries. The dispersion of hard ceramic particles in the Al soft matrix produces lightweight composites with interesting properties, as environmental resistance, high specific strength and stiffness, high thermal and electrical conductivity, and good wear resistance, encouraging their technological use. Powder metallurgy techniques like mechanical alloying (MA) are very attractive to design metal matrix composites, as they are able to achieve a homogeneous distribution of well dispersed particles inside the metal matrix. In this work, pure aluminum has been reinforced with particles of Niobium carbide (NbC), an extremely hard and stable refractory ceramic. NbC is frequently used as a grain growth inhibitor in micro-alloyed steel due to their low solubility in austenite. In the present work, NbC is expected to act as a reinforcing phase by its fine dispersion into the aluminum matrix, produced by MA. Composite powders produced after different milling times (up to 50h), with 10 and 20% (volume) of NbC were characterized by diffraction laser particle size analysis, scanning electron microscopy (SEM) and by X-ray diffraction (DRX), in order to establish a relationship between the milling time and the characteristics of the powder produced, as size and morphology, crystallite size and reinforcement distribution. This characterization is important in defining the MA process for production of composites for further consolidation by hot extrusion process. (author)

  10. Rubber bulge forming of single-stage bellows of TiNi shape memory alloy using the displacement control method

    International Nuclear Information System (INIS)

    Senba, Hiromasa; Yamaji, Toru; Okita, Keisuke; Okabe, Nagatoshi; Yamauchi, Kiyoshi; Matsumoto, Kenya

    2005-01-01

    This paper deals with the bulge process for forming the single-stage bellows of TiNi shape memory alloys, which is proposed as a new type of seismic applications, and especially considering the material's special behavior. Thin walled tubes with 20% cold work, whose composition is Ti-51.0 at% Ni, were prepared. First they are appropriately heat-treated and then the rubber bulge process is introduced for the tubes under the condition of austenite phase at room temperature. Displacement control method is adapted to the process. Theoretical prediction of change in outer diameter of the tube on compression is derived, and modified taking into account the progress of the stress-induced martensite transformation on tube's surface by observing the detachment of the oxide layer of the surface. Finally theoretical relationship between compressive displacement and the outer diameter of the tube, which is the most important for the design of the bellows shape, is cleared. (author)

  11. Nanosized-Particle Dispersion-Strengthened Al Matrix Composites Fabricated by the Double Mechanical Alloying Process.

    Science.gov (United States)

    Kim, Chungseok

    2018-03-01

    The objective of this study was to fabricate an Al metal matrix composite strengthened by nanosized Al3Ti particles via double mechanical alloying process. Several Al-xTi alloys were fabricated, including Al-12%Ti, Al-15%Ti, and Al-12%Ti-1%Y2O3. The lattice parameter of as-milled state was calculated to be 4.0485 Å; after a milling time of 540 min, it was 4.0401 Å. This decrease was induced by Ti solutionizing into the Al matrix. The equivalent size of a coarse Al3Ti particle was 200-500 nm after the heat treatment; however, the particles were uniformly distributed and were refined through the MA2 process. The particle size of a Al3Ti phase was 30 nm or less, and the particles were uniformly distributed. These particles remained in a fine state in the matrix without growth and coarsening, even after the hot extrusion process. The microstructure of hot extruded alloys consisted of a uniform distribution of Al3Ti particles and other dispersoids in the Al matrix.

  12. Matrix composition effects on the tensile properties of tungsten-molybdenum heavy alloys

    International Nuclear Information System (INIS)

    Bose, A.; German, R.N.

    1990-01-01

    Tungsten-base heavy alloys are liquid-phase sintered from mixed tungsten, nickel, and iron powders. The sintered product is a composite consisting of interlaced tungsten and solidified matrix (W-Ni-Fe) phases. These alloys are most useful in applications requiring high density, strength, and toughness. The design of improved tungsten heavy alloys has been the subject of several research investigations. Much success has taken place through improved processing, but parallel compositional studies have resulted in new microstructure-property combinations. As part of these investigations, the Ni/Fe ratio has been varied, with the general conclusion that optimal strength and ductility occur with a ratio between 2 and 4. Brittle intermetallic phases can form outside of this composition range. Historically, a 7/3 Ni/Fe ratio has been selected for processing studies. Recently, others reported higher ductilities and impact energies for 90 and 93 pct W heavy alloys with the 8/2 Ni/Fe ratio. Alternatively, these alloys can be strengthened by both solid solution and grain size refinement through incorporation of molybdenum, tantalum, or rhenium. These additions are soluble in both the tungsten and matrix phases and retard solution-reprecipitation during liquid phase sintering. In this study, the alloy composition was varied in the nickel/iron ratio and molybdenum was partially substituted for tungsten. The sintered tensile properties are assessed vs these compositional variations

  13. Computational design of precipitation-strengthened titanium-nickel-based shape memory alloys

    Science.gov (United States)

    Bender, Matthew D.

    Motivated by performance requirements of future medical stent applications, experimental research addresses the design of novel TiNi-based, superelastic shape-memory alloys employing nanoscale precipitation strengthening to minimize accommodation slip for cyclic stability and to increase output stress capability for smaller devices. Using a thermodynamic database describing the B2 and L21 phases in the Al-Ni-Ti-Zr system, Thermo-Calc software was used to assist modeling the evolution of phase composition during 600°C isothermal evolution of coherent L21 Heusler phase precipitation from supersaturated TiNi-based B2 phase matrix in an alloy experimentally characterized by atomic-scale Local Electrode Atom Probe (LEAP) microanalysis. Based on measured evolution of the alloy hardness (under conditions stable against martensitic transformation) a model for the combined effects of solid solution strengthening and precipitation strengthening was calibrated, and the optimum particle size for efficient strengthening was identified. Thermodynamic modeling of the evolution of measured phase fractions and compositions identified the interfacial capillary energy enabling thermodynamic design of alloy microstructure with the optimal strengthening particle size. Extension of alloy designs to incorporate Pt and Pd for reducing Ni content, enhancing radiopacity, and improving manufacturability were considered using measured Pt and Pd B2/L2 1 partitioning coefficients. After determining that Pt partitioning greatly increases interphase misfit, full attention was devoted to Pd alloy designs. A quantitative approach to radiopacity was employed using mass attenuation as a metric. Radiopacity improvements were also qualitatively observed using x-ray fluoroscopy. Transformation temperatures were experimentally measured as a function of Al and Pd content. Redlich-Kister polynomial modeling was utilized for the dependence of transformation reversion Af temperature on B2 matrix phase

  14. Shape memory characteristics of sputter-deposited Ti-Ni thin films

    International Nuclear Information System (INIS)

    Miyazaki, Shuichi; Ishida, Akira.

    1994-01-01

    Ti-Ni shape memory alloy thin films were deposited using an RF magnetron sputtering apparatus. The as-sputtered films were heat-treated in order to crystallize and memorize. After the heat treatment, the shape memory characteristics have been investigated using DSC and thermomechanical tests. Upon cooling the thin films, the solution-treated films showed a single peak in the DSC curve indicating a single stage transformation occurring from B2 to the martensitic phase, while the age-treated films showed double peaks indicating a two-stage transformation, i.e., from B2 to the R-phase, then to the martensitic phase. A perfect shape memory effect was achieved in these sputter-deposited Ti-Ni thin films in association both with the R-phase and martensitic transformations. Transformation temperatures increased linearly with increasing applied stress. The transformation strain also increased with increasing stress. The shape memory characteristics were strongly affected by heat-treatment conditions. (author)

  15. High temperature annealing effect on structural and magnetic properties of Ti/Ni multilayers

    International Nuclear Information System (INIS)

    Bhatt, Pramod; Ganeshan, V.; Reddy, V.R.; Chaudhari, S.M.

    2006-01-01

    High temperature annealing effect on structural and magnetic properties of Ti/Ni multilayer (ML) up to 600 deg. C have been studied and reported in this paper. Ti/Ni multilayer samples having constant layer thicknesses of 50 A each are deposited on float glass and Si(1 1 1) substrates using electron-beam evaporation technique under ultra-high vacuum (UHV) conditions at room temperatures. The micro-structural parameters and their evolution with temperature for as-deposited as well as annealed multilayer samples up to 600 deg. C in a step of 100 deg. C for 1 h are determined by using X-ray diffraction (XRD) and grazing incidence X-ray reflectivity techniques. The X-ray diffraction pattern recorded at 300 deg. C annealed multilayer sample shows interesting structural transformation (from crystalline to amorphous) because of the solid-state reaction (SSR) and subsequent re-crystallization at higher temperatures of annealing, particularly at ≥400 deg. C due to the formation of TiNi 3 and Ti 2 Ni alloy phases. Sample quality and surface morphology are examined by using atomic force microscopy (AFM) technique for both as-deposited as well as annealed multilayer samples. In addition to this, a temperature dependent dc resistivity measurement is also used to study the structural transformation and subsequent alloy phase formation due to annealing treatment. The corresponding magnetization behavior of multilayer samples after each stage of annealing has been investigated by using Magneto-Optical Kerr Effect (MOKE) technique and results are interpreted in terms of observed micro-structural changes

  16. Effects of ultraviolet irradiation on bonding strength between Co-Cr alloy and citric acid-crosslinked gelatin matrix.

    Science.gov (United States)

    Inoue, Motoki; Sasaki, Makoto; Katada, Yasuyuki; Taguchi, Tetsushi

    2014-02-01

    Novel techniques for creating a strong bond between polymeric matrices and biometals are required. We immobilized polymeric matrices on the surface of biometal for drug-eluting stents through covalent bond. We performed to improve the bonding strength between a cobalt-chromium alloy and a citric acid-crosslinked gelatin matrix by ultraviolet irradiation on the surface of cobalt-chromium alloy. The ultraviolet irradiation effectively generated hydroxyl groups on the surface of the alloy. The bonding strength between the gelatin matrix and the alloy before ultraviolet irradiation was 0.38 ± 0.02 MPa, whereas it increased to 0.48 ± 0.02 MPa after ultraviolet irradiation. Surface analysis showed that the citric acid derivatives occurred on the surface of the cobalt-chromium alloy through ester bond. Therefore, ester bond formation between the citric acid derivatives active esters and the hydroxyl groups on the cobalt-chromium alloy contributed to the enhanced bonding strength. Ultraviolet irradiation and subsequent immobilization of a gelatin matrix using citric acid derivatives is thus an effective way to functionalize biometal surfaces.

  17. TinyOS Alliance Structure

    DEFF Research Database (Denmark)

    Bonnet, Philippe; Culler, David; Estrin, Deborah

    2006-01-01

    This memo describes the goals and organization structure of the TinyOS Alliance. It covers membership, the working group forums for contribution, intellectual property, source licensing, and the TinyOS Steering Committee (TSC)....

  18. Characterization of Al-Cu alloy reinforced fly ash metal matrix ...

    African Journals Online (AJOL)

    user

    Graphite crucible was used for melting of matrix alloy, and the addition and mixing of particulates were made into ... specimen was cut as per ASTM-E23 by diamond blade using CNC machine. ... there will be no change in the size of the flyash.

  19. Adhesive bonding of super-elastic titanium-nickel alloy castings with a phosphate metal conditioner and an acrylic adhesive.

    Science.gov (United States)

    Matsumura, H; Tanoue, N; Yanagida, H; Atsuta, M; Koike, M; Yoneyama, T

    2003-06-01

    The purpose of the current study was to evaluate the bonding characteristics of super-elastic titanium-nickel (Ti-Ni) alloy castings. Disk specimens were cast from a Ti-Ni alloy (Ti-50.85Ni mol%) using an arc centrifugal casting machine. High-purity titanium and nickel specimens were also prepared as experimental references. The specimens were air-abraded with alumina, and bonded with an adhesive resin (Super-Bond C & B). A metal conditioner containing a phosphate monomer (Cesead II Opaque Primer) was also used for priming the specimens. Post-thermocycling average bond strengths (MPa) of the primed groups were 41.5 for Ti-Ni, 30.4 for Ti and 19.5 for Ni, whereas those of the unprimed groups were 21.6 for Ti, 19.3 for Ti-Ni and 9.3 for Ni. Application of the phosphate conditioner elevated the bond strengths of all alloy/metals (P elastic Ti-Ni alloy castings can be achieved with a combination of a phosphate metal conditioner and a tri-n-butylborane-initiated adhesive resin.

  20. In situ crystallization of sputter-deposited TiNi by ion irradiation

    International Nuclear Information System (INIS)

    Ikenaga, Noriaki; Kishi, Yoichi; Yajima, Zenjiro; Sakudo, Noriyuki

    2013-01-01

    Highlights: ► We developed a sputtering deposition process equipped with an ion irradiation system. ► Ion irradiation enables crystallization at lower substrate temperature. ► Ion fluence has an effective range for low-temperature crystallization. ► Crystallized films made on polyimide by the process show the shape memory effect. -- Abstract: TiNi is well known as a typical shape-memory alloy, and the shape-memory property appears only when the structure is crystalline. Until recently, the material has been formed as amorphous film by single-target sputtering deposition at first and then crystallized by being annealed at high temperature over 500 °C. Therefore, it has been difficult to make crystalline TiNi film directly on a substrate of polymer-based material because of the low heat resistance of substrate. In order to realize an actuator from the crystallized TiNi film on polymer substrates, the substrate temperature should be kept below 200 °C throughout the whole process. In our previous studies we have found that deposited film can be crystallized at very low temperature without annealing but with simultaneous irradiation of Ar ions during sputter-deposition. And we have also demonstrated the shape-memory effect with the TiNi film made by the new process. In order to investigate what parameters of the process contribute to the low-temperature crystallization, we have focused to the ion fluence of the ion irradiation. Resultantly, it was found that the transition from amorphous structure to crystal one has a threshold range of ion fluence

  1. Effect of cold rolling on fatigue crack propagation of TiNi/A16061 shape memory composite

    International Nuclear Information System (INIS)

    Lee, Jin Kyung; Lee, Sang Pill; Park, Young Chul; Lee, Kyu Chang; Cho, Youn Ho; Lee, Joon Hyun

    2005-01-01

    TiNi alloy fiber was used to recover the original shape of materials using its shape memory effect. The shape memory alloy plays an important role within the metal matrix composite. The shape memory alloy can control the crack propagation in metal matrix composite, and improve the tensile strength of the composite. In this study, TiNi/A16061 Shape Memory Alloy(SMA) composite was fabricated by hot press method, and pressed by a roller for its strength improvement. The four kinds of specimens were fabricated with 0%, 3.2%, 5.2% and 7% volume fraction of TiNi alloy fiber, respectively. A fatigue test has performed to evaluate the crack initiation and propagation for the TiNi/A16061 SMA composite fabricated by this method. In order to study the shape memory effect of the TiNi alloy fiber, the test has also done under both conditions of the room temperature and high temperature. The relationship between the crack growth rate and the stress intensity factor was clarified for the composite, and the cold rolling effect was also studied

  2. Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate

    Directory of Open Access Journals (Sweden)

    B. Bobic

    2010-03-01

    Full Text Available The corrosion behaviour of MMCs with aluminium alloy matrix was presented. The corrosion characteristics of boron-, graphite-, silicon carbide-, alumina- and mica- reinforced aluminium MMCs were reviewed. The reinforcing phase influence on MMCs corrosion rate as well as on various corrosion forms (galvanic, pitting, stress corrosion cracking, corrosion fatique, tribocorrosion was discussed. Some corrosion protection methods of aluminium based MMCs were described

  3. Applications and development of shape-memory and superelastic alloys in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Takaoka, S.; Horikawa, H. [Furukawa Electric Co., Ltd., Hiratsuka (Japan); Kobayashi, J. [Japan Association of Shape Memory Alloys, Yokohama (Japan); Shimizu, K. [Kanazawa Inst. of Tech., Matsutou (Japan)

    2002-07-01

    The present situation of the applications and development of shape memory and superelastic alloys in Japan will collectively be introduced. Of many shape memory alloys, TiNi alloy systems have mostly been used for the applications from the point of view of fatigue and corrosion characteristics. Shape memory effect has been utilized for mainly thermal actuators with the form of coil springs. The effect associated with the B2 to R-phase transformation and its reversion exhibits recoverable strain of approximately 1%, and after a million thermal cycles the recovery characteristics are not affected. Thus, the effect is widely utilized as sensor flap of the air conditioner, water flow control valve, underfloor vent, automatic oil volume adjusting equipment for Shinkansen and water mixing valve. Another effect associated with the B2 to orthorhombic transformation and its reversion, as in TiNiCu alloys containing Cu more than 8%, can be applied to actuators required for 10,000 to 50,000 times life, and thus it is utilized as rice cooker, coffee maker and anti-scald valve. In Japan, however, the TiNi shape memory alloy systems are mainly used for applications using the superelasticity, like a rubber material. The superelasticity associated with the B2 to monoclinic stress-induced transformation and its reversion upon un-loading has been utilized as brassiere wire, eye glasses flame, antenna core wire for cellular phone and fishing wire, and that associated with the B2 to orthorhombic stress-induced transformation and its reversion upon un-loading has been as orthodontic wire, because the TiNiCu alloy wire exhibits smaller stress hysteresis than that of usual TiNi alloy wire. The TiNi shape memory alloy systems are now developed to make various shapes, such as tapes, foils and tubes, and the alloys with those shapes are examined to apply to medical uses, such as guide wire for catheter and catheter tube itself, and to any other uses. The development in Japan is rapidly

  4. Aluminium EN AW-2124 alloy matrix composites reinforced with Ti(C,N), BN and Al2O3 particles

    International Nuclear Information System (INIS)

    Dobrzanski, L.A.; Wlodarczyk, A.; Adamiak, M.

    2003-01-01

    Investigation results of the aluminium alloy EN AW-2124 matrix composite materials with particles of the powders Ti(C,N), BN and Al 2 O 3 (15 wt.%) are presented in the paper. In order to obtain uniform distribution of reinforcement particles in aluminium alloy matrix powders of composite components have been milled in the rotary ball-bearing pulverizer. The composites have been pressed in laboratory vertical press at room temperature under the pressure of 500 kN. Obtained die samplings have been heated to the temperature 520-550 o C and extruded. Bars of diameter 8 mm have been received as a final product. Metallographic examination of the composites materials' structure shows non-uniform distribution of reinforced powders in the aluminium alloy matrix banding of reinforcements particles corresponds to the extrusion direction. Particles of reinforcement distribution in aluminium alloy matrix is irregular, some agglomerations of powder of aluminium oxide and porosity of different size have been noticed. Investigations of hardness and ultimate compressive strength show that the particles of reinforcement improve mechanical properties of composite materials. Investigations of compressive strength, carried out at room temperature, enable to compare mechanical properties of matrix and composite. (author)

  5. Development and selection of a matrix alloy for 85Kr encapsulation

    International Nuclear Information System (INIS)

    Knoll, R.W.; McClanahan, E.D.; Tingey, G.L.; McDonald, E.L.

    1986-07-01

    Pacific Northwest Laboratory has developed and demonstrated a pilot-scale process for stable, long-term storage of radioactive 85 Kr gas from spent nuclear fuel. The process entraps the Kr into a solid metal matrix that can be safely stored at ambient pressure. For this matrix numerous alloys were first screened; those that best satisfied the selection criteria were Cu-Y, Ni-Y, and Ni-La. Of these, Cu-Y alloys containing approximately 20 at.% Y were recommended for use in the pilot-scale system. Reasons for this decision, based on the development work described in Section 5, are summarized here. Thick Cu-Y-Kr deposits (greater than or equal to1 mm) exhibit much better thermal and mechanical stability than do those of Ni-La-Kr and are at least as stable as Ni-Y-Kr deposits. Cu-Y-Kr coatings are very compatible with the sputtering process. They adhere well to the substrate, do not spall significantly during deposition, and can be deposited at higher rates than the Ni-base alloys. This faster deposition helps compensate, in terms of process efficiency, for the lower Kr capacity of Cu-Y-Kr alloys. Another advantage of Cu-Y over Ni-base alloys is the higher vapor pressure of Cu compared to Ni. This reduces the unwanted buildup of Cu on the hot anode surface, whereas deposition of Ni is a problem with Ni-Y, for example. Cu-Y-Kr deposits containing 17 to 20 at. % Y and 6 to 8 at. % Kr compared favorably to Ni 80 La 10 Kr 10 in terms of long-term Kr retention characteristics. The measurements of Cu-Y-Kr by differential scanning calorimetry also indicated stable retention of Kr because rapid release did not occur below approx.650 0 C. Finally, Cu-Y alloys are satisfactory in terms of materials costs and producibility of the sputtering target. 13 refs., 9 figs., 4 tabs

  6. Research on development and application of titanium and zirconium alloys

    International Nuclear Information System (INIS)

    Suzuki, Toshiyuki; Sasano, Hisaoki; Uehara, Shigeaki; Nakano, Osamu; Shibata, Michio

    1983-01-01

    It can be said that titanium and zirconium are new metals from the viewpoint of the history of metals, but both have grown to the materials supporting modern industries, titanium alloys in aerospace and ocean development, and zirconium alloys in nuclear power application. However, the properties of both alloys have not yet been clarified. In this study, the synthesis of TiNi and its properties, precipitation hardening type titanium alloys, and the effect of oxygen on the mechanical properties of both alloys were examined. TiNi is the typical intermetallic compound which shows the peculiar properties. The method of its synthesis by diffusion was examined, and it was clarified that it is useful as a structural material and also as a functional material. Precipitation hardening type alloys have not been developed in titanium alloys, but in this study, the feasibility of several alloy systems was found. Both titanium and zirconium have large affinity to oxygen, and the oxygen absorbed in the manufacturing process cannot be reduced. The tensile property of both alloys was examined in wide temperature range, and the effect of oxygen was clarified. (Kako, I.)

  7. Microstructure and functional properties of the TiNi- and CuAl-based SMA thin films and coats produced by PVD technique

    International Nuclear Information System (INIS)

    Kolomytsev, V.; Musienko, R.; Nevdacha, V.; Panarin, V.; Pasko, A.; Cesari, E.; Segui, C.; Humbeeck, J. van

    2000-01-01

    The TiNi- and CuAl-based shape memory alloy thin films and wear/corrosion resistant surface coats have been produced by the ion-plasma deposition method with an arc dispersion of the cathode/target. This technique was widely used for production of the coats from a sprayed pure metal or a single-phase alloy. We have offered to use this process for dispersion of the heterophase alloys like shape memory alloys. The arguments for choosing of this technique are discussed with respect to creation of the conditions for preservation not only chemical composition, but also phase structure of an alloy in a covering, thus the shape memory/superelastic effects to be kept in a coat. (orig.)

  8. Martensitic transformation and shape memory effect in polycomponent TiNi-based alloys

    International Nuclear Information System (INIS)

    Khachin, V.N.; Voronin, V.P.; Sivokha, V.P.; Pushin, V.G.

    1995-01-01

    The results of martesitic transformation (MT) and shape memory effect (SME) in quaternary Ti 50 (NiCoCu) 50 , Ti 50 (NiFeCu) 50 and (TiAl) 50 (NiCu) 50 alloys studies are generalized in this paper. On alloying TiNi simultaneously by two elements, their individual effect on MT and SME is conserved. Martensitic transformations B2→R and B2→B19' are almost simultaneously realizing in a binary TiNi. One can selectively control each of two MT channels by selecting property of alloying elements. As a result, the alloys having any sequences of MT and their realizations temperatures, including simultaneous realization of two MTs at low temperatures, which was not observed earlier, can be produced. (orig.)

  9. Thermal expansion properties of Bi-2212 in Ag or an Ag-alloy matrix

    International Nuclear Information System (INIS)

    Tenbrink, J.; Krauth, H.

    1994-01-01

    The thermal expansion properties of polycrystalline Bi 2 Sr 2 Ca 1 Cu 2 O 8+x melt-processed bulk specimens, and Bi 2 Sr 2 Ca 1 Cu 2 O 8+x monocore as well as multifilamentary round wires in Ag or Ag-alloy matrix have been investigated over the temperature range from -150 to 800 degrees C. Although the thermal expansion of Bi 2 Sr 2 Ca 1 Cu 2 O 8+x is distinctly lower compared with Ag, the thermal expansion properties of the Bi 2 Sr 2 Ca 1 Cu 2 O 8+x -Ag or AgNiMg-alloy composite conductors are essentially governed by the matrix material. The thermal expansion of the encountered oxide-dispersion-strengthened AgNiMg alloys is only slightly lower compared with that of pure Ag. Therefore the thermal expansion of all investigated Bi 2 Sr 2 Ca 1 Cu 2 O 8+x -Ag or Ag-alloy composite wires was found to be close to that of pure Ag. The reason for this striking behaviour is shown to be related to a surprisingly low elastic modulus of the polycrystalline Bi-2212 wire cores of the order of 10 to a maximum 40 GPa. (author)

  10. Fabrication and AE characteristics of TiNi/A16061 shape memory alloy composite

    International Nuclear Information System (INIS)

    Park, Young Chul; Lee, Jin Kyung

    2004-01-01

    TiNi/A16061 Shape Memory Alloy (SMA) composite was fabricated by hot press method to investigate the microstructure and mechanical properties. Interface bonding between TiNi reinforcement and A1 matrix was observed by using SEM and EDS. Pre-strain was imposed to generate compressive residual stress inside composite. A tensile test for specimen, which underwent pre-strain, was performed at high temperature to evaluate the variation of strength and the effect of pre-strain. It was shown that interfacial reactions occurred at the bonding between matrix and fiber, creating two inter-metallic layers. And yield stress increased with the amount of pre-strain. Acoustic emission technique was also used to nondestructively clarify the microscopic damage behavior at high temperature and the effect of pre-strain of TiNi/A16061 SMA composite

  11. Explosive device of conduit using Ti Ni alloy

    Directory of Open Access Journals (Sweden)

    A. Yu. Kolobov

    2014-01-01

    Full Text Available Presently, materials have been developed which are capable at changing temperate to return significant inelastic deformations, exhibit rubber-like elasticity, convert heat into mechanical work, etc. The aggregate of these effects is usually called the shape memory effect.At present a great number of compounds and alloys with a shape memory effect has been known.These are alloys based on titanium nickelide (TiNi, copper-based alloys (Cu-Al, Cu-Sn, Cu-Al-Ni, Cu-Zn-Si, etc., gold and silver (Ag-Cd, Au-Ag-Cd, Au-Cd-Cu, Au-Zn-Cu, etc., manganese (Mn-Cr, Fe-Cu, Mn-Cu-Ni, Mn-Cu-Zr, Mn-Ni, etc., iron (Fe-Mn, Fe-Ni, Fe-Al, etc., and other compounds.The alloys based on titanium nickelide (nitinol are the most widely used.Alloys with shape memory effect find various applications in engineering and medicine, namely connecting devices, actuators, transformable design, multipurpose medical implants, etc.There is a task of breaking fuel conduit during separating the spacecraft from the rocket in space technology.The paper examines the procedure for design calculation of the separating device of conduit with the use of Ti-Ni alloy. This device can be used instead of the pyro-knives.The device contains two semi-rings from Ti-Ni alloy. In the place of break on the conduit an annular radius groove is made.At a temperature of martensite passage the semi-rings undergo deformation and in the strained state are set in the device. With heating to the temperature of the austenitic passage of bushing macro-deformation the energy stored by the nitinol bushing is great enough to break the conduit on the neck.The procedures of design calculation and response time of device are given.

  12. Cytocompatibility evaluation and surface characterization of TiNi deformed by high-pressure torsion

    Energy Technology Data Exchange (ETDEWEB)

    Awang Shri, Dayangku Noorfazidah, E-mail: AWANGSHRI.Dayangku@nims.go.jp [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Structural Materials Unit, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan); Tsuchiya, Koichi [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Structural Materials Unit, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan); Yamamoto, Akiko [Biomaterials Unit, International Center for Material Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan)

    2014-10-01

    Effect of high-pressure torsion (HPT) deformation on biocompatibility and surface chemistry of TiNi was systematically investigated. Ti–50 mol% Ni was subjected to HPT straining for different numbers of turns, N = 0.25, 0.5, 1, 5 and 10 at a rotation speed of 1 rpm. X-ray photoelectron spectroscopy observations after 7 days of cell culture revealed the changes in the surface oxide composition, enrichment of Ti and detection of nitrogen derived from organic molecules in the culture medium. Plating efficiency of L929 cells was slightly increased by HPT deformation though no significant difference was observed. Albumin adsorption was higher in HPT-deformed samples, while vitronectin adsorption was peaked at N = 1. HPT deformation was also found to effectively suppress the Ni ion release from the TiNi samples into the cell culture medium even after the low degree of deformation at N = 0.25. - Highlights: • Nanostructured Ti–50 mol%Ni alloy was produced using high-pressure torsion. • HPT deformation improved L929 growth on TiNi samples. • Changes in surface chemistry were observed in HPT deformed samples. • Protein adsorption behavior was influenced by the surface chemistry. • Ni ion release was suppressed in HPT deformed samples.

  13. Study on microstructure and properties of extruded Mg-2Nd-0.2Zn alloy as potential biodegradable implant material.

    Science.gov (United States)

    Li, Junlei; Tan, Lili; Wan, Peng; Yu, Xiaoming; Yang, Ke

    2015-04-01

    Mg-2Nd-0.2Zn (NZ20) alloy was prepared for the application as biodegradable implant material in this study. The effects of the extrusion process on microstructure, mechanical and corrosion properties of the alloy were investigated. The as-cast alloy was composed of α-Mg matrix and Mg12Nd eutectic compound. The solution treatment could lead to the Mg12Nd phase dissolution and the grain coarsening. The alloy (E1) preheated at 380°C for 1h and extruded at 390°C presents fine grains with amounts of tiny Mg12Nd particles uniformly dispersed throughout the boundaries and the interior of the grains. The alloy (E2) preheated at 480°C for 1h and extruded at 500°C exhibits relatively larger grains with few nano-scale Mg12Nd phase particles dispersed. The alloy of E1, compared with E2, showed relatively lower corrosion rate, higher yield strength and slightly lower elongation. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Calculations of the properties of superconducting alloys via the average T-matrix approximation

    International Nuclear Information System (INIS)

    Chatterjee, P.

    1980-01-01

    The theoretical formula of McMillan, modified via the multiple-scattering theory by Gomersall and Gyorffy, has been very successful in computing the electron-phonon coupling constant (lambda) and the transition temperature (Tsub(c)) of many superconducting elements and compounds. For disordered solids, such as substitutional alloys, however, this theory fails because of the breakdown of the translational symmetry used in the multiple-scattering theory. Under these conditions the problem can still be solved if the t-matrix is averaged in the random phase approximation (average T-matrix approximation). Gomersall and Gyorffy's expression is reformulated for lambda in the random phase approximation. This theory is applied to calculate lambda and Tsub(c) of the binary substitutional NbMo alloy system at different concentrations. The results appear to be in fair agreement with experiments. (author)

  15. Crystallization and Martensitic Transformation Behavior of Ti-Ni-Si Alloy Ribbons Prepared via Melt Spinning.

    Science.gov (United States)

    Park, Ju-Wan; Kim, Yeon-Wook; Nam, Tae-Hyun

    2018-09-01

    Ti-(50-x)Ni-xSi (at%) (x = 0.5, 1.0, 3.0, 5.0) alloy ribbons were prepared via melt spinning and their crystallization procedure and transformation behavior were investigated using differential scanning calorimtry, X-ray diffraction, and transmission electron microscopy. Ti-Ni-Si alloy ribbons with Si content less than 1.0 at% were crystalline, whereas those with Si content more than 3.0 at% were amorphous. Crystallization occurred in the sequence of amorphous →B2 → B2 → Ti5Si4 + TiNi3 → B2 + Ti5Si4 + TiNi3 + TiSi in the Ti-47.0Ni-3.0Si alloy and amorphous →R → R + Ti5Si4 + TiNi3 → R + Ti5Si4 + TiNi3 + TiSi in the Ti-45.0Ni-5.0Si alloy. The activation energy for crystallization was 189 ±8.6 kJ/mol for the Ti-47Ni-3Si alloy and 212±8.6 kJ/mol for the Ti-45Ni-5Si alloy. One-stage B2-R transformation behavior was observed in Ti-49.5Ni-0.5Si, Ti-49.0Ni-1.0Si, and Ti-47.0Ni- 3.0Si alloy ribbons after heating to various temperatures in the range of 873 K to 1073 K. In the Ti-45.0Ni-5.0Si alloy, one-stage B2-R transformation occurred after heating to 893 K, two-stage B2-R-B19' occurred after heating to 973 K, and two-stage B2-R-B19' occurred on cooling and one-stage B19'-B2 occurred on heating, after heating to 1073 K.

  16. Nuclear reactor fuel structure containing uranium alloy wires embedded in a metallic matrix plate

    Science.gov (United States)

    Travelli, Armando

    1988-01-01

    A flat or curved plate structure, to be used as fuel in a nuclear reactor, comprises elongated fissionable wires or strips embedded in a metallic continuous non-fissionable matrix plate. The wires or strips are made predominantly of a malleable uranium alloy, such as uranium silicide, uranium gallide or uranium germanide. The matrix plate is made predominantly of aluminum or an aluminum alloy. The wires or strips are located in a single row at the midsurface of the plate, parallel with one another and with the length dimension of the plate. The wires or strips are separated from each other, and from the surface of the plate, by sufficient thicknesses of matrix material, to provide structural integrity and effective fission product retention, under neutron irradiation. This construction makes it safely feasible to provide a high uranium density, so that the uranium enrichment with uranium 235 may be reduced below about 20%, to deter the reprocessing of the uranium for use in nuclear weapons.

  17. Study on the fabrication of Al matrix composites strengthened by combined in-situ alumina particle and in-situ alloying elements

    International Nuclear Information System (INIS)

    Huang Zanjun; Yang Bin; Cui Hua; Zhang Jishan

    2003-01-01

    A new idea to fabricate aluminum matrix composites strengthened by combined in-situ particle strengthening and in-situ alloying has been proposed. Following the concept of in-situ alloying and in-situ particle strengthening, aluminum matrix composites reinforced by Cu and α-Al 2 O 3 particulate (material I) and the same matrix reinforced by Cu, Si alloying elements and α-Al 2 O 3 particulate (material II) have been obtained. SEM observation, EDS and XRD analysis show that the alloy elements Cu and Si exist in the two materials, respectively. In-situ Al 2 O 3 particulates are generally spherical and their mean size is less than 0.5 μm. TEM observation shows that the in-situ α-Al 2 O 3 particulates have a good cohesion with the matrix. The reaction mechanism of the Al 2 O 3 particulate obtained by this method was studied. Thermodynamic considerations are given to the in-situ reactions and the distribution characteristic of in-situ the α-Al 2 O 3 particulate in the process of solidification is also discussed

  18. TiNi shape memory alloys: effects of the fabrication route, the oxygen content and the zirconium or hafnium additions on the metallurgical characteristics and the thermomechanical properties; Alliages a memoires de forme de base TiNi: influence du mode de fabrication de la teneur en oxygene et de l`ajout de Zr ou Hf sur les caracteristiques metallurgiques et les proprietes mecaniques

    Energy Technology Data Exchange (ETDEWEB)

    Olier, P.

    1996-12-31

    In order to promote the development of Ti-Ni shape memory alloys, we have studied the correlation between the fabrication route, the chemical composition (O{sub 2} content, Zr or Hf additions), the metallurgical characteristics and the thermomechanical properties. A conventional sintering does not allow to obtain a homogeneous compound of pure Ti{sub 50}Ni{sub 50} alloy because of the occurrence of Kirkendall porosities which act as a diffusion barrier. An original process including combustion synthesis and hot-extrusion was successfully developed. Resulting products exhibit a smaller grain size (15-20{mu}m) and an enhanced workability in comparison with products obtained by arc-melting and subsequent hot rolling. The presence of oxygen in equiatomic Ti-Ni alloy induces the oxide precipitation of Ti{sub 4}Ni{sub 2}O{sub x} type (with x {<=} 1). The precipitated particle fraction is proportional to the oxygen nominal content of the alloy. We show that the decrease of the transformation temperatures is correlated with the decrease of Ti in solid solution due to Ti{sub 4}Ni{sub 2}O precipitation. Moreover, we find that a fine and homogenous oxide dispersion is suitable to decrease the grain size during hot rolling and to enhance to the one way shape memory properties. An increase of the typical transformation temperatures is obtained through of Zr or Hf (in substitution to Ti). But, an increase of the hardness is measured, and consequently the workability of the ternary alloys becomes reduced. However, it is worthwhile to point out that a Ti{sub 38}Ni{sub 50}Hf{sub 12} product obtained by arc melting and hot extrusion is able to fully recover an apparent plastic strain of more than 4% during tensile tests performed under special loading conditions. Such as behaviour is of great interest with respect to potential applications in a temperature range higher that 100 deg. C. (author). 105 refs.

  19. The mechanical properties of magnesium matrix composites reinforced with 10 wt.% W14Al86 alloy particles

    International Nuclear Information System (INIS)

    Tang, H.G.; Ma, X.F.; Zhao, W.; Cai, S.G.; Zhao, B.; Qiao, Z.H.

    2007-01-01

    The Mg-based metal matrix composite reinforced by 10 wt.% W 14 Al 86 alloy particles has been prepared by mechanical alloying and press-forming process. X-ray diffraction studies confirm the formation of the composite. Microstructure characterization of the samples reveals the uniform distribution of fine W 14 Al 86 alloy. Mechanical properties characterization revealed that the reinforcement of W 14 Al 86 alloy lead to a significant increase in hardness and tensile strength of Mg and AZ91

  20. Effect of sintering processing on microstructure, mechanical properties and corrosion resistance of Ti–24Nb–4Zr–7.9Sn alloy for biomedical applications

    International Nuclear Information System (INIS)

    Guo, Shibo; Chu, Aimin; Wu, Haijiang; Cai, Chunbo; Qu, Xuanhui

    2014-01-01

    Highlights: • Ti–24Nb–4Zr–7.9Sn alloy is prepared by powder metallurgy method. • The alloy prepared at 1250 °C for 2 h has more β-matrix and tiny α-precipitation. • The alloy prepared at 1250 °C for 2 h possesses good mechanical properties. • The alloy prepared at 1250 °C for 2 h exhibits better corrosion resistance. - Abstract: Ti–24Nb–4Zr–7.9Sn alloy was prepared by Powder Metallurgy (PM) method using titanium hydride powder, niobium powder, zirconium powder, and tin powder as raw materials. The effect of sintering processing on microstructure, mechanical properties, and corrosion resistance was investigated in details. The alloy possessed dominant β-matrix and a little α-precipitation. The mechanical properties of the alloy sintered at 1250 °C for 2 h were better than those of the alloys with other sintering processing, which would avoid stress shielding and thus prevent bone resorption in orthopedic implants applications. As long-term stability in biological environment is required, the electrochemical behaviors in a simulated body fluid (Hank’s solution and simulated saliva solution) were also evaluated. Potentiodynamic polarization curves exhibited that the sample sintered at 1250 °C for 2 h had better corrosion properties than those of other sintering processing. The good corrosion resistance combined with better mechanical biocompatibility made the Ti–24Nb–4Zr–7.9Sn alloy suitable for use as orthopedic implants

  1. Endurance in Al Alloy Melts and Wear Resistance of Titanium Matrix Composite Shot-Sleeve for Aluminum Alloy Die-casting

    International Nuclear Information System (INIS)

    Choi, Bong-Jae; Kim, Young-Jig; Sung, Si-Young

    2012-01-01

    The main purpose of this study was to evaluate the endurance against Al alloy melts and wear resistance of an in-situ synthesized titanium matrix composite (TMC) sleeve for aluminum alloy die-casting. The conventional die-casting shot sleeve material was STD61 tool steel. TMCs have great thermal stability, wear and oxidation resistance. The in-situ reaction between Ti and B4C leads to two kinds of thermodynamically stable reinforcements, such as TiBw and TiCp. To evaluate the feasibility of the application to a TMCs diecasting shot sleeve, the interfacial reaction behavior was examined between Al alloys melts with TMCs and STD61 tool steel. The pin-on-disk type dry sliding wear test was also investigated for TMCs and STD61 tool steel.

  2. Magnetic properties of Co and Ni based alloy nanoparticles dispersed in a silica matrix

    Energy Technology Data Exchange (ETDEWEB)

    De Julian Fernandez, C. E-mail: dejulian@padova.infm.it; Sangregorio, C.; Mattei, G.; Maurizio, C.; Battaglin, G.; Gonella, F.; Lascialfari, A.; Lo Russo, S.; Gatteschi, D.; Mazzoldi, P.; Gonzalez, J.M.; D' Acapito, F

    2001-04-01

    A comparative study of the magnetic properties of Co and Ni based alloy nanoparticles (Ni-Co, Ni-Cu and Co-Cu) formed in a silica matrix by ion implantation is presented. Different ion doses and implantation sequences were realized in order to obtain different nanostructures. The structural and magnetic properties observed for the Cu{sub 50}Ni{sub 50} nanoparticles are similar to those of the Cu{sub 60}Ni{sub 40} bulk alloy. The crystal structure of Co{sub x}Ni{sub 1-x} (0{<=}x{<=}1) nanoparticles is similar to that of the corresponding bulk alloy. The magnetic properties depend on the ion-implanted dose and on the alloy composition. The samples prepared by implanting a 15x10{sup 16} ions/cm{sup 2} total dose contain nanoparticles, which are superparamagnetic at room temperature and their magnetic behavior is influenced by dipolar interparticle interactions. The magnetization of the CoNi samples at high magnetic field is larger than that of the corresponding bulk alloy and follows the same composition dependence of that quantity measured in the alloy.

  3. Magnetic properties of Co and Ni based alloy nanoparticles dispersed in a silica matrix

    International Nuclear Information System (INIS)

    De Julian Fernandez, C.; Sangregorio, C.; Mattei, G.; Maurizio, C.; Battaglin, G.; Gonella, F.; Lascialfari, A.; Lo Russo, S.; Gatteschi, D.; Mazzoldi, P.; Gonzalez, J.M.; D'Acapito, F.

    2001-01-01

    A comparative study of the magnetic properties of Co and Ni based alloy nanoparticles (Ni-Co, Ni-Cu and Co-Cu) formed in a silica matrix by ion implantation is presented. Different ion doses and implantation sequences were realized in order to obtain different nanostructures. The structural and magnetic properties observed for the Cu 50 Ni 50 nanoparticles are similar to those of the Cu 60 Ni 40 bulk alloy. The crystal structure of Co x Ni 1-x (0≤x≤1) nanoparticles is similar to that of the corresponding bulk alloy. The magnetic properties depend on the ion-implanted dose and on the alloy composition. The samples prepared by implanting a 15x10 16 ions/cm 2 total dose contain nanoparticles, which are superparamagnetic at room temperature and their magnetic behavior is influenced by dipolar interparticle interactions. The magnetization of the CoNi samples at high magnetic field is larger than that of the corresponding bulk alloy and follows the same composition dependence of that quantity measured in the alloy

  4. Thin film shape memory alloys for optical sensing applications

    International Nuclear Information System (INIS)

    Fu, Y Q; Luo, J K; Huang, W M; Flewitt, A J; Milne, W I

    2007-01-01

    Based on shape memory effect of the sputtered thin film shape memory alloys, different types of micromirror structures were designed and fabricated for optical sensing application. Using surface micromachining, TiNi membrane mirror structure has been fabricated, which can be actuated based on intrinsic two-way shape memory effect of the free-standing TiNi film. Using bulk micromachining, TiNi/Si and TiNi/Si 3 N 4 microcantilever mirror structures were fabricated

  5. Investigation of Selective Laser Melting Surface Alloyed Aluminium Metal Matrix Dispersive Reinforced Layers

    Science.gov (United States)

    Kamburov, V. V.; Dimitrova, R. B.; Kandeva, M. K.; Sofronov, Y. P.

    2018-01-01

    The aim of the paper is to investigate the improvement of mechanical properties and in particular wear resistance of laser surface alloyed dispersive reinforced thin layers produced by selective laser melting (SLM) technology. The wear resistance investigation of aluminium matrix composite layers in the conditions of dry friction surface with abrasive particles and nanoindentation tests were carried out. The process parameters (as scan speed) and their impact on the wear resistant layers have been evaluated. The alloyed layers containing metalized SiC particles were studied by Optical and Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray microanalysis (EDX). The obtained experimental results of the laser alloyed thin layers show significant development of their wear resistance and nanohardness due to the incorporated reinforced phase of electroless nickel coated SiC particles.

  6. Adherence of extracellular matrix components to modified surfaces of titanium alloys

    International Nuclear Information System (INIS)

    Stelzer, C; Uhlmann, E; Meinke, M; Lademann, J; Hansen, U

    2009-01-01

    The adherence of biological materials on metal surfaces is of special importance in biology and medicine. The underlying interactions between surface and biological materials (e.g. extracellular matrix components or cells) are responsible for the application as a medical device. Numerous products are made of pure titanium and titanium alloys. This paper shows the influence of a laser production technology on machined surfaces of TiAl 6 V 4 and the resulting adherence of biological material on the basis of the surface characterisation. In this study, different machined TiAl 6 V 4 surfaces were used for coatings with extracellular matrix components. For this process, different coating with collagen I monomers and a complex mixture of extracellular matrix proteins derived from the dermal-epidermal basement membrane zone were analysed. The efficiency of the coating was analysed by different methods and the results are presented in this paper

  7. Effect of plastic strain on shape memory characteristics in sputter-deposited Ti-Ni thin films

    International Nuclear Information System (INIS)

    Nomura, K.

    1995-01-01

    The plastic strain which is introduced during cooling and heating under a constant stress has an influence upon the transformation and deformation characteristics of sputter-deposited Ti-Ni shape memory alloy thin films. With increasing the accumulated plastic strain, Ms rises and recovery strain increases. The changes in such characteristics are due to the internal stress field that is formed by plastic deformation. However, the change in Ms in Ti-50.5at%Ni is larger than that in Ti-48.9at%Ni, although the plastic strain in the former is lower than that in the latter. In order to understand this point, the effective internal stresses were estimated in both alloys; the internal stress in the former is more effectively created by the introduction of plastic strain than in the latter. (orig.)

  8. Study of a Ti Ni-based shape memory alloy aiming applications in pipeline connections of the oil and gas industry; Estudo de uma liga base Ti-Ni com memoria de forma visando aplicacoes em conexoes de tubulacoes na industria do petroleo e gas

    Energy Technology Data Exchange (ETDEWEB)

    Silva, M.M. da; Silva, N.J. da; Gomes, A.A.C.; Reis, R.P.B.; Araujo, C.J. de; Santos, M.A. dos [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Lab. Multidisciplinar de Materiais e Estruturas Ativas (LaMMEA)], e-mail: carlos@dem.ufcg.edu.br

    2006-07-01

    The objective of this paper is to study the technical feasibility of a TiNi-based Shape Memory Alloy (SMA) with potential application in connections of the oil and gas Sector. The employment of this alloy would increase the reliability of these unions. Thus, a 45,0 Ti-55,0 Ni (% wt) SMA has been manufactured through the plasma skull melting and with subsequent conformation by the Push-Pull method. Samples of this SMA were heat treated at 1173 K during 900s, followed by water quenching. These samples were characterized by optic microscopy, microhardness, differential scanning calorimetry (DSC), and force generation tests. The obtained TiNi SMA has presented an important wide temperature hysteresis. The generated forces substantiate the potential application of these alloys in connection systems of the oil and gas Sector. (author)

  9. Helium sequestration at nanoparticle-matrix interfaces in helium + heavy ion irradiated nanostructured ferritic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Parish, C.M., E-mail: parishcm@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Unocic, K.A.; Tan, L. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Zinkle, S.J. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); University of Tennessee, Knoxville, TN 37996 (United States); Kondo, S. [Institute of Advanced Energy, Kyoto University, Uji, Kyoto, 611-0011 (Japan); Snead, L.L. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Hoelzer, D.T.; Katoh, Y. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2017-01-15

    We irradiated four ferritic alloys with energetic Fe and He ions: one castable nanostructured alloy (CNA) containing Ti-W-Ta-carbides, and three nanostructured ferritic alloys (NFAs). The NFAs were: 9Cr containing Y-Ti-O nanoclusters, and two Fe-12Cr-5Al NFAs containing Y-Zr-O or Y-Hf-O clusters. All four were subjected to simultaneous dual-beam Fe + He ion implantation (650 °C, ∼50 dpa, ∼15 appm He/dpa), simulating fusion-reactor conditions. Examination using scanning/transmission electron microscopy (STEM) revealed high-number-density helium bubbles of ∼8 nm, ∼10{sup 21} m{sup −3} (CNA), and of ∼3 nm, 10{sup 23} m{sup −3} (NFAs). STEM combined with multivariate statistical analysis data mining suggests that the precipitate-matrix interfaces in all alloys survived ∼50 dpa at 650 °C and serve as effective helium trapping sites. All alloys appear viable structural material candidates for fusion or advanced fission energy systems. Among these developmental alloys the NFAs appear to sequester the helium into smaller bubbles and away from the grain boundaries more effectively than the early-generation CNA.

  10. Rapid thermal annealing of Ti-rich TiNi thin films: A new approach to fabricate patterned shape memory thin films

    International Nuclear Information System (INIS)

    Motemani, Y.; Tan, M.J.; White, T.J.; Huang, W.M.

    2011-01-01

    This paper reports the rapid thermal annealing (RTA) of Ti-rich TiNi thin films, synthesized by the co-sputtering of TiNi and Ti targets. Long-range order of aperiodic alloy could be achieved in a few seconds with the optimum temperature of 773 K. Longer annealing (773 K/240 s), transformed the film to a poorly ordered vitreous phase, suggesting a novel method for solid state amorphization. Reitveld refinement analyses showed significant differences in structural parameters of the films crystallized by rapid and conventional thermal annealing. Dependence of the elastic modulus on the valence electron density (VED) of the crystallized films was studied. It is suggested that RTA provides a new approach to fabricate patterned shape memory thin films.

  11. Simultaneous multielement analysis of zirconium alloys by chlorination separation of matrix/ICP-AES

    International Nuclear Information System (INIS)

    Kato, Kaneharu

    1990-01-01

    An analytical method combined chlorination separation of matrix with ICP-AES has been developed for reactor grade Zr alloys (Zircaloy-2). A sample (1 g) is taken into a Pt boat and chlorinated with HCl gas of 100 ml/min in a glass reaction tube at ca. 330degC. Matrix Zr of the sample is volatilized and separated as ZrCl 4 . The analytic elements remaining quantitatively as chlorination residue are dissolved in a mixture of mineral acids (6 M HCl 3 ml+conc. HNO 3 0.5 ml+conc. H 2 SO 4 0.2 ml) and diluted to 20 ml with distilled water after filtration. ICP-AES was used for simultaneous multielement determination using a calibration curve method. The present method has the following advantages: simple sample preparation procedure; applicability to any form of samples to determine multielements; simple ICP-AES calibration procedure. This method was successfully applied to the determination of Fe, Ni, Cu, Co, Mn and Pb in the Zr alloys of JAERI CRM's and NBS SRM's. (author)

  12. Tiny plastic lung mimics human pulmonary function

    Science.gov (United States)

    Careers Inclusion & Diversity Work-Life Balance Career Resources Apply for a Job Postdocs Students Goals Recycling Green Purchasing Pollution Prevention Reusing Water Resources Environmental Management Releases - 2016 » April » Tiny plastic lung mimics human pulmonary function Tiny plastic lung mimics

  13. Fabrication and study of double sintered TiNi-based porous alloys

    Science.gov (United States)

    Sergey, Anikeev; Valentina, Hodorenko; Timofey, Chekalkin; Victor, Gunther; Ji-hoon, Kang; Ji-soon, Kim

    2017-05-01

    Double-sintered porous TiNi-based alloys were fabricated and their structural characteristics and physico-mechanical properties were investigated. A fabrication technology of powder mixtures is elaborated in this article. Sintering conditions were chosen experimentally to ensure good structure and properties. The porous alloys were synthesized by solid-state double diffusion sintering (DDS) of Ti-Ni powder and prepare to obtain dense, crack-free, and homogeneous samples. The Ti-Ni compound sintered at various temperatures was investigated by scanning electron microscopy. Phase composition of the sintered alloys was determined by x-ray diffraction. Analysis of the data confirmed the morphology and structural parameters. Mechanical and physical properties of the sintered alloys were evaluated. DDS at 1250 °C was found to be optimal to produce porous samples with a porosity of 56% and mean pore size of 90 μm. Pore size distribution was unimodal within the narrow range of values. The alloys present enhanced strength and ductility, owing to both the homogeneity of the macrostructure and relative elasticity of the bulk, which is hardened by the Ni-rich precipitates. These results suggest the possibility to manufacture porous TiNi-based alloys for application as a new class of dental implants.

  14. Neutron irradiation effect on thermomechanical properties of shape memory alloys

    International Nuclear Information System (INIS)

    Abramov, V.Ya.; Ionajtis, R.R.; Kotov, V.V.; Loguntsev, E.N.; Ushakov, V.P.

    1996-01-01

    Alloys of Ti-Ni, Ti-Ni-Pd, Fe-Mn-Si, Mn-Cu-Cr, Mn-Cu, Cu-Al-Mn, Cu-Al-Ni systems are investigated after irradiation in IVV-2M reactor at various temperatures with neutron fluence of 10 19 - 10 20 cm -2 . The degradation of shape memory effect in titanium nickelide base alloys is revealed after irradiation. Mn-Cu and Mn-Cu-Cr alloys show the best results. Trends in shape memory alloy behaviour depending on irradiation temperature are found. A consideration is given to the possibility of using these alloys for components of power reactor control and protection systems [ru

  15. Fabrication and Performance Test of Aluminium Alloy-Rice Husk Ash Hybrid Metal Matrix Composite as Industrial and Construction Material

    Directory of Open Access Journals (Sweden)

    Md. Rahat Hossain

    2017-12-01

    Full Text Available Aluminium matrix composites (AMCs used extensively in various engineering fields due to their exceptional mechanical properties. In this present study, aluminium matrix composites (AMCs such as aluminium alloy (A356 reinforced with rice husk ash particles (RHA are made to explore the possibilities of reinforcing aluminium alloy. The stir casting method was applied to produce aluminium alloy (A356 reinforced with various amounts of (2%, 4%, and 6% rice husk ash (RHA particles. Physical treatment was carried out before the rice husk ash manufacturing process. The effect of mechanical strength of the fabricated hybrid composite was investigated. Therefore, impact test, tensile stress, compressive stress, and some other tests were carried out to analyse the mechanical properties. From the experimental results, it was found that maximum tensile, and compressive stress were found at 6% rice husk ash (RHA and aluminium matrix composites (AMCs. In future, the optimum percentages of rice husk ash (RHA to fabricate the hybrid composites will be determined. Also, simulation by finite element method (FEM will be applied for further investigation.

  16. Detection of tiny amounts of fissile materials in large-sized containers with radioactive waste

    Science.gov (United States)

    Batyaev, V. F.; Skliarov, S. V.

    2018-01-01

    The paper is devoted to non-destructive control of tiny amounts of fissile materials in large-sized containers filled with radioactive waste (RAW). The aim of this work is to model an active neutron interrogation facility for detection of fissile ma-terials inside NZK type containers with RAW and determine the minimal detectable mass of U-235 as a function of various param-eters: matrix type, nonuniformity of container filling, neutron gen-erator parameters (flux, pulse frequency, pulse duration), meas-urement time. As a result the dependence of minimal detectable mass on fissile materials location inside container is shown. Nonu-niformity of the thermal neutron flux inside a container is the main reason of the space-heterogeneity of minimal detectable mass in-side a large-sized container. Our experiments with tiny amounts of uranium-235 (<1 g) confirm the detection of fissile materials in NZK containers by using active neutron interrogation technique.

  17. Detection of tiny amounts of fissile materials in large-sized containers with radioactive waste

    Directory of Open Access Journals (Sweden)

    Batyaev V.F.

    2018-01-01

    Full Text Available The paper is devoted to non-destructive control of tiny amounts of fissile materials in large-sized containers filled with radioactive waste (RAW. The aim of this work is to model an active neutron interrogation facility for detection of fissile ma-terials inside NZK type containers with RAW and determine the minimal detectable mass of U-235 as a function of various param-eters: matrix type, nonuniformity of container filling, neutron gen-erator parameters (flux, pulse frequency, pulse duration, meas-urement time. As a result the dependence of minimal detectable mass on fissile materials location inside container is shown. Nonu-niformity of the thermal neutron flux inside a container is the main reason of the space-heterogeneity of minimal detectable mass in-side a large-sized container. Our experiments with tiny amounts of uranium-235 (<1 g confirm the detection of fissile materials in NZK containers by using active neutron interrogation technique.

  18. Gaseous Phase and Electrochemical Hydrogen Storage Properties of Ti50Zr1Ni44X5 (X = Ni, Cr, Mn, Fe, Co, or Cu for Nickel Metal Hydride Battery Applications

    Directory of Open Access Journals (Sweden)

    Jean Nei

    2016-07-01

    Full Text Available Structural, gaseous phase hydrogen storage, and electrochemical properties of a series of the Ti50Zr1Ni44X5 (X = Ni, Cr, Mn, Fe, Co, or Cu metal hydride alloys were studied. X-ray diffraction (XRD and scanning electron microscopy (SEM revealed the multi-phase nature of all alloys, which were composed of a stoichiometric TiNi matrix, a hyperstoichiometric TiNi minor phase, and a Ti2Ni secondary phase. Improvement in synergetic effects between the main TiNi and secondary Ti2Ni phases, determined by the amount of distorted lattice region in TiNi near Ti2Ni, was accomplished by the substitution of an element with a higher work function, which consequently causes a dramatic increase in gaseous phase hydrogen storage capacity compared to the Ti50Zr1Ni49 base alloy. Capacity performance is further enhanced in the electrochemical environment, especially in the cases of the Ti50Zr1Ni49 base alloy and Ti50Zr1Ni44Co5 alloy. Although the TiNi-based alloys in the current study show poorer high-rate performances compared to the commonly used AB5, AB2, and A2B7 alloys, they have adequate capacity performances and also excel in terms of cost and cycle stability. Among the alloys investigated, the Ti50Zr1Ni44Fe5 alloy demonstrated the best balance among capacity (394 mAh·g−1, high-rate performance, activation, and cycle stability and is recommended for follow-up full-cell testing and as the base composition for future formula optimization. A review of previous research works regarding the TiNi metal hydride alloys is also included.

  19. The Tiny Terminators

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 5. The Tiny Terminators - Mosquitoes and Diseases. P K Sumodan. General Article Volume 6 Issue 5 May 2001 pp 48-55. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/006/05/0048-0055 ...

  20. Neutron activation of chlorine in zirconium and zirconium alloys use of the matrix as comparator

    International Nuclear Information System (INIS)

    Cohen, I.M.; Gomez, C.D.; Mila, M.I.

    1981-01-01

    A procedure is described for neutron activation analysis of chlorine in zirconium and zirconium alloys. Calculation of chlorine concentration is performed relative to zirconium concentration in the matrix in order to minimize effects of differences in irradiation and counting geometry. Principles of the method and the results obtained are discussed. (author)

  1. Applications of shape memory alloys in Japan

    International Nuclear Information System (INIS)

    Asai, M.; Suzuki, Y.

    2000-01-01

    In Japan, a first application of shape memory TiNi alloy was a moving flap in an air-conditioner which was developed as sensing function of shape memory alloy at Matsushista Electric Industrial Co. Then, shape memory utilized in a coffee maker, an electric rice-cooker, a thermal mixing valve and etc. were commercialized in Japan. And brassiere wires, a guide wire for medical treatment, an antenna for portable telephone and others were commercialized utilizing superelasticity. At the same time with these commercial products, there was not only progress in fabrication technology to effect accurate transformation temperature, but also the discovery of small hysteresis alloy such as R-phase or TiNiCu alloy and low transformation temperature alloy such as TiNiFe, TiNiV and TiNiCo alloys. Therefore the shape memory alloy market has expanded widely to electric appliances, automobile, residence, medical care and other field today. (orig.)

  2. The influence of Fe content on spreading ability of tungsten heavy alloys matrix on tungsten surface

    Directory of Open Access Journals (Sweden)

    A. Krzyńska

    2011-07-01

    Full Text Available The results of experimental study of tungsten spreading ability with W-Ni-Co-Fe matrix are presented. The aim of these investigations was to see how Fe concentration in W – Ni – Co matrix influences the wettability of tungsten grains during liquid phase sintering. Four green compact specimens containing 50%W, 10%Co and Ni + Fe = 40% but with different Ni to Fe ratio were prepared. The cylindrical specimen 5mm diameter and 5mm height were put on clean pure tungsten substrate and then 20 minutes heated at 1520oC in hydrogen atmosphere. After heating the specimens were carefully measured and then the specimens for structure observations were prepared. It was concluded, that increase of Fe content decrease the melting temperature of W – Ni – Co alloy. The melting point decrease caused by Fe content increase substantially the spreading ability of tungsten substrate with W – Ni – Co alloy. Metallography investigations showed some microstructure changes in “reaction zone” identified in tungsten substrate – (WNi40-xCo10Fex interface. The results of the study confirmed our earlier observations that even relative small Fe addition promotes Weight Heavy Alloys (WHA liquid phase sintering.

  3. PROPERTY DATABASE FOR THE DEVELOPMENT OF SHAPE MEMORY ALLOY APPLICATIONS

    OpenAIRE

    Tang , W.; CederstrÖm , J.; SandstrÖm , R.

    1991-01-01

    Important points involving the selection of shape memory alloy (SMA) application projects are discussed. The development of a property database for SMA is initiated. Both conventional data as well as characteristics which are unique for SMA are stored. As an application example of the database SMA-SELECT, important properties for Ti-Ni alloys near equi-atomic composition, such as temperature window width for superelasticity (SE), stress rate, critical yield stress, and their interaction have ...

  4. Structural analysis of an off-grid tiny house

    Science.gov (United States)

    Calluari, Karina Arias; Alonso-Marroquín, Fernando

    2017-06-01

    The off-grid technologies and tiny house movement have experimented an unprecedented growth in recent years. Putting both sides together, we are trying to achieve an economic and environmental friendly solution to the higher cost of residential properties. This solution is the construction of off-grid tiny houses. This article presents a design for a small modular off-grid house made by pine timber. A numerical analysis of the proposed tiny house was performed to ensure its structural stability. The results were compared with the suggested serviceability limit state criteria, which are contended in the Australia Guidelines Standards making this design reliable for construction.

  5. Surface modification of 5083 Al alloy by electrical discharge alloying processing with a 75 mass% Si-Fe alloy electrode

    Energy Technology Data Exchange (ETDEWEB)

    Stambekova, Kuralay [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo-Kuang Rd., Taichung 40227, Taiwan (China); Lin, Hung-Mao [Department of Mechanical Engineering, Far East University, No. 49, Zhonghua Rd., Xinshi Dist., Tainan City 74448, Taiwan (China); Uan, Jun-Yen, E-mail: jyuan@dragon.nchu.edu.tw [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo-Kuang Rd., Taichung 40227, Taiwan (China)

    2012-03-01

    This study experimentally investigates the surface modification of 5083 Al alloy by the electrical discharge alloying (EDA) process with a Si-Fe alloy as an electrode. Samples were analyzed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), micro-hardness and corrosion resistance tests. The micro-hardness of EDA alloyed layer was evidently higher than that of the base metal (5083 Al alloy). The TEM results show that the matrix of the alloyed layer has an amorphous-like structure; the matrix contains fine needle-like Si particles, block-like Si particles and nano-size Al{sub 4.5}FeSi and Al{sub 13}Fe{sub 4} particles. The TEM results support experimental results for the high hardness of the alloyed layer. Moreover, the EDA alloyed layer with composite microstructures has good corrosion resistance in NaCl aqueous solution.

  6. Synthesis Of NiCrAlC alloys by mechanical alloying

    International Nuclear Information System (INIS)

    Silva, A.K.; Pereira, J.I.; Vurobi Junior, S.; Cintho, O.M.

    2010-01-01

    The purpose of the present paper is the synthesis of nickel alloys (NiCrAlC), which has been proposed like a economic alternative to the Stellite family Co alloys using mechanical alloying, followed by sintering heat treatment of milled material. The NiCrAlC alloys consist of a chromium carbides dispersion in a Ni 3 Al intermetallic matrix, that is easily synthesized by mechanical alloying. The use of mechanical alloying enables higher carbides sizes and distribution control in the matrix during sintering. We are also investigated the compaction of the processed materials by compressibility curves. The milling products were characterized by X-ray diffraction, and the end product was featured by conventional metallography and scanning electronic microscopy (SEM), that enabled the identification of desired phases, beyond microhardness test, which has been shown comparable to alloys manufactured by fusion after heat treating. (author)

  7. Investigation of the Self-Healing Behavior of Sn-Bi Metal Matrix Composite Reinforced with NiTi Shape Memory Alloy Strips Under Flexural Loading

    Science.gov (United States)

    Poormir, Mohammad Amin; Khalili, Seyed Mohammad Reza; Eslami-Farsani, Reza

    2018-06-01

    Utilizing intelligent materials such as shape memory alloys as reinforcement in metal matrix composites is a novel method to mimic self-healing behavior. In this study, the bending behavior of a self-healing metal matrix composite made from Sn-13 wt.% Bi alloy as matrix and NiTi shape memory alloy (SMA) strips as reinforcement is investigated. Specimens were fabricated in different reinforcement vol.% (0.78, 1.55, 2.33) and in various pre-strains (0, 2, 6%) and were healed at three healing temperatures (170°C, 180°C, 190°C). Results showed that shape recovery was accomplished in all the specimens, but not all of them were able to withstand second loading after healing. Only specimens with 2.33 vol.% of SMA strips, 1.55 vol.% of SMA, and 6% pre-strain could endure bending force after healing, and they gained 35.31-51.83% of bending force self-healing efficiency.

  8. TinyOS-based quality of service management in wireless sensor networks

    Science.gov (United States)

    Peterson, N.; Anusuya-Rangappa, L.; Shirazi, B.A.; Huang, R.; Song, W.-Z.; Miceli, M.; McBride, D.; Hurson, A.; LaHusen, R.

    2009-01-01

    Previously the cost and extremely limited capabilities of sensors prohibited Quality of Service (QoS) implementations in wireless sensor networks. With advances in technology, sensors are becoming significantly less expensive and the increases in computational and storage capabilities are opening the door for new, sophisticated algorithms to be implemented. Newer sensor network applications require higher data rates with more stringent priority requirements. We introduce a dynamic scheduling algorithm to improve bandwidth for high priority data in sensor networks, called Tiny-DWFQ. Our Tiny-Dynamic Weighted Fair Queuing scheduling algorithm allows for dynamic QoS for prioritized communications by continually adjusting the treatment of communication packages according to their priorities and the current level of network congestion. For performance evaluation, we tested Tiny-DWFQ, Tiny-WFQ (traditional WFQ algorithm implemented in TinyOS), and FIFO queues on an Imote2-based wireless sensor network and report their throughput and packet loss. Our results show that Tiny-DWFQ performs better in all test cases. ?? 2009 IEEE.

  9. Preliminary investigations on TINI based distributed instrumentation systems

    International Nuclear Information System (INIS)

    Bezboruah, T.; Kalita, M.

    2006-04-01

    A prototype web enabled distributed instrumentation system is being proposed in the Department of Electronics Science, Gauhati University, Assam, India. The distributed instrumentation system contains sensors, legacy hardware, TCP/IP protocol converter, TCP/IP network Ethernet, Database Server, Web/Application Server and Client PCs. As part of the proposed work, Tiny Internet Interface (TINI, TBM390: Dallas Semiconductor) has been deployed as TCP/IP stack, and java programming language as software tools. A feature supported by Java, that is particularly relevant to the distributed system is its applet. An applet is a java class that can be downloaded from the web server and can be run in a context application such as web browser or an applet viewer. TINI has been installed as TCP/IP stack, as it is the best suited embedded system with java programming language and it has been uniquely designed for communicating over One Wire Devices (OWD) over network. Here we will discuss the hardware and software aspects of TINI with OWD for the present system. (author)

  10. Oxide nanoparticles in an Al-alloyed oxide dispersion strengthened steel: crystallographic structure and interface with ferrite matrix

    DEFF Research Database (Denmark)

    Zhang, Zhenbo; Pantleon, Wolfgang

    2017-01-01

    Oxide nanoparticles are quintessential for ensuring the extraordinary properties of oxide dispersion strengthened (ODS) steels. In this study, the crystallographic structure of oxide nanoparticles, and their interface with the ferritic steel matrix in an Al-alloyed ODS steel, i.e. PM2000, were...

  11. The Importance of Rare-Earth Additions in Zr-Based AB2 Metal Hydride Alloys

    Directory of Open Access Journals (Sweden)

    Kwo-Hsiung Young

    2016-07-01

    Full Text Available Effects of substitutions of rare earth (RE elements (Y, La, Ce, and Nd to the Zr-based AB2 multi-phase metal hydride (MH alloys on the structure, gaseous phase hydrogen storage (H-storage, and electrochemical properties were studied and compared. Solubilities of the RE atoms in the main Laves phases (C14 and C15 are very low, and therefore the main contributions of the RE additives are through the formation of the RENi phase and change in TiNi phase abundance. Both the RENi and TiNi phases are found to facilitate the bulk diffusion of hydrogen but impede the surface reaction. The former is very effective in improving the activation behaviors. −40 °C performances of the Ce-doped alloys are slightly better than the Nd-doped alloys but not as good as those of the La-doped alloys, which gained the improvement through a different mechanism. While the improvement in ultra-low-temperature performance of the Ce-containing alloys can be associated with a larger amount of metallic Ni-clusters embedded in the surface oxide, the improvement in the La-containing alloys originates from the clean alloy/oxide interface as shown in an earlier transmission electron microscopy study. Overall, the substitution of 1 at% Ce to partially replace Zr gives the best electrochemical performances (capacity, rate, and activation and is recommended for all the AB2 MH alloys for electrochemical applications.

  12. Electrochemical process for the manufacturing of titanium alloy matrix composites

    Directory of Open Access Journals (Sweden)

    V. Soare

    2009-07-01

    Full Text Available The paper presents a new method for precursors’ synthesis of titanium alloys matrix composites through an electrochemical process in molten calcium chloride. The cathode of the cell was made from metallic oxides powders and reinforcement ceramic particles, which were pressed and sintered into disk form and the anode from graphite. The process occurred at 850 °C, in two stages, at 2,7 / 3,2 V: the ionization of the oxygen in oxides and the reduction with calcium formed by electrolysis of calcium oxide fed in the electrolyte. The obtained composite precursors, in a form of metallic sponge, were consolidated by pressing and sintering. Chemical and structural analyses on composites samples were performed.

  13. Research Progress in Plasma arc welding of Magnesium Alloys and Magnesium Matrix Composites

    Science.gov (United States)

    Hui, Li; Yang, Zou; Yongbo, Li; Lei, Jiao; Ruijun, Hou

    2017-11-01

    Magnesium alloys and magnesium matrix composites by means of its excellent performance have wide application prospect in electronics, automotive, biotechnology, aerospace field, and welding technology has become a key of restricting its application. This paper describes the welding characteristics of magnesium, the obvious advantages in the application and the domestic and foreign research advance technology of plasma arc welding of magnesium, and summarizes the existing problems and development trends of plasma arc welding technology of magnesium.

  14. Superconducting alloys

    International Nuclear Information System (INIS)

    Bowers, J.E.

    1976-01-01

    Reference is made to superconductors having high critical currents. The superconductor described comprises an alloy consisting of a matrix of a Type II superconductor which is a homogeneous mixture of 50 to 95 at.% Pb and 5 to 40 at.%Bi and/or 10 to 50 at.%In. Dispersed in the matrix is a material to provide pinning centres comprising from 0.01% to 20% by volume of the alloy; this material is a stable discontinuous phase of discrete crystalline particles of Cu, Mn, Te, Se, Ni, Ca, Cr, Ce, Ge or La, either in the form of the element or a compound with a component of the matrix. These particles should have an average diameter of not more than 2μ. A method for making this alloy is described. (U.K.)

  15. CaO-matrix processing of MnBi alloys for permanent magnets

    Directory of Open Access Journals (Sweden)

    A. M. Gabay

    2017-05-01

    Full Text Available The possibility to suppress agglomeration of MnBi alloy particles during milling and their unwanted sintering during subsequent annealing was explored by embedding the particles in CaO through co-milling. A 15 h annealing of the micron-sized MnBi particles embedded in the CaO matrix at 300 °C is not accompanied by sintering or growth of the particles while it significantly increases their coercivity – presumably by healing the milling-induced crystal defects. After separation from the CaO matrix, the annealed MnBi powder combines a calculated energy product of 10 MGOe with a room-temperature coercivity of 14.4 kOe. At the same time, the partial loss and degradation of the MnBi low-temperature phase during warm compaction of the powders makes the effect of the CaO-matrix annealing less pronounced in the case of fully dense magnets; the residue from the solvents employed for the removal of the CaO might have contributed to the decline of the properties. Still, a relatively high room-temperature coercivity of 8.5 kOe was obtained for the fuslly-dense MnBi magnet exhibiting an energy product of 5.3 MGOe.

  16. Energy-Saving Melting and Revert Reduction Technology (E-SMARRT): Development of Elevated Temperature Aluminum Metal Matrix Composite (MMC) Alloy and Its Processing Technology

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, David C. [Eck Industreis, Inc.; Gegal, Gerald A.

    2014-04-15

    The objective of this project was to provide a production capable cast aluminum metal matrix composite (MMC) alloy with an operating temperature capability of 250-300°C. Important industrial sectors as well as the military now seek lightweight aluminum alloy castings that can operate in temperature ranges of 250-300°C. Current needs in this temperature range are being satisfied by the use of titanium alloy castings. These have the desired strength properties but the end components are heavier and significantly more costly. Also, the energy requirements for production of titanium alloy castings are significantly higher than those required for production of aluminum alloys and aluminum alloy castings.

  17. Acoustic properties of TiNiMoFe base alloys

    International Nuclear Information System (INIS)

    Gyunter, V.Eh.; Chernyshev, V.I.; Chekalkin, T.L.

    2000-01-01

    The regularity of changing the acoustic properties of the TiNi base alloys in dependence on the alloy composition and impact temperature is studied. It is shown that the oscillations of the TiNiMoFe base alloys within the temperature range of the B2 phase existence and possible appearance of the martensite under the load differ from the traditional materials oscillations. After excitation of spontaneous oscillations within the range of M f ≤ T ≤ M d there exists the area of long-term and low-amplitude low-frequency acoustic oscillations. It is established that free low-frequency oscillations of the TH-10 alloy sample are characterized by the low damping level in the given temperature range [ru

  18. Synthesis and characterization of ZA-27 alloy matrix composites reinforced with zinc oxide nanoparticles

    Directory of Open Access Journals (Sweden)

    B.O. Fatile

    2017-06-01

    Full Text Available An investigation has been carried out on the synthesis and characterization of ZA-27 alloy composites reinforced with zinc oxide nanoparticles. This was aimed at developing high performance ZA-27 matrix nanocomposite with low density. The particle size and morphology of the zinc oxide (ZnO nanoparticles were investigated by Transmission Electron Microscope (TEM and the elemental composition was obtained from Energy Dispersive Spectroscopy (EDS attached to TEM and X-ray fluorescence spectroscopy (XRF. ZA-27 nanocomposite samples were developed using 0, 1, 2, 3, 4 and 5 wt% of ZnO nanoparticles by double steps stir casting technique. Mechanical properties and Microstructural examination were used to characterize the composite samples produced. The results show that hardness and ultimate tensile strength of the composite samples increased progressively with increase in weight percentage of ZnO nanoparticles. Increase in Ultimate tensile strength (UTS of 10.2%, 21.1%, 22.3%, 35.5%, 33.4% and increase in hardness value of 8.2%, 14.8%, 21.7%, 27.9%, 27.1% were observed for nanocomposites reinforced with 1 wt%, 2 wt%, 3 wt%, 4 wt%, and 5 wt% ZnO nanoparticles respectively in comparison with unreinforced alloy. It was generally observed that composite sample containing 4 wt% of reinforcement has the highest tensile strength and hardness values. However, the fracture toughness and percent elongation of the composites samples slightly decreased with increase in ZnO nanoparticles content. Results obtained from the Microstructural examination using optical microscope and Scanning Electron Microscope (SEM show that the nanoparticles were well dispersed in the ZA-27 alloy matrix.

  19. Thermal and mechanical behavior of metal matrix and ceramic matrix composites

    Science.gov (United States)

    Kennedy, John M. (Editor); Moeller, Helen H. (Editor); Johnson, W. S. (Editor)

    1990-01-01

    The present conference discusses local stresses in metal-matrix composites (MMCs) subjected to thermal and mechanical loads, the computational simulation of high-temperature MMCs' cyclic behavior, an analysis of a ceramic-matrix composite (CMC) flexure specimen, and a plasticity analysis of fibrous composite laminates under thermomechanical loads. Also discussed are a comparison of methods for determining the fiber-matrix interface frictional stresses of CMCs, the monotonic and cyclic behavior of an SiC/calcium aluminosilicate CMC, the mechanical and thermal properties of an SiC particle-reinforced Al alloy MMC, the temperature-dependent tensile and shear response of a graphite-reinforced 6061 Al-alloy MMC, the fiber/matrix interface bonding strength of MMCs, and fatigue crack growth in an Al2O3 short fiber-reinforced Al-2Mg matrix MMC.

  20. Effect of Al-5Ti-0.62C-0.2Ce Master Alloy on the Microstructure and Tensile Properties of Commercial Pure Al and Hypoeutectic Al-8Si Alloy

    Directory of Open Access Journals (Sweden)

    Wanwu Ding

    2017-06-01

    Full Text Available Al-5Ti-0.62C-0.2Ce master alloy was synthesized by a method of thermal explosion reaction in pure molten aluminum and used to modify commercial pure Al and hypoeutectic Al-8Si alloy. The microstructure and tensile properties of commercial pure Al and hypoeutectic Al-8Si alloy with different additions of Al-5Ti-0.62C-0.2Ce master alloy were investigated. The results show that the Al-5Ti-0.62C-0.2Ce alloy was composed of α-Al, granular TiC, lump-like TiAl3 and block-like Ti2Al20Ce. Al-5Ti-0.62C-0.2Ce master alloy (0.3 wt %, 5 min can significantly refine macro grains of commercial pure Al into tiny equiaxed grains. The Al-5Ti-0.62C-0.2Ce master alloy (0.3 wt %, 30 min still has a good refinement effect. The tensile strength and elongation of commercial pure Al modified by the Al-5Ti-0.62C-0.2Ce master alloy (0.3 wt %, 5 min increased by roughly 19.26% and 61.83%, respectively. Al-5Ti-0.62C-0.2Ce master alloy (1.5 wt %, 10 min can significantly refine both α-Al grains and eutectic Si of hypoeutectic Al-8Si alloy. The dendritic α-Al grains were significantly refined to tiny equiaxed grains. The morphology of the eutectic Si crystals was significantly refined from coarse needle-shape or lath-shape to short rod-like or grain-like eutectic Si. The tensile strength and elongation of hypoeutectic Al-8Si alloy modified by the Al-5Ti-0.62C-0.2Ce master alloy (1.5 wt %, 10 min increased by roughly 20.53% and 50%, respectively. The change in mechanical properties corresponds to evolution of the microstructure.

  1. Oxide nanoparticles in an Al-alloyed oxide dispersion strengthened steel: crystallographic structure and interface with ferrite matrix

    Science.gov (United States)

    Zhang, Zhenbo; Pantleon, Wolfgang

    2017-07-01

    Oxide nanoparticles are quintessential for ensuring the extraordinary properties of oxide dispersion strengthened (ODS) steels. In this study, the crystallographic structure of oxide nanoparticles, and their interface with the ferritic steel matrix in an Al-alloyed ODS steel, i.e. PM2000, were systematically investigated by high-resolution transmission electron microscopy. The majority of oxide nanoparticles were identified to be orthorhombic YAlO3. During hot consolidation and extrusion, they develop a coherent interface and a near cuboid-on-cube orientation relationship with the ferrite matrix in the material. After annealing at 1200 °C for 1 h, however, the orientation relationship between the oxide nanoparticles and the matrix becomes arbitrary, and their interface mostly incoherent. Annealing at 1300 °C leads to considerable coarsening of oxide nanoparticles, and a new orientation relationship of pseudo-cube-on-cube between oxide nanoparticles and ferrite matrix develops. The reason for the developing interfaces and orientation relationships between oxide nanoparticles and ferrite matrix under different conditions is discussed.

  2. The solidification velocity of nickel and titanium alloys

    Science.gov (United States)

    Altgilbers, Alex Sho

    2002-09-01

    The solidification velocity of several Ni-Ti, Ni-Sn, Ni-Si, Ti-Al and Ti-Ni alloys were measured as a function of undercooling. From these results, a model for alloy solidification was developed that can be used to predict the solidification velocity as a function of undercooling more accurately. During this investigation a phenomenon was observed in the solidification velocity that is a direct result of the addition of the various alloying elements to nickel and titanium. The additions of the alloying elements resulted in an additional solidification velocity plateau at intermediate undercoolings. Past work has shown a solidification velocity plateau at high undercoolings can be attributed to residual oxygen. It is shown that a logistic growth model is a more accurate model for predicting the solidification of alloys. Additionally, a numerical model is developed from simple description of the effect of solute on the solidification velocity, which utilizes a Boltzmann logistic function to predict the plateaus that occur at intermediate undercoolings.

  3. Martensitic transformation behavior in Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jai-young; Chun, Su-jin; Kim, Nam-suk; Cho, Jeung-won; Kim, Jae-hyun [School of Materials Science and Engineering, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of); Yeom, Jong-taek [Light Metal Division, Korea Institute of Materials Science (KIMS), Changwon 642-831 (Korea, Republic of); Kim, Jae-il [Materials Science and Engineering, University of Dong-A, Hadan-dong, Saha-gu, Busan 604-714 (Korea, Republic of); Nam, Tae-hyun, E-mail: tahynam@gnu.ac.kr [School of Materials Science and Engineering, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of)

    2013-12-15

    Graphical abstract: - Highlights: • Ag, In and Sn were soluble in TiNi matrix, while Sb, Te, Tl, Pb and Bi were not. • The B2-R-B19′transformation occurred in Ti-Ni-(Ag, In, Sn) alloys. • Solid solution hardening was essential for inducing the B2-R transformation. - Abstract: The microstructures and transformation behaviors of Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys were investigated using electron probe micro-analysis (EPMA), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Micro Vickers hardness tests. All specimens consisted of Ti–Ni matrices and second phase particles. Ag, In and Sn were soluble in Ti–Ni matrices with a limited solubility (≤1.0 at%), while Sb, Te, Tl, Pb and Bi were not soluble. Two-stage B2-R-B19′ transformation occurred in Ti–48.8Ni–1.2Ag, Ti–49.0Ni–1.0In and Ti–49.0Ni–1.0Sn alloys, while one-stage B2-B19′ transformation occurred in Ti–49.0Ni–1.0Ag, Ti–49.0Ni–1.0Sb, Ti–49.0Ni–1.0Te, Ti–49.0Ni–1.0Pb and Ti–49.0Ni–1.0Bi alloys. Micro Vickers hardness of the alloys displaying the B2-R-B19′ transformation (Hv 250–368) was much larger than that (alloys displaying the B2-B19′ transformation. Solid solution hardening was an important factor for inducing the B2-R transformation in Ti–Ni–X (X = non-transition elements) alloys.

  4. Martensitic transformation behavior in Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys

    International Nuclear Information System (INIS)

    Jang, Jai-young; Chun, Su-jin; Kim, Nam-suk; Cho, Jeung-won; Kim, Jae-hyun; Yeom, Jong-taek; Kim, Jae-il; Nam, Tae-hyun

    2013-01-01

    Graphical abstract: - Highlights: • Ag, In and Sn were soluble in TiNi matrix, while Sb, Te, Tl, Pb and Bi were not. • The B2-R-B19′transformation occurred in Ti-Ni-(Ag, In, Sn) alloys. • Solid solution hardening was essential for inducing the B2-R transformation. - Abstract: The microstructures and transformation behaviors of Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys were investigated using electron probe micro-analysis (EPMA), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Micro Vickers hardness tests. All specimens consisted of Ti–Ni matrices and second phase particles. Ag, In and Sn were soluble in Ti–Ni matrices with a limited solubility (≤1.0 at%), while Sb, Te, Tl, Pb and Bi were not soluble. Two-stage B2-R-B19′ transformation occurred in Ti–48.8Ni–1.2Ag, Ti–49.0Ni–1.0In and Ti–49.0Ni–1.0Sn alloys, while one-stage B2-B19′ transformation occurred in Ti–49.0Ni–1.0Ag, Ti–49.0Ni–1.0Sb, Ti–49.0Ni–1.0Te, Ti–49.0Ni–1.0Pb and Ti–49.0Ni–1.0Bi alloys. Micro Vickers hardness of the alloys displaying the B2-R-B19′ transformation (Hv 250–368) was much larger than that (< Hv 200) of the alloys displaying the B2-B19′ transformation. Solid solution hardening was an important factor for inducing the B2-R transformation in Ti–Ni–X (X = non-transition elements) alloys

  5. Tiny Devices Project Sharp, Colorful Images

    Science.gov (United States)

    2009-01-01

    Displaytech Inc., based in Longmont, Colorado and recently acquired by Micron Technology Inc. of Boise, Idaho, first received a Small Business Innovation Research contract in 1993 from Johnson Space Center to develop tiny, electronic, color displays, called microdisplays. Displaytech has since sold over 20 million microdisplays and was ranked one of the fastest growing technology companies by Deloitte and Touche in 2005. Customers currently incorporate the microdisplays in tiny pico-projectors, which weigh only a few ounces and attach to media players, cell phones, and other devices. The projectors can convert a digital image from the typical postage stamp size into a bright, clear, four-foot projection. The company believes sales of this type of pico-projector may exceed $1.1 billion within 5 years.

  6. The effect of TiB2 reinforcement on the mechanical properties of an Al-Cu-Li alloy-based metal-matrix composite

    Science.gov (United States)

    1991-01-01

    The addition of ceramic particles to aluminum based alloys can substantially improve mechanical properties, especially Young's modulus and room and elevated temperature strengths. However, these improvements typically occur at the expense of tensile ductility. The mechanical properties are evaluated to a metal matrix composite (MMC) consisting of an ultrahigh strength aluminum lithium alloy, Weldalite (tm) 049, reinforced with TiB2 particles produced by an in situ precipitation technique called the XD (tm) process. The results are compared to the behavior of a nonreinforced Weldalite 049 variant. It is shown that both 049 and 049-TiB2 show very attractive warm temperature properties e.g., 625 MPa yield strength at 150 C after 100 h at temperature. Weldalite 049 reinforced with a nominal 4 v pct. TiB2 shows an approx. 8 pct. increase in modulus and a good combination of strength (529 MPa UTS) and ductility (6.5 pct.) in the T3 temper. And the high ductility of Weldalite 049 in the naturally aged and underaged tempers makes the alloy a good, high strength matrix for ceramic reinforcement.

  7. Magnesium secondary alloys: Alloy design for magnesium alloys with improved tolerance limits against impurities

    Energy Technology Data Exchange (ETDEWEB)

    Blawert, C., E-mail: carsten.blawert@gkss.d [GKSS Forschungszentrum Geesthacht GmbH, Max-Planck-Str. 1, 21502 Geesthacht (Germany); Fechner, D.; Hoeche, D.; Heitmann, V.; Dietzel, W.; Kainer, K.U. [GKSS Forschungszentrum Geesthacht GmbH, Max-Planck-Str. 1, 21502 Geesthacht (Germany); Zivanovic, P.; Scharf, C.; Ditze, A.; Groebner, J.; Schmid-Fetzer, R. [TU Clausthal, Institut fuer Metallurgie, Robert-Koch-Str. 42, 38678 Clausthal-Zellerfeld (Germany)

    2010-07-15

    The development of secondary magnesium alloys requires a completely different concept compared with standard alloys which obtain their corrosion resistance by reducing the levels of impurities below certain alloy and process depending limits. The present approach suitable for Mg-Al based cast and wrought alloys uses a new concept replacing the {beta}-phase by {tau}-phase, which is able to incorporate more impurities while being electro-chemically less detrimental to the matrix. The overall experimental effort correlating composition, microstructure and corrosion resistance was reduced by using thermodynamic calculations to optimise the alloy composition. The outcome is a new, more impurity tolerant alloy class with a composition between the standard AZ and ZC systems having sufficient ductility and corrosion properties comparable to the high purity standard alloys.

  8. Thermokinetic Simulation of Precipitation in NiTi Shape Memory Alloys

    Science.gov (United States)

    Cirstea, C. D.; Karadeniz-Povoden, E.; Kozeschnik, E.; Lungu, M.; Lang, P.; Balagurov, A.; Cirstea, V.

    2017-06-01

    Considering classical nucleation theory and evolution equations for the growth and composition change of precipitates, we simulate the evolution of the precipitates structure in the classical stages of nucleation, growth and coarsening using the solid-state transformation Matcalc software. The formation of Ni3Ti, Ni4Ti3 or Ni3Ti2 precipitate is the key to hardening phenomenon of the alloys, which depends on the nickel solubility in the bulk alloys. The microstructural evolution of metastable Ni4Ti3 and Ni3Ti2 precipitates in Ni-rich TiNi alloys is simulated by computational thermokinetics, based on thermodynamic and diffusion databases. The simulated precipitate phase fractions are compared with experimental data.

  9. Influence of the Sr and Mg Alloying Additions on the Bonding Between Matrix and Reinforcing Particles in the AlSi7Mg/SiC-Cg Hybrid Composite

    Directory of Open Access Journals (Sweden)

    Dolata A. J.

    2016-06-01

    Full Text Available The aim of the work was to perform adequate selection of the phase composition of the composite designated for permanent - mould casting air compressor pistons. The hybrid composites based on AlSi7Mg matrix alloy reinforced with mixture of silicon carbide (SiC and glassy carbon (Cg particles were fabricated by the stir casting method. It has been shown that the proper selection of chemical composition of matrix alloy and its modification by used magnesium and strontium additions gives possibility to obtain both the advantageous casting properties of composite suspensions as well as good bonding between particles reinforcements and matrix.

  10. Nuclear reactor fuel structure containing uranium alloy wires embedded in a metallic matrix plate

    International Nuclear Information System (INIS)

    Travelli, A.

    1988-01-01

    A nuclear fuel-containing plate structure for a nuclear reactor is described; such structure comprising a pair of malleable metallic non-fissionable matrix plates having confronting surfaces which are pressure bonded together and fully united to form a bonded surface, and elongated malleable wire-like fissionable fuel members separately confined and fully enclosed between the matrix plates along the interface to afford a high fuel density as well as structural integrity and effective retention of fission products. The plates have separate recesses formed in the confronting surfaces for closely receiving the wire-like fissionable fuel members. The wire-like fissionable fuel members are made of a maleable uranium alloy capable of being formed into elongated wire-like members and capable of withstanding pressure bonding. The wire-like fissionable fuel members are completely separated and isolated by fully united portions of the interface

  11. Effect of mechanical alloying on FeCrC reinforced Ni alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, S. Osman [Univ. of Namik Kemal, Tekirdag (Turkey); Teker, Tanju [Adiyaman Univ. (Turkey). Dept. of Metallurgical and Materials Engineering; Demir, Fatih [Batman Univ. (Turkey)

    2016-05-01

    Mechanical alloying (MA) is a powder metallurgy processing technique involving cold welding, fracturing and rewelding of powder particles in a high-energy ball mill. In the present study, the intermetallic matrix composites (IMCs) of Ni-Al reinforced by M{sub 7}C{sub 3} were produced by powder metallurgical routes via solid state reaction of Ni, Al and M{sub 7}C{sub 3} particulates by mechanical alloying processes. Ni, Al and M{sub 7}C{sub 3} powders having 100 μm were mixed, mechanical alloyed and the compacts were combusted in a furnace. The mechanically alloyed (MAed) powders were investigated by X-ray diffraction (XRD), microhardness measurement, optic microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The presence of the carbides depressed the formation of unwanted NiAl intermetallic phases. The mechanical alloyed M{sub 7}C{sub 3} particles were unstable and decomposed partially within the matrix during alloying and sintering, and the morphology of the composites changed with the dissolution ratio of M{sub 7}C{sub 3} and sintering temperature.

  12. Microstructure and high-temperature oxidation resistance of TiN/Ti3Al intermetallic matrix composite coatings on Ti6Al4V alloy surface by laser cladding

    Science.gov (United States)

    Zhang, Xiaowei; Liu, Hongxi; Wang, Chuanqi; Zeng, Weihua; Jiang, Yehua

    2010-11-01

    A high-temperature oxidation resistant TiN embedded in Ti3Al intermetallic matrix composite coating was fabricated on titanium alloy Ti6Al4V surface by 6kW transverse-flow CO2 laser apparatus. The composition, morphology and microstructure of the laser clad TiN/Ti3Al intermetallic matrix composite coating were characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). In order to evaluate the high-temperature oxidation resistance of the composite coatings and the titanium alloy substrate, isothermal oxidation test was performed in a conventional high-temperature resistance furnace at 600°C and 800°C respectively. The result shows that the laser clad intermetallic composite coating has a rapidly solidified fine microstructure consisting of TiN primary phase (granular-like, flake-like, and dendrites), and uniformly distributed in the Ti3Al matrix. It indicates that a physical and chemical reaction between the Ti powder and AlN powder occurred completely under the laser irradiation. In addition, the microhardness of the TiN/Ti3Al intermetallic matrix composite coating is 844HV0.2, 3.4 times higher than that of the titanium alloy substrate. The high-temperature oxidation resistance test reveals that TiN/Ti3Al intermetallic matrix composite coating results in the better modification of high-temperature oxidation behavior than the titanium substrate. The excellent high-temperature oxidation resistance of the laser cladding layer is attributed to the formation of the reinforced phase TiN and Al2O3, TiO2 hybrid oxide. Therefore, the laser cladding TiN/Ti3Al intermetallic matrix composite coating is anticipated to be a promising oxidation resistance surface modification technique for Ti6Al4V alloy.

  13. Impact toughness of laser alloyed aluminium AA1200 alloys

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2013-08-01

    Full Text Available ),. 559-563. [2] T. Tomida, K. Nakata, S. Saji, T. Kubo, T, Formation of metal matrix composite layer on aluminium alloy with TiC-Cu powder by laser surface alloying process; Surface and Coatings Technology; vol. 142-144, 2001, 585-589. [3] L. A. B...

  14. Corrosion behaviour of 2124 aluminium alloy-silicon carbide metal matrix composites in sodium chloride environment

    International Nuclear Information System (INIS)

    Singh, Nirbhay; Vadera, K.K.; Ramesh Kumar, A.V.; Singh, R.S.; Monga, S.S.; Mathur, G.N.

    1999-01-01

    Aluminium alloy based particle reinforced metal matrix composites (MMCs) are being considered for a range of applications. Their mechanical properties have been investigated in detail, but more information about their corrosion resistance is needed. In this investigation, the corrosion behaviour of silicon carbide particulates (SiC p )-2124 aluminium metal matrix composites was studied in 3 wt% sodium chloride solution by means of electrochemical technique and optical microscope. The effects of weight percentages and particle size of silicon carbide particulates on corrosion behaviour of the composite were studied in NaCl and it was observed that corrosion rate increases linearly with the increasing weight percentage of SiC p . The corrosion rate of the MMC increases by increasing the size of SiC particles. Anodization improved corrosion resistance of the composites. (author)

  15. Spark plasma sintering of TiNi nano-powders for biological application

    International Nuclear Information System (INIS)

    Fu, Y Q; Gu, Y W; Shearwood, C; Luo, J K; Flewitt, A J; Milne, W I

    2006-01-01

    Nano-sized TiNi powder with an average size of 50 nm was consolidated using spark plasma sintering (SPS) at 800 deg. C for 5 min. A layer of anatase TiO 2 coating was formed on the sintered TiNi by chemical reaction with a hydrogen peroxide (H 2 O 2 ) solution at 60 deg. C followed by heat treatment at 400 deg. C to enhance the bioactivity of the metal surface. Cell culture using osteoblast cells and a biomimetic test in simulated body fluid proved the biocompatibility of the chemically treated SPS TiNi

  16. Ti Ni shape memory alloy film-actuated microstructures for a MEMS probe card

    Science.gov (United States)

    Namazu, Takahiro; Tashiro, Youichi; Inoue, Shozo

    2007-01-01

    This paper describes the development of a novel silicon (Si) cantilever beam device actuated by titanium-nickel (Ti-Ni) shape memory alloy (SMA) films. A Ti-Ni SMA film can yield high work output per unit volume, so a Ti-Ni film-actuated Si cantilever beam device is a prospective tool for use as a microelectromechanical system (MEMS) probe card that provides a relatively large contact force between the probe and electrode pad in spite of its minute size. Before fabrication of the device, the thermomechanical deformation behavior of Ti-Ni SMA films with various compositions was investigated in order to determine a sufficient constituent film for a MEMS actuator. As a result, Ti-Ni films having a Ti content of 50.2 to 52.6 atomic% (at%) were found to be usable for operation as a room temperature actuator. We have developed a Ti-Ni film-actuated Si cantilever beam device, which can produce a contact force by the cantilever bending when in contact, and also by the shape memory effect (SME) of the Ti-Ni film arising from Joule heating. The SME of the Ti-Ni film can generate an additional average contact force of 200 µN with application of 500 mW to the film. In addition to physical contact, a dependable electric contact between the Au film-coated probe tip and the Al film electrode was achieved. However, the contact resistance exhibited an average value of 25 Ω, which would have to be reduced for practical use. Reliability tests confirmed the durability of the Ti-Ni film-actuated Si cantilever-beam, in that the contact resistance was constant throughout a large number of physical contacts (>104 times).

  17. Nanostructure and magnetic properties of CoNi-alloy-based nanoparticles dispersed in a silica matrix

    International Nuclear Information System (INIS)

    De Julian, C.; Sangregorio, C.; Mattei, G.; Battaglin, G.; Cattaruzza, E.; Gonella, F.; Lo Russo, S.; D'Orazio, F.; Lucari, F.; De, G.; Gatteschi, D.; Mazzoldi, P.

    2001-01-01

    A comparative study of the magnetic behavior of FCC alloy CoNi (1:1) nanoparticles, embedded in a silica matrix and prepared by the ion implantation and sol-gel techniques, is presented. The blocking temperature is related to the size distribution, and, at least for the ion-implanted samples, only an enhanced effective anisotropy explains the experimental results. The hysteretic behavior is explained in terms of the temperature dependence of the anisotropy and of the particle volume fraction that determines the dipolar interactions

  18. Nanostructure and magnetic properties of CoNi-alloy-based nanoparticles dispersed in a silica matrix

    Energy Technology Data Exchange (ETDEWEB)

    De Julian, C. E-mail: dejulian@padova.infm.it; Sangregorio, C.; Mattei, G.; Battaglin, G.; Cattaruzza, E.; Gonella, F.; Lo Russo, S.; D' Orazio, F.; Lucari, F.; De, G.; Gatteschi, D.; Mazzoldi, P

    2001-05-01

    A comparative study of the magnetic behavior of FCC alloy CoNi (1:1) nanoparticles, embedded in a silica matrix and prepared by the ion implantation and sol-gel techniques, is presented. The blocking temperature is related to the size distribution, and, at least for the ion-implanted samples, only an enhanced effective anisotropy explains the experimental results. The hysteretic behavior is explained in terms of the temperature dependence of the anisotropy and of the particle volume fraction that determines the dipolar interactions.

  19. Influence of pretreatment on creep-rupture-strength and creep-behaviour of a matrix-hardening Ni-base-alloy

    International Nuclear Information System (INIS)

    Schirra, M.

    1982-01-01

    The creep and time-to-rupture behaviour of the matrix hardening Nickel base alloy Inconel 625 was investigated in the temperature range 650-800 0 C. Three different thermo-mechanical pretreatment were used: I = Hot rolled finish; II = 870 0 C annealed; III = Sol. treatment 1150 0 C 1 h. The temperature range of this study is for samples which have undergone treatment I and II well above the temperatures normally used. The results show an anomalous stress dependence of creep and time-to-rupture at around 750 0 C. The reason is to be found in the very complex precipitation processes occurring while the stress is applied. The results are explained according to findings about precipitation in this type of alloy. (orig.) [de

  20. Characterization and modeling of three-dimensional self-healing shape memory alloy-reinforced metal-matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Manuel, Michele Viola [University of Florida, Gainesville; Zhu, Pingping [Northwestern University, Evanston; Newman, John A. [NASA Langely Research Center (LaRC), Virginia; Wright, M Clara [NASA Kennedy Space Center, FL; Brinson, L Catherine [Northwestern University, Evanston; Kesler, Michael S. [ORNL

    2016-09-10

    In this paper, three-dimensional metal-matrix composites (MMCs) reinforced by shape memory alloy (SMA) wires are modeled and simulated, by adopting an SMA constitutive model accounting for elastic deformation, phase transformation and plastic behavior. A modeling method to create composites with pre-strained SMA wires is also proposed to improve the self-healing ability. Experimental validation is provided with a composite under three-point bending. This modeling method is applied in a series of finite element simulations to investigate the self-healing effects in pre-cracked composites, especially the role of the SMA reinforcement, the softening property of the matrix, and the effect of pre-strain in the SMA. The results demonstrate that SMA reinforcements provide stronger shape recovery ability than other, non-transforming materials. The softening property of the metallic matrix and the pre-strain in SMA are also beneficial to help crack closure and healing. This modeling approach can serve as an efficient tool to design SMA-reinforced MMCs with optimal self-healing properties that have potential applications in components needing a high level of reliability.

  1. Improving the corrosion wear resistance of AISI 316L stainless steel by particulate reinforced Ni matrix composite alloying layer

    Science.gov (United States)

    Xu, Jiang; Zhuo, Chengzhi; Tao, Jie; Jiang, Shuyun; Liu, Linlin

    2009-01-01

    In order to overcome the problem of corrosion wear of AISI 316L stainless steel (SS), two kinds of composite alloying layers were prepared by a duplex treatment, consisting of Ni/nano-SiC and Ni/nano-SiO2 predeposited by brush plating, respectively, and subsequent surface alloying with Ni-Cr-Mo-Cu by a double glow process. The microstructure of the two kinds of nanoparticle reinforced Ni-based composite alloying layers was investigated by means of SEM and TEM. The electrochemical corrosion behaviour of composite alloying layers compared with the Ni-based alloying layer and 316L SS under different conditions was characterized by potentiodynamic polarization test and electrochemical impedance spectroscopy. Results showed that under alloying temperature (1000 °C) conditions, amorphous nano-SiO2 particles still retained the amorphous structure, whereas nano-SiC particles were decomposed and Ni, Cr reacted with SiC to form Cr6.5Ni2.5Si and Cr23C6. In static acidic solution, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO2 particles interlayer is lower than that of the Ni-based alloying layer. However, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO2 particles interlayer is prominently superior to that of the Ni-based alloying layer under acidic flow medium condition and acidic slurry flow condition. The corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiC particles interlayer is evidently lower than that of the Ni-based alloying layer, but higher than that of 316L SS under all test conditions. The results show that the highly dispersive nano-SiO2 particles are helpful in improving the corrosion wear resistance of the Ni-based alloying layer, whereas carbides and silicide phase are deleterious to that of the Ni-based alloying layer due to the fact that the preferential removal of the matrix around the precipitated phase takes place by the chemical

  2. Strain aging in tungsten heavy alloys

    International Nuclear Information System (INIS)

    Dowding, R.J.; Tauer, K.J.

    1991-01-01

    This paper reports on tungsten heavy alloys which are two-phase mixtures of body center cubic (BCC) tungsten surrounded by a face center cubic (FCC) matrix. The matrix is most often composed of nickel and iron in a ratio of 70:30 but, occasionally, the matrix may also contain cobalt or copper. Nickel, however, is always the primary matrix component. The tungsten heavy alloy is fabricated through powder metallurgy techniques. Elemental powders are blended, pressed to shape, and sintered. Depending upon the tungsten content, the sintering temperatures are usually in the range of 1450 degrees C to 1525 degrees C. These temperatures are high enough that, as a result, the matrix is at the liquid phase and the process is known as liquid phase sintering. At the liquid phase temperature, the matrix becomes saturated with tungsten, but this does not change the FCC character of the matrix. The sintering is usually done in a hydrogen atmosphere furnace in order to reduce the oxides on the tungsten powder surfaces and create clean, active surfaces which will enhance the adherence between the tungsten and the matrix. The hydrogen atmosphere also creates the presence of excess dissolved hydrogen in the alloy. It has been shown that the hydrogen degrades the toughness and ductility of the heavy alloy. A post-sintering vacuum heat treatment is generally required to insure that there is no residual hydrogen present. The as-sintered tensile strength of a 90% tungsten, 7% nickel, 3% iron alloy (90W) is in the range of 800 to 940 MPa and can be increased significantly by cold working, usually rolling or swaging. Swaging to reductions in area of 20% can result in tensile strengths of 1250 MPa or more. As the strength increases, the elongation, which may have been 30% or more, decreases to less than 5%

  3. Characterization and study of the behavior of wire Ti-Ni with shape memory effect enables manufacture of actuators; Estudo da caracterizacao e do comportamento de fios de Ti-Ni com efeito memoria de forma viabilizando fabricacao de atuadores

    Energy Technology Data Exchange (ETDEWEB)

    Pina, E.A.C.; Araujo Filho, O.O. de; Urtiga Filho, S.L.; Gonzalez, C.H., E-mail: kikipina@hotmail.co [Universidade Federal de Pernambuco (DEM/CTG/UFPE), Recife, PE (Brazil). Centro de Tecnologia e Geociencias. Dept. de Engenharia Mecanica

    2010-07-01

    This work aims to characterize the wire commercial Ti-Ni of 1.27 mm in diameter with shape memory effect for the development of helical springs with the function of sensor / actuator. After heat treatment, the transformation temperatures, the presence of precipitates, the degree of damping, maximum stress of rupture, modulus of elasticity, the presence of phase R, the behavior of the alloy under tension, will be analyzed and compared in each situation. For characterization we used several methods including: heat treatment, Differential Scanning Calorimetry (DSC), tensile, dynamic mechanical analysis (DMA), X-ray diffraction, thermomechanical cycling. The wires were cut into pieces and heat-treated at 400 deg C with variation of time in muffle furnaces and quenching in water at 25 deg C. (author)

  4. Crystal structure of TiNi nanoparticles obtained by Ar ion beam deposition

    International Nuclear Information System (INIS)

    Castro, A. Torres; Cuellar, E. Lopez; Mendez, U. Ortiz; Yacaman, M. Jose

    2008-01-01

    Nanoparticles are a state of matter that have properties different from either molecules or bulk solids, turning them into a very interesting class of materials to study. In the present work, the crystal structure of TiNi nanoparticles obtained by ion beam deposition is characterized. TiNi nanoparticles were obtained from TiNi wire samples by sputtering with Ar ions using a Gatan precision ion polishing system. The TiNi nanoparticles were deposited on a Lacey carbon film that was used for characterization by transmission electron microscopy. The nanoparticles were characterized by high-resolution transmission electron microscopy, high-angle annular dark-field imaging, electron diffraction, scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy. Results of nanodiffraction seem to indicate that the nanoparticles keep the same B2 crystal structure as the bulk material but with a decreased lattice parameter

  5. Matrix effects in ion-induced emission as observed in Ne collisions with Cu-Mg and Cu-Al alloys

    Science.gov (United States)

    Ferrante, J.; Pepper, S. V.

    1983-01-01

    Ion induced Auger electron emission is used to study the surfaces of Al, Mg, Cu - 10 at. % Al, Cu - 19.6 at. % Al, and Cu - 7.4 at. % Mg. A neon (Ne) ion beam whose energy is varied from 0.5 to 3 keV is directed at the surface. Excitation of the lighter Ne occurs by the promotion mechanism of Barat and Lichten in asymmetric collisions with Al or Mg atoms. Two principal Auger peaks are observed in the Ne spectrum: one at 22 eV and one at 25 eV. Strong matrix effects are observed in the alloys as a function of energy in which the population of the second peak is greatly enhanced relative to the first over the pure materials. For the pure material over this energy range this ratio is 1.0. For the alloys it can rise to the electronic structure of alloys and to other surface tools such as secondary ion mass spectroscopy.

  6. Physicists tackles questions of tiny dimensions

    CERN Multimedia

    Moran, Barbara

    2003-01-01

    Today's physicists have a dilemna: they are using two separate theories to describe the universe. General relativity, which describes gravity, works for large objects like planets. Quantum mechanics, which involves the other forces, works for tiny objects like atoms. Unfortunately, the two theories don't match up.

  7. Type II pp-wave matrix models from point-like gravitons

    International Nuclear Information System (INIS)

    Lozano, Yolanda; RodrIguez-Gomez, Diego

    2006-01-01

    The BMN Matrix model can be regarded as a theory of coincident M-theory gravitons, which expand by Myers dielectric effect into the 2-sphere and 5-sphere giant graviton vacua of the theory. In this note we show that, in the same fashion, Matrix String theory in Type IIA pp-wave backgrounds arises from the action for coincident Type IIA gravitons. In Type IIB, we show that the action for coincident gravitons in the maximally supersymmetric pp-wave background gives rise to a Matrix model which supports fuzzy 3-sphere giant graviton vacua with the right behavior in the classical limit. We discuss the relation between our Matrix model and the Tiny Graviton Matrix theory

  8. Microstructure and Mechanical Behaviour of Stir-Cast Al-Mg-Sl Alloy Matrix Hybrid Composite Reinforced with Corn Cob Ash and Silicon Carbide

    Directory of Open Access Journals (Sweden)

    Oluwagbenga Babajide Fatile

    2014-10-01

    Full Text Available In this present study, the microstructural and mechanical behaviour of Al-Mg-Si alloy matrix composites reinforced with silicon carbide (SiC and Corn cob ash (An agro‑waste was investigated. This research work was aimed at assessing the suitability of developing low cost- high performance Al-Mg-Si hybrid composite. Silicon carbide (SiC particulates added with 0,1,2,3 and 4 wt% Corn cob ash (CCA were utilized to prepare 10 wt% of the reinforcing phase with Al-Mg-Si alloy as matrix using two-step stir casting method. Microstructural characterization, density measurement, estimated percent porosity, tensile testing, and micro‑hardness measurement were used to characterize the composites produced. From the results obtained, CCA has great potential to serve as a complementing reinforcement for the development of low cost‑high performance aluminum hybrid composites.

  9. Lead and lead-based alloys as waste matrix materials

    International Nuclear Information System (INIS)

    Arustamov, A.E.; Ojovan, M.I.; Kachalov, M.B.

    1999-01-01

    Metals and alloys with relatively low melting temperatures such as lead and lead-based alloys are considered in Russia as prospective matrices for encapsulation of spent nuclear fuel in containers in preparation for final disposal in underground repositories. Now lead and lead-based alloys are being used for conditioning spent sealed radioactive sources at radioactive waste disposal facilities

  10. A 'tiny-orange' spectrometer for electrons

    International Nuclear Information System (INIS)

    Silva, N.C. da.

    1990-01-01

    An tiny-orange electron spectrometer was designed and constructed using flat permanent magnets and a surface barrier detector. The transmission functions of different system configurations were determined for energies in the 200-1100 KeV range. A mathematical model for the system was developed. (L.C.J.A.)

  11. Refining U-Zr-Nb alloys by remelting

    International Nuclear Information System (INIS)

    Aguiar, B.M.; Kniess, C.T.; Riella, H.G.; Ferraz, W.B.

    2011-01-01

    The high density U-Zr-Nb and U-Nb uranium-based alloys can be employed as nuclear fuel in a PWR reactor due to their high density and nuclear properties. These alloys can stabilize the gamma phase, however, according to TTT diagrams, at the working temperature of a PWR reactor, all gamma phase transforms to α'' phase in a few hours. To avoid this kind of transformation during the nuclear reactor operation, the U-Zr-Nb alloy and U-Nn are used in α'' phase. The stability of α'' phase depends on the alloy composition and cooling rate. The alloy homogenization has to be very effective to eliminate precipitates rich in Zr and Nb to avoid changes in the alloying elements contents in the matrix. The homogenization was obtained by remelting the alloy and keeping it in the liquid state for enough time to promote floating of the precipitates (usually carbides, less dense) and leaving the matrix free of precipitates. However, this floating by density difference may result in segregation between the alloying elements (Nb and Zr, at the top) and uranium (at the bottom). The homogenized alloys were characterized in terms of metallographic techniques, optical microscopy, scanning electronic microscopy, EDS and X-ray diffraction. In this paper, it is shown that the contents of Zr and Nb at the bottom and at the top of the matrix are constant. (author)

  12. Microstructure and wear characteristics on Al alloy matrix composite reinforced with Ni perform

    Energy Technology Data Exchange (ETDEWEB)

    Park, Won Jo; Park, Cheol Hong; Kim, Hyung Jin; Huh, Sun Chul [Gyeongsang National University, Tongyeong, (Korea, Republic of)

    2012-06-15

    Al based composite reinforced with Nickel is used for diesel engine piston, because the thermal properties, strength and corrosion resistant are for better than Al alloy alone. For processing, the intermetallic compounds of Ni and Al improves wear resistance due to its high hardness. Existing process methods for MMC (metal matrix composite) using preform were manufactured under high-pressure. However, this causes deformation of the preform or weaknesses in the completed MMC. Low-pressure infiltration can prevent these problems, and there is an advantage of cost reduction in of production with small-scale of production equipment. In this study, the microstructure and wear characteristics of Al-based composite with Ni preform as reinforcement with low-pressure infiltration was analyzed.

  13. Influence of Microstructure on Corrosion Property of Mg-Al-Zn Alloy

    International Nuclear Information System (INIS)

    Lee, Jeong Ja; Na, Seung Chan; Yang, Won Seong; Hwang, WoonSuk; Jang, Si Sung; Yoo, Hwang Ryong

    2006-01-01

    Influence of microstructure on the corrosion property of Mg-Al-Zn Alloy was investigated using potentiodynamic polarization experiments, galvanic coupling experiments, and scanning electron microscopy in sodium chloride solutions. Pitting was the mot common form of attack in chloride solution, and filiform corrosion was also occurred in AZ91D-T4 alloy. On the contrary, filiform attack in the bulk matrix was predominant corrosion form in AZ91D-T6 alloy, and the number and size of pit were decreased than those of AZ91D-T4 alloy. Galvanic coupling effect between Mg 17 Al 12 and matrix was existed, but the propagation of galvanic corrosion was localized only near the Mg 17 Al 12 phase in AZ91D-6T alloy. The corrosion resistance of Mg-Al matrix increased with decreasing Al content in the matrix. And, it could be regarded that Al content in the matrix is decreased by precipitation of Mg 17 Al 12 curing the aging treatment and it decreases the anodic reaction rate of the matrix and galvanic effect in AZ91D-T6 alloy. It could be considered that the composition and macrostructure of surface protective layer would be varied by precipitation of Mg 17 Al 12 and subsequent decreasing of Al content in the matrix. And it would contribute the corrosion resistance of AZ91D-T6 aging alloy

  14. Leros: A Tiny Microcontroller for FPGAs

    DEFF Research Database (Denmark)

    Schoeberl, Martin

    2011-01-01

    Leros is a tiny microcontroller that is optimized for current low-cost FPGAs. Leros is designed with a balanced logic to on-chip memory relation. The design goal is a microcontroller that can be clocked in about half of the speed a pipelined on-chip memory and consuming less than 300 logic cells...

  15. Radiation-induced evolution of austenite matrix in silicon-modified AISI 316 alloys

    International Nuclear Information System (INIS)

    Garner, F.A.; Brager, H.R.

    1980-01-01

    The microstructures of a series of silicon-modified AISI 316 alloys irradiated to fast neutron fluences of about 2-3 and 10 x 10 22 n/cm 2 (E > 0.1 MeV at temperatures ranging from 400 0 C to 600 0 C have been examined. The irradiation of AISI 316 leads to an extensive repartition of several elements, particularly nickel and silicon, between the matrix and various precipitate phases. The segregation of nickel at void and grain boundary surfaces at the expense of other faster-diffusing elements is a clear indication that one of the mechanisms driving the microchemical evolution is the Inverse Kirkendall effect. There is evidence that at one sink this mechanism is in competition with the solute drag process associated with interstitial gradients

  16. Lithium alloy negative electrodes

    Science.gov (United States)

    Huggins, Robert A.

    The 1996 announcement by Fuji Photo Film of the development of lithium batteries containing convertible metal oxides has caused a great deal of renewed interest in lithium alloys as alternative materials for use in the negative electrode of rechargeable lithium cells. The earlier work on lithium alloys, both at elevated and ambient temperatures is briefly reviewed. Basic principles relating thermodynamics, phase diagrams and electrochemical properties under near-equilibrium conditions are discussed, with the Li-Sn system as an example. Second-phase nucleation, and its hindrance under dynamic conditions plays an important role in determining deviations from equilibrium behavior. Two general types of composite microstructure electrodes, those with a mixed-conducting matrix, and those with a solid electrolyte matrix, are discussed. The Li-Sn-Si system at elevated temperatures, and the Li-Sn-Cd at ambient temperatures are shown to be examples of mixed-conducting matrix microstructures. The convertible oxides are an example of the solid electrolyte matrix type. Although the reversible capacity can be very large in this case, the first cycle irreversible capacity required to convert the oxides to alloys may be a significant handicap.

  17. Titanium alloys. Advances in alloys, processes, products and applications

    International Nuclear Information System (INIS)

    Blenkinsop, P.A.

    1993-01-01

    The last few years have been a period of consolidation of existing alloys and processes. While the aerospace industry remains the principal driving force for alloy development, the paper illustrates examples of new markets being established in 'older' alloys, by a combination of product/process development and a re-examination of engineering design parameters. Considerable attention is still being directed towards the titanium aluminide systems, but other more conventional alloy developments are underway aimed at specific engineering and process requirements, both in the aerospace and non-aerospace sectors. Both the advanced high temperature and conventional alloy developments are considered, before the paper goes on to assess the potential of new processes and products, like spray-forming, metal matrix composites and shaped-plate rolling. (orig.)

  18. The Effect of Heat Treatment on the Thermo-Elastic Behavior of Ti Ni Shape Memory Alloy

    International Nuclear Information System (INIS)

    Ahmed, K.

    2008-01-01

    The Ti-Ni shape memory alloys are used in industrial, medical and biological applications because of their outstanding mechanical properties . Research work has been done to design a remote handling unit using such alloy to work in a high neutron irradiated areas .The pre-alloyed powder is supplied by Memory-Metalle GmbH with composition Ti-49.5 at % Ni. The Metal Injection Molding (MIM) technique has been used to fabricate the alloy and subsequent different heat treatments, spectroscopic and thermal analysis have been done to test the alloy performance. Regarding to this pre-alloyed powder composition, the thermo-elastic behavior is perfect. Transformation temperature in the range 27 degree C - 63 degree C has been achieved .The final sintering quality is not satisfactory. The results show that the proposed heat treatments are not able to release the generated internal stress

  19. Characterization and study of the behavior of wire Ti-Ni with shape memory effect enables manufacture of actuators

    International Nuclear Information System (INIS)

    Pina, E.A.C.; Araujo Filho, O.O. de; Urtiga Filho, S.L.; Gonzalez, C.H.

    2010-01-01

    This work aims to characterize the wire commercial Ti-Ni of 1.27 mm in diameter with shape memory effect for the development of helical springs with the function of sensor / actuator. After heat treatment, the transformation temperatures, the presence of precipitates, the degree of damping, maximum stress of rupture, modulus of elasticity, the presence of phase R, the behavior of the alloy under tension, will be analyzed and compared in each situation. For characterization we used several methods including: heat treatment, Differential Scanning Calorimetry (DSC), tensile, dynamic mechanical analysis (DMA), X-ray diffraction, thermomechanical cycling. The wires were cut into pieces and heat-treated at 400 deg C with variation of time in muffle furnaces and quenching in water at 25 deg C. (author)

  20. Effect of cerium addition on microstructures of carbon-alloyed iron ...

    Indian Academy of Sciences (India)

    All the alloys exhibited a typical two-phase microstructure consisting of Fe3AlC carbides in an iron aluminide matrix. In the alloy without Ce addition, large bulky carbides were equally distributed throughout the matrix with many smaller precipitates interspersed in between. In the alloy with Ce addition, the carbide grain sizes ...

  1. Refining U-Zr-Nb alloys by remelting

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, B.M.; Kniess, C.T.; Riella, H.G., E-mail: bmaguiar@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Ferraz, W.B. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    The high density U-Zr-Nb and U-Nb uranium-based alloys can be employed as nuclear fuel in a PWR reactor due to their high density and nuclear properties. These alloys can stabilize the gamma phase, however, according to TTT diagrams, at the working temperature of a PWR reactor, all gamma phase transforms to {alpha}'' phase in a few hours. To avoid this kind of transformation during the nuclear reactor operation, the U-Zr-Nb alloy and U-Nn are used in {alpha}'' phase. The stability of {alpha}'' phase depends on the alloy composition and cooling rate. The alloy homogenization has to be very effective to eliminate precipitates rich in Zr and Nb to avoid changes in the alloying elements contents in the matrix. The homogenization was obtained by remelting the alloy and keeping it in the liquid state for enough time to promote floating of the precipitates (usually carbides, less dense) and leaving the matrix free of precipitates. However, this floating by density difference may result in segregation between the alloying elements (Nb and Zr, at the top) and uranium (at the bottom). The homogenized alloys were characterized in terms of metallographic techniques, optical microscopy, scanning electronic microscopy, EDS and X-ray diffraction. In this paper, it is shown that the contents of Zr and Nb at the bottom and at the top of the matrix are constant. (author)

  2. Revenge of tiny Miranda

    International Nuclear Information System (INIS)

    Goldreich, P.; Nicholson, P.

    1977-01-01

    Reference is made to Dermott and Gold (Nature 267: 590 (1977)) who proposed a resonance model for the rings of Uranus. They assumed that the rings are composed of small particles librating about stable resonances determined by pairs of satellites, either Ariel and Titania or Ariel and Oberon. They dismissed as insignificant resonances involving 'tiny Miranda'. It is reported here that, by a wide margin, the strongest resonances are all associated with Miranda. It is also shown that the hypothesis that the rings are made up of librating particles, whilst original and ingenious, is incorrect. (author)

  3. Morphology and dispersion of FeCo alloy nanoparticles dispersed in a matrix of IR pyrolized polyvinyl alcohol

    Science.gov (United States)

    Vasilev, A. A.; Dzidziguri, E. L.; Muratov, D. G.; Zhilyaeva, N. A.; Efimov, M. N.; Karpacheva, G. P.

    2018-04-01

    Metal-carbon nanocomposites consisting of FeCo alloy nanoparticles dispersed in a carbon matrix were synthesized by the thermal decomposition method of a precursor based on polyvinyl alcohol and metals salts. The synthesized powders were investigated by X-ray diffraction (XRD), X-ray fluorescent spectrometry (XRFS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Surface characteristics of materials were measured by BET-method. The morphology and dispersity of metal nanoparticles were studied depending on the metals ratio in the composite.

  4. Microstructure and Mechanical Behavior of Microwave Sintered Cu50Ti50 Amorphous Alloy Reinforced Al Metal Matrix Composites

    Science.gov (United States)

    Reddy, M. Penchal; Ubaid, F.; Shakoor, R. A.; Mohamed, A. M. A.

    2018-06-01

    In the present work, Al metal matrix composites reinforced with Cu-based (Cu50Ti50) amorphous alloy particles synthesized by ball milling followed by a microwave sintering process were studied. The amorphous powders of Cu50Ti50 produced by ball milling were used to reinforce the aluminum matrix. They were examined by x-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness and compression testing. The analysis of XRD patterns of the samples containing 5 vol.%, 10 vol.% and 15 vol.% Cu50Ti50 indicates the presence of Al and Cu50Ti50 peaks. SEM images of the sintered composites show the uniform distribution of reinforced particles within the matrix. Mechanical properties of the composites were found to increase with an increasing volume fraction of Cu50Ti50 reinforcement particles. The hardness and compressive strength were enhanced to 89 Hv and 449 MPa, respectively, for the Al-15 vol.% Cu50Ti50 composites.

  5. Polarization Behavior of Squeeze Cast Al2O3 Fiber Reinforced Aluminum Matrix Composites

    International Nuclear Information System (INIS)

    Ham, S. H.; Kang, Y. C.; Cho, K. M.; Park, I. M.

    1992-01-01

    Electrochemical polarization behavior of squeeze cast Al 2 O 3 short fiber reinforced Al alloy matrix composites was investigated for the basic understanding of the corrosion properties of the composites. The composites were fabricated with variations of fiber volume fraction and matrix alloys. It was found that the reinforced composites are more susceptible to corrosion attack than the unreinforced matrix alloys in general. Corrosion resistance shows decreasing tendency with increasing Al 2 O 3 fiber volume fraction in AC8A matrix. Effect of the matrix alloys revealed that the AC8A Al matrix composite is less susceptible to corrosion attack than the 2024 and 7075 Al matrix composites. Effect of plastic deformation on electrochemical polarization behavior of the squeeze cast Al/Al 2 O 3 composites was examined after extrusion of AC8A-10v/o Al 2 O 3 . Result shows that corrosion resistance is deteriorated after plastic deformation

  6. Phase separation and formation of omega phase in the beta matrix of a Ti-V-Cu alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ng, H.P. [ARC Centre of Excellence for Design in Light Metals, Department of Materials Engineering, Monash University, Victoria 3800 (Australia); Devaraj, A.; Nag, S. [Center for Advanced Research and Technology, Department of Materials Science and Engineering, University of North Texas, Denton, TX (United States); Bettles, C.J. [ARC Centre of Excellence for Design in Light Metals, Department of Materials Engineering, Monash University, Victoria 3800 (Australia); Gibson, M. [CSIRO Process Science and Engineering, Locked Bag 10, Clayton South, Victoria 3169 (Australia); Fraser, H.L. [Center for the Accelerated Maturation of Materials, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH (United States); Muddle, B.C. [ARC Centre of Excellence for Design in Light Metals, Department of Materials Engineering, Monash University, Victoria 3800 (Australia); Banerjee, R., E-mail: rajarshi.banerjee@unt.edu [Center for Advanced Research and Technology, Department of Materials Science and Engineering, University of North Texas, Denton, TX (United States)

    2011-05-15

    The formation of the {omega} phase in the presence of simultaneous development of compositional modulations (or phase separation) within the body-centered cubic {beta} matrix phase of a Ti-10V-6Cu (wt.%) alloy during continuous cooling has been investigated using a combination of transmission electron microscopy and atom probe tomography. While a water quench from the high-temperature {beta} phase field allows apparently athermal formation of {omega} domains without any significant partitioning of solute or modulation in matrix composition, subsequent annealing at 500 {sup o}C for just 60 s leads to unusually rapid growth of the {omega} domains concurrent with, but apparently independent of, a slower development of finer-scale modulations in solute composition occurring apparently uniformly across both {omega} and {beta} phases. In contrast, on slower air cooling from the solution treatment temperature, there are pronounced compositional fluctuations within the {beta} phase, presumably as a product of spinodal decomposition, that are detectable prior to the formation of {omega} phase. The {omega} phase subsequently forms preferentially in solute-depleted regions of the matrix {beta}, with a composition reflecting the local matrix composition and a solute content significantly lower than the average matrix composition. As a result, it has a cuboidal morphology, distinguishably different from the elliposoidal form that is observed in samples water-quenched and annealed at 500 deg. C.

  7. Quasicrystal-reinforced Mg alloys.

    Science.gov (United States)

    Kyun Kim, Young; Tae Kim, Won; Hyang Kim, Do

    2014-04-01

    The formation of the icosahedral phase (I-phase) as a secondary solidification phase in Mg-Zn-Y and Mg-Zn-Al base systems provides useful advantages in designing high performance wrought magnesium alloys. The strengthening in two-phase composites (I-phase + α -Mg) can be explained by dispersion hardening due to the presence of I-phase particles and by the strong bonding property at the I-phase/matrix interface. The presence of an additional secondary solidification phase can further enhance formability and mechanical properties. In Mg-Zn-Y alloys, the co-presence of I and Ca 2 Mg 6 Zn 3 phases by addition of Ca can significantly enhance formability, while in Mg-Zn-Al alloys, the co-presence of the I-phase and Mg 2 Sn phase leads to the enhancement of mechanical properties. Dynamic and static recrystallization are significantly accelerated by addition of Ca in Mg-Zn-Y alloy, resulting in much smaller grain size and more random texture. The high strength of Mg-Zn-Al-Sn alloys is attributed to the presence of finely distributed Mg 2 Sn and I-phase particles embedded in the α -Mg matrix.

  8. Effect of cooling rate on the phase transformation behavior and mechanical properties of Ni-rich NiTi shape memory alloy

    Energy Technology Data Exchange (ETDEWEB)

    Motemani, Y. [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Nili-Ahmadabadi, M. [School of Metallurgy and Materials Engineering, Faculty of Engineering, University of Tehran, 14395-731 Tehran (Iran, Islamic Republic of); Tan, M.J. [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore)], E-mail: mmjtan@ntu.edu.sg; Bornapour, M.; Rayagan, Sh. [School of Metallurgy and Materials Engineering, Faculty of Engineering, University of Tehran, 14395-731 Tehran (Iran, Islamic Republic of)

    2009-02-05

    TiNi alloy is a well-known shape memory alloy and has been widely used for bio-medical, mechanical and electrical applications. In this study, a Ni-rich NiTi alloy was prepared by vacuum arc melting in a water-cooled copper crucible. Three samples of this alloy were heated to 1000 deg. C and cooled in three media: furnace, water, and dry-ice bath. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), hardness measurement and tensile test were carried out to investigate the effect of cooling rate on transformation temperature and mechanical properties. The results show that Ni{sub 3}Ti intermetallic compounds have a great influence on martensitic phase transformation temperature. These tests clearly showed the correlation between cooling rate and properties of the alloy.

  9. Dispersoid reinforced alloy powder and method of making

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver E.; Terpstra, Robert L.

    2017-12-05

    A method of making dispersion-strengthened alloy particles involves melting an alloy having a corrosion and/or oxidation resistance-imparting alloying element, a dispersoid-forming element, and a matrix metal wherein the dispersoid-forming element exhibits a greater tendency to react with a reactive species acquired from an atomizing gas than does the alloying element. The melted alloy is atomized with the atomizing gas including the reactive species to form atomized particles so that the reactive species is (a) dissolved in solid solution to a depth below the surface of atomized particles and/or (b) reacted with the dispersoid-forming element to form dispersoids in the atomized particles to a depth below the surface of said atomized particles. The atomized alloy particles are solidified as solidified alloy particles or as a solidified deposit of alloy particles. Bodies made from the dispersion strengthened alloy particles, deposit thereof, exhibit enhanced fatigue and creep resistance and reduced wear as well as enhanced corrosion and/or oxidation resistance at high temperatures by virtue of the presence of the corrosion and/or oxidation resistance imparting alloying element in solid solution in the particle alloy matrix.

  10. Dispersoid reinforced alloy powder and method of making

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver E.; Terpstra, Robert L.

    2017-10-10

    A method of making dispersion-strengthened alloy particles involves melting an alloy having a corrosion and/or oxidation resistance-imparting alloying element, a dispersoid-forming element, and a matrix metal wherein the dispersoid-forming element exhibits a greater tendency to react with a reactive species acquired from an atomizing gas than does the alloying element. The melted alloy is atomized with the atomizing gas including the reactive species to form atomized particles so that the reactive species is (a) dissolved in solid solution to a depth below the surface of atomized particles and/or (b) reacted with the dispersoid-forming element to form dispersoids in the atomized particles to a depth below the surface of said atomized particles. The atomized alloy particles are solidified as solidified alloy particles or as a solidified deposit of alloy particles. Bodies made from the dispersion strengthened alloy particles, deposit thereof, exhibit enhanced fatigue and creep resistance and reduced wear as well as enhanced corrosion and/or oxidation resistance at high temperatures by virtue of the presence of the corrosion and/or oxidation resistance imparting alloying element in solid solution in the particle alloy matrix.

  11. Modelling of high temperature interfacial reactions in continuously reinforced Ti/SiC metal matrix composites (MMCs)

    International Nuclear Information System (INIS)

    Fox, K.M.

    1993-01-01

    Previous experimental work by Gundel and Wawner showed that the matrix alloy has a strong effect on reaction layer growth in Ti alloy/SCS-6 composite systems. A finite difference technique was used to model the reaction layer growth, which predicts the same trends as those exhibited by the experimental data. Matrix alloying elements such as Mo and Cr in metastable β alloys will affect the equilibrium compositions and diffusivities in the matrix, but matrix diffusion is not found to be rate controlling. Regular solution thermodynamic models indicate that the main affect of matrix composition is in controlling carbon-flux through the reaction layer by altering equilibrium C-TiC-Ti interfacial compositions. (orig.)

  12. Phase separation and antisite defects in the thermoelectric TiNiSn half-Heusler alloys

    International Nuclear Information System (INIS)

    Kirievsky, K.; Gelbstein, Y.; Fuks, D.

    2013-01-01

    The half-Heusler TiNiSn alloys have recently gained an attention as promising candidates for thermoelectric applications. Improvement of these alloys for such applications can be obtained by both electronic and compositional optimizations. The latter can result in a miscibility gap, allowing a phase separation in the nano-scale and consequently a thermal conductivity reduction. Combination of ab initio calculations and statistical thermodynamics was applied for studying the relative stability of a number of superstructures in TiNiSn based alloys. The quasi-binary phase diagram beyond T=0 K for TiNiSn–TiNi 2 Sn solid solutions was calculated using energy parameters extracted from the total energy calculations for ordered structures in the Ni sublattice. We demonstrated that a decomposition of the off-stoichiometric Ni-rich half-Heusler alloy into the stoichiometric TiNiSn phase and into Ni deficient Heusler TiNi 2 Sn phase occurs at elevated temperatures—an effect which recently had been observed experimentally. Furthermore, favorable energetic conditions for antisite defects formation were deduced, based on calculations of the energy of formation, an effect which was explained as a cooperative process of partial disordering on the Ni sublattice. The influence of these two effects on improvement of the thermoelectric performance of TiNiSn based half Heusler compounds is discussed. - Graphical abstract: Phase separation and antisite defects in the thermoelectric TiNiSn alloy, are covered as methods for nanostructuring and thereby enhancement of the thermoelectric potential. - Highlights: • Ab initio calculations/statistical thermodynamics was applied for studying the TiNiSn system. • The phase diagram for TiNiSn–TiNi 2 Sn solid solutions was calculated. • Decomposition of the Ni-rich HH into TiNiSn and Ni deficient TiNi 2 Sn phases was observed. • Favorable energetic conditions for antisite defects formation were deduced

  13. Study of formation mechanism of incipient melting in thixo-cast Al–Si–Cu–Mg alloys

    Energy Technology Data Exchange (ETDEWEB)

    Du, Kang, E-mail: du126kang@126.com; Zhu, Qiang, E-mail: zhu.qiang@grinm.com; Li, Daquan, E-mail: lidaquan@grinm.com; Zhang, Fan, E-mail: sk_zf@163.com

    2015-08-15

    Mechanical properties of thixo-cast Al–Si–Cu–Mg alloys can be enhanced by T61 heat treatment. Copper and magnesium atoms in aluminum matrix can form homogeneously distributed precipitations after solution and aging treatment which harden the alloys. However, microsegregation of these alloying elements could form numerous tiny multi-compound phases during solidification. These phases could cause incipient melting defects in subsequent heat treatment process and degrade the macro-mechanical properties of productions. This study is to present heterogeneous distribution of Cu, Si, and Mg elements and formation of incipient melting defects (pores). In this study, incipient melting pores that occurred during solution treatment at various temperatures, even lower than common melting points of various intermetallic phases, were identified, in terms of a method of investigating the same surface area in the samples before and after solution treatment in a vacuum environment. The results also show that the incipient melting mostly originates at the clusters with fine intermetallic particles while also some at the edge of block-like Al{sub 2}Cu. The fine particles were determined being Al{sub 2}Cu, Al{sub 5}Cu{sub 2}Mg{sub 8}Si{sub 6} and Al{sub 8}Mg{sub 3}FeSi{sub 2}. Tendency of the incipient melting decreases with decreases of the width of the clusters. The formation mechanism of incipient melting pores in solution treatment process was discussed using both the Fick law and the LSW theory. Finally, a criterion of solution treatment to avoid incipient melting pores for the thixo-cast alloys is proposed. - Highlights: • In-situ comparison technique was used to analysis the change of eutectic phases. • The ralationship between eutectic phase size and incipient melting was studied. • Teat treatment criterion for higher incipient melting resistance was proposed.

  14. Study of formation mechanism of incipient melting in thixo-cast Al–Si–Cu–Mg alloys

    International Nuclear Information System (INIS)

    Du, Kang; Zhu, Qiang; Li, Daquan; Zhang, Fan

    2015-01-01

    Mechanical properties of thixo-cast Al–Si–Cu–Mg alloys can be enhanced by T61 heat treatment. Copper and magnesium atoms in aluminum matrix can form homogeneously distributed precipitations after solution and aging treatment which harden the alloys. However, microsegregation of these alloying elements could form numerous tiny multi-compound phases during solidification. These phases could cause incipient melting defects in subsequent heat treatment process and degrade the macro-mechanical properties of productions. This study is to present heterogeneous distribution of Cu, Si, and Mg elements and formation of incipient melting defects (pores). In this study, incipient melting pores that occurred during solution treatment at various temperatures, even lower than common melting points of various intermetallic phases, were identified, in terms of a method of investigating the same surface area in the samples before and after solution treatment in a vacuum environment. The results also show that the incipient melting mostly originates at the clusters with fine intermetallic particles while also some at the edge of block-like Al 2 Cu. The fine particles were determined being Al 2 Cu, Al 5 Cu 2 Mg 8 Si 6 and Al 8 Mg 3 FeSi 2 . Tendency of the incipient melting decreases with decreases of the width of the clusters. The formation mechanism of incipient melting pores in solution treatment process was discussed using both the Fick law and the LSW theory. Finally, a criterion of solution treatment to avoid incipient melting pores for the thixo-cast alloys is proposed. - Highlights: • In-situ comparison technique was used to analysis the change of eutectic phases. • The ralationship between eutectic phase size and incipient melting was studied. • Teat treatment criterion for higher incipient melting resistance was proposed

  15. Surface characterization of TiNi deformed by high-pressure torsion

    Energy Technology Data Exchange (ETDEWEB)

    Awang Shri, Dayangku Noorfazidah [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Structural Materials Unit, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan); Tsuchiya, Koichi, E-mail: tsuchiya.koichi@nims.go.jp [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan); Structural Materials Unit, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan); Yamamoto, Akiko [Biomaterials Unit, International Center for Material Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan)

    2014-01-15

    Effect of grain refinements and amorphization by high-pressure torsion (HPT) on surface chemistry was investigated on TiNi. X-ray diffraction and micro-Vickers tests were used to check the phase changes and hardness before and after HPT. X-ray photoelectron spectroscopy was used to observe the changes in the natural passive film formation on the surface. Phase analysis reveals the change of crystalline TiNi to nanostructured one with increased hardness with straining by HPT. Grain refinement and amorphization caused by HPT reduce the amount of metallic Ni in the passive films and also increase the thickness of the film.

  16. The use of Nb in rapid solidified Al alloys and composites

    Energy Technology Data Exchange (ETDEWEB)

    Audebert, F., E-mail: metal@fi.uba.ar [Advanced Materials Group, Facultad de Ingeniería, Universidad de Buenos Aires, Paseo Colón 850, Ciudad de Buenos Aires 1063 (Argentina); Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Department of Mechanical Engineering and Mathematical Sciences, Oxford Brookes University, Wheatley Campus, OX33 1HX Oxford (United Kingdom); Galano, M. [Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Saporiti, F. [Advanced Materials Group, Facultad de Ingeniería, Universidad de Buenos Aires, Paseo Colón 850, Ciudad de Buenos Aires 1063 (Argentina)

    2014-12-05

    Highlights: • The use of Nb in RS Al alloys and composites has been reviewed. • Nb was found to improve the GFA of rapid solidified Al–Fe and Al–Ni alloys. • Nb has higher effect in increasing the corrosion resistance than RE in Al–Fe alloys. • Nb improves the stability of the Al–Fe–Cr icosahedral phase. • Nb improves strength, ductility and toughness of nanoquasicrystalline Al matrix composites. - Abstract: The worldwide requirements for reducing the energy consumption and pollution have increased the demand of new and high performance lightweight materials. The development of nanostructured Al-based alloys and composites is a key direction towards solving this demand. High energy prices and decreased availability of some alloying elements open up the opportunity to use non-conventional elements in Al alloys and composites. In this work the application of Nb in rapid solidified Al-based alloys and Al alloys matrix composites is reviewed. New results that clarify the effect of Nb on rapid solidified Al alloys and composites are also presented. It is observed that Nb stabilises the icosahedral Al–Fe/Cr clusters, enhances the glass forming ability and shifts the icosahedral phase decomposition towards higher temperatures. Nb provides higher corrosion resistance with respect to the pure Al and Al–Fe–RE (RE: rare earth) alloys in the amorphous and crystalline states. The use of Nb as a reinforcement to produce new Al alloy matrix composites is explored. It is observed that Nb provides higher strength, ductility and toughness to the nanoquasicrystalline matrix composite. Nb appears as a new key element that can improve several properties in rapid solidified Al alloys and composites.

  17. Transformation-Induced Creep and Creep Recovery of Shape Memory Alloy.

    Science.gov (United States)

    Takeda, Kohei; Tobushi, Hisaaki; Pieczyska, Elzbieta A

    2012-05-22

    If the shape memory alloy is subjected to the subloop loading under the stress-controlled condition, creep and creep recovery can appear based on the martensitic transformation. In the design of shape memory alloy elements, these deformation properties are important since the deflection of shape memory alloy elements can change under constant stress. The conditions for the progress of the martensitic transformation are discussed based on the kinetics of the martensitic transformation for the shape memory alloy. During loading under constant stress rate, temperature increases due to the stress-induced martensitic transformation. If stress is held constant during the martensitic transformation stage in the loading process, temperature decreases and the condition for the progress of the martensitic transformation is satisfied, resulting in the transformation-induced creep deformation. If stress is held constant during the reverse transformation stage in the unloading process, creep recovery appears due to the reverse transformation. The details for these thermomechanical properties are investigated experimentally for TiNi shape memory alloy, which is most widely used in practical applications. The volume fraction of the martensitic phase increases in proportion to an increase in creep strain.

  18. Synthesis Of NiCrAlC alloys by mechanical alloying; Sintese de ligas NiCrAlC por moagem de alta energia

    Energy Technology Data Exchange (ETDEWEB)

    Silva, A.K.; Pereira, J.I.; Vurobi Junior, S.; Cintho, O.M., E-mail: alissonkws@gmail.co [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil)

    2010-07-01

    The purpose of the present paper is the synthesis of nickel alloys (NiCrAlC), which has been proposed like a economic alternative to the Stellite family Co alloys using mechanical alloying, followed by sintering heat treatment of milled material. The NiCrAlC alloys consist of a chromium carbides dispersion in a Ni{sub 3}Al intermetallic matrix, that is easily synthesized by mechanical alloying. The use of mechanical alloying enables higher carbides sizes and distribution control in the matrix during sintering. We are also investigated the compaction of the processed materials by compressibility curves. The milling products were characterized by X-ray diffraction, and the end product was featured by conventional metallography and scanning electronic microscopy (SEM), that enabled the identification of desired phases, beyond microhardness test, which has been shown comparable to alloys manufactured by fusion after heat treating. (author)

  19. Studies on the optimization of deformation processed metal metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, Tim W. [Iowa State Univ., Ames, IA (United States)

    1994-01-04

    A methodology for the production of deformation processed metal metal matrix composites from hyper-eutectic copper-chromium alloys was developed. This methodology was derived from a basic study of the precipitation phenomena in these alloys encompassing evaluation of microstructural, electrical, and mechanical properties. The methodology developed produces material with a superior combination of electrical and mechanical properties compared to those presently available in commercial alloys. New and novel alloying procedures were investigated to extend the range of production methods available for these material. These studies focused on the use of High Pressure Gas Atomization and the development of new containment technologies for the liquid alloy. This allowed the production of alloys with a much more refined starting microstructure and lower contamination than available by other methods. The knowledge gained in the previous studies was used to develop two completely new families of deformation processed metal metal matrix composites. These composites are based on immissible alloys with yttrium and magnesium matrices and refractory metal reinforcement. This work extends the physical property range available in deformation processed metal metal matrix composites. Additionally, it also represents new ways to apply these metals in engineering applications.

  20. Surface Properties of the IN SITU Formed Ceramics Reinforced Composite Coatings on TI-3AL-2V Alloys

    Science.gov (United States)

    Liu, Peng; Guo, Wei; Hu, Dakui; Luo, Hui; Zhang, Yuanbin

    2012-04-01

    The synthesis of hard composite coating on titanium alloy by laser cladding of Al/Fe/Ni+C/Si3N4 pre-placed powders has been investigated in detail. SEM result indicated that a composite coating with metallurgical joint to the substrate was formed. XRD result indicated that the composite coating mainly consisted of γ-(Fe, Ni), FeAl, Ti3Al, TiC, TiNi, TiC0.3N0.7, Ti2N, SiC, Ti5Si3 and TiNi. Compared with Ti-3Al-2V substrate, an improvement of the micro-hardness and the wear resistance was observed for this composite coating.

  1. SURFACE PROPERTIES OF THE IN SITU FORMED CERAMICS REINFORCED COMPOSITE COATINGS ON TI-3AL-2V ALLOYS

    OpenAIRE

    PENG LIU; WEI GUO; DAKUI HU; HUI LUO; YUANBIN ZHANG

    2012-01-01

    The synthesis of hard composite coating on titanium alloy by laser cladding of Al/Fe/Ni+C/Si3N4 pre-placed powders has been investigated in detail. SEM result indicated that a composite coating with metallurgical joint to the substrate was formed. XRD result indicated that the composite coating mainly consisted of γ-(Fe, Ni), FeAl, Ti3Al, TiC, TiNi, TiC0.3N0.7, Ti2N, SiC, Ti5Si3 and TiNi. Compared with Ti-3Al-2V substrate, an improvement of the micro-hardness and the wear resistance was obser...

  2. Investigating aluminum alloy reinforced by graphene nanoflakes

    Energy Technology Data Exchange (ETDEWEB)

    Yan, S.J., E-mail: shaojiuyan@126.com [Beijing Institute of Aeronautical Materials, Beijing 100095 (China); Dai, S.L.; Zhang, X.Y.; Yang, C.; Hong, Q.H.; Chen, J.Z. [Beijing Institute of Aeronautical Materials, Beijing 100095 (China); Lin, Z.M. [Aviation Industry Corporation of China, Beijing 100022 (China)

    2014-08-26

    As one of the most important engineering materials, aluminum alloys have been widely applied in many fields. However, the requirement of enhancing their mechanical properties without sacrificing the ductility is always a challenge in the development of aluminum alloys. Thanks to the excellent physical and mechanical properties, graphene nanoflakes (GNFs) have been applied as promising reinforcing elements in various engineering materials, including polymers and ceramics. However, the investigation of GNFs as reinforcement phase in metals or alloys, especially in aluminum alloys, is still very limited. In this study, the aluminum alloy reinforced by GNFs was successfully prepared via powder metallurgy approach. The GNFs were mixed with aluminum alloy powders through ball milling and followed by hot isostatic pressing. The green body was then hot extruded to obtain the final GNFs reinforced aluminum alloy nanocomposite. The scanning electron microscopy and transmission electron microscope analysis show that GNFs were well dispersed in the aluminum alloy matrix and no chemical reactions were observed at the interfaces between the GNFs and aluminum alloy matrix. The mechanical properties' testing results show that with increasing filling content of GNFs, both tensile and yield strengths were remarkably increased without losing the ductility performance. These results not only provided a pathway to achieve the goal of preparing high strength aluminum alloys with excellent ductilitybut they also shed light on the development of other metal alloys reinforced by GNFs.

  3. Effect of Dynamic Composite Refinement and Modification on Microstructure of A356 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    WANG Zheng-jun

    2017-01-01

    Full Text Available To make up for the inadequacy of Sr modification,Al-5Ti-1B-1RE master alloy refiner was prepared,then were used together with Al-10Sr master alloy for dynamic composite refinement and modification of A356 alloy.The A356 alloy microstructure of modification was studied and compared with the theoretical calculating results.The results show that the melt is fiercely stirred and vibrated by the JJ-1 laboratory electric stirrer;the refining effect of α-Al phase is excellent;the coarse and needle-like eutectic Si phase transforms into tiny,widely dispersed spherical particles and well-distributed at the grain boundaries.And mechanical property of the A356 alloy increases obviously.The grain size control study results are consistent with Johnson-Mehl equation theory.At the same time,the contents of gases of the A356 alloy are significantly reduced,which can not be achieved by Sr alone.Quantitative calculating results of degassing mechanism are consistent with the approximate calculating equations of thermodynamics and Stokes Law.

  4. My Experience with Ti-Ni-Based and Ti-Based Shape Memory Alloys

    Science.gov (United States)

    Miyazaki, Shuichi

    2017-12-01

    The present author has been studying shape memory alloys including Cu-Al-Ni, Ti-Ni-based, and Ni-free Ti-based alloys since 1979. This paper reviews the present author's research results for the latter two materials since 1981. The topics on the Ti-Ni-based alloys include the achievement of superelasticity in Ti-Ni alloys through understanding of the role of microstructures consisting of dislocations and precipitates, followed by the contribution to the development of application market of shape memory effect and superelasticity, characterization of the R-phase and monoclinic martensitic transformations, clarification of the basic characteristics of fatigue properties, development of sputter-deposited shape memory thin films and fabrication of prototypes of microactuators utilizing thin films, development of high temperature shape memory alloys, and so on. The topics of Ni-free Ti-based shape memory alloys include the characterization of the orthorhombic phase martensitic transformation and related shape memory effect and superelasticity, the effects of texture, omega phase and adding elements on the martensitic transformation and shape memory properties, clarification of the unique effects of oxygen addition to induce non-linear large elasticity, Invar effect and heating-induced martensitic transformation, and so on.

  5. Chrome-free Samarium-based Protective Coatings for Magnesium Alloys

    Science.gov (United States)

    Hou, Legan; Cui, Xiufang; Yang, Yuyun; Lin, Lili; Xiao, Qiang; Jin, Guo

    The microstructure of chrome-free samarium-based conversion coating on magnesium alloy was investigated and the corrosion resistance was evaluated as well. The micro-morphology, transverse section, crystal structure and composition of the coating were observed by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and X- ray photoelectron spectroscopy (XPS), respectively. The corrosion resistance was evaluated by potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS). The results reveal that the morphology of samarium conversion coating is of crack-mud structure. Tiny cracks distribute in the compact coating deposited by samarium oxides. XRD, EDS and XPS results characterize that the coating is made of amorphous and trivalent-samarium oxides. The potentiodynamic polarization curve, EIS and OCP indicate that the samarium conversion coating can improve the corrosion resistance of magnesium alloys.

  6. Torsional Properties of TiNi Shape Memory Alloy Tape for Rotary Actuator

    Science.gov (United States)

    Takeda, K.; Tobushi, H.; Mitsui, K.; Nishimura, Y.; Miyamoto, K.

    2012-12-01

    In order to develop novel shape memory actuators, the torsional deformation of a shape memory alloy (SMA) tape and the actuator models driven by the tape were investigated. The results obtained can be summarized as follows. In the SMA tape subjected to torsion, the martensitic transformation appears along both edges of the tape due to elongation of these elements and grows to the central part. The fatigue life in both the pulsating torsion and alternating torsion is expressed by the unified relationship of the dissipated work in each cycle. Based on an opening and closing door model and a solar-powered active blind model, the two-way rotary driving actuator with a small and simple mechanism can be developed by using torsion of the SMA tape.

  7. Phase distribution studies in metallic alloy SIMFUEL

    International Nuclear Information System (INIS)

    Kolay, S.; Basu, M.; Kaity, S.; Das, D.

    2014-01-01

    Utilization of U-Pu based alloy fuel in the three stage nuclear power generation program in India is one of the important mandate due to shorter doubling time for breeding of the fissile isotopes ( 239 Pu and 233 U) to be used in Th based driver fuel in the 3rd stage. Reported information shows successful performance of fuel with porous alloy matrix in achieving 10-15 atom % burn-up. The porosity and microstructure of this alloy are strongly dependent on the composition and phases of the fission products incorporated in the matrix. The porosity influences the extent of fuel swelling and fission gas release, which affects the performance and integrity of the fuel. This study addresses to these issues taking the base alloy U-10wt% Zr

  8. Enhancement of Impact Toughness by Delamination Fracture in a Low-Alloy High-Strength Steel with Al Alloying

    Science.gov (United States)

    Sun, Junjie; Jiang, Tao; Liu, Hongji; Guo, Shengwu; Liu, Yongning

    2016-12-01

    The effect of delamination toughening of martensitic steel was investigated both at room and low temperatures [253 K and 233 K (-20 °C and -40 °C)]. Two low-alloy martensitic steels with and without Al alloying were both prepared. Layered structure with white band and black matrix was observed in Al alloyed steel, while a homogeneous microstructure was displayed in the steel without Al. Both steels achieved high strength (tensile strength over 1600 MPa) and good ductility (elongation over 11 pct), but they displayed stark contrasts on impact fracture mode and Charpy impact energy. Delamination fracture occurred in Al alloyed steel and the impact energies were significantly increased both at room temperature (from 75 to 138 J, i.e., nearly improved up to 2 times) and low temperatures [from 47.9 to 71.3 J at 233 K (-40 °C)] compared with the one without Al. Alloying with Al promotes the segregation of Cr, Mn, Si and C elements to form a network structure, which is martensite with higher carbon content and higher hardness than that of the matrix. And this network structure evolved into a band structure during the hot rolling process. The difference of yield stress between the band structure and the matrix gives rise to a delamination fracture during the impact test, which increases the toughness greatly.

  9. Superplasticity in powder metallurgy aluminum alloys and composites

    International Nuclear Information System (INIS)

    Mishra, R.S.; Bieler, T.R.; Mukherjee, A.K.

    1995-01-01

    Superplasticity in powder metallurgy Al alloys and composites has been reviewed through a detailed analysis. The stress-strain curves can be put into 4 categories: classical well-behaved type, continuous strain hardening type, continuous strain softening type and complex type. The origin of these different types of is discussed. The microstructural features of the processed material and the role of strain have been reviewed. The role of increasing misorientation of low angle boundaries to high angle boundaries by lattice dislocation absorption is examined. Threshold stresses have been determined and analyzed. The parametric dependencies for superplastic flow in modified conventional aluminum alloys, mechanically alloyed alloys and Al alloy matrix composites is determined to elucidate the superplastic mechanism at high strain rates. The role of incipient melting has been analyzed. A stress exponent of 2, an activation energy equal to that for grain boundary diffusion and a grain size dependence of 2 generally describes superplastic flow in modified conventional Al alloys and mechanically alloyed alloys. The present results agree well with the predictions of grain boundary sliding models. This suggests that the mechanism of high strain rate superplasticity in the above-mentioned alloys is similar to conventional superplasticity. The shift of optimum superplastic strain rates to higher values is a consequence of microstructural refinement. The parametric dependencies for superplasticity in aluminum alloy matrix composites, however, is different. A true activation energy of superplasticity in aluminum alloy matrix composites, however, is different. A true activation energy of 313 kJ/mol best describes the composites having SiC reinforcements. The role of shape of the reinforcement (particle or whisker) and processing history is addressed. The analysis suggests that the mechanism for superplasticity in composites is interface diffusion controlled grain boundary sliding

  10. The kinetics of Cr layer coated on TiNi films for hydrogen absorption

    Indian Academy of Sciences (India)

    The effect of hydrogen absorption on electrical resistance with temperature for TiNi and TiNi–Cr thin films was investigated. The TiNi thin films of thickness 800 Å were deposited at different angles ( = 0°, 30°, 45°, 60° and 75°) under 10−5 Torr pressure by thermal evaporation on the glass substrate at room temperature.

  11. Struggling to Hear? Tiny Devices Can Keep You Connected

    Science.gov (United States)

    ... Human Services Search form Search Site Menu Home Latest Issue Past Issues Special Issues Subscribe May 2018 Print this issue Struggling to Hear? Tiny Devices Can Keep You Connected En español Send us ...

  12. Epoxy resins and low melting point alloy composites

    OpenAIRE

    Ł. Wierzbicki; J. Stabik

    2011-01-01

    Purpose: The goal of this work was to describe manufacturing process of polymer matrix composite materials reinforced with Wood’s alloy particles and to observe changes of structure.Design/methodology/approach: Polymer matrix composite materials reinforced with the Wood’s alloy particles fabricating method was developed during the investigations, making it possible to obtain materials with good mechanical, electrical and thermal properties . Microscopic examination of samples cross- sections ...

  13. Comparison of three Ni-Hard I alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, Omer N.; Hawk, Jeffrey A.; Rice, J. (Texaloy Foundry Co., Inc., Floresville, Texas)

    2004-09-01

    This report documents the results of an investigation which was undertaken to reveal the similarities and differences in the mechanical properties and microstructural characteristics of three Ni-Hard I alloys. One alloy (B1) is ASTM A532 class IA Ni-Hard containing 4.2 wt. pct. Ni. The second alloy (B2) is similar to B1 but higher in Cr, Si, and Mo. The third alloy (T1) also falls in the same ASTM specification, but it contains 3.3 wt. pct. Ni. The alloys were evaluated in both as-cast and stress-relieved conditions except for B2, which was evaluated in the stress-relieved condition only. While the matrix of the high Ni alloys is composed of austenite and martensite in both conditions, the matrix of the low Ni alloy consists of a considerable amount of bainite, in addition to the martensite and the retained austenite in as cast condition, and primarily bainite, with some retained austenite, in the stress relieved condition. It was found that the stress relieving treatment does not change the tensile strength of the high Ni alloy. Both the as cast and stress relieved high Ni alloys had a tensile strength of about 350 MPa. On the other hand, the tensile strength of the low Ni alloy increased from 340 MPa to 452 MPa with the stress relieving treatment. There was no significant difference in the wear resistance of these alloys in both as-cast and stressrelieved conditions.

  14. Tool material effect on the friction stir butt welding of AA2124-T4 Alloy Matrix MMC

    Directory of Open Access Journals (Sweden)

    Yahya Bozkurt

    2018-01-01

    Full Text Available The purpose of the present work is to study on the effect of material properties tool on friction stir butt welding of AA2124-T4 alloy matrix MMC. Uncoated tool, coated tool with a CrN, and coated tool with AlTiN were used to weld aluminum MMC plates. Macrostructure and microstructure observations, ultimate tensile strength, wear resistance, and chemical analysis were carried out to determine the appropriate tool for joining these composite plates. Results showed that the good welded joints could be obtained when a tool is coated with AlTiN.

  15. XPS characterization of surface and interfacial structure of sputtered TiNi films on Si substrate

    International Nuclear Information System (INIS)

    Fu Yongqing; Du Hejun; Zhang, Sam; Huang Weimin

    2005-01-01

    TiNi films were prepared by co-sputtering TiNi and Ti targets. X-ray photoelectron spectroscopy (XPS) was employed to study surface chemistry of the films and interfacial structure of Si/TiNi system. Exposure of the TiNi film to the ambient atmosphere (23 deg. C and 80% relatively humidity) facilitated quick adsorption of oxygen and carbon on the surface. With time, carbon and oxygen content increased drastically at the surface, while oxygen diffused further into the layer. After a year, carbon content at the surface became as high as 65.57% and Ni dropped below the detection limit of XPS. Depth profiling revealed that significant inter-diffusion occurred between TiNi film and Si substrate with a layer of 90-100 nm. The detailed bond changes of different elements with depth were obtained using XPS and the formation of titanium silicides at the interface were identified

  16. Ductile tungsten-nickel alloy and method for making same

    Science.gov (United States)

    Snyder, Jr., William B.

    1976-01-01

    The present invention is directed to a ductile, high-density tungsten-nickel alloy which possesses a tensile strength in the range of 100,000 to 140,000 psi and a tensile elongation of 3.1 to 16.5 percent in 1 inch at 25.degree.C. This alloy is prepared by the steps of liquid phase sintering a mixture of tungsten-0.5 to 10.0 weight percent nickel, heat treating the alloy at a temperature above the ordering temperature of approximately 970.degree.C. to stabilize the matrix phase, and thereafter rapidly quenching the alloy in a suitable liquid to maintain the matrix phase in a metastable, face-centered cubic, solid- solution of tungsten in nickel.

  17. Improvement of the performance of Mg-based alloy electrodes at ambient temperatures

    International Nuclear Information System (INIS)

    Liu, H.K.; Chen, J.; Sun, L.; Bradhurst, D.H.; Dou, S.X.

    1998-01-01

    Full text: Rechargeable batteries are finding increased application in modern communications, computers, and electric vehicles. The Nickel-Metal Hydride (Ni-MH) battery has the best comprehensive properties. It is known that the important step to increase the energy density of Ni-MH battery is to improve the negative (metal hydride) electrode properties. Of all the hydrogen storage alloys studied previously, (the best know alloys are LaNi 5 , Mg 2 Ni, Ti 2 Ni , TiNi and Zr 2 Ni), the intermetallic compound Mg 2 Ni has the highest theoretical hydrogen storage capacity. The Mg 2 Ni-based hydrogen storage alloy is a promising material for increasing the negative electrode capacity of Ni-MH batteries because this alloy is superior to the LaNi 5 -system or the Zr-based alloys in materials cost and hydrogen absorption capacity. A serious disadvantage, however, is that the reactions of most magnesium based alloys with hydrogen require relatively high temperature (>300 deg C) and pressure (up to 10 atm) due to the slowness of the hydriding/dehydriding reactions. In this paper it is shown that with a combination of modifications to the alloy composition and methods of electrode preparation, magnesium-based alloys can be made into electrodes which will not only be useful at ambient temperatures but will have a useful cycle life and extremely high capacity

  18. Impact toughness of laser surface alloyed Aluminium

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2012-03-01

    Full Text Available with intermetallic phases and metal matrix composites were achieved during laser alloying. Brittle fracture of the SiC particles and transgranular cracking of the intermetallic phases was observed for the laser alloyed samples, while ductile fracture was observed...

  19. From tiny microalgae to huge biorefineries

    OpenAIRE

    Gouveia, L.

    2014-01-01

    Microalgae are an emerging research field due to their high potential as a source of several biofuels in addition to the fact that they have a high-nutritional value and contain compounds that have health benefits. They are also highly used for water stream bioremediation and carbon dioxide mitigation. Therefore, the tiny microalgae could lead to a huge source of compounds and products, giving a good example of a real biorefinery approach. This work shows and presents examples of experimental...

  20. THE ROLE OF TINY GRAINS ON THE ACCRETION PROCESS IN PROTOPLANETARY DISKS

    International Nuclear Information System (INIS)

    Bai Xuening

    2011-01-01

    Tiny grains such as polycyclic aromatic hydrocarbons (PAHs) have been thought to dramatically reduce the coupling between the gas and magnetic fields in weakly ionized gas such as in protoplanetary disks (PPDs) because they provide a tremendous surface area to recombine free electrons. The presence of tiny grains in PPDs thus raises the question of whether the magnetorotational instability (MRI) is able to drive rapid accretion consistent with observations. Charged tiny grains have similar conduction properties as ions, whose presence leads to qualitatively new behaviors in the conductivity tensor, characterized by n-bar /n e >1, where n e and n-bar denote the number densities of free electrons and all other charged species, respectively. In particular, Ohmic conductivity becomes dominated by charged grains rather than by electrons when n-bar /n e exceeds about 10 3 , and Hall and ambipolar diffusion (AD) coefficients are reduced by a factor of ( n-bar /n e ) 2 in the AD-dominated regime relative to that in the Ohmic regime. Applying the methodology of Bai, we find that in PPDs, when PAHs are sufficiently abundant (∼> 10 -9 per H 2 molecule), there exists a transition radius r trans of about 10-20 AU, beyond which the MRI active layer extends to the disk midplane. At r trans , the optimistically predicted MRI-driven accretion rate M-dot is one to two orders of magnitude smaller than that in the grain-free case, which is too small compared with the observed rates, but is in general no smaller than the predicted M-dot with solar-abundance 0.1 μm grains. At r > r trans , we find that, remarkably, the predicted M-dot exceeds the grain-free case due to a net reduction of AD by charged tiny grains and reaches a few times 10 -8 M sun yr -1 . This is sufficient to account for the observed M-dot in transitional disks. Larger grains (∼> 0.1 μm) are too massive to reach such high abundance as tiny grains and to facilitate the accretion process.

  1. Design of powder metallurgy titanium alloys and composites

    International Nuclear Information System (INIS)

    Liu, Y.; Chen, L.F.; Tang, H.P.; Liu, C.T.; Liu, B.; Huang, B.Y.

    2006-01-01

    Low cost and good performance are two major factors virtually important for Ti alloy development. In this paper, we have studied the effects of alloying elements, thermo-mechanical treatment and particle reinforcement on microstructures and mechanical properties of powder metallurgy (PM) Ti alloys and their composites. Our results indicate that low cost PM Ti alloys and their composites with attractive properties can be fabricated through a single compaction-sintering process, although secondary treatments are required for high performance applications. Three new PM Ti alloys and one TiC/Ti composite of high performance are developed, and new design principles are also proposed. For design of PM Ti alloys, addition of alloying elements has the beneficial effect of enhanced sintering and/or improved mechanical properties. For example, Fe element accelerates the sintering process, Mo and Al are good candidates for solution strengthening, and rare earth elements effectively increase the material ductility by scavenging oxygen from the Ti matrix. For the design of Ti-based composites, in situ formation of strengthening particles and solid solution hardening of the matrix both should be considered simultaneously for alloy development. Cr 3 C 2 is found to be a very suitable additive for processing particle reinforced Ti composites

  2. La doping effect on TZM alloy oxidation behavior

    International Nuclear Information System (INIS)

    Yang, Fan; Wang, Kuai-She; Hu, Ping; He, Huan-Cheng; Kang, Xuan-Qi; Wang, Hua; Liu, Ren-Zhi; Volinsky, Alex A.

    2014-01-01

    Highlights: • The oxidation can be resisted by doping La into TZM alloy. • La doped TZM alloy has more compact organization. • It can rise the starting temperature of severe oxidation reaction by more than 50 °C. • Effectively slow down the oxidation rate. • Provide guidance for experiments of improving high-temperature oxidation resistance. - Abstract: Powder metallurgy methods were utilized to prepare lanthanum-doped (La-TZM) and traditional TZM alloy plates. High temperature oxidation experiments along with the differential thermal analysis were employed to study the oxidation behavior of the two kinds of TZM alloys. An extremely volatile oxide layer was generated on the surface of traditional TZM alloy plates when the oxidation started. Molybdenum oxide volatilization exposed the alloy matrix, which was gradually corroded by oxygen, losing its quality with serious surface degradation. The La-TZM alloy has a more compact structure due to the lanthanum doping. The minute lanthanum oxide particles are pinned at the grain boundaries and refine the grains. Oxide layer generated on the matrix surface can form a compact coating, which effectively blocks the surface from being corroded by oxidation. The oxidation resistance of La-TZM alloys has been enhanced, expanding its application range

  3. Electrochemical behavior of anodized AA6063-T6 alloys affected by matrix structures

    International Nuclear Information System (INIS)

    Huang, Yung-Sen; Shih, Teng-Shih; Wu, Chen-En

    2013-01-01

    Highlights: ► Deformation after solution treatment introduced Al matrix to have deformation bands and few Si particles. ► Dislocations remained in the matrix lift up field potential and produce AlOOH oxide in the AAO film. ► The silicon-containing particles were found to trap in the AAO film. ► The silicon particles and the Al(OOH) oxide is significantly to influence the electrochemical behavior of AAO films. - Abstract: AA 6063 alloys were cold-rolled (CR) either before or after solution treatment (S) and then different samples were artificially aged (T6) to obtain different samples (CRST6 and SCRT6). The highest dislocation density was observed in the SCRT6 sample which also showed the lowest particle count among the three samples; ST6, CRST6 and SCRT6. Subsequently, all samples were anodized in a 15 wt% sulfuric acid solution for different time spans to obtain anodic aluminum oxide (AAO) films. The anodized samples were further analyzed with X-ray Photoelectron Spectroscopy (XPS) analysis. We determined that the constituent phases in the AAO film were composed of hydrated amorphous alumina, hydrated oxide (Al(OH) 3 ) and oxyhydroxide (AlOOH) phases together with some silicon-containing particles trapped in the films on all samples. In the electrochemical test, the silicon-containing particles and hydrated Al(OH) 3 oxide that existed at the electrolyte/film (e/f) interface were found to inversely influence the corrosion resistance of the anodized samples.

  4. Investigation of wetting property between liquid lead lithium alloy and several structural materials for Chinese DEMO reactor

    Science.gov (United States)

    Lu, Wei; Wang, Weihua; Jiang, Haiyan; Zuo, Guizhong; Pan, Baoguo; Xu, Wei; Chu, Delin; Hu, Jiansheng; Qi, Junli

    2017-10-01

    The dual-cooled lead lithium (PbLi) blanket is considered as one of the main options for the Chinese demonstration reactor (DEMO). Liquid PbLi alloy is used as the breeder material and coolant. Reduced activation ferritic/martensitic (RAFM) steel, stainless steel and the silicon carbide ceramic matrix composite (SiCf) are selected as the substrate materials for different use. To investigate the wetting property and inter-facial interactions of PbLi/RAFM steel, PbLi/SS316L, PbLi/SiC and PbLi/SiCf couples, in this paper, the special vacuum experimental device is built, and the 'dispensed droplet' modification for the classic sessile droplet technique is made. Contact angles are measured between the liquid PbLi and the various candidate materials at blanket working temperature from 260 to 480 °C. X-ray photoelectron spectroscopy (XPS) is used to characterize the surface components of PbLi droplets and substrate materials, in order to study the element trans-port and corrosion mechanism. Results show that SiC composite (SiCf) and SiC ceramic show poor wetting properties with the liquid PbLi alloy. Surface roughness and testing temperature only provide tiny improvements on the wetting property below 480 °C. RAFM steel performs better wetting properties and corrosion residence when contacted with molten PbLi, while SS316L shows low corrosion residence above 420 °C for the decomposition of protective surface film mainly consisted of chromic sesquioxide. The results could provide meaningful compatibility database of liquid PbLi alloy and valuable reference in engineering design of candidate structural and functional materials for future fusion blanket.

  5. Microstructure, Friction and Wear of Aluminum Matrix Composites

    Science.gov (United States)

    Florea, R. M.

    2018-06-01

    MMCs are made by dispersing a reinforcing material into a metal matrix. They are prepared by casting, although several technical challenges exist with casting technology. Achieving a homogeneous distribution of reinforcement within the matrix is one such challenge, and this affects directly on the properties and quality of composite. The aluminum alloy composite materials consist of high strength, high stiffness, more thermal stability, more corrosion and wear resistance, and more fatigue life. Aluminum alloy materials found to be the best alternative with its unique capacity of designing the materials to give required properties. In this work a composite is developed by adding silicon carbide in Aluminum metal matrix by mass ratio 5%, 10% and 15%. Mechanical tests such as hardness test and microstructure test are conducted.

  6. High strength corrosion-resistant zirconium aluminum alloys

    International Nuclear Information System (INIS)

    Schulson, E.M.; Cameron, D.J.

    1976-01-01

    A zirconium-aluminum alloy is described possessing superior corrosion resistance and mechanical properties. This alloy, preferably 7.5-9.5 wt% aluminum, is cast, worked in the Zr(Al)-Zr 2 Al region, and annealed to a substantially continuous matrix of Zr 3 Al. (E.C.B.)

  7. Micromechanical Analysis of Crack Closure Mechanism for Intelligent Material Containing TiNi Fibers

    Science.gov (United States)

    Araki, Shigetoshi; Ono, Hiroyuki; Saito, Kenji

    In our previous study, the micromechanical modeling of an intelligent material containing TiNi fibers was performed and the stress intensity factor KI at the tip of the crack in the material was expressed in terms of the magnitude of the shape memory shrinkage of the fibers and the thermal expansion strain in the material. In this study, the value of KI at the tip of the crack in the TiNi/epoxy material is calculated numerically by using analytical expressions obtained in our first report. As a result, we find that the KI value decreases with increasing shrink strain of the fibers, and this tendency agrees with that of the experimental result obtained by Shimamoto etal.(Trans. Jpn. Soc. Mech. Eng., Vol. 65, No. 634 (1999), pp. 1282-1286). Moreover, there exists an optimal value of the shrink strain of the fibers to make the KI value zero. The change in KI with temperature during the heating process from the reference temperature to the inverse austenitic finishing temperature of TiNi fiber is also consistent with the experimental result. These results can be explained by the changes in the shrink strain, the thermal expansion strain, and the elastic moduli of TiNi fiber with temperature. These results may be useful in designing intelligent materials containing TiNi fibers from the viewpoint of crack closure.

  8. Tungsten wire-nickel base alloy composite development

    Science.gov (United States)

    Brentnall, W. D.; Moracz, D. J.

    1976-01-01

    Further development and evaluation of refractory wire reinforced nickel-base alloy composites is described. Emphasis was placed on evaluating thermal fatigue resistance as a function of matrix alloy composition, fabrication variables and reinforcement level and distribution. Tests for up to 1,000 cycles were performed and the best system identified in this current work was 50v/o W/NiCrAlY. Improved resistance to thermal fatigue damage would be anticipated for specimens fabricated via optimized processing schedules. Other properties investigated included 1,093 C (2,000 F) stress rupture strength, impact resistance and static air oxidation. A composite consisting of 30v/o W-Hf-C alloy fibers in a NiCrAlY alloy matrix was shown to have a 100-hour stress rupture strength at 1,093 C (2,000 F) of 365 MN/square meters (53 ksi) or a specific strength advantage of about 3:1 over typical D.S. eutectics.

  9. Salt fog corrosion behavior in a powder-processed icosahedral-phase-strengthened aluminum alloy

    International Nuclear Information System (INIS)

    Watson, T.J.; Gordillo, M.A.; Ernst, A.T.; Bedard, B.A.; Aindow, M.

    2017-01-01

    Highlights: • Pitting corrosion resistance has been evaluated for an Al-Cr-Mn-Co-Zr alloy. • Pit densities and depths are far lower than for other high-strength Al alloys. • Corrosion proceeds by selective oxidation of the Al matrix around the other phases. - Abstract: The pitting corrosion resistance has been evaluated for a powder-processed Al-Cr-Mn-Co-Zr alloy which contains ≈35% by volume of an icosahedral quasi-crystalline phase and a little Al 9 Co 2 in an Al matrix. ASTM standard salt fog exposure tests show that the alloy exhibits far lower corrosion pit densities and depths than commercial high-strength aerospace Al alloys under the same conditions. Electron microscopy data show that the salt fog exposure leads to the selective oxidation of the face-centered cubic Al matrix around the other phases, and to the development of a porous outer oxide scale.

  10. HIGH TEMPERATURE EROSION WEAR OF CERMET PARTICLES REINFORCED SELF-FLUXING ALLOY MATRIX HVOF SPRAYED COATINGS

    Directory of Open Access Journals (Sweden)

    Andrei Surzhenkov

    2015-09-01

    Full Text Available In the present paper, the resistance of high velocity oxy-fuel (HVOF sprayed TiC-NiMo and Cr3C2-Ni cermet particles reinforced NiCrSiB self-fluxing alloy matrix coatings to high temperature erosion wear is studied. Microstructure of the coatings was examined by SEM, phase composition was determined by XRD. A four-channel centrifugal particle accelerator was applied to study the high temperature erosion wear of the coatings. The impact angles were 30 and 90 degrees, initial particle velocity was 50 m/s, temperature of the test - 650 degrees. Volume wear of the coatings was calculated and compared to the respective values of the reference materials. Wear mechanisms were studied by SEM.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7617

  11. Fast Response Shape Memory Effect Titanium Nickel (TiNi) Foam Torque Tubes

    Science.gov (United States)

    Jardine, Peter

    2014-01-01

    Shape Change Technologies has developed a process to manufacture net-shaped TiNi foam torque tubes that demonstrate the shape memory effect. The torque tubes dramatically reduce response time by a factor of 10. This Phase II project matured the actuator technology by rigorously characterizing the process to optimize the quality of the TiNi and developing a set of metrics to provide ISO 9002 quality assurance. A laboratory virtual instrument engineering workbench (LabVIEW'TM')-based, real-time control of the torsional actuators was developed. These actuators were developed with The Boeing Company for aerospace applications.

  12. Galled by the Gallbladder?: Your Tiny, Hard-Working Digestive Organ

    Science.gov (United States)

    ... Galled by the Gallbladder? Your Tiny, Hard-Working Digestive Organ En español Send us your comments Most ... among the most common and costly of all digestive system diseases. By some estimates, up to 20 ...

  13. Acoustic emission during R-phase and martensitic transformations in a Ti50.2Ni48.3Fe1.5 alloy

    International Nuclear Information System (INIS)

    Takashima, K.; Nishida, M.

    1995-01-01

    Acoustic emission (AE) signals generated during phase transformations in a Ti 50.2 Ni 48.3 Fe 1.5 shape memory alloy have been measured, and the AE parameters have been correlated with the phase transformation events. The AE count rate curve during cooling of the specimen was found to have two distinct peaks at temperatures of approximately 8 and -30 C. These peaks were confirmed by both optical microscopy and differential scanning calorimetry to correspond to the B2 to R phase transformation (at 8 C) and the R to B19' transformation (at -30 C) respectively. This is the first detection of the AE events associated with the R-phase transformation in Ti-Ni shape memory alloys. Although the amplitude distributions during both transformations were almost identical, both the duration and the rise time of AE events during the B2 to R phase transformation were larger than those during the R to B19' transformation. These observations suggest that the transformation velocity of the R-phase transformation is slower than that of the martensitic transformation, and are consistent with the nature of both these transformations. It is concluded that the AE technique can be applied to the determination of transformation temperatures of Ti-Ni alloys on cooling as well as DSC and electrical resistivity measurement. (orig.)

  14. Evaluation of Synthesizing Al2O3 Nano Particles in Copper Matrix by Mechanical Alloying of Cu-1% Al and Copper Oxide

    Directory of Open Access Journals (Sweden)

    S. Safi

    2017-06-01

    Full Text Available Strengthening of copper matrix by dispersion of metallic oxides particles as an efficient way to increase strength without losing thermal and electrical conductivities has been recognized for many years. Such a composite can withstand high temperatures and keep its properties. Such copper alloys have many applications especially in high temperature including resistance welding electrodes, electrical motors and switches. In the present work, at first, the Cu-1%Al solid solution was prepared by the mechanical alloying process via 48 hours of milling. Subsequently, 0.66 gr of copper oxide was added to Cu-1%Al solid solution and mechanically milled for different milling times of 0,16, 32, 48 hours. The milled powder mixtures were investigated by X-Ray Diffraction and scanning electron microscopy techniques. The lattice parameter of Cu increased at first, but then decreased at longer milling times. The internal strain increased and the average Cu crystal size decreased during milling process.The particle size decreased during the whole process. With increasing annealing temprature from 450°C to 750°C, the microhardness values of samples decreased at the beginning but then increased. From these results, it can be concluded that nanosize aluminaparticles are formed in the copper matrix.

  15. Chemical compatibility between cladding alloys and advanced fuels

    International Nuclear Information System (INIS)

    Fee, D.C.; Johnson, C.E.

    1975-05-01

    The National Advanced Fuels Program requires chemical, mechanical, and thermophysical properties data for cladding alloys. The compatibility behavior of cladding alloys with advanced fuels is critically reviewed. in carbide fuel pins, the principal compatibility problem is cladding carburization, diffusion of carbon into the cladding matrix accompanied by carbide precipitation. Carburization changes the mechanical properties of the cladding alloy. The extent of carburization increases in sodium (versus gas) bonded fuels. The depth of carburization increases with increasing sesquicarbide (M 2 C 3 ) content of the fuel. In nitride fuel pins, the principal compatibility problem is cladding nitriding, diffusion of nitrogen into the cladding matrix accompanied by nitride precipitation. Nitriding changes the mechanical properties of the cladding alloy. In both carbide and nitride fuel pins, fission products do not migrate appreciably to the cladding and do not appear to contribute to cladding attack. 77 references. (U.S.)

  16. A new method for soldering particle-reinforced aluminum metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jinbin; Mu, Yunchao [Zhongyuan University of Technology, Zhengzhou 450007 (China); Luo, Xiangwei [Zhengzhou University, Zhengzhou 450002 (China); Niu, Jitai, E-mail: niujitai@163.com [Zhongyuan University of Technology, Zhengzhou 450007 (China)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer Soldering of 55% SiCp/Al composite and Kovar is first achieved in the world. Black-Right-Pointing-Pointer The nickel plating is required on the surface of the composites before soldering. Black-Right-Pointing-Pointer Low welding temperature is set to avoid overheating of the matrix. Black-Right-Pointing-Pointer Chemical and metallurgical bonding of composites and Kovar is carried out. Black-Right-Pointing-Pointer High tension strength of 225 MPa in soldering seam has been obtained. - Abstract: Soldering of aluminum metal matrix composites (Al-SiC) to other structural materials, or even to themselves, has proved unsuccessful mainly due to the poor wetting of these composites by conventional soldering alloys. This paper reports a new approach, which improves the wetting properties of these composites by molting solder alloys to promote stronger bonds. The new approach relies on nickel-plating of the composite's faying surface prior to application of a solder alloy. Based on this approach, an aluminum metal matrix composite containing 55 vol.% SiC particles is successfully soldered to a Fe-Ni-Co alloy (commercially known as Kovar 4J29). The solder material is a zinc-based alloy (Zn-Cd-Ag-Cu) with a melting point of about 400 Degree-Sign C. Microscopic examinations of the aluminum metal matrix composites (Al-MMCs)-Kovar interfaces show that the nickel-plating, prior to soldering, could noticeably enhance the reaction between the molten solder and composites. The fractography of the shear-tested samples revealed that fracture occurs within the composite (i.e. cohesive failure), indicating a good adhesion between the solder alloy and the Al-SiC composite.

  17. A new method for soldering particle-reinforced aluminum metal matrix composites

    International Nuclear Information System (INIS)

    Lu, Jinbin; Mu, Yunchao; Luo, Xiangwei; Niu, Jitai

    2012-01-01

    Highlights: ► Soldering of 55% SiCp/Al composite and Kovar is first achieved in the world. ► The nickel plating is required on the surface of the composites before soldering. ► Low welding temperature is set to avoid overheating of the matrix. ► Chemical and metallurgical bonding of composites and Kovar is carried out. ► High tension strength of 225 MPa in soldering seam has been obtained. - Abstract: Soldering of aluminum metal matrix composites (Al–SiC) to other structural materials, or even to themselves, has proved unsuccessful mainly due to the poor wetting of these composites by conventional soldering alloys. This paper reports a new approach, which improves the wetting properties of these composites by molting solder alloys to promote stronger bonds. The new approach relies on nickel-plating of the composite's faying surface prior to application of a solder alloy. Based on this approach, an aluminum metal matrix composite containing 55 vol.% SiC particles is successfully soldered to a Fe–Ni–Co alloy (commercially known as Kovar 4J29). The solder material is a zinc-based alloy (Zn–Cd–Ag–Cu) with a melting point of about 400 °C. Microscopic examinations of the aluminum metal matrix composites (Al-MMCs)–Kovar interfaces show that the nickel-plating, prior to soldering, could noticeably enhance the reaction between the molten solder and composites. The fractography of the shear-tested samples revealed that fracture occurs within the composite (i.e. cohesive failure), indicating a good adhesion between the solder alloy and the Al–SiC composite.

  18. Atomic bonding and mechanical properties of Al-Mg-Zr-Sc alloy

    Institute of Scientific and Technical Information of China (English)

    高英俊; 班冬梅; 韩永剑; 钟夏平; 刘慧

    2004-01-01

    The valence electron structures of Al-Mg alloy with minor Sc and Zr were calculated according to the empirical electron theory(EET) in solid. The results show that because of the strong interaction of Al atom with Zr and Sc atom in melting during solidification, the Al3 Sc and Al3 (Sc1-xZrx) particles which act as heterogeneous nuclear are firstly crystallized in alloy to make grains refine. In progress of solidification, the Al-Sc, Al-Zr-Sc segregation regions are formed in solid solution matrix of Al-Mg alloy owing to the strong interaction of Al atom with Zr, Scatoms in bulk of alloy, so in the following homogenization treatment, the finer dispersed Al3 Sc and Al3 (Sc1-x Zrx) second-particles which are coherence with the matrix are precipitated in the segregation region. These finer second particles with the strong Al-Zr, Al-Sc covalent bonds can strengthen the covalent bonds in matrix of the alloy, and also enhance the hardness and strength of Al-Mg alloy. Those finer second-particles precipitated in interface of sub-grains can also strengthen the covalence bonds there, and effectively hinder the interface of sub-grains from migrating and restrain the sub-grains from growing, and cause better thermal stability of Al-Mg alloy.

  19. Nano ZrO{sub 2} particles in nanocrystalline Fe–14Cr–1.5Zr alloy powders

    Energy Technology Data Exchange (ETDEWEB)

    Xu, W.Z.; Li, L.L.; Saber, M.; Koch, C.C.; Zhu, Y.T., E-mail: ytzhu@ncsu.edu; Scattergood, R.O.

    2014-09-15

    Here we report on the formation of nano ZrO{sub 2} particles in Fe–14Cr–1.5Zr alloy powders synthesized by mechanical alloying. The nano ZrO{sub 2} particles were found uniformly dispersed in the ferritic matrix powders with an average size of about 3.7 nm, which rendered the alloy powders so stable that it retained nanocrystalline structure after annealing at 900 °C for 1 h. The ZrO{sub 2} nanoparticles have a tetragonal crystal structure and the following orientation relationship with the matrix: (0 0 2){sub ZrO2}//(0 0 2){sub Matrix} and [0 1 0]{sub ZrO2}//[1 2 0]{sub Matrix}. The size and dispersion of the ZrO{sub 2} particles are comparable to those of Y–Ti–O enriched oxides reported in irradiation-resistant ODS alloys. This suggests a potential application of the new alloy powders for nuclear energy applications.

  20. Fabrication, microstructural characterization and wear characteristics of A380 alloy-alumina composites

    KAUST Repository

    Nurani, Sheikh Jaber

    2016-03-10

    To obtain better mechanical and tribological properties than aluminium alloys aluminium is reinforced with alumina particles making aluminium metal matrix composites. In this work scrap piston A380 alloy was used as the matrix alloy. Alumina particles were added by 5%, 10% and 15% into matrix alloy respectively to form desired composites by stir casting technique. Pin on disc wear testing machine with counter surface as steel disc of hardness HRC 32 and surface roughness of 0.62 μm was used to conduct the wear test. In result composites showed superior wear resistance property over A380 alloy. The effect of load, sliding speed and sliding distance on wear behaviour were also examined in this study. Wear mechanism was identified from the worn surface. Both optical and scanning electron microscope (SEM) of the composites was performed to determine the microstructures. Optical micrograph shows grain size decreases with addition of alumina particles. EDS analysis was performed to confirm the presence of α-Al matrix, primary Si particles and intermetallic. As a general method, phase compositions were analyzed by using a scanning electron microscope (SEM) equipped with an energy dispersive spectroscopy (EDS). Optical microstructures were consistent with the SEM micrographs. © 2015 IEEE.

  1. Bonding of aluminium matrix composites for application in the transport industry

    International Nuclear Information System (INIS)

    Urena, A.; Gomez de Salazar, J.M.

    1993-01-01

    A discontinuously reinforced MMC containing 12 vol % SiC particles in an Al-Cu-Mg alloy (AA 2124) matrix has been diffusion bonded. Thick interlayers of different superplastic aluminium alloys (Al-Li 8090 and Al-Cu SUPRAL) were used to reduce the bonding pressure and ensure complete surface contact. Microstructural studies shown higher continuity in joints bonded with 8090 interlayer than with other alloys. Precipitation of rich-copper intermetallic was detected, after bonding, in the interlayer because diffusion of Cu from 2124 matrix. Results suggest that Li contained in the interlayer favours the partial disruption of the aluminium oxide film, making easier the solid state bonding. (orig.)

  2. Influence of the particle size on phase transformation temperatures of Ni-49at.%Ti shape memory alloy powders

    International Nuclear Information System (INIS)

    Anselmo, George Carlos. S.; Castro, Walman B. de; Araujo, Carlos Jose de

    2009-01-01

    It is important to control the martensitic transformation start temperature (Ms) of Ti-Ni alloys because it determines the temperature range over which the shape memory effect and superelasticity appear. Powder metallurgy (PM) is known to provide the possibility of material saving and automated fabrication of at least semi-finished products as well as net-shape components for NiTi alloys. In this study powder with different particle sizes was subjected by gas atomization. The evolution of the control the martensitic transformation start temperature (Ms) was studied by differential scanning calorimetry. The effect of the particle size of powders on the transformation temperatures behaviors was discussed. (author)

  3. Phase transformation and precipitation in aged Ti-Ni-Hf high-temperature shape memory alloys

    International Nuclear Information System (INIS)

    Meng, X.L.; Cai, W.; Zheng, Y.F.; Zhao, L.C.

    2006-01-01

    More attention has been paid to ternary Ti-Ni-Hf high-temperature shape memory alloys (SMAs) due to their high phase transformation temperatures, good thermal stability and low cost. However, the Ti-Ni-Hf alloys have been found to have low ductility and only about 3% shape memory effect and these have hampered their applications. It is well known that there are three methods to improve the shape memory properties of high-temperature SMAs: (a) cold rolling + annealing; (b) adding another element to the alloy; (c) aging. These methods are not suitable to improve the properties of Ti-Ni-Hf alloys. In this paper, a method of conditioning Ni-rich Ti-Ni-Hf alloys as high-temperature SMAs by aging is presented. For Ni-rich Ti 80-x Ni x Hf 20 alloys (numbers indicate at.%) the phase transformation temperatures are on average increased by more than 100 K by aging at 823 K for 2 h. Especially for those alloys with Ni contents less than 50.6 at.%, the martensitic transformation start temperatures (M s ) are higher than 473 K after aging. Transmission electron microscopy shows the presence of (Ti + Hf) 3 Ni 4 precipitates after aging. Compared with the precipitation of Ti 3 Ni 4 particles in Ni-rich Ti-Ni alloys, the precipitation of (Ti + Hf) 3 Ni 4 particles in Ni-rich Ti-Ni-Hf alloys needs higher temperatures and longer times

  4. Lave phase precipitation in Nb- and Ti-based alloys

    International Nuclear Information System (INIS)

    Tewari, R.; Vishwanadh, B.; Dey, G.K.

    2010-01-01

    In multicomponent Nb-based alloys system, which are potential candidate materials for high temperature applications, the presence of Laves phase was noticed along with the silicides in equilibrium with the soft β-matrix. In Ti-Cr alloys, which show a tendency for inverse melting, the formation of the phase was noticed in the β matrix upon aging. The Laves phase being topologically closed pack structure appears to have strong tendency for the formation provided the criterion of atomic size factor is met

  5. Treatment of patella fracture by claw-like shape memory alloy.

    Science.gov (United States)

    Hao, Wei; Zhou, Lugang; Sun, Yujie; Shi, Peng; Liu, Hongzhi; Wang, Xin

    2015-07-01

    Titanium-nickel shape memory alloy (Ti-Ni SMA) is characterized by shape-memory effect, super-elasticity, excellent fatigue behavior, corrosion resistance, acceptable biocompatibility and high damping capacity. Claw-like Ti-Ni SMA fixator (SMA-claw) has been used to treat transverse fracture of patella. 29 patients (19 males, 10 females) aged from 21 to 71 years old (averaged 43.0 years old) have been received open reduction and internal fixation with SMA-claw from January 2011 to December 2011. After operation, patients have been received gradual knee function exercises, followed by radiographic analysis and Lysholm Knee Score at 1, 2, 3, 6, 9 and 12 months postoperation. The mean follow-up time was 11.48 months (25 patients finished, 1 lost after 6 months and 3 lost after 9 months). Radiographic bone union occurred at 2 months (7 patients) or 3 months (22 patients). Satisfied range of motion for the knee joint has been observed with 1.90/141.72° (hyperextension/flexion) at 3 months, 4.83/143.97° at 6 months, 4.82/144.82° at 9 months and 5.2/145° at 12 months postsurgery. The Ti-Ni SMA-claw fixator produced good osteosynthesis effect by continuous recovery stress with relatively simple and minimally invasive handling process, which can be introduced as an alternative to traditional tension band technique for treatment of patellar transverse fracture.

  6. Strengthening mechanisms of Fe nanoparticles for single crystal Cu–Fe alloy

    International Nuclear Information System (INIS)

    Shi, Guodong; Chen, Xiaohua; Jiang, Han; Wang, Zidong; Tang, Hao; Fan, Yongquan

    2015-01-01

    A single crystal Cu–Fe alloy with finely dispersed precipitate Fe nanoparticles was fabricated in this study. The interface relationship of iron nanoparticle and copper matrix was analyzed with a high-resolution transmission electron microscope (HRTEM), and the effect of Fe nanoparticles on mechanical properties of single crystal Cu–Fe alloy was discussed. Results show that, the finely dispersed Fe nanoparticles can be obtained under the directional solidification condition, with the size of 5–50 nm and the coherent interface between the iron nanoparticle and the copper matrix. Single crystal Cu–Fe alloy possesses improved tensile strength of 194.64 MPa, and total elongation of 44.72%, respectively, at room temperature, in contrast to pure Cu sample. Nanoparticles which have coherent interface with matrix can improve the dislocation motion state. Some dislocations can slip through the nanoparticle along the coherent interface and some dislocations can enter into the nanoparticles. Thus to improve the tensile strength of single crystal Cu–Fe alloy without sacrificing the ductility simultaneously. Based on the above analyses, strengthening mechanisms of Fe nanoparticles for single crystal Cu–Fe alloy was described

  7. Manufacturing techniques for titanium aluminide based alloys and metal matrix composites

    Science.gov (United States)

    Kothari, Kunal B.

    Dual phase titanium aluminides composed vastly of gamma phase (TiAl) with moderate amount of alpha2 phase (Ti3Al) have been considered for several high temperature aerospace and automobile applications. High specific strength coupled with good high temperature performance in the areas of creep and oxidation resistance makes titanium aluminides "materials of choice" for next generation propulsion systems. Titanium alumnides are primarily being considered as potential replacements for Ni-based superalloys in gas turbine engine components with aim of developing more efficient and leaner engines exhibiting high thrust-to-weight ratio. Thermo-mechanical treatments have shown to enhance the mechanical performance of titanium aluminides. Additionally, small additions of interstitial elements have shown further and significant improvement in the mechanical performance of titanium alumnide alloys. However, titanium aluminides lack considerably in room temperature ductility and as a result manufacturing processes of these aluminides have greatly suffered. Traditional ingot metallurgy and investment casting based methods to produce titanium aluminide parts in addition to being expensive, have also been unsuccessful in producing titanium aluminides with the desired mechanical properties. Hence, the manufacturing costs associated with these methods have completely outweighed the benefits offered by titanium aluminides. Over the last two decades, several powder metallurgy based manufacturing techniques have been studied to produce titanium aluminide parts. These techniques have been successful in producing titanium aluminide parts with a homogeneous and refined microstructure. These powder metallurgy techniques also hold the potential of significant cost reduction depending on the wide market acceptance of titanium aluminides. In the present study, a powder metallurgy based rapid consolidation technique has been used to produce near-net shape parts of titanium aluminides. Micron

  8. Design of Radiation-Tolerant Structural Alloys for Generation IV Nuclear Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Allen, T.R.; Was, G.S.; Bruemmer, S.M.; Gan, J.; Ukai, S.

    2005-12-28

    The objective of this program is to improve the radiation tolerance of both austenitic and ferritic-martensitic (F-M) alloys projected for use in Generation IV systems. The expected materials limitations of Generation IV components include: creep strength, dimensional stability, and corrosion/stress corrosion compatibility. The material design strategies to be tested fall into three main categories: (1) engineering grain boundaries; (2) alloying, by adding oversized elements to the matrix; and (3) microstructural/nanostructural design, such as adding matrix precipitates. These three design strategies were tested across both austenitic and ferritic-martensitic alloy classes

  9. Virginia Tech researchers find tiny bubbles a storehouse of knowledge

    OpenAIRE

    Trulove, Susan

    2005-01-01

    Fluid inclusions -- tiny bubbles of fluid or vapor trapped inside rock as it forms-- are clues to the location of ores and even petroleum; and they are time capsules that contain insights on the power of volcanos and hints of life in the universe.

  10. Experimental Studies on SiC and Rice Husk Ash Reinforced Al Alloy Composite

    Directory of Open Access Journals (Sweden)

    Shivaprakash Y. M.

    2018-01-01

    Full Text Available In this research work Aluminium alloy with Cu (4.5% as the major alloying element is used as the matrix in which SiC and Rice Husk Ash (RHA are dispersed to develop a hybrid composite. The dispersion is done by the motorized stir casting arrangement. The composite is fabricated by varying the proportions of the reinforcements in the base alloy. The composite specimens were tested for density changes, hardness and the wear. The microstructure images showed a uniform dispersion of the reinforcements in the matrix and this resulted in higher strength to weight ratio. The increase in strength of the composite is probably attributed to the increase in the dislocation density. Also, the abrasive wear resistance of the produced composite is found to be superior as compared to the matrix alloy because of the hard-ceramic particles in the reinforcements.

  11. Rheological Behavior and Microstructure of Ceramic Particulate/Aluminum Alloy Composites. Ph.D. Thesis Final Technical Report

    Science.gov (United States)

    Moon, Hee-Kyung

    1990-01-01

    The rheological behavior and microstructure were investigated using a concentric cylinder viscometer for three different slurries: semi-solid alloy slurries of a matrix alloy, Al-6.5wt percent Si: composite slurries, SiC (sub p) (8.5 microns)/Al-6.5wt percent Si, with the same matrix alloy in the molten state, and composite slurries of the same composition with the matrix alloy in the semi-solid state. The pseudoplasticity of these slurries was obtained by step changes of the shear rate from a given initial shear rate. To study the thixotropic behavior of the system, a slurry was allowed to rest for different periods of time, prior to shearing at a given initial shear rate. In the continuous cooling experiments, the viscosities of these slurries were dependent on the shear rate, cooling rate, volume fraction of the primary solid of the matrix alloy, and volume fraction of silicon carbide. In the isothermal experiments, all three kinds of slurries exhibited non-Newtonian behavior, depending on the volume fraction of solid particles.

  12. Anodic Fabrication of Ti-Ni-O Nanotube Arrays on Shape Memory Alloy

    Directory of Open Access Journals (Sweden)

    Qiang Liu

    2014-04-01

    Full Text Available Surface modification with oxide nanostructures is one of the efficient ways to improve physical or biomedical properties of shape memory alloys. This work reports a fabrication of highly ordered Ti-Ni-O nanotube arrays on Ti-Ni alloy substrates through pulse anodization in glycerol-based electrolytes. The effects of anodization parameters and the annealing process on the microstructures and surface morphology of Ti-Ni-O were studied using scanning electron microscope and Raman spectroscopy. The electrolyte type greatly affected the formation of nanotube arrays. A formation of anatase phase was found with the Ti-Ni-O nanotube arrays annealed at 450 °C. The oxide nanotubes could be crystallized to rutile phase after annealing treatment at 650 °C. The Ti-Ni-O nanotube arrays demonstrated an excellent thermal stability by keeping their nanotubular structures up to 650 °C.

  13. Transmission electron microscopy characterization of microstructural features in aluminum-lithium-copper alloys

    Science.gov (United States)

    Avalos-Borja, M.; Larson, L. A.; Pizzo, P. P.

    1984-01-01

    A transmission electron microscopy (TEM) examination of aluminum-lithium-copper alloys was conducted. The principal purpose is to characterize the nature, size, and distribution of stringer particles which result from the powder metallurgy (P/M) processing of these alloys. Microstructural features associated with the stringer particles are reported that help explain the stress corrosion susceptibility of the powder metallurgy-processed Al-Li-Cu alloys. In addition, matrix precipitaton events are documented for a variety of heat treatments and process variations. Hot rolling is observed to significantly alter the nature of matrix precipitation, and the observations are correlated with concomitant mechanical property variations.

  14. Self-assembly growth of alloyed NiPt nanocrystals with holothuria-like shape for oxygen evolution reaction with enhanced catalytic activity

    Directory of Open Access Journals (Sweden)

    Tao Ding

    2016-01-01

    Full Text Available Self-assembly growth of alloyed NiPt nanocrystals with holothuria-like wire shape has been achieved via a facile and moderate hydrothermal process at 120 °C for 1 h from the reaction of nickel nitrate and chloroplatinic acid in alkaline solution in the presence of ethanediamine and hydrazine hydrate. The holothuria-like alloyed NiPt wires are Ni-rich in composition (Ni23.6Pt and uniform in diameter with many tiny tips outstretched from the wires surface. The holothuria-like wires are assembled from granular subunits with the assistance of capping molecular of ethanediamine and the wires display an improved oxygen evolution reaction catalytic activity.

  15. Effect of heat treatment on corrosion behavior of low pressure sand cast Mg-10Gd-3Y-0.5Zr alloys

    Directory of Open Access Journals (Sweden)

    Qian-qian Wu

    2016-07-01

    Full Text Available The corrosion behaviors of low-pressure sand cast Mg-10Gd-3Y-0.5Zr (wt.% alloys in as-cast, solution treated (T4 and aged (T6 conditions were studied by means of immersion test and electrochemical measurements in 5wt.% NaCl solution saturated with Mg(OH2. It was observed that the corrosion rate in the T4 condition was lower than that of the as-cast and T6 conditions by both sand casting and permanent mold casting with the same order of as-cast>T6>T4; while the corrosion resistance of the permanent mold casting is superior to the sand casting. The morphologies of the corrosion products are similar porous structures consisting of tiny erect flakes perpendicular to the corroded surface of the alloy, irrespective of the heat treatment conditions. Especially, the corrosion film in T4 condition is more compact than that in the other two conditions. In addition, the severer corrosion happening to the as-cast condition is correlated with the galvanic corrosion between the matrix and the eutectic compounds; while improved corrosion resistance for the T4 and T6 conditions is ascribed to the dissolution of the secondary eutectic compounds. The measured corrosion current densities of Mg-10Gd-3Y-0.5Zr alloys in as-cast, T4, and T6 conditions are 36 μA·cm-2, 10 μA·cm-2, and 33 μA·cm-2, respectively. The proposed equivalent circuit [Rs(CPE1(Rt(RfCPE2] by Zview software matches well with the tested electrochemical impedance spectra (EIS data.

  16. Fast LIBS Identification of Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Tawfik W.

    2007-04-01

    Full Text Available Laser-induced breakdown spectroscopy (LIBS has been applied to analysis aluminum alloy targets. The plasma is generated by focusing a 300 mJ pulsed Nd: YAG laser on the target in air at atmospheric pressure. Such plasma emission spectrum was collected using a one-meter length wide band fused-silica optical fiber connected to a portable Echelle spectrometer with intensified CCD camera. Spectroscopic analysis of plasma evolution of laser produced plasmas has been characterized in terms of their spectra, electron density and electron temperature assuming the LTE and optically thin plasma conditions. The LIBS spectrum was optimized for high S/N ratio especially for trace elements. The electron temperature and density were determined using the emission intensity and stark broadening, respectively, of selected aluminum spectral lines. The values of these parameters were found to change with the aluminum alloy matrix, i.e. they could be used as a fingerprint character to distinguish between different aluminum alloy matrices using only one major element (aluminum without needing to analysis the rest of elements in the matrix. Moreover, It was found that the values of T e and N e decrease with increasing the trace elements concentrations in the aluminum alloy samples. The obtained results indicate that it is possible to improve the exploitation of LIBS in the remote on-line industrial monitoring application, by following up only the values of T e and N e for aluminum in aluminum alloys as a marker for the correct alloying using an optical fiber probe.

  17. Effects of aluminum substitution in C14-rich multi-component alloys for NiMH battery application

    International Nuclear Information System (INIS)

    Young, K.; Regmi, R.; Lawes, G.; Ouchi, T.; Reichman, B.; Fetcenko, M.A.; Wu, A.

    2010-01-01

    The effects of aluminum substitution to the structural, electrochemical, and gas phase hydrogen storage properties of C14-rich alloys are reported. Minor phases, including C15 and TiNi, were identified by X-ray diffraction analysis. Entropy and enthalpy were estimated from equilibrium pressure at a fixed hydrogen concentration due to the large slope factor in pressure-concentration-temperature isotherms. The stability of hydrides from these materials, determined from the pressure-concentration isotherm equilibrium pressure and maximum storage capacities has a better correlation with the change in entropy than that in enthalpy. Alloys having smaller unit cell volume, relatively low hydride heat of formation, and relatively higher degree of disorder exhibit lower plateau pressure, higher storage capacity, and smaller hydrogen diffusion coefficient. Comparing to the Co substitution in the same base alloy, Al substitution makes better contribution to both bulk hydrogen transport and surface reaction. Substituting 0.4% Al and 1.5% Co to AB2 alloy is found to be the best combination in terms of general nickel metal hydride battery performance.

  18. Strain-Induced Martensitic Transformation and Texture Evolution in Cold-Rolled Co–Cr Alloys

    Directory of Open Access Journals (Sweden)

    Yusuke Onuki

    2018-05-01

    Full Text Available Co–Cr alloys have been used in biomedical purposes such as stents and artificial hip joints. However, the difficulty of plastic deformation limits the application of the alloys. During the deformation, Co–Cr alloys often exhibit strain-induced martensitic transformation (SIMT, which is a possible reason for the low formability. The distinct increase in dislocation density in the matrix phase may also result in early fractures. Since these microstructural evolutions accompany the textural evolution, it is crucial to understand the relationship among the SIMT, the increase in dislocations, and the texture evolution. To characterize those at the same time, we conducted time-of-flight neutron diffraction experiments at iMATERIA beamline at the Japan Proton Accelerator Research Complex (J-PARC Materials and Life Science Experimental Facility (MLF, Ibaraki, Japan. The cold-rolled sheets of Co–29Cr–6Mo (CCM and Co–20Cr–15W–10Ni (CCWN alloys were investigated in this study. As expected from the different stacking fault energies, the SIMT progressed more rapidly in the CCM alloy. The dislocation densities of the matrix phases of the CCM and CCWN alloys increased similarly with an increase in the rolling reduction. These results suggest that the difference in deformability between the CCM and CCWN alloys originate not from the strain hardening of the matrix phase but from the growth behaviors of the martensitic phase.

  19. Microstructure, Texture, and Mechanical Behavior of As-cast Ni-Fe-W Matrix Alloy

    Science.gov (United States)

    Rao, A. Sambasiva; Manda, Premkumar; Mohan, M. K.; Nandy, T. K.; Singh, A. K.

    2018-04-01

    This article describes the tensile properties, flow, and work-hardening behavior of an experimental alloy 53Ni-29Fe-18W in as-cast condition. The microstructure of the alloy 53Ni-29Fe-18W displays single phase (fcc) in as-cast condition along with typical dendritic features. The bulk texture of the as-cast alloy reveals the triclinic sample symmetry and characteristic nature of coarse-grained materials. The alloy exhibits maximum strength ( σ YS and σ UTS) values along the transverse direction. The elongation values are maximum and minimum along the transverse and longitudinal directions, respectively. Tensile fracture surfaces of both the longitudinal and transverse samples display complete ductile fracture features. Two types of slip lines, namely, planar and intersecting, are observed in deformed specimens and the density of slip lines increases with increasing the amount of deformation. The alloy displays moderate in-plane anisotropy ( A IP) and reasonably low anisotropic index ( δ) values, respectively. The instantaneous or work-hardening rate curves portray three typical stages (I through III) along both the longitudinal and transverse directions. The alloy exhibits dislocation-controlled strain hardening during tensile testing, and slip is the predominant deformation mechanism.

  20. The application of Tiny Triplet Finder (TTF) in BTeV pixel trigger

    International Nuclear Information System (INIS)

    Wu, Jin-Yuan; Wang, M.; Gottschalk, E.; Shi, Z.; Fermilab

    2006-01-01

    We describe a track segment recognition scheme called the Tiny Triplet Finder (TTF) that involves grouping of three hits satisfying a constraint such as forming of a straight line. The TTF performs this O(n 3 ) function in O(n) time, where n is number of hits in each detector plane. The word ''tiny'' reflects the fact that the FPGA resource usage is small. The number of logic elements needed for the TTF is O(Nlog(N)), where N is the number of bins in the coordinate considered, which for large N, is significantly smaller than O(N 2 ) needed for typical implementations of similar functions. The TTF is also suitable for software implementations as well as many other pattern recognition problems

  1. Irradiation-assisted stress corrosion cracking in HTH Alloy X-750 and Alloy 625

    International Nuclear Information System (INIS)

    Bajaj, R.; Mills, W.J.; Lebo, M.R.; Hyatt, B.Z.; Burke, M.G.

    1995-01-01

    In-reactor testing of bolt-loaded compact tension specimens was performed in 360 C water to determine the irradiation-assisted stress corrosion cracking (IASCC) behavior of HTH Alloy X-750 and direct-aged Alloy 625. New data confirm previous results showing that high irradiation levels reduce SCC resistance in Alloy X-750. Heat-to-heat variability correlates with boron content, with low boron heats showing improved IASCC properties. Alloy 625 is resistant to IASCC, as no cracking was observed in any Alloy 625 specimens. Microstructural, microchemical and deformation studies were performed to characterize the mechanisms responsible for IASCC in Alloy X-750 and the lack of an effect in Alloy 625. The mechanisms under investigation are: boron transmutation effects, radiation-induced changes in microstructure and deformation characteristics, and radiation-induced segregation. Irradiation of Alloy X-750 caused significant strengthening and ductility loss that was associated with the formation of cavities and dislocation loops. High irradiation levels did not cause significant segregation of alloying or trace elements in Alloy X-750. Irradiation of Alloy 625 resulted in the formation of small dislocation loops and a fine body-centered-orthorhombic phase. The strengthening due to the loops and precipitates was apparently offset by a partial dissolution of γ double-prime precipitates, as Alloy 625 showed no irradiation-induced strengthening or ductility loss. In the nonirradiated condition, an IASCC susceptible HTH heat containing 28 ppm B showed grain boundary segregation of boron, whereas a nonsusceptible HTH heat containing 2 ppm B and Alloy 625 with 20 ppm B did not show significant boron segregation. Transmutation of boron to helium at grain boundaries, coupled with matrix strengthening, is believed to be responsible for IASCC in Alloy X-750, and the absence of these two effects results in the superior IASCC resistance displayed by Alloy 625

  2. Transmission electron microscopy of Ti-12Mo-13Nb Alloy aged after heat forging

    International Nuclear Information System (INIS)

    Oliveira, Nathalia Rodrigues; Baldan, Renato; Gabriel, Sinara Borborema

    2014-01-01

    Metastable β-Ti alloys possess mechanical properties, in particular a elastic modulus that depends not only on its composition but also the applied thermomechanical treatments. These alloys require high mechanical strength and a low Young’s modulus to avoid stress shielding. Preliminary studies on the development of Ti- 13Nb-12Mo alloy showed than the better properties were obtained at aged at 500 ° C / 24 h after cold forging , whose microstructure consisted of bimodal α phase in the β matrix. In this work, Ti-12Mo-13Nb alloy was heat forged and aged at 500 deg C for 24h and the microstructure was analyzed by employing X-ray diffraction and transmission electron microscopy. According to the results, while the cold forging resulted in bimodal α phase in the β matrix, hot forging resulted in a fine and homogeneous α phase in the β matrix. (author)

  3. Cellular Magnesium Matrix Foam Composites for Mechanical Damping Applications

    Science.gov (United States)

    Shunmugasamy, Vasanth Chakravarthy; Mansoor, Bilal; Gupta, Nikhil

    2016-01-01

    The damping characteristics of metal alloys and metal matrix composites are relevant to the automotive, aerospace, and marine structures. Use of lightweight materials can help in increasing payload capacity and in decreasing fuel consumption. Lightweight composite materials possessing high damping capabilities that can be designed as structural members can greatly benefit in addressing these needs. In this context, the damping properties of lightweight metals such as aluminum and magnesium and their respective composites have been studied in the existing literature. This review focuses on analyzing the damping properties of aluminum and magnesium alloys and their cellular composites. The damping properties of various lightweight alloys and composites are compared on the basis of their density to understand the potential for weight saving in structural applications. Magnesium alloys are observed to possess better damping properties in comparison to aluminum. However, aluminum matrix syntactic foams reinforced with silicon carbide hollow particles possess a damping capacity and density comparable to magnesium alloy. By using the data presented in the study, composites with specific compositions and properties can be selected for a given application. In addition, the comparison of the results helps in identifying the areas where attention needs to be focused to address the future needs.

  4. Refining processes of selected copper alloys

    Directory of Open Access Journals (Sweden)

    S. Rzadkosz

    2009-04-01

    Full Text Available The analysis of the refining effectiveness of the liquid copper and selected copper alloys by various micro additions and special refiningsubstances – was performed. Examinations of an influence of purifying, modifying and deoxidation operations performed in a metal bath on the properties of certain selected alloys based on copper matrix - were made. Refining substances, protecting-purifying slag, deoxidation and modifying substances containing micro additions of such elements as: zirconium, boron, phosphor, sodium, lithium, or their compounds introduced in order to change micro structures and properties of alloys, were applied in examinations. A special attention was directed to macro and micro structures of alloys, their tensile and elongation strength and hot-cracks sensitivity. Refining effects were estimated by comparing the effectiveness of micro structure changes with property changes of copper and its selected alloys from the group of tin bronzes.

  5. Effect of Forging Parameters on Low Cycle Fatigue Behaviour of Al/Basalt Short Fiber Metal Matrix Composites

    Directory of Open Access Journals (Sweden)

    R. Karthigeyan

    2013-01-01

    Full Text Available This paper deals with metal matrix composites (MMCs of Al 7075 alloy containing different weight percentage (2.5, 5, 7.5, and 10 basalt short fiber reinforcement and unreinforced matrix alloy. The samples were produced by the permanent stir casting technique. The casting ingots were cut into blanks to be forged in single stage and double stage, using MN press and graphite-based lubricant. The microstructures and fatigue properties of the matrix alloy and MMC samples were investigated in the as cast state and in the single and double stage forging operations. The microstructure results showed that the forged sample had a uniform distribution of the basalt short fiber throughout the specimens. Evaluation of the fatigue properties showed that the forged samples had higher values than those of the as cast counterparts. After forging, the enhancement of the fatigue strength of the matrix alloy was so significant and high in the case of 2.5 and 5.0 wt. percentage basalt short fiber reinforced MMC, and there was no enhancement in 7.5 and 10 weight percentages short fiber reinforced MMCs. The fracture damage was mainly due to decohesion at the matrix-fiber interface.

  6. Effect of forging parameters on low cycle fatigue behaviour of Al/basalt short fiber metal matrix composites.

    Science.gov (United States)

    Karthigeyan, R; Ranganath, G

    2013-01-01

    This paper deals with metal matrix composites (MMCs) of Al 7075 alloy containing different weight percentage (2.5, 5, 7.5, and 10) basalt short fiber reinforcement and unreinforced matrix alloy. The samples were produced by the permanent stir casting technique. The casting ingots were cut into blanks to be forged in single stage and double stage, using MN press and graphite-based lubricant. The microstructures and fatigue properties of the matrix alloy and MMC samples were investigated in the as cast state and in the single and double stage forging operations. The microstructure results showed that the forged sample had a uniform distribution of the basalt short fiber throughout the specimens. Evaluation of the fatigue properties showed that the forged samples had higher values than those of the as cast counterparts. After forging, the enhancement of the fatigue strength of the matrix alloy was so significant and high in the case of 2.5 and 5.0 wt. percentage basalt short fiber reinforced MMC, and there was no enhancement in 7.5 and 10 weight percentages short fiber reinforced MMCs. The fracture damage was mainly due to decohesion at the matrix-fiber interface.

  7. Understanding hydride formation in Zr-1Nb alloy through microstructural characterization

    International Nuclear Information System (INIS)

    Neogy, S.; Srivastava, D.; Tewari, R.; Singh, R.N.; Dey, G.K.; De, P.K.; Banerjee, S.

    2003-07-01

    In this study the experimental results of hydride formation and their microstructure evolution in Zr-1Nb alloy is presented. This Zr-1Nb binary alloy and other Zr-1 Nb based ternary and quaternary alloys are being used as fuel tube materials and have the potential for meeting the requirement of high burn up fuel. Hydriding of Zr-1Nb alloy having a microstructure comprising equiaxed α grains and a uniform distribution of spherical particles of the β phase has been carried out in this study. The specimens have been hydrided by gaseous charging method to different hydrogen levels. The microstructures of hydrided samples were examined as a function of hydrogen content. The formation of δ hydride in slow cooled specimens and formation of γ hydride in rapidly cooled specimens has been studied with their morphology, habit plane and orientation relationship with the α matrix in view. The habit planes of either type of hydride phase has been determined and compared with those observed in other Zr-Nb alloys. The orientation relationship between the α matrix and the δ hydride was found to be the following: (0001) α // (111) δ and [1120] α // [110] δ . The orientation relationship between the α matrix and the γ hydride was of the following type: (0001) α // (111) γ and [1120] α // [110] γ . The internal structure of both types of hydride has been examined. The effect of the presence of the spherical β phase particles in the a matrix on the growth of the hydride plates has been investigated. (author)

  8. Fast LIBS Identification of Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Tawfik W.

    2007-04-01

    Full Text Available Laser-induced breakdown spectroscopy (LIBS has been applied to analysis aluminum alloy targets. The plasma is generated by focusing a 300 mJ pulsed Nd: YAG laser on the target in air at atmospheric pressure. Such plasma emission spectrum was collected using a one-meter length wide band fused-silica optical fiber connected to a portable Echelle spectrometer with intensified CCD camera. Spectroscopic analysis of plasma evolution of laser produced plasmas has been characterized in terms of their spectra, electron density and electron temperature assuming the LTE and optically thin plasma conditions. The LIBS spectrum was optimized for high S/N ratio especially for trace elements. The electron temperature and density were determined using the emission intensity and stark broadening, respectively, of selected aluminum spectral lines. The values of these parameters were found to change with the aluminum alloy matrix, i.e. they could be used as a fingerprint character to distinguish between different aluminum alloy matrices using only one major element (aluminum without needing to analysis the rest of elements in the matrix. Moreover, It was found that the values of T(e and N(e decrease with increasing the trace elements concentrations in the aluminum alloy samples. The obtained results indicate that it is possible to improve the exploitation of LIBS in the remote on-line industrial monitoring application, by following up only the values of T(e and N(e for the aluminum in aluminum alloys using an optical fiber probe.

  9. Nickel-base alloys having a low coefficient of thermal expansion

    International Nuclear Information System (INIS)

    Baldwin, J.F.; Maxwell, D.H.

    1975-01-01

    Alloy compositions consisting predominantly of nickel, chromium, molybdenum, carbon, and boron are disclosed. The alloys possess a duplex structure consisting of a nickel--chromium--molybdenum matrix and a semi-continuous network of refractory carbides and borides. A combination of desirable properties is provided by these alloys, including elevated temperature strength, resistance to oxidation and hot corrosion, and a very low coefficient of thermal expansion

  10. Synergistic alloying effect on microstructural evolution and mechanical properties of Cu precipitation-strengthened ferritic alloys

    International Nuclear Information System (INIS)

    Wen, Y.R.; Li, Y.P.; Hirata, A.; Zhang, Y.; Fujita, T.; Furuhara, T.; Liu, C.T.; Chiba, A.; Chen, M.W.

    2013-01-01

    We report the influence of alloying elements (Ni, Al and Mn) on the microstructural evolution of Cu-rich nanoprecipitates and the mechanical properties of Fe–Cu-based ferritic alloys. It was found that individual additions of Ni and Al do not give rise to an obvious strengthening effect, compared with the binary Fe–Cu parent alloy, although Ni segregates at the precipitate/matrix interface and Al partitions into Cu-rich precipitates. In contrast, the co-addition of Ni and Al results in the formation of core–shell nanoprecipitates with a Cu-rich core and a B2 Ni–Al shell, leading to a dramatic improvement in strength. The coarsening rate of the core–shell precipitates is about two orders of magnitude lower than that of monolithic Cu-rich precipitates in the binary and ternary Fe–Cu alloys. Reinforcement of the B2 Ni–Al shells by Mn partitioning further improves the strength of the precipitation-strengthened alloys by forming ultrastable and high number density core–shell nanoprecipitates

  11. Mössbauer and XRD study of the Fe65Si35 alloy obtained by mechanical alloying

    International Nuclear Information System (INIS)

    Vélez, G. Y.; Rodríguez, R. R.; Melo, C. A.; Pérez Alcázar, G. A.; Zamora, Ligia E.; Tabares, J. A.

    2011-01-01

    A study was made on the alloy Fe 65 Si 35 using x-ray diffraction and Mössbauer spectrometry. The alloy was obtained by mechanical alloying in a high energy planetary mill, with milling times of 15, 30, 50, 75 and 100 h. The results show that in the alloys two structural phases are present, a Fe-Si BCC disordered phase and ferromagnetic, and a Fe-Si SC phase, whose nature is paramagnetic and which decreases with milling time. In the temporal evolution of the milling two stages are differentiated: one between 15 and 75 h of milling, in which silicon atoms diffuse into the bcc matrix of iron and its effect is to reduce the hyperfine magnetic field; the other, after 75 h of milling, where the alloy is consolidated, the effect of the milling is only to increase the disorder of the system, increasing the magnetic order.

  12. Influence of W-phase on mechanical properties and damping capacity of Mg–Zn–Y–Nd–Zr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Hao, E-mail: haofeng804@gmail.com [College of Science, Hebei North University, Zhangjiakou 075000, Hebei (China); Yang, Yang [College of Science, Hebei North University, Zhangjiakou 075000, Hebei (China); Chang, Haixia [College of Law and Politics, Hebei North University, Zhangjiakou 075000 (China)

    2014-07-15

    This work mainly investigated the influence of W-phase on the mechanical properties and damping capacities of as-cast Mg–Zn–Y–Nd–Zr alloys with Zn/RE (rare element) ratio about 1.0. Obtained results indicate that the alloys with Zn and RE addition are composed of α-Mg matrix and W-phase. With the contents of Zn and RE increasing, the diffraction peaks of W-phase are gradually intensified and the morphology of W-phase transforms from fine-network microstructure to coarse-network microstructure. The tensile strength and fracture mechanism are strongly dependent on the quality of W-phase and the alloy with W-phase content of 8.0% has the highest strength as a result of strong atomic bonding between the W-phase and the Mg matrix. The damping capacities of Mg–Zn–Y–Nd–Zr alloys decrease gradually with the increasing amount of W-phase and then maintain at high level at high strain amplitude. The decline of damping capacity can be explained by the forming of W-phase, which makes more phases and interfaces form in the alloys. And the mobile dislocation densities in the alloys increase as residual stress at the interface of W-phase/Mg matrix and long dislocations generate in the α-Mg matrix. Therefore, the damping of alloy with high W-phase content improves accordingly with the increasing amount of moving dislocations.

  13. Effect of Bi on the corrosion resistance of zirconium alloys

    International Nuclear Information System (INIS)

    Yao Meiyi; Zhou Bangxin; Li Qiang; Zhang Weipeng; Zhu Li; Zou Linghong; Zhang Jinlong; Peng Jianchao

    2014-01-01

    In order to investigate systematically the effect of Bi addition on the corrosion resistance of zirconium alloys, different zirconium-based alloys, including Zr-4 (Zr-l.5Sn-0.2Fe-0.1Cr), S5 (Zr-0.8Sn-0.35Nb-0.4Fe-0.1Cr), T5 (Zr-0.7Sn-l.0Nb-0.3Fe-0.1Cr) and Zr-1Nb, were adopted to prepare the zirconium alloys containing Bi of 0∼0.5% in mass fraction. These alloys were denoted as Zr-4 + xBi, S5 + xBi, T5 + xBi and Zr-1Nb + xBi, respectively. The corrosion behavior of these specimens was investigated by autoclave testing in lithiated water with 0.01 M LiOH or deionized water at 360 ℃/18.6 MPa and in superheated steam at 400 ℃/10.3 MPa. The microstructure of the alloys was examined by TEM and the second phase particles (SPPs) were analyzed by EDS. Microstructure observation shows that the addition of Bi promotes the precipitation of Sn as second phase particles (SPPs) because Sn is in solid solution in α-Zr matrix in Zr-4, S5 and T5 alloys. The concentration of Bi dissolved in α-Zr matrix increase with the increase of Nb in the alloys, and the excess Bi precipitates as Bi-containing SPPs. The corrosion results show that the effect of Bi addition on the corrosion behavior of different zirconium-based alloys is very complicated, depending on their compositions and corrosion conditions. In the case of higher Bi concentration in α-Zr, the zirconium alloys exhibit better corrosion resistance. However, in the case of precipitation of Bi-containing SPPs, the corrosion resistance gets worse. This indicates that the solid solution of Bi in α-Zr matrix can improve the corrosion resistance, while the precipitation of the Bi-containing SPPs is harmful to the corrosion resistance. (authors)

  14. Microstructure and mechanical properties of TiC0.5 reinforced copper matrix composites

    International Nuclear Information System (INIS)

    Li, Mengqi; Zhai, Hongxiang; Huang, Zhenying; Liu, Xiaohan; Zhou, Yang; Li, Shibo; Li, Cuiwei

    2013-01-01

    Cu–Al alloy matrix composites containing in-situ TiC 0.5 particles were fabricated by sintering of a mixture of Cu and Ti 2 AlC powders at 1150 °C for 60 min in Ar atmosphere. The micron-sized Ti 2 AlC particles were decomposed into submicron TiC 0.5 grains during the sintering process, meanwhile, Al atoms entered into Cu to form Cu–Al alloy matrix. It was shown that the Cu–Al alloy matrix also consisted of ultrafine grains. Compression tests indicate TiC 0.5 particles can improve mechanical properties significantly, and the ductility maintains at a comparatively high level. The fracture strength of 40Ti 2 AlC/Cu sample reaches 1126 MPa with 12.8% fracture strain. The 20Ti 2 AlC/Cu and 30Ti 2 AlC/Cu samples keep undamaged even after the strain of 26.7%

  15. Aging properties studies in a Cu-Ag-Cr Alloy

    International Nuclear Information System (INIS)

    Jia, S.G.; Zheng, M.S.; Liu, P.; Ren, F.Z.; Tian, B.H.; Zhou, G.S.; Lou, H.F.

    2006-01-01

    A Cu-Ag-Cr alloy was produced by means of vacuum induction melting. The effects of aging processes on microhardness and conductivity of Cu-Ag-Cr alloy were studied. The microstructure of the alloy was examined using transmission electron microscope (TEM). Aging at 450 deg. C for 4 h, the alloy has an excellent combination of microhardness and conductivity, the microhardness and conductivity reach 132 HV and 80% IACS, respectively. The precipitates responsible for the age-hardening effect are fcc Cr. The fine and dispersed precipitates are fully coherent with the Cu matrix and make the Cu-Ag-Cr alloy possesses higher hardness and conductivity

  16. The application of Tiny Triplet Finder (TTF) in BTeV pixel trigger

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jin-Yuan; Wang, M.; Gottschalk, E.; Shi, Z.; /Fermilab

    2006-03-01

    We describe a track segment recognition scheme called the Tiny Triplet Finder (TTF) that involves grouping of three hits satisfying a constraint such as forming of a straight line. The TTF performs this O(n{sup 3}) function in O(n) time, where n is number of hits in each detector plane. The word ''tiny'' reflects the fact that the FPGA resource usage is small. The number of logic elements needed for the TTF is O(Nlog(N)), where N is the number of bins in the coordinate considered, which for large N, is significantly smaller than O(N{sup 2}) needed for typical implementations of similar functions. The TTF is also suitable for software implementations as well as many other pattern recognition problems.

  17. Bulk metallic glass matrix composites

    International Nuclear Information System (INIS)

    Choi-Yim, H.; Johnson, W.L.

    1997-01-01

    Composites with a bulk metallic glass matrix were synthesized and characterized. This was made possible by the recent development of bulk metallic glasses that exhibit high resistance to crystallization in the undercooled liquid state. In this letter, experimental methods for processing metallic glass composites are introduced. Three different bulk metallic glass forming alloys were used as the matrix materials. Both ceramics and metals were introduced as reinforcement into the metallic glass. The metallic glass matrix remained amorphous after adding up to a 30 vol% fraction of particles or short wires. X-ray diffraction patterns of the composites show only peaks from the second phase particles superimposed on the broad diffuse maxima from the amorphous phase. Optical micrographs reveal uniformly distributed particles in the matrix. The glass transition of the amorphous matrix and the crystallization behavior of the composites were studied by calorimetric methods. copyright 1997 American Institute of Physics

  18. Homogenization of stationary Navier–Stokes equations in domains with tiny holes

    Czech Academy of Sciences Publication Activity Database

    Feireisl, Eduard; Lu, Y.

    2015-01-01

    Roč. 17, č. 2 (2015), s. 381-392 ISSN 1422-6928 Keywords : compressible Navier - Stokes system * homogenization * tiny holes Subject RIV: BA - General Mathematics Impact factor: 1.023, year: 2015 http://link.springer.com/article/10.1007%2Fs00021-015-0200-2

  19. Effect of aging hardening on in situ synthesis magnesium matrix composites

    International Nuclear Information System (INIS)

    Zhang Xiuqing; Liao Lihua; Ma Naiheng; Wang Haowei

    2006-01-01

    Magnesium matrix composites reinforced with TiC particulates was synthesized using in situ synthesis technique. The result of XRD revealed the presence of TiC in precursor blocks and TiC/AZ91 composites. Effect of aging hardening on the composites was described using Brinell hardness measurements and scanning electron microscopy (SEM). The results revealed that the aging hardening peak of TiC/AZ91 composite appeared earlier comparatively with that of AZ91 magnesium alloy. And the appearance of aging hardening peak was earlier under the higher aging temperature such as 200 deg. C. The precipitating behavior of Mg 17 Al 12 phase in AZ91 alloy and TiC/AZ91 composites was described. Little discontinuous was discovered in the composites, and the amount of continuous precipitate in the composite matrix is smaller comparatively to that of AZ91 alloy. These results were analyzed with the fine grain size, much more interface between TiC and magnesium and high-density dislocation in magnesium matrix, which was contributed to the addition of TiC particulates

  20. Encapsulation of Mg-Zr alloy in metakaolin-based geo-polymer

    International Nuclear Information System (INIS)

    Rooses, Adrien; Steins, Prune; Dannoux-Papin, Adeline; Lambertin, David; Poulesquen, Arnaud; Frizon, Fabien

    2013-01-01

    Investigations were carried out to propose a suitable material for the encapsulation of Mg-Zr alloy wastes issued from fuel cladding of the first generation nuclear reactors. Stability over time, good mechanical properties and low gas production are the main requirements that embedding matrices must comply with in order to be suitable for long run storage. One of the main issues encapsulating Mg-Zr alloy in mineral binder is the hydrogen production related to Mg-Zr alloys corrosion and water radiolysis process. In this context, metakaolin geo-polymers offer an interesting outlook: corrosion densities of Mg-Zr alloys are significantly lower than in Portland cement. This work firstly presents the hydrogen production of Mg-Zr alloy embedded in geo-polymers prepared from different the activation solution (NaOH or KOH). The effect of addition of fluorine on the magnesium corrosion in geo-polymer has been investigated too. The results point out that sodium geo-polymer is a suitable binder for Mg-Zr alloy encapsulation with respect to magnesium corrosion resistance. Furthermore the presence of fluorine reduces significantly the hydrogen release. Then, the impact of fluorine on the geo-polymer network formation was studied by rheological, calorimetric and 19 F NMR measurements. No direct effect resulting from the addition of fluorine has been shown on the geo-polymer binder. Secondly, the formulation of the encapsulation matrix has been adjusted to fulfil the expected physical and mechanical properties. Observations, dimensional evolutions and compressive strengths demonstrated that addition of sand to the geo-polymer binder is efficient to meet the storage criteria. Consequently, a matrix formulation compatible with Mg-Zr alloy encapsulation has been proposed. Finally, irradiation tests have been carried out to assess the hydrogen radiolytic yield of the matrix under exposure to γ radiation. (authors)

  1. High strength and large ductility in spray-deposited Al–Zn–Mg–Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Hongchun, E-mail: hcyu@hnu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083, Hunan (China); Wang, Mingpu; Jia, Yanlin [School of Materials Science and Engineering, Central South University, Changsha 410083, Hunan (China); Xiao, Zhu, E-mail: xiaozhu8417@gmail.com [School of Engineering, University of Liverpool, Liverpool L69 3GH (United Kingdom); Chen, Chang; Lei, Qian; Li, Zhou; Chen, Wei [School of Materials Science and Engineering, Central South University, Changsha 410083, Hunan (China); Zhang, Hao [Jiangsu Haoran Spray Forming Alloys Co., Ltd., Zhengjiang 212009, Jiangsu (China); Wang, Yanguo; Cai, Canying [School of Physics and Microelectronics, Hunan University, Changsha 410082, Hunan (China)

    2014-07-15

    Highlights: • Spray deposition process was used to produce Al alloys with excellent performance. • The deposited alloys exhibited a high strength of 690 MPa and elongation up to 17.2%. • The η′ phase was coherent with α-Al and their orientation relationship was studied. • The interface misfits and the transition matrixes of two phases were calculated. - Abstract: The mechanical properties and microstructure of large-scale Al–Zn–Mg–Cu alloys fabricated by spray deposition/rapid solidification technology were investigated in detail. The as-extruded alloys under peak-aging temper exhibited ultimate tensile strength (UTS), yield strength (YS) and elongation of 690 MPa, 638 MPa and 17.2%, respectively. The simultaneous coexisting of high strength and large tensile ductility of the alloys were achieved in our experiment. It was considered that the high-density nano-precipitates distributed uniformly in the peak-aged alloys may be responsible for the high strength and improved ductility. Orientation relationship between η′ precipitates and α-Al matrix were verified by high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction patterns (SADPs) observations. The η′ phases in the alloy were fully coherent with the aluminum matrix, with the orientation relationship of (101{sup ¯}0){sub η{sup ′}}//{110}{sub Al} and [1{sup ¯}21{sup ¯}0]{sub η{sup ′}}//<1{sup ¯}12>{sub Al}. The relationship between the lattice parameters of η′ phase and the related plane-spacing of the aluminum were a{sub η{sup ′}}=3d{sub (112){sub A{sub l}}} and c{sub η{sup ′}}=6d{sub (111){sub A{sub l}}}. Based on obtained orientation relationship, the transition matrix of η′ phases were also calculated.

  2. Room temperature deformation of in-situ grown quasicrystals embedded in Al-based cast alloy

    Directory of Open Access Journals (Sweden)

    Boštjan Markoli

    2013-12-01

    Full Text Available An Al-based cast alloy containing Mn, Be and Cu has been chosen to investigate the room temperature deformation behavior of QC particles embedded in Al-matrix. Using LOM, SEM (equipped with EDS, conventional TEM with SAED and controlled tensile and compression tests, the deformation response of AlMn2Be2Cu2 cast alloy at room temperature has been examined. Alloy consisted of Al-based matrix, primary particles and eutectic icosahedral quasicrystalline (QC i-phase and traces of Θ-Al2Cu and Al10Mn3. Tensile and compression specimens were used for evaluation of mechanical response and behavior of QC i-phase articles embedded in Al-cast alloy. It has been established that embedded QC i-phase particles undergo plastic deformation along with the Al-based matrix even under severe deformation and have the response resembling that of the metallic materials by formation of typical cup-and-cone feature prior to failure. So, we can conclude that QC i-phase has the ability to undergo plastic deformation along with the Al-matrix to greater extent contrary to e.g. intermetallics such as Θ-Al2Cu for instance.

  3. Silver Matrix Composites - Structure and Properties

    Directory of Open Access Journals (Sweden)

    Wieczorek J.

    2016-03-01

    Full Text Available Phase compositions of composite materials determine their performance as well as physical and mechanical properties. Depending on the type of applied matrix and the kind, amount and morphology of the matrix reinforcement, it is possible to shape the material properties so that they meet specific operational requirements. In the paper, results of investigations on silver alloy matrix composites reinforced with ceramic particles are presented. The investigations enabled evaluation of hardness, tribological and mechanical properties as well as the structure of produced materials. The matrix of composite material was an alloy of silver and aluminium, magnesium and silicon. As the reinforcing phase, 20-60 μm ceramic particles (SiC, SiO2, Al2O3 and Cs were applied. The volume fraction of the reinforcing phase in the composites was 10%. The composites were produced using the liquid phase (casting technology, followed by plastic work (the KOBO method. The mechanical and tribological properties were analysed for plastic work-subjected composites. The mechanical properties were assessed based on a static tensile and hardness tests. The tribological properties were investigated under dry sliding conditions. The analysis of results led to determination of effects of the composite production technology on their performance. Moreover, a relationship between the type of reinforcing phase and the mechanical and tribological properties was established.

  4. Microcapillary Features in Silicon Alloyed High-Strength Cast Iron

    Directory of Open Access Journals (Sweden)

    R.K. Hasanli

    2017-04-01

    Full Text Available Present study explores features of silicon micro capillary in alloyed high-strength cast iron with nodular graphite (ductile iron produced in metal molds. It identified the nature and mechanism of micro liquation of silicon in a ductile iron alloyed with Nickel and copper, and demonstrated significant change of structural-quality characteristics. It was concluded that the matrix of alloyed ductile iron has a heterogeneous structure with cross reinforcement and high-silicon excrement areas.

  5. Heat treatment of nickel alloys

    International Nuclear Information System (INIS)

    Smith, D.F. Jr.; Clatworthy, E.F.

    1975-01-01

    A heat treating process is described that can be used to produce desired combinations of strength, ductility, and fabricability characteristics in heat resistant age-hardenable alloys having precipitation-hardening amounts of niobium, titanium, and/or tantalum in a nickel-containing matrix. (U.S.)

  6. Characterization of Dispersion Strengthened Copper Alloy Prepared by Internal Oxidation Combined with Mechanical Alloying

    Science.gov (United States)

    Zhao, Ziqian; Xiao, Zhu; Li, Zhou; Zhu, Mengnan; Yang, Ziqi

    2017-11-01

    Cu-3.6 vol.% Al2O3 dispersion strengthened alloy was prepared by mechanical alloying (MA) of internal oxidation Cu-Al powders. The lattice parameter of Cu matrix decreased with milling time for powders milled in argon, while the abnormal increase of lattice parameter occurred in the air resulting from mechanochemical reactions. With a quantitative analysis, the combined method makes residual aluminum oxidized completely within 10-20 h while mechanical alloying method alone needs longer than 40 h. Lamellar structure formed and the thickness of lamellar structure decreased with milling time. The size of Al2O3 particles decreased from 46 to 22 nm after 40 h milling. After reduction, core-shell structure was found in MAed powders milled in the air. The compacted alloy produced by MAed powders milled in the argon had an average hardness and electrical conductivity of 172.2 HV and 82.1% IACS while the unmilled alloy's were 119.8 HV and 74.1% IACS due to the Al2O3 particles refinement and residual aluminum in situ oxidization.

  7. Study on microstructure and properties of Mg-alloy surface alloying layer fabricated by EPC

    Directory of Open Access Journals (Sweden)

    Chen Dongfeng

    2010-02-01

    Full Text Available AZ91D surface alloying was investigated through evaporative pattern casting (EPC technology. Aluminum powder (0.074 to 0.104 mm was used as the alloying element in the experiment. An alloying coating with excellent properties was fabricated, which mainly consisted of adhesive, co-solvent, suspending agent and other ingredients according to desired proportion. Mg-alloy melt was poured under certain temperature and the degree of negative pressure. The microstructure of the surface layer was examined by means of scanning electron microscopy. It has been found that a large volume fraction of network new phases were formed on the Mg-alloy surface, the thickness of the alloying surface layer increased with the alloying coating increasing from 0.3 mm to 0.5 mm, and the microstructure became compact. Energy dispersive X-ray (EDX analysis was used to determine the chemical composition of the new phases. It showed that the new phases mainly consist of β-Mg17Al12, in addition to a small quantity of inter-metallic compounds and oxides. A micro-hardness test and a corrosion experiment to simulate the effect of sea water were performed. The result indicated that the highest micro-hardness of the surface reaches three times that of the matrix. The corrosion rate of alloying samples declines to about a fifth of that of the as-cast AZ91D specimen.

  8. Tiny Integrated Network Analyzer for Noninvasive Measurements of Electrically Small Antennas

    DEFF Research Database (Denmark)

    Buskgaard, Emil Feldborg; Krøyer, Ben; Tatomirescu, Alexandru

    2016-01-01

    the system. The tiny integrated network analyzer is a stand-alone Arduino-based measurement system that utilizes the transmit signal of the system under test as its reference. It features a power meter with triggering ability, on-board memory, universal serial bus, and easy extendibility with general...

  9. Corrosion performance of new Zircaloy-2-based alloys

    International Nuclear Information System (INIS)

    Rudling, P.; Mikes-Lindbaeck, M.; Lethinen, B.; Andren, H.O.; Stiller, K.

    1994-01-01

    A material development project was initiated to develop a new zirconium alloy, outside the ASTM specifications for Zircaloy-2 and Zircaloy-4, with optimized hydriding and corrosion properties for both boiling water reactors and pressurized water reactors. A number of different alloys were manufactured. These alloys were long-term corrosion tested in autoclaves at 400 C in steam. Also, a 520 C/24 h steam test was carried out. The zirconium metal microstructure and the chemistry of precipitates were characterized by analytical electron microscopy. The metal matrix chemistry was determined by atom probe analysis. The paper describes the correlations between corrosion material performance and zirconium alloy microstructure

  10. Effect of Silicon in U-10Mo Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kautz, Elizabeth J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Devaraj, Arun [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kovarik, Libor [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Joshi, Vineet V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-08-31

    This document details a method for evaluating the effect of silicon impurity content on U-10Mo alloys. Silicon concentration in U-10Mo alloys has been shown to impact the following: volume fraction of precipitate phases, effective density of the final alloy, and 235-U enrichment in the gamma-UMo matrix. This report presents a model for calculating these quantities as a function of Silicon concentration, which along with fuel foil characterization data, will serve as a reference for quality control of the U-10Mo final alloy Si content. Additionally, detailed characterization using scanning electron microscope imaging, transmission electron microscope diffraction, and atom probe tomography showed that Silicon impurities present in U-10Mo alloys form a Si-rich precipitate phase.

  11. Investigation on wear resistance and corrosion resistance of electron beam cladding co-alloy coating on Inconel617

    Science.gov (United States)

    Liu, Hailang; Zhang, Guopei; Huang, Yiping; Qi, Zhengwei; Wang, Bo; Yu, Zhibiao; Wang, Dezhi

    2018-04-01

    To improve surface properties of Inconel 617 alloy (referred to as 617 alloy), co-alloy coating metallurgically bonded to substrate was prepared on the surface of 617 alloy by electron beam cladding. The microstructure, phase composition, microhardness, tribological properties and corrosion resistance of the coatings were investigated. The XRD results of the coatings reinforced by co-alloy (Co800) revealed the presence of γ-Co, CoCx and Cr23C6 phase as matrix and new metastable phases of Cr2Ni3 and Co3Mo2Si. These hypoeutectic structures contain primary dendrites and interdendritic eutectics. The metallurgical bonding forms well between the cladding layer and the matrix of 617 alloy. In most studied conditions, the co-alloy coating displays a better hardness, tribological performance, i.e., lower coefficient of frictions and wear rates, corrosion resistance in 1 mol L‑1 HCl solution, than the 617 alloy.

  12. Influence of multiple reflection and optical interference on the magneto-optical properties of Co-Pt alloy films investigated by using the characteristic matrix method

    International Nuclear Information System (INIS)

    Zou, Z. Q.; Lee, Y. P.; Kim, K. W.

    2000-01-01

    The magneto-optical Kerr effect (MOKE) of a multilayered system was described by using the characteristic matrix method based on the electromagnetic wave theory. In addition to the multiple reflection and the optical interference, a contribution from the plasma resonance absorption of a metallic layer can be included in the formulation. As an example, we carried out a simulation of the MOKE for Co 0.25 Pt 0.75 alloy films with and without a Pt buffer layer. It was found that the Kerr rotation and the read-out figure of merit of a film directly deposited on a glass substrate were enhanced at a thickness below 40 nm owing to the multiple reflection and the optical interference. This enhancement was more remakable at long wavelengths when light was incident on the substrate side. However, the introduction of a Pt buffer layer was not beneficial in improving the Kerr rotation and the figure of merit, although it promoted the perpendicular magnetic anisotropy of the film, as reported. The simulated results for an alloy thickness beyond the penetration depth of light agreed well with the experimental data for a prepared 'thick' alloy film

  13. The aging time effect on super elasticity characteristic of Ti-50.85% at.Ni shape memory alloy

    International Nuclear Information System (INIS)

    Panjaitan, Elman; Sukarjo, Sulistioso Giat

    2000-01-01

    The stressed and strained recoverable phenomenon on fix temperature is observation used optical microscope and tensile test methods on TiNi alloy resulted from solution treatmen on 1000 o C for 1 hour followed by water quenching and aging treatment on 500 o C for 1,5,10,30 hours. Observation results showed that super elasticities are affected by aging treatment, and aging time for 10 hours yielded SME at about 4.48% martensite phase arranged by fine laths.(author)

  14. Preparation and characterization of aluminium-silica metal matrix composite

    Science.gov (United States)

    Mallikarjuna, G. B.; Basavaraj, E.

    2018-04-01

    Aluminum alloys are widely used in aerospace and automobile industries due to their low density and good mechanical properties, better corrosion resistance and wear, low thermal coefficient of expansion as compared to conventional metals and alloys. The excellent properties of these materials and relatively low production cost make them a very attractive for a variety of applications. In this present work, Al alloy LM13-SiO2 composites were produced by stir casting method. The reinforcement SiO2 particle size used for preparation of composites are 106 µm, 150 µm, 250 µm and 355 µm with varying amount of 3 to 12 wt% in steps of 3. The prepared composite specimens were machined as per test standards. Effects of weight percentage of SiO2 particles on wear, tensile strength of Al alloy LM13-SiO2 composites have been investigated. The microstructures of the composites were studied to know the dispersion of the SiO2 particles in matrix. Experimental results shows that there is enhanced mechanical properties, when silica weighing 9% was added to the base aluminium alloy and also similar trend exists in all four different micron size of silica and also it has been observed that addition of SiO2 particles significantly improves wear resistance properties as compared with that of unreinforced matrix.

  15. Eutectic Al-Si-Cu-Fe-Mn alloys with enhanced mechanical properties at room and elevated temperature

    International Nuclear Information System (INIS)

    Wang, E.R.; Hui, X.D.; Chen, G.L.

    2011-01-01

    Highlights: → Fabricated a kind of high performance Al-Si alloy with low production costs. → Clarified two different morphologies of α-Fe and corresponding crystal structures. → Analyzed the crystallography of Cu-rich phases before and after T6 treatment. → Fracture mechanism of precipitates in experimental alloys during tensile process. -- Abstract: In this paper, we report a novel kind of eutectic Al-Si-Cu-Fe-Mn alloy with ultimate tensile strength up to 336 MPa and 144.3 MPa at room temperature and 300 o C, respectively. This kind of alloy was prepared by metal mold casting followed by T6 treatment. The microstructure is composed of eutectic and primary Si, α-Fe, Al 2 Cu and α-Al phases. Iron-rich phases, which were identified as BCC type of α-Fe (Al 15 (Fe,Mn) 3 Si 2 ), exist in blocky and dendrite forms. Tiny blocky Al 2 Cu crystals disperse in α-Fe dendrites or at the grain boundaries of α-Al. During T6 treatment, Cu atoms aggregate from the super-saturation solid solution to form GP zones, θ'' or θ'. Further analysis found that the enhanced mechanical properties of the experimental alloy are mainly attributed to the formation of α-Fe and copper-rich phases.

  16. Thermal Exposure Effects on Properties of Al-Li Alloy Plate Products

    Science.gov (United States)

    Shah, Sandeep; Wells, Douglas; Wagner, John; Babel, Henry

    2003-01-01

    The objective of this viewgraph representation is to evaluate the effects of thermal exposure on the mechanical properties of both production mature and developmental Al-Li alloys. The researchers find for these alloys, the data clearly shows that there is no deficit in mechanical properties at lower exposure temperatures in some cases, and a signficant deficit in mechanical properties at higher exposure temperatures in all cases. Topics considered include: Al-Li alloys composition, key characteristics of Al-Li alloys and thermal exposure matrix.

  17. Studies of CoSn grains in the carbon matrix structure of nanostructured tin–cobalt–carbon

    International Nuclear Information System (INIS)

    Ferguson, P.P.; Fleischauer, M.D.; LaForge, J.M.; Todd, A.D.W.; Li, P.; Dahn, J.R.

    2012-01-01

    Highlights: ► Sn–Co–C alloys as negative electrode for Li-ion batteries. ► Sn–Co–C alloys prepared by mechanical alloying and by sputtering. ► CoSn grains embedded in carbon matrix structure was observed from SANS and TEM. ► SANS quickly characterized Sn–Co–C alloys equivalently to TEM. - Abstract: Small angle neutron scattering (SANS) and transmission electron microscopy (TEM) have been used to qualitatively analyze the structure of Sn 30 Co 30 C 40 alloys produced by vertical axis mechanical attriting to those produced by magnetron sputter deposition. From SANS and TEM, CoSn grains embedded in a carbon matrix structure were observed for all samples. The size of CoSn grains in the attrited samples was approximately 10 ± 3 nm by both TEM and SANS, while that of the sputtered samples was about 7 times smaller.

  18. Evidence of zirconium nano-agglomeration in as-cast dilute U–Zr alloys

    International Nuclear Information System (INIS)

    Mukherjee, S.; Kaity, S.; Saify, M.T.; Jha, S.K.; Pujari, P.K.

    2014-01-01

    Microstructure evaluation of as-cast and annealed U–Zr (Zr = 2, 6 and 10 wt.%) alloys has been carried out for the first time using positrons as a probe. The chemical signature in the matter–antimatter annihilation gamma and the positron lifetime data suggests that majority of positrons are annihilating from Zr sites in the as-cast alloys. The results have been interpreted as due to the presence of Zr nano-agglomerates in the as-cast alloys which have a higher positron affinity as compared to the rest of the U matrix. A minimum agglomerate size of ∼2 nm diameter has been calculated from the difference in positron affinity between the agglomerates and the matrix. Upon annealing, the Zr signature in the annihilation gamma photons vanishes suggesting that the Zr agglomerates diffuse out of U matrix and form micron-sized precipitates. This has been confirmed by scanning electron microscopy which shows a 3 times increase in the surface density of the precipitates in the annealed alloys as compared to the as-cast ones. Shorter positron diffusion length (measured using slow positron beam) as compared to precipitate separation has been invoked to explain the observed data

  19. Behavior and effect of Ti2Ni phase during processing of NiTi shape memory alloy wire from cast ingot

    International Nuclear Information System (INIS)

    Bhagyaraj, J.; Ramaiah, K.V.; Saikrishna, C.N.; Bhaumik, S.K.; Gouthama

    2013-01-01

    Highlights: •Ti 2 Ni second phase particles forms in different sizes and shapes in cast ingot. •TEM evidences showed shearing/fragmentation of Ti 2 Ni during processing. •Matrix close to Ti 2 Ni experienced severe plastic deformation lead to amorphisation. •Ti 2 Ni interfaces were mostly faceted and assist in nucleation of martensite. •Heterogeneity of microstructure observed near to and away from Ti 2 Ni. -- Abstract: Binary NiTi alloy is one of the commercially successful shape memory alloys (SMAs). Generally, the NiTi alloy composition used for thermal actuator application is slightly Ti-rich. In the present study, vacuum arc melted alloy of 50.2Ti–Ni (at.%) composition was prepared and characterized using optical, scanning and transmission electron microcopy. Formation of second phase particles (SPPs) in the cast alloy and their influence on development of microstructure during processing of the alloy into wire form has been investigated. Results showed that the present alloy contained Ti 2 Ni type SPPs in the matrix. In the cast alloy, the Ti 2 Ni particles form in varying sizes (1–10 μm) and shapes. During subsequent thermo-mechanical processing, these SPPs get sheared/fragmented into smaller particles with low aspect ratio. The presence of SPPs plays a significant role in refinement of the microstructure during processing of the alloy. During deformation of the alloy, the matrix phase around the SPPs experiences conditions similar to that observed in severe plastic deformation of metallic materials, leading to localized amorphisation of the matrix phase

  20. The role of Si and Ca on new wrought Mg-Zn-Mn based alloy

    International Nuclear Information System (INIS)

    Ben-Hamu, G.; Eliezer, D.; Shin, K.S.

    2007-01-01

    The development of new wrought magnesium alloys for automotive industry has increased in recent years due to their high potential as structural materials for low density and high strength/weight ratio demands. However, the poor mechanical properties of the magnesium alloys have led to search a new kind of magnesium alloys for better strength and ductility. Magnesium alloys show strong susceptibility to localized corrosion in chlorides solutions due to their inhomogeneous microstructure. The existence of intermetallics in the microstructure of magnesium alloys might represent initiation sites for localized corrosion. This is due to the formation of galvanic couples between the intermetallics and the surrounding matrix. The main objective of this research is to investigate the corrosion behavior of new magnesium alloys; Mg-Zn-Mn-Si-Ca (ZSMX) alloys. The ZSM6X1 + YCa alloys were prepared by using hot extrusion method. AC and DC polarization tests were carried out on the extruded rods, which contain different amounts of silicon or calcium. The potential difference in air between different phases and the matrix was examined using scanning Kelvin probe force microscopy (SKPFM). The phases present in the alloys have been identified by optical microscopy and scanning electron microscopy/energy dispersive X-ray spectroscopy. Four different phases were found, i.e. intermetallics containing Si-Mn, Mg-Si, Mg-Zn and Mg-Si-Ca phase. All phases exhibited higher potential differences relative to magnesium matrix indicating a cathodic behavior. The potential difference revealed significant dependence on the chemical composition of the phases. Based on the results obtained from the scanning Kelvin probe force microscopy, the cathodic phases are effective sites for the initiation of localized corrosion in Mg-Zn-Mn-Si-Ca alloys

  1. Superconducting properties of the hexagonal-close-packed alloy system TcZr

    International Nuclear Information System (INIS)

    Chatterjee, P.

    1984-01-01

    The theoretical formula of McMillan, modified via the multiple-scattering theory of Gomersall and Gyorffy, is very successful in computing the electron-phonon coupling constant (lambda) and the superconducting transition temperature (T/sub c/) of elements and compounds from quantities readily obtainable from band structure work or approaches based on the scattering theory. However, for disordered solids this theory fails because of the breakdown of the translational symmetry used in the multiple scattering theory. In the particular case of substitutional alloys, the problem can still be solved however if, at each lattice point, the t-matrix of an individual scatterer is replaced by a configurational average of the t-matrices of the alloying materials (average t-matrix approximation). This modified theory, which has already been successfully applied to some cubic substitutional alloys, is herein used to predict lambda and T/sub c/ for the h.c.p. TcZr alloy system. The results indicate that this system has good superconducting properties. (author)

  2. Insight into the Effects of Reinforcement Shape on Achieving Continuous Martensite Transformation in Phase Transforming Matrix Composites

    Science.gov (United States)

    Zhang, Xudong; Ren, Junqiang; Wang, Xiaofei; Zong, Hongxiang; Cui, Lishan; Ding, Xiangdong

    2017-12-01

    A continuous martensite transformation is indispensable for achieving large linear superelasticity and low modulus in phase transforming metal-based composites. However, determining how to accurately condition the residual martensite in a shape memory alloy matrix though the reinforcement shape to achieve continuous martensite transformation has been a challenge. Here, we take the finite element method to perform a comparative study of the effects of nanoinclusion shape on the interaction and martensite phase transformation in this new composite. Two typical samples are compared: one reinforced by metallic nanowires and the other by nanoparticles. We find that the residual martensite within the shape memory alloy matrix after a pretreatment can be tailored by the reinforcement shape. In particular, our results show that the shape memory alloy matrix can retain enough residual martensite phases to achieve continuous martensite transformation in the subsequent loading when the aspect ratio of nanoreinforcement is larger than 20. In contrast, the composites reinforced with spherical or low aspect ratio reinforcement show a typical nonlinear superelasticity as a result of a low stress transfer-induced discontinuous martensite transformation within the shape memory alloy matrix.

  3. A Brief Research Review for Improvement Methods the Wettability between Ceramic Reinforcement Particulate and Aluminium Matrix Composites

    Science.gov (United States)

    Razzaq, Alaa Mohammed; Majid, Dayang Laila Abang Abdul; Ishak, M. R.; B, Uday M.

    2017-05-01

    The development of new methods for addition fine ceramic powders to Al aluminium alloy melts, which would lead to more uniform distribution and effective incorporation of the reinforcement particles into the aluminium matrix alloy. Recently the materials engineering research has moved to composite materials from monolithic, adapting to the global need for lightweight, low cost, quality, and high performance advanced materials. Among the different methods, stir casting is one of the simplest ways of making aluminium matrix composites. However, it suffers from poor distribution and combination of the reinforcement ceramic particles in the metal matrix. These problems become significantly effect to reduce reinforcement size, more agglomeration and tendency with less wettability for the ceramic particles in the melt process. Many researchers have carried out different studies on the wettability between the metal matrix and dispersion phase, which includes added wettability agents, fluxes, preheating the reinforcement particles, coating the reinforcement particles, and use composting techniques. The enhancement of wettability of ceramic particles by the molten matrix alloy and the reinforcement particles distribution improvement in the solidified matrix is the main objective for many studies that will be discussed in this paper.

  4. Direct evidence for stress-induced transformation between coexisting multiple martensites in a Ni–Mn–Ga multifunctional alloy

    International Nuclear Information System (INIS)

    Huang, L; Cong, D Y; Dong, Y H; Zhang, Y; Wang, Y D; Wang, Z L; Nie, Z H; Ren, Y

    2015-01-01

    The structural response of coexisting multiple martensites to stress field in a Ni–Mn–Ga multifunctional alloy was investigated by the in situ high-energy x-ray diffraction technique. Stress-induced transformation between coexisting multiple martensites was observed at 110 K, at which five-layered modulated (5M), seven-layered modulated (7M) and non-modulated (NM) martensites coexist. We found that a tiny stress of as low as 0.5 MPa could trigger the transformation from 5M and 7M martensites to NM martensite and this transformation is partly reversible. Besides the transformation between coexisting multiple martensites, rearrangement of martensite variants also occurs during loading, at least at high stress levels. The present study is instructive for designing advanced multifunctional alloys with easy actuation. (paper)

  5. The effect of the electronic structure, phase transition, and localized dynamics of atoms in the formation of tiny particles of gold

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Mubarak, E-mail: mubarak74@comsats.edu.pk, E-mail: mubarak74@mail.com [COMSATS Institute of Information Technology, Department of Physics (Pakistan); Lin, I-Nan [Tamkang University, Department of Physics (China)

    2017-01-15

    In addition to self-governing properties, tiny-sized particles of metallic colloids are the building blocks of large-sized particles; thus, their study has been the subject of a large number of publications. In the present work, it has been discussed that geometry structure of tiny particle made through atom-to-atom amalgamation depends on attained dynamics of gold atoms along with protruded orientations. The localized process conditions direct two-dimensional structure of a tiny particle at atomically flat air-solution interface while heating locally dynamically approached atoms, thus, negate the role of van der Waals interactions. At electronphoton-solution interface, impinging electrons stretch or deform atoms of tiny particles depending on the mechanism of impingement. In addition, to strike regular grid of electrons ejected on split of atoms not executing excitations and de-excitations of their electrons, atoms of tiny particles also deform or stretch while occupying various sites depending on the process of synergy. Under suitable impinging electron streams, those tiny particles in monolayer two-dimensional structure electron states of their atoms are diffused in the direction of transferred energy, thus, coincide to the next adjacent atoms in each one-dimensional array dealing the same sort of behavior. Instantaneously, photons of adequate energy propagate on the surfaces of such electronic structures and modify those into smooth elements, thus, disregard the phenomenon of localized surface plasmons. This study highlights the fundamental process of formation of tiny particles where the role of localized dynamics of atoms and their electronic structure along with interaction to light are discussed. Such a tool of processing materials, in nonequilibrium pulse-based process, opens a number of possibilities to develop engineered materials with specific chemical, optical, and electronic properties.

  6. Microstructure and transformation behaviour of Ni75−XTiXPd25 high temperature shape memory alloys

    International Nuclear Information System (INIS)

    Ramaiah, K.V.; Saikrishna, C.N.; Gouthama; Bhaumik, S.K.

    2013-01-01

    Highlights: ► Partitioning of elements during solidification of cast NiTiPd results in cored microstructure. ► Homogenized alloys consists of NiTiPd matrix with Ti2(Ni,Pd) precipitates. ► Transformation temperatures of NiTiPd alloy is strongly dependent on Ti content. ► Transformation hysteresis was found to be relatively low, in the range 7–12 °C. ► Lower fraction of second phases and twinless/small twin ratio martensite led to low hysteresis. -- Abstract: The effect of composition on microstructure, transformation behaviour and thermal stability of cast and homogenized Ni 75−X Ti X Pd 25 alloys (X = 49.7, 50.0 and 50.3 at.%) were studied. Results showed significant partitioning of the alloying elements during solidification, resulting in cored microstructure in the cast alloys. The interdendritic regions were depleted in Pd and richer in Ni compared to dendritic regions. The interdendritic regions also showed presence of a thread-like Ti-rich second phase. The microstructure of the homogenized alloys consisted of NiTiPd matrix phase interspersed with Ti 2 (Ni,Pd) second phase precipitates. The precipitate phase was found to be rich in Ni and depleted in Pd. EPMA analysis showed that significant redistribution of Ni concentration in the matrix and the precipitate phase takes place during homogenization. X-ray diffraction study confirmed the matrix phase at room temperature to be of orthorhombic B19 structure. Study showed that the transformation temperatures of the alloys were strongly dependent on Ti content. The martensite finish temperature (M f ) of 157 °C for stoichiometric-Ti alloy increased to 179 °C and decreased to 105 °C for Ti-rich and Ti-lean alloys, respectively. Also, the alloys showed relatively low transformation hysteresis in the range 7–12 °C. TEM micrographs showed the presence of twinless/small twin ratio martensite which minimizes the interfacial energy and hence lower hysteresis. The transformation stability upon stress

  7. Dynamic and Thermal Properties of Aluminum Alloy A356/Silicon Carbide Hollow Particle Syntactic Foams

    Directory of Open Access Journals (Sweden)

    James Cox

    2014-12-01

    Full Text Available Aluminum alloy A356 matrix syntactic foams filled with SiC hollow particles (SiCHP are studied in the present work. Two compositions of syntactic foams are studied for quasi-static and high strain rate compression. In addition, dynamic mechanical analysis is conducted to study the temperature dependent energy dissipation and damping capabilities of these materials. The thermal characterization includes study of the coefficient of thermal expansion (CTE. A356/SiCHP syntactic foams are not strain rate sensitive as the compressive strength displayed little variation between the tested strain rates of 0.001–2100 s−1. Microscopic analysis of the high strain rate compression tested specimens showed that the fracture is initiated by the failure of hollow particles at the onset of the plastic deformation region. This is followed by plastic deformation of the matrix material and further crushing of particles. The syntactic foams showed decrease in storage modulus with increasing temperature and the trend was nearly linear up to 500 °C. The alloy shows a similar behavior at low temperature but the decrease in storage modulus increases sharply over 375 °C. The loss modulus is very small for the tested materials because of lack of viscoelasticity in metallic materials. The trend in the loss modulus is opposite, where the matrix alloy has lower loss modulus than syntactic foams at low temperature. However, over 250 °C the matrix loss modulus starts to increase rapidly and attains a peak around 460 °C. Syntactic foams have higher damping parameter at low temperatures than the matrix alloy. Incorporation of SiCHP helps in decreasing CTE. Compared to the CTE of the matrix alloy, 23.4 × 10−6 °C−1, syntactic foams showed CTE values as low as 11.67 × 10−6 °C−1.

  8. Microstructure and mechanical properties of TiC{sub 0.5} reinforced copper matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Li, Mengqi; Zhai, Hongxiang, E-mail: hxzhai@sina.com; Huang, Zhenying; Liu, Xiaohan; Zhou, Yang; Li, Shibo; Li, Cuiwei

    2013-12-20

    Cu–Al alloy matrix composites containing in-situ TiC{sub 0.5} particles were fabricated by sintering of a mixture of Cu and Ti{sub 2}AlC powders at 1150 °C for 60 min in Ar atmosphere. The micron-sized Ti{sub 2}AlC particles were decomposed into submicron TiC{sub 0.5} grains during the sintering process, meanwhile, Al atoms entered into Cu to form Cu–Al alloy matrix. It was shown that the Cu–Al alloy matrix also consisted of ultrafine grains. Compression tests indicate TiC{sub 0.5} particles can improve mechanical properties significantly, and the ductility maintains at a comparatively high level. The fracture strength of 40Ti{sub 2}AlC/Cu sample reaches 1126 MPa with 12.8% fracture strain. The 20Ti{sub 2}AlC/Cu and 30Ti{sub 2}AlC/Cu samples keep undamaged even after the strain of 26.7%.

  9. Effects of Alloyed Carbon on the General Corrosion and the Pitting Corrosion Behavior of FeCrMnN Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Heon-Young; Lee, Tae-Ho; Kim, Sung-Joon [Korea Institute of Materials Science, Changwon (Korea, Republic of)

    2011-10-15

    The effects of alloyed carbon on the pitting corrosion, the general corrosion, and the passivity behavior of Fe{sub 1}8Cr{sub 1}0Mn{sub 0}.4Nx{sub C} (x=0 ⁓ 0.38 wt%) alloys were investigated by various electrochemical methods and XPS analysis. The alloyed carbon increased the general corrosion resistance of the FeCrMnN matrix. Carbon enhanced the corrosion potential, reduced the metal dissolution rate, and accelerated the hydrogen evolution reaction rate in various acidic solutions. In addition, carbon promoted the pitting corrosion resistance of the matrix in a chloride solution. The alloyed carbon in the matrix increased the chromium content in the passive film, and thus the passive film became more protective.

  10. Mechanical properties of molybdenum alloyed liquid phase-sintered tungsten-based composites

    International Nuclear Information System (INIS)

    Kemp, P.B.; German, R.M.

    1995-01-01

    Tungsten-based composites are fabricated from mixed elemental powders using liquid phase sintering, usually with a nickel-iron matrix. During sintering, the tungsten undergoes grain growth, leading to microstructure coarsening that lowers strength but increases ductility. Often the desire is to increase strength at the sacrifice of ductility, and historically, this has been performed by postsintering deformation. There has been considerable research on alloying to adjust the as-sintered mechanical properties to match those of swaged alloys. Prior reports cover many additions, seemingly including much of the periodic table. Unfortunately, many of the modified alloys proved disappointing, largely due to degraded strength at the tungsten-matrix interface. Of these modified alloys, the molybdenum-containing systems exhibit a promising combination of properties, cost, and processing ease. For example, the 82W-8Mo-7Ni-3Fe alloy gives a yield strength that is 34% higher than the equivalent 90W-7Ni-3Fe alloy (from 535 to 715 MPa) but with a 33% decrease in fracture elongation (from 30 to 20% elongation). This article reports on experiments geared to promoting improved properties in the W-Mo-Ni-Fe alloys. However, unlike the prior research which maintained a constant Ni + Fe content and varied the W:Mo ratio, this study considers the Mo:(Ni + Fe) ratio effect for 82, 90, and 93 wt pct W

  11. Ostwald ripening of decomposed phases in Cu-Ni-Cr alloys

    International Nuclear Information System (INIS)

    Hernandez-Santiago, Felipe; Lopez-Hirata, Victor; Dorantes-Rosales, Hector J.; Saucedo-Munoz, Maribel L.; Gonzalez-Velazquez, Jorge L.; Paniagua-Mercado, Ana Ma.

    2008-01-01

    A study of the coarsening process of the decomposed phases was carried out in the Cu-34 wt.% Ni-4 wt.% Cr and Cu-45 wt.% Ni-10 wt.% Cr alloys using transmission electron microscopy. As aging progressed, the morphology of the coherent decomposed Ni-rich phase changed from cuboids to platelets aligned in the Cu-rich matrix directions. Prolonged aging caused the loss of coherency between the decomposed phases and the morphology of the Ni-rich phase changed to ellipsoidal. The variation of mean radius of the coherent decomposed phases with aging time followed the modified LSW theory for thermally activated growth in ternary alloy systems. The linear variation of the density number of precipitates and matrix supersaturation with aging time, also confirmed that the coarsening process followed the modified LSW theory in both alloys. The coarsening rate was faster in the symmetrical Cu-45 wt.% Ni-10 wt.% Cr alloy due to its higher volume fraction of precipitates. The activation energy for thermally activated growth was determined to be about 182 and 102 kJ mol -1 in the Cu-34 wt.% Ni-4 wt.% Cr and Cu-45 wt.% Ni-10 wt.% Cr alloys, respectively. The lower energy for the former alloy seems to be related to an increase in the atomic diffusion process as the chromium content increases. The size distributions of precipitates in the Cu-Ni-Cr alloys were broader and more symmetric than that predicted by the modified LSW theory for ternary alloys

  12. Phase separation in equiatomic AlCoCrFeNi high-entropy alloy

    Energy Technology Data Exchange (ETDEWEB)

    Manzoni, A., E-mail: anna.manzoni@helmholtz-berlin.de [Helmholtz-Zentrum Berlin, Institute of Applied Materials, D-14109 Berlin (Germany); Daoud, H.; Völkl, R.; Glatzel, U. [Metals and Alloys, University Bayreuth, Ludwig-Thoma-Strasse 36b, D-95447 Bayreuth (Germany); Wanderka, N. [Helmholtz-Zentrum Berlin, Institute of Applied Materials, D-14109 Berlin (Germany)

    2013-09-15

    The microstructure of the as-cast AlCoCrFeNi high entropy alloy has been investigated by transmission electron microscopy and atom probe tomography. The alloy shows a very pronounced microstructure with clearly distinguishable dendrites and interdendrites. In both regions a separation into an Al–Ni rich matrix and Cr–Fe-rich precipitates can be observed. Moreover, fluctuations of single elements within the Cr–Fe rich phase have been singled out by three dimensional atom probe measurements. The results of investigations are discussed in terms of spinodal decomposition of the alloying elements inside the Cr–Fe-rich precipitates. - Highlights: ► The Alloy separates into an Al–Ni rich matrix and Cr–Fe-rich precipitates. ► Concentration depth profiles in the Cr–Fe rich regions show opposite fluctuations. ► They have been attributed to the spinodal decomposition of Fe- and Cr-rich phases. ► The Al–Ni rich region corresponds well to the Al–Ni rich phases observed in the 6 component AlCoCrCuFeNi alloy.

  13. Relationship of microstructure and mechanical properties for V-Cr-Ti alloys

    International Nuclear Information System (INIS)

    Loomis, B.A.; Gazda, J.; Nowicki, L.J.; Smith, D.L.; Danyluk, S.

    1993-08-01

    Relation of composition, number density, and diameter of precipitates in microstructures of unalloyed V and V-Cr-Ti alloys to the yield strength, hardness, creep stress, and ductile-brittle transition temperature (DBTT) for these materials was determined from analytical electron microscopy analyses of precipitates in these materials and from mechanical properties data. Unalloyed V and V-Cr-Ti alloys with ≤3 wt. % Ti contained VC and TI(CNO) precipitates that were coherent with the matrix. The most common precipitates in the alloys were Ti(C 1-x-y N x O y ) that were non-coherent with the matrix. The number density of non-coherent precipitates was maximum in V-3Ti and V-5Cr-3Ti alloys, and the average diameter of non-coherent precipitates was minimum in V-(1--3)Ti and V-5Cr-3Ti alloys. The increase of yield strength and hardness of V on alloying with Ti and Cr was shown to be primarily due to coherent precipitate, solute-atom misfit, and shear-modulus difference effects. The creep stress for rupture in 1000 hours was related to the number density of precipitates, whereas the DBTT was related to the volume fraction of precipitates

  14. Fracture mechanism of a dispersion-hardened molybdenum alloy with strong structural interfaces

    International Nuclear Information System (INIS)

    Vasil'ev, A.D.; Malashenko, I.S.; Moiseev, V.F.; Pechkovskij, Eh.P.; Sul'zhenko, V.K.; Trefilov, V.I.; AN Ukrainskoj SSR, Kiev. Inst. Ehlektrosvarki)

    1978-01-01

    Fracture mechanism in the two-phase Mo-15wt.%Nb-3.5 vol.% TiN alloy known to be of ''brittle matrix-strong interfaces'' type has been investigated depending on tensile test temperature. Several temperature intervals of fracture have been found, each of them having its own peculiarities. A scheme is suggested for fracture mechanism changes in dispersion-hardened alloys with strong interfaces. At low test temperatures brittle cleavage fracture takes place. With temperature increase fracture mechanisms change in the following way: brittle intergranular fracture; fracture of ''microvoid coalescence'' type; fracture typical for reinforced materials with ductile matrix; intergran laru fracture. Particles of strengthening phase have been shown to play different roles depending on the test temperature in the fracture of the alloys studied

  15. High-Strength Low-Alloy (HSLA) Mg-Zn-Ca Alloys with Excellent Biodegradation Performance

    Science.gov (United States)

    Hofstetter, J.; Becker, M.; Martinelli, E.; Weinberg, A. M.; Mingler, B.; Kilian, H.; Pogatscher, S.; Uggowitzer, P. J.; Löffler, J. F.

    2014-04-01

    This article deals with the development of fine-grained high-strength low-alloy (HSLA) magnesium alloys intended for use as biodegradable implant material. The alloys contain solely low amounts of Zn and Ca as alloying elements. We illustrate the development path starting from the high-Zn-containing ZX50 (MgZn5Ca0.25) alloy with conventional purity, to an ultrahigh-purity ZX50 modification, and further to the ultrahigh-purity Zn-lean alloy ZX10 (MgZn1Ca0.3). It is shown that alloys with high Zn-content are prone to biocorrosion in various environments, most probably because of the presence of the intermetallic phase Mg6Zn3Ca2. A reduction of the Zn content results in (Mg,Zn)2Ca phase formation. This phase is less noble than the Mg-matrix and therefore, in contrast to Mg6Zn3Ca2, does not act as cathodic site. A fine-grained microstructure is achieved by the controlled formation of fine and homogeneously distributed (Mg,Zn)2Ca precipitates, which influence dynamic recrystallization and grain growth during hot forming. Such design scheme is comparable to that of HSLA steels, where low amounts of alloying elements are intended to produce a very fine dispersion of particles to increase the material's strength by refining the grain size. Consequently our new, ultrapure ZX10 alloy exhibits high strength (yield strength R p = 240 MPa, ultimate tensile strength R m = 255 MPa) and simultaneously high ductility (elongation to fracture A = 27%), as well as low mechanical anisotropy. Because of the anodic nature of the (Mg,Zn)2Ca particles used in the HSLA concept, the in vivo degradation in a rat femur implantation study is very slow and homogeneous without clinically observable hydrogen evolution, making the ZX10 alloy a promising material for biodegradable implants.

  16. Effect of external magnetic field on the Kβ/Kα X-ray intensity ratios of TixNi1-x alloys excited by 59.54 and 22.69keV photons.

    Science.gov (United States)

    Perişanoğlu, Ufuk; Alım, Bünyamin; Uğurlu, Mine; Demir, Lütfü

    2016-09-01

    The effects of external magnetic field and exciting photon energies on the Kβ/Kα X-ray intensity ratios of various alloy compositions of Ti-Ni transition metal alloys have been investigated in this work using X-ray fluorescence spectroscopy. The spectrum of characteristic K-X-ray photons from pure Ti, pure Ni and TixNi1-x (x=0.30; 0.40; 0.50; 0.60; 0.70) alloys were detected with a high resolution Si (Li) solid-state detector. Firstly, Kβ/Kα X-ray intensity ratios of pure Ti, pure Ni and TixNi1-x alloys were measured following excitation by 59.54keV γ-rays from a 200mCi (241)Am radioactive point source without any magnetic field and under 0.5 and 1T external magnetic fields, separately. Later, the same measurements were repeated under the same experimental conditions for 22.69keV X-rays from a 370 MBq(1)(0)(9)Cd radioactive point source. The results obtained for Kβ/Kα X-ray intensity ratios of pure Ti, pure Ni, Ti and Ni in various Ti-Ni alloys were evaluated in terms of both external magnetic field effect and exciting photon energy effect. When the results obtained for both exciting photon energies are evaluated in terms of changing of Kβ/Kα X-ray intensity ratios depending on the alloy composition, the tendency of these changes are observed to be similar. Also, Kβ/Kα X-ray intensity ratios for all samples examined have changed with increasing external magnetic field. Therefore, the results obtained have shown that Kβ/Kα X-ray intensity ratios of Ti and Ni in TixNi1-x alloys are connected with the external magnetic field. The present study makes it possible to perform reliable interpretation of experimental Kβ/Kα X-ray intensity ratios for Ti, Ni and TixNi1-x alloys and can also provide quantitative information about the changes of the Kβ/Kα X-ray intensity ratios of these metals with alloy composition. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. A study on the damping capacity of BaTiO3-reinforced Al-matrix ...

    Indian Academy of Sciences (India)

    the results showed that the damping capacity of Al-matrix composites can increase greatly [3–5]. Therefore, reinforcing. Al alloy matrix with higher damping particles could be an efficient way to obtain Al-matrix composites with both high strength and high damping capacity. Ferroelectric and piezoelectric ceramics can exhibit ...

  18. Development of an Extrusion Process to Ameliorate the Tribological Properties of Heat Treated Al Mg Si (Cu System Alloys Matrix Composites in Consolidated State

    Directory of Open Access Journals (Sweden)

    M.O. Shabani

    2012-09-01

    Full Text Available The developments of AA6061 aluminum matrix composites are of great interest in industrial applications for lighter materials with high specific strength, stiffness and wear resistance. In this article, the dry wear behavior of AA6061 matrix composites was investigated under different sliding speeds and applied loads. It is observed that the composites exhibit higher friction coefficients and greater wear resistances than the Al alloy against the steel disc surface. Low-speed wear rates are associated with abrasive wear,indicating the dominant wear mechanism, though minor, delamination wear may be produced. Abrasive wear associates with the formation of deep scratches on the worn surface in the sliding direction. For a given load and sliding velocity the extent of iron transfer is highest in case of 15 % SiC reinforced Al6061 composite among all the material studied.

  19. Summary of the U.S. specimen matrix for the HFIR 13J varying temperature irradiation capsule

    International Nuclear Information System (INIS)

    Zinkle, S.J.

    1998-01-01

    The US specimen matrix for the collaborative DOE/Monbusho HFIR 13J varying temperature irradiation capsule contains two ceramics and 29 different metals, including vanadium alloys, ferritic/martensitic steels, pure iron, austenitic stainless steels, nickel alloys, and copper alloys. This experiment is designed to provide fundamental information on the effects of brief low-temperature excursions on the tensile properties and microstructural evolution of a wide range of materials irradiated at nominal temperatures of 350 and 500 C to a dose of ∼5 dpa. A total of 340 miniature sheet tensile specimens and 274 TEM disks are included in the US-supplied matrix for the irradiation capsule

  20. Electronic structure and properties of disordered alloys of d-elements

    International Nuclear Information System (INIS)

    Demidenko, V.S.; Kal'yanov, A.P.

    1983-01-01

    On the basis of coherent potential approximation the fundamental characteristics in which transition element alloys differ have been established. Connection of the characteristics with position of the elements alloyed in the Mendeleev table is considered. It is confirmed by calculations that electronic structure and, consequently, physical properties of the alloys of a certain value potential disturbing matrix, change qualitatively. Results of the calculation of electron energy state density, diagrams of partial and average magnetic momenta in binary and ternary alloys of the first transition period, are presented. Besides, calculation results of bond energy in d-metals and energy of segregation formation in their alloys are also given. Comparison with experiment confirms the efficiency of concepts given in the paper

  1. Origins of tiny neutrino mass and large flavor mixings

    International Nuclear Information System (INIS)

    Haba, Naoyuki

    2015-01-01

    Active neutrino masses are extremely smaller than those of other quarks and leptons, and there are large flavor mixings in the lepton sector, contrary to the quark sector. They are great mysteries in the standard model, but also excellent hints of new physics beyond the standard model. Thus, questions 'What is an origin of tiny neutrino mass?' and 'What is an origin of large lepton flavor mixings?' are very important. In this paper, we overview various attempts to solve these big questions. (author)

  2. The kinetics of Cr layer coated on TiNi films for hydrogen absorption

    Indian Academy of Sciences (India)

    Abstract. The effect of hydrogen absorption on electrical resistance with temperature ... pressure by thermal evaporation on the glass substrate at room temperature. ... and charging rate becomes faster in comparison to FeTi and TiNi thin films.

  3. Long the fixation of physicists worldwide, a tiny particle is found

    CERN Multimedia

    2006-01-01

    "After decades of intensive effort by both experimental and theoretical physicists worldwide, a tiny particle with no charge, a very low mass and a lifetime much shorter than a nanosecond, dubbed the "axion", has now been detected by the University at Buffalo physicist who first suggested its existence in a little-read paper as early as 194." (2 pages)

  4. In-situ ductile metal/bulk metallic glass matrix composites formed by chemical partitioning

    Science.gov (United States)

    Kim, Choong Paul; Hays, Charles C.; Johnson, William L.

    2004-03-23

    A composite metal object comprises ductile crystalline metal particles in an amorphous metal matrix. An alloy is heated above its liquidus temperature. Upon cooling from the high temperature melt, the alloy chemically partitions, forming dendrites in the melt. Upon cooling the remaining liquid below the glass transition temperature it freezes to the amorphous state, producing a two-phase microstructure containing crystalline particles in an amorphous metal matrix. The ductile metal particles have a size in the range of from 0.1 to 15 micrometers and spacing in the range of from 0.1 to 20 micrometers. Preferably, the particle size is in the range of from 0.5 to 8 micrometers and spacing is in the range of from 1 to 10 micrometers. The volume proportion of particles is in the range of from 5 to 50% and preferably 15 to 35%. Differential cooling can produce oriented dendrites of ductile metal phase in an amorphous matrix. Examples are given in the Zr--Ti--Cu--Ni--Be alloy bulk glass forming system with added niobium.

  5. Ductility and microstructure of precipitation-strengthened alloys irradiated in HFIR

    International Nuclear Information System (INIS)

    Yang, W.J.S.; Hamilton, M.L.

    1983-08-01

    Six γ' and γ'/γ'' strengthened Ni-base alloys have shown near-zero ductility after irradiation at 300 to 600 0 C in HFIR to a peak exposure of 9 dpa. Microstructural examination of the irradiated specimens showed that the loss of ductility in these alloys arises from the simultaneous existence of a strong matrix and weak grain boundaries. The strong matrix is attributed to the irradiation-induced γ' and γ'/γ'' precipitates, the faulted loops and a high density of fine helium bubbles. The weak grain boundaries are attributed to the formation of an unfavorable precipitate, such as eta-plates, recrystallized grains, a thin layer of γ' and helium bubbles

  6. Laser surface alloying of aluminium with WC+Co+NiCr for improved wear resistance

    CSIR Research Space (South Africa)

    Nath, S

    2012-03-01

    Full Text Available Department of Metallurgical & Materials Engineering, IIT Kharagpur, West Bengal, India 2National Laser Centre, CSIR, Pretoria, South Africa Abstract In the present study, laser surface alloying of aluminium with WC+Co+NiCr (in the ratio of 70... be used for dispersion of ceramic materials into metallic matrix and hence, form a ceramic dispersed metal matrix composite on metallic substrate [3]. The advantages of laser surface alloying include refinement of the microstructure, uniform dispersion...

  7. Fabrication and structure of bulk nanocrystalline Al-Si-Ni-mishmetal alloys

    International Nuclear Information System (INIS)

    Latuch, Jerzy; Cieslak, Grzegorz; Kulik, Tadeusz

    2007-01-01

    Al-based alloys of structure consisting of nanosized Al crystals, embedded in an amorphous matrix, are interesting for their excellent mechanical properties, exceeding those of the commercial crystalline Al-based alloys. Recently discovered nanocrystalline Al alloys containing silicon (Si), rare earth metal (RE) and late transition metal (Ni), combine high tensile strength and good wear resistance. The aim of this work was to manufacture bulk nanocrystalline alloys from Al-Si-Ni-mishmetal (Mm) system. Bulk nanostructured Al 91-x Si x Ni 7 Mm 2 (x = 10, 11.6, 13 at.%) alloys were produced by ball milling of nanocrystalline ribbons followed by high pressure hot isostating compaction

  8. Improving the corrosion resistance of AZ91D magnesium alloy through reinforcement with titanium carbides and borides

    Directory of Open Access Journals (Sweden)

    Mohamed Gobara

    2015-06-01

    Full Text Available A composite consisting of magnesium matrix reinforced with a network of TiC–Ti2AlC–TiB2 particulates has been fabricated using a practical in-situ reactive infiltration technique. The microstructural and phase composition of the magnesium matrix composite (R-Mg was investigated using SEM/EDS and XRD. The analyses revealed the complete formation of TiC, Ti2AlC and TiB2 particles in the magnesium matrix. Comparative compression tests of R-Mg and AZ91D alloy showed that the reinforcing particles improve the mechanical properties of Mg alloy. EIS and potentiodynamic polarization results indicated that the reinforcing particles significantly improve the corrosion resistance of the reinforced alloy in 3.5% NaCl solution.

  9. Study on isothermal precision forging process of rare earth intensifying magnesium alloy

    International Nuclear Information System (INIS)

    Shan, Debin; Xu, Wenchen; Han, Xiuzhu; Huang, Xiaolei

    2012-01-01

    A three dimensional rigid-plastic finite element model is established to simulate the isothermal precision forging process of the magnesium alloy bracket based on DEFORM 3D in order to analyze the material flow rule and determine the forging process scheme. Some problems such as underfilling and too large forging pressure are predicted and resolved through optimizing the shapes of the billet successfully. Compared to the initial microstructure, the isothermal-forged microstructure of the alloy refines obviously and amounts of secondary phases precipitate on the matrix during isothermal forging process. In subsequent ageing process, large quantities of secondary phases precipitate from α-Mg matrix with increasing ageing time. The optimal comprehensive mechanical properties of the alloy have been obtained after aged at 473 K, 63 h with the ultimate tensile strength, tensile yield strength and elongation 380 MPa, 243 MPa and 4.07% respectively, which shows good potential for application of isothermal forging process of rare earth intensifying magnesium alloy.

  10. TinyONet: A Cache-Based Sensor Network Bridge Enabling Sensing Data Reusability and Customized Wireless Sensor Network Services

    Science.gov (United States)

    Jung, Eui-Hyun; Park, Yong-Jin

    2008-01-01

    In recent years, a few protocol bridge research projects have been announced to enable a seamless integration of Wireless Sensor Networks (WSNs) with the TCP/IP network. These studies have ensured the transparent end-to-end communication between two network sides in the node-centric manner. Researchers expect this integration will trigger the development of various application domains. However, prior research projects have not fully explored some essential features for WSNs, especially the reusability of sensing data and the data-centric communication. To resolve these issues, we suggested a new protocol bridge system named TinyONet. In TinyONet, virtual sensors play roles as virtual counterparts of physical sensors and they dynamically group to make a functional entity, Slice. Instead of direct interaction with individual physical sensors, each sensor application uses its own WSN service provided by Slices. If a new kind of service is required in TinyONet, the corresponding function can be dynamically added at runtime. Beside the data-centric communication, it also supports the node-centric communication and the synchronous access. In order to show the effectiveness of the system, we implemented TinyONet on an embedded Linux machine and evaluated it with several experimental scenarios. PMID:27873968

  11. Development of high performance ODS alloys

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Lin [Texas A & M Univ., College Station, TX (United States); Gao, Fei [Univ. of Michigan, Ann Arbor, MI (United States); Garner, Frank [Texas A & M Univ., College Station, TX (United States)

    2018-01-29

    This project aims to capitalize on insights developed from recent high-dose self-ion irradiation experiments in order to develop and test the next generation of optimized ODS alloys needed to meet the nuclear community's need for high strength, radiation-tolerant cladding and core components, especially with enhanced resistance to void swelling. Two of these insights are that ferrite grains swell earlier than tempered martensite grains, and oxide dispersions currently produced only in ferrite grains require a high level of uniformity and stability to be successful. An additional insight is that ODS particle stability is dependent on as-yet unidentified compositional combinations of dispersoid and alloy matrix, such as dispersoids are stable in MA957 to doses greater than 200 dpa but dissolve in MA956 at doses less than 200 dpa. These findings focus attention on candidate next-generation alloys which address these concerns. Collaboration with two Japanese groups provides this project with two sets of first-round candidate alloys that have already undergone extensive development and testing for unirradiated properties, but have not yet been evaluated for their irradiation performance. The first set of candidate alloys are dual phase (ferrite + martensite) ODS alloys with oxide particles uniformly distributed in both ferrite and martensite phases. The second set of candidate alloys are ODS alloys containing non-standard dispersoid compositions with controllable oxide particle sizes, phases and interfaces.

  12. Swimming of a Tiny Subtropical Sea Butterfly with Coiled Shell

    Science.gov (United States)

    Murphy, David; Karakas, Ferhat; Maas, Amy

    2017-11-01

    Sea butterflies, also known as pteropods, include a variety of small, zooplanktonic marine snails. Thecosomatous pteropods possess a shell and swim at low Reynolds numbers by beating their wing-like parapodia in a manner reminiscent of insect flight. In fact, previous studies of the pteropod Limacina helicina have shown that pteropod swimming hydrodynamics and tiny insect flight aerodynamics are dynamically similar. Studies of L. helicina swimming have been performed in polar (0 degrees C) and temperate conditions (12 degrees C). Here we present measurements of the swimming of Heliconoides inflatus, a smaller yet morphologically similar pteropod that lives in warm Bermuda seawater (21 degrees C) with a viscosity almost half that of the polar seawater. The collected H. inflatus have shell sizes less than 1.5 mm in diameter, beat their wings at frequencies up to 11 Hz, and swim upwards in sawtooth trajectories at speeds up to approximately 25 mm/s. Using three-dimensional wing and body kinematics collected with two orthogonal high speed cameras and time-resolved, 2D flow measurements collected with a micro-PIV system, we compare the effects of smaller body size and lower water viscosity on the flow physics underlying flapping-based swimming by pteropods and flight by tiny insects.

  13. Vacuum brazing of aluminium metal matrix composite (55 vol.% SiC{sub p}/A356) using aluminium-based filler alloy

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Jitai, E-mail: niujitai@163.com [Harbin Institute of Technology (China); Zhengzhou University (China); Luo, Xiangwei; Tian, Hao [Zhengzhou University (China); Brnic, Josip [University of Rijka (Croatia)

    2012-11-20

    Highlights: Black-Right-Pointing-Pointer The proper filler metal has been developed, especially for contents of Mg and Si. Black-Right-Pointing-Pointer The pressure device has been designed for specimen in vacuum brazing process. Black-Right-Pointing-Pointer The accurate measurement method for shear strength of lap joint has been found. Black-Right-Pointing-Pointer The brazing temperature of 560 Degree-Sign C has been optimised. Black-Right-Pointing-Pointer The micro-mechanism has been discussed for SiC{sub p}/Al composites' brazing joint. - Abstract: Aluminium matrix composites with high volume fractions of SiC particles, as the reinforcements, are potentially suitable materials for electronic packaging. These composites, due to their poor weldability, however, have very limited applications. The microstructure and shear strengths of the bonds made in 55 vol.% SiC{sub p}/A356 composite, using an aluminium based filler alloy containing Cu, Si, Mg and Ni, were investigated in this paper. The brazing temperature had a clear effect on the bond integrity, and the samples brazed at 560 Degree-Sign C demonstrated good bonding between the filler alloy and the SiC particles. The maximum shear strength achieved in this work was 102 MPa.

  14. Corrosion performance of 7075 alloy under laser heat treatment

    Science.gov (United States)

    Liu, Tong; Su, Ruiming; Qu, Yingdong; Li, Rongde

    2018-05-01

    Microstructure, exfoliation corrosion (EXCO), intergranular corrosion (IGC) and potentidynamic polarization test of the 7075 aluminum alloy after retrogression and re-aging (RRA) treatment, and laser retrogression and re-aging (LRRA), respectively, were studied by using scanning electron microscope, and transmission electron microscope (TEM). The results show that after pre-aging, laser treatment (650 W, 2 mm s‑1) and re-aging a lot of matrix precipitates of alloy were precipitated again. The semi-continuous grain boundary precipitates and the wider precipitate-free zones (PFZ) improve the corrosion resistance of the alloy. The corrosion properties of the alloy after LRRA (650 W, 2 mm s‑1) treatment are better than that after RRA treatment.

  15. Formation and Disruption of W-Phase in High-Entropy Alloys

    Directory of Open Access Journals (Sweden)

    Sephira Riva

    2016-05-01

    Full Text Available High-entropy alloys (HEAs are single-phase systems prepared from equimolar or near-equimolar concentrations of at least five principal elements. The combination of high mixing entropy, severe lattice distortion, sluggish diffusion and cocktail effect favours the formation of simple phases—usually a bcc or fcc matrix with minor inclusions of ordered binary intermetallics. HEAs have been proposed for applications in which high temperature stability (including mechanical and chemical stability under high temperature and high mechanical impact is required. On the other hand, the major challenge to overcome for HEAs to become commercially attractive is the achievement of lightweight alloys of extreme hardness and low brittleness. The multicomponent AlCrCuScTi alloy was prepared and characterized using powder X-ray diffraction (PXRD, scanning-electron microscope (SEM and atomic-force microscope equipped with scanning Kelvin probe (AFM/SKP techniques. Results show that the formation of complex multicomponent ternary intermetallic compounds upon heating plays a key role in phase evolution. The formation and degradation of W-phase, Al2Cu3Sc, in the AlCrCuScTi alloy plays a crucial role in its properties and stability. Analysis of as-melted and annealed alloy suggests that the W-phase is favoured kinetically, but thermodynamically unstable. The disruption of the W-phase in the alloy matrix has a positive effect on hardness (890 HV, density (4.83 g·cm−3 and crack propagation. The hardness/density ratio obtained for this alloy shows a record value in comparison with ordinary heavy refractory HEAs.

  16. Effect of V or Zr addition on the mechanical properties of the mechanically alloyed Al-8wt%Ti alloys

    International Nuclear Information System (INIS)

    Moon, I.H.; Lee, J.H.; Lee, K.M.; Kim, Y.D.

    1995-01-01

    Mechanical alloying (MA) of Al-Ti alloy, being a solid state process, offers the unique advantage of producing homogeneous and fine dispersions of thermally stable Al 3 Ti phase, where the formation of the fine Al 3 Ti phase by the other method is restricted from the thermodynamic viewpoint. The MA Al-Ti alloys show substantially higher strength than the conventional Al alloys at the elevated temperature due to the presence of Al 3 Ti as well as Al 4 C 3 and Al 2 O 3 , of which the last two phases were introduced during MA process. The addition of V or Zr to Al-Ti alloy was known to decrease the lattice mismatch between the intermetallic compound and the aluminum matrix, and such decrease in lattice mismatching can influence positively the high temperature mechanical strength of the MA Al-Ti by increasing the resistance to dispersoid coarsening at the elevated temperature. In the present study, therefore, the mechanical behavior of the MA Al-Ti-V and Al-Ti-Zr alloys were investigated in order to evaluate the effect of V or Zr addition on the mechanical properties of the MA Al-8Ti alloy at high temperature

  17. HREM studies on the microstructure of severely cold-rolled TiNi alloy after reverse martensitic transformation

    International Nuclear Information System (INIS)

    Zheng, Y.F.; Zhao, L.C.

    2000-01-01

    The microstructure of Ti-49.8at.%Ni alloy, which was cold rolled to about 30% reduction in thickness in its martensitic condition and subsequently heated up to 200 C for half an hour, has been studied by high resolution electron microscopy. The interface between parent phase and martensite is not smooth and well coherent. The boundary between two subgrains of the parent phase is not straight but perfectly coherent, with partial dislocation observed at the interface. Inside some parent phase grains, thin plate-like {114} and spear-like {112} twin-related parent phase variant pairs are observed. The {114} twinning boundary is relatively straight, but with two or three atomic-height blurred layers existing near the interface. (orig.)

  18. Influence on SME and microstructure in FeMnSiCrNi SMA for strengthening of austenite matrix

    International Nuclear Information System (INIS)

    Gu, N.; Lin, C.; Song, X.; Peng, H.; Yin, F.

    2000-01-01

    Influences of solution- and deformation-strengthening on SME and the microstructures of FeMnSiCrNi SMA were researched. SME and the training effect were both obviously improved when 0.3%C added into the alloy. It was observed that some thermo-induced martensites, distributing disorderly in the matrix, formed in the alloy without carbon, while in the alloy with carbon, more stress-induced martensites, distributing orderly in the matrix, were found, thus resulting in the better SME. As far as the treatment methods were concerned, one time deformation-strengthening could be better than training many times. The ε-martensites in the strengthened alloy appeared larger in amount, short plate in shape and distributed with nearly the same orientation, which is closely related to the better SME. (orig.)

  19. Heterogeneous tiny energy: An appealing opportunity to power wireless sensor motes in a corrosive environment

    International Nuclear Information System (INIS)

    Qiao, Guofu; Sun, Guodong; Li, Hui; Ou, Jinping

    2014-01-01

    Highlights: • Ultra-low ambient energy was scavenged to power the first of its kind wireless corrosion sensors. • Three feasible tiny-energy sources were exploited for long-term corrosion monitoring. • Automatic recharging control of heterogeneous tiny energy was proposed for human-free monitoring. • Corrosion itself was applied as an energy source to power the wireless corrosion-monitoring motes. - Abstract: Reinforcing steel corrosion is a significant factor leading to the durability deterioration of reinforced concrete (RC) structures. The on-line monitoring of the corrosion of RC structures in a long-term, human-free manner is not only valuable in industry, but also a significant challenge in academia. This paper presents the first of its kind corrosion-monitoring approach that only exploits three heterogeneous tiny energy sources to power commercial-off-the-shelf wireless sensor motes such that the corrosion-related data are automatically and autonomously captured and sent to users via wireless channels. We first investigated the availability of these three tiny energy sources: corrosion energy, a cement battery, and a weak solar energy. In particular, the two former energy sources inherently exist in RC structures and can be generated continually in the service-life of RC structures, which beneficial for the prospects of long-term corrosion monitoring. We then proposed a proof-of-concept prototype, which consisted of a Telosb wireless sensor mote and an energy harvester in order to evaluate the feasibility and effectiveness of the ultralow-power ambient energy as a type of power supply in corrosion monitoring applications. The critical metrics for the holographic monitoring of RC structures, including electrochemical noise, humidity and temperature, were successfully acquired and analysed using a post-processing program. This paper describes a unique and novel approach towards the realisation of smart structural monitoring and control system in the

  20. Nanocellulose, a tiny fiber with huge applications.

    Science.gov (United States)

    Abitbol, Tiffany; Rivkin, Amit; Cao, Yifeng; Nevo, Yuval; Abraham, Eldho; Ben-Shalom, Tal; Lapidot, Shaul; Shoseyov, Oded

    2016-06-01

    Nanocellulose is of increasing interest for a range of applications relevant to the fields of material science and biomedical engineering due to its renewable nature, anisotropic shape, excellent mechanical properties, good biocompatibility, tailorable surface chemistry, and interesting optical properties. We discuss the main areas of nanocellulose research: photonics, films and foams, surface modifications, nanocomposites, and medical devices. These tiny nanocellulose fibers have huge potential in many applications, from flexible optoelectronics to scaffolds for tissue regeneration. We hope to impart the readers with some of the excitement that currently surrounds nanocellulose research, which arises from the green nature of the particles, their fascinating physical and chemical properties, and the diversity of applications that can be impacted by this material. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Phase martensitic transformation study in mechanically alloyed Ti{sub 50}Ni{sub 25}Fe{sub 25} alloy via high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Joao Cardoso de; Ferreira, Ailton da Silva, E-mail: joao.cardoso.lima@ufsc.br [Universidade Federal de Santa Catarina (UFSC), Florianopolis (Brazil); Rovani, Pablo Roberto; Pereira, Altair Soria [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre (Brazil)

    2016-07-01

    Full text: Alloys based on titanium and nickel with shape memory effect (SME) have been widely investigated due to potential use in different areas of science and technology, such as electronics, medicine, and space.1 Among them, the superalloys Ti-Ni-Fe show high corrosion resistance and good mechanical properties even at high temperatures that make them suitable for use in applications such as power plant components that work under aggressive conditions. At room temperature, the TiNi alloy has a monoclinic (B19'), known as the martensitic phase. With increasing temperature, the B19' phase transforms into a trigonal/hexagonal (B19) phase, known as the R- or pre martensitic phase, which, in its turn, transforms into a cubic (B2) structure, known as the austenitic phase. On cooling to room temperature, the reverse B2→B19→B19' phase transformations are observed. Since the B19↔B19' transformation occurs at a temperature low enough to inhibit diffusion-controlled processes, it belongs to a class of diffusionless phase transformations known as martensitic transformations. For this study, a Ti{sub 50}Ni{sub 25}Fe{sub 25} (B2) alloy was prepared by mechanical alloying, and the effects of high pressures up to 18 GPa will be presented. The structural changes with increasing pressure were followed by recording in situ angle-dispersive X-ray diffraction (ADXRD) diffractograms, in transmission geometry, using a long fine focus Mo X-ray tube and an imaging plate detector. The obtained results were already reported in Ref [1]. (1) A. S. Ferreira, P. R. Rovani, J. C. de Lima, A. S. Pereira, J. Appl. Phys. 117 (2015). (author)

  2. Spectrophotometric determination of silicon in silumin matrix

    International Nuclear Information System (INIS)

    Samanta, Papu; Pandey, K.L.; Kumar, Pradeep; Bagchi, A.C.; Abdulla, K.K.

    2015-01-01

    In dispersion fuel, fissile material is dispersed in inert matrix. Aluminum-silicon-nickel (silumin) alloy is employed as inert matrix owing to its high thermal conductivity, high castability, high corrosion resistance. All these properties depend on the chemical composition and the structure of silumin. Silicon is stringent specification in silumin. A spectrophotometric method has been developed for the determination of silicon content in silumin matrix. Silumin matrix was fused with LiOH and subsequent dissolution in water along with few drops of conc. sulphuric acid. The molybodo-silicic formed by the addition of ammonium molybdate is reduced to molybdenum blue by ascorbic acid in the presence of antimony. The absorbance was measured at 810 nm. Aluminum and nickel were found to be non-interfering with the silicon determination. (author)

  3. Effect of CaO Addition on the High-Temperature Oxidation of AM30 Magnesium Alloys

    International Nuclear Information System (INIS)

    Won, Sung-Bin; Lee, Dong Bok

    2014-01-01

    AM30 + (0, 0.5, 1, 1.5) wt%CaO magnesium alloys were cast and oxidized at 625 ℃ and 650 ℃ in atmospheric air. The CaO particles that were added during casting allowed casting the AM30 alloys in air without using environmentally hazardous SF_6 or SO_2 gases. They decomposed to dissolve in the α-Mg matrix and also to precipitate along the matrix grain boundaries as Al_2Ca during casting. The ignition temperatures were 584.6 ℃ for AM30, 604.5 ℃ for AM30 + 0.5 wt%CaO, and 691.7 ℃ for AM30 + 1 wt%CaO. No ignition occurred for AM30 + 1.5 wt%CaO up to 700 ℃. During oxidation, CaO-rich oxide scales formed on the alloy surface, which prevented direct contact of the alloy with air and fast oxidation of the alloy in air

  4. Effect of CaO Addition on the High-Temperature Oxidation of AM30 Magnesium Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Won, Sung-Bin; Lee, Dong Bok [Sungkyunkwan University, Suwon (Korea, Republic of)

    2014-03-15

    AM30 + (0, 0.5, 1, 1.5) wt%CaO magnesium alloys were cast and oxidized at 625 ℃ and 650 ℃ in atmospheric air. The CaO particles that were added during casting allowed casting the AM30 alloys in air without using environmentally hazardous SF{sub 6} or SO{sub 2} gases. They decomposed to dissolve in the α-Mg matrix and also to precipitate along the matrix grain boundaries as Al{sub 2}Ca during casting. The ignition temperatures were 584.6 ℃ for AM30, 604.5 ℃ for AM30 + 0.5 wt%CaO, and 691.7 ℃ for AM30 + 1 wt%CaO. No ignition occurred for AM30 + 1.5 wt%CaO up to 700 ℃. During oxidation, CaO-rich oxide scales formed on the alloy surface, which prevented direct contact of the alloy with air and fast oxidation of the alloy in air.

  5. Precipitate strengthening of nanostructured aluminium alloy.

    Science.gov (United States)

    Wawer, Kinga; Lewandowska, Malgorzata; Kurzydlowski, Krzysztof J

    2012-11-01

    Grain boundaries and precipitates are the major microstructural features influencing the mechanical properties of metals and alloys. Refinement of the grain size to the nanometre scale brings about a significant increase in the mechanical strength of the materials because of the increased number of grain boundaries which act as obstacles to sliding dislocations. A similar effect is obtained if nanoscale precipitates are uniformly distributed in coarse grained matrix. The development of nanograin sized alloys raises the important question of whether or not these two mechanisms are "additive" and precipitate strengthening is effective in nanostructured materials. In the reported work, hydrostatic extrusion (HE) was used to obtain nanostructured 7475 aluminium alloy. Nanosized precipitates were obtained by post-HE annealing. It was found that such annealing at the low temperatures (100 degrees C) results in a significant increase in the microhardness (HV0.2) and strength of the nanostructured 7475 aluminium alloy. These results are discussed in terms of the interplay between the precipitation and deformation of nanocrystalline metals.

  6. Functional Properties of Porous Ti-48.0 at.% Ni Shape Memory Alloy Produced by Self-Propagating High-Temperature Synthesis

    Science.gov (United States)

    Resnina, Natalia; Belyaev, Sergey; Voronkov, Andrew

    2018-03-01

    The functional behavior of the porous shape memory alloy produced by self-propagating high-temperature synthesis from the Ti-48.0 at.% Ni powder mixture was studied. It was found that a large unelastic strain recovered on unloading and it was not attributed to the pseudoelasticity effect. A decrease in deformation temperatures did not influence the value of strain that recovered on unloading, while the effective modulus decreased from 1.9 to 1.44 GPa. It was found that the porous Ti-48.0 at.% Ni alloy revealed the one-way shape memory effect, where the maximum recoverable strain was 5%. The porous Ti-48.0 at.% Ni alloy demonstrated the transformation plasticity and the shape memory effects on cooling and heating under a stress. An increase in stress did not influence the shape memory effect value, which was equal to 1%. It was shown that the functional properties of the porous alloy were determined by the TiNi phase consisted of the two volumes Ti49.3Ni50.7 and Ti50Ni50 where the martensitic transformation occurred at different temperatures. The results of the study showed that the existence of the Ti49.3Ni50.7 volumes in the porous Ti-48.0 at.% Ni alloy improved the functional properties of the alloy.

  7. Influence of (TiC+TiB) on the microstructure and tensile properties of Ti-B20 matrix alloy

    Energy Technology Data Exchange (ETDEWEB)

    Rahoma, H.K.S. [National Key Laboratory of Science and Technology on Precision Heat Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China); Chen, Y.Y., E-mail: yychen@hit.edu.cn [National Key Laboratory of Science and Technology on Precision Heat Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Wang, X.P.; Xiao, S.L. [National Key Laboratory of Science and Technology on Precision Heat Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China)

    2015-04-05

    Highlights: • After forging, the microstructure was significantly refined and uniform. • The presence of carbide and boride also led to uniform and finer precipitation of α during aging as compared to the matrix alloy. • The size of secondary α phase increased with the increase of aging temperature. This trend leads to the decrease of strength and the increase of ductility. - Abstract: A hybrid of (TiB+TiC) reinforced beta titanium matrix (Ti-B20) were produced by non-consumable arc-melting technology and hot-forging. Microstructures of the composites were observed by optical microscopy (OM), transmission electron microscope (TEM) and scanning electron microscopy (SEM). The results show that both the TiB whiskers and TiC particles tend to segregate at β boundaries. The β grain size and secondary α lath width are refined by reinforcements and aging treatment. Evolution of tensile properties shows that enhancement in yield strength and ultimate tensile strength with the addition of reinforcements, as well as the remarkable increase in the ductility can be attributed to aging treatment at 600 °C and 650 °C. The size of secondary α phase increased with the increase of aging temperature. This trend leads to the decrease of strength and the increase of ductility to get good balance of properties. The fracture mechanism of the composite can be attributed to the cracking of the reinforcements.

  8. Kulturní hodnoty tzv. Mariánského trojúhelníku - Sloup, Vranov, Křtiny

    OpenAIRE

    Bezděková, Veronika

    2009-01-01

    In the Moravian Karst there are three big churches consecrated to The Virgin Mary. These are visited by many pilgrims and have their own calendar of pilgrimages. They are Vranov, Křtiny and Sloup. Churches in these towns are consecrated to The Virgin Mary: Vranov commemorates the birth of The Virgin Mary, Křtiny commemorates the name of The Virgin Mary and Sloup commemorates the sufferings of The Virgin Mary. So we talk about the triangle of The Virgin Mary. This term is the main point of my ...

  9. Unirradiated characteristics of U-Si alloys as dispersed-phase fuels

    International Nuclear Information System (INIS)

    Domagala, R.F.; Wiencek, T.C.

    1987-06-01

    To satisfy the power demands of many research reactors, a new LEU fuel with a high density and U content was needed. Any fuel must be compatible with Al and its alloys so that it may be fabricable as a dispersed-phase in Al alloy and Al matrix plate-type elements following, as nearly as possible, established commercial manufacturing techniques. U-Si and U-Si-Al alloys at or near the composition of U 3 Si were immediately attractive because of work documented by the Canadians. 8 refs., 2 figs

  10. Surface coatings of mixed hard alloy powder metals sintered-on in vacuo

    International Nuclear Information System (INIS)

    Knotek, O.; Reimann, H.

    1980-01-01

    No technological difficulties are to be encountered in the processing of pseudo hard alloys in the form of powder compounds of conventional nickel base hard alloys with carbides. There is a great alloy influence on the resulting structures of the surface layers. Under some processing conditions the tungsten carbide is completely dissolved from molten matrix alloy. Hard phases on chromium carbide basis resulted upon cooling. Induced chromium carbide Cr 3 C 2 retains its structure while absorbing large amounts of iron into its grid. It can be concluded that not only alloying properties, but also eminently structural criterions are decisive for the stability of the applied supplementary hard phases. (orig.) [de

  11. Improved Mechanical and Tribological Properties of Metal-Matrix Composites Dispersion-Strengthened by Nanoparticles

    Directory of Open Access Journals (Sweden)

    Evgenii Levashov

    2009-12-01

    Full Text Available Co- and Fe-based alloys produced by powder technology are being widely used as a matrix for diamond-containing composites in cutting, drilling, grinding pplications, etc. The severe service conditions demand that the mechanical and tribological properties of these alloys be improved. Development of metal-matrix composites (MMCs and alloys reinforced with nanoparticles is a promising way to resolve this problem. In this work, we have investigated the effect of nano-sized WC, ZrO2, Al2O3, and Si3N4 additives on the properties of sintered dispersion-strengthened Co- and Fe-based MMCs. The results show an increase in the hardness (up to 10 HRB, bending strength (up to 50%, wear resistance (by a factor of 2–10 and a decrease in the friction coefficient (up to 4-fold of the dispersion-strengthened materials. The use of designed alloys as a binder of cutting diamond tools gave a 4-fold increment in the service life, without reduction in their cutting speed.

  12. Effect of Bi-content on hardness and micro-creep behavior of Sn-3.5Ag rapidly solidified alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kamal, M. [Metal Physics Laboratory, Faculty of Science, Mansoura University (Egypt); Gouda, El Said [Metal Physics Laboratory, Department of Solid State Physics, Physics Division, National Research Center, Dokki, Giza (Egypt); Marei, L.K. [Faculty of Petroleum and Mining Engineering, Suez Canal University, Suez (Egypt)

    2009-12-15

    In the present paper, the influence of 1, 3, 5 and 10 % Bi (weight %) as ternary additions on structure, melting and mechanical properties of rapidly solidified Sn-3.5Ag alloy has been investigated. The effect of Bi was discussed based on the experimental results. The experimental results showed that the alloys of Sn-3.5Ag, Sn-3.5Ag-1Bi and Sn-3.5Ag-3Bi are composed of two phases; Ag{sub 3}Sn IMC embedded in Sn matrix phase, which indicated that the solubility of Bi phase in Sn-matrix was extended to 3 % as a result of rapid solidification. Bi precipitation in Sn matrix was only observed in Sn-3.5Ag-5Bi and Sn-3.5Ag-10Bi alloys. Also, addition of Bi decreased continuously the melting point of the eutectic Sn-3.5Ag alloy to 202.6 C at 10 % Bi. Vickers hardness of Sn-3.5Ag rapidly solidified alloy increased with increasing Bi content up to 3 % due to supersaturated solid solution strengthening hardening mechanism of Bi phase in Sn matrix, while the alloys contain 5 and 10 % Bi exhibited lower values of Vickers hardness. The lower values can be attributed to the precipitation of Bi as a secondary phase which may form strained regions due to the embrittlement of Bi atom. In addition, the effect of Bi addition on the micro-creep behavior of Sn-3.5Ag alloy as well as the creep rate have been described and has been calculated at room temperature. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Corrosion of Graphite Aluminum Metal Matrix Composites

    Science.gov (United States)

    1991-02-01

    cathodic protection of G/AI MMCs resulted in overprotection 13. Overprotection resulted from a local increase in pH near cathodic sites during...34Cathodic Overprotection of SiC/6061-T6 and G/6061- T6 Aluminum Alloy Metal Matrix Composites," Scripta Metallurgica, 22 (1988) 413-418. 14. R

  14. Physical and welding metallurgy of Gd-enriched austenitic alloys for spent nuclear fuel applications. Part II, nickel base alloys

    International Nuclear Information System (INIS)

    Mizia, Ronald E.; Michael, Joseph Richard; Williams, David Brian; Dupont, John Neuman; Robino, Charles Victor

    2004-01-01

    The physical and welding a metallurgy of gadolinium- (Gd-) enriched Ni-based alloys has been examined using a combination of differential thermal analysis, hot ductility testing. Varestraint testing, and various microstructural characterization techniques. Three different matrix compositions were chosen that were similar to commercial Ni-Cr-Mo base alloys (UNS N06455, N06022, and N06059). A ternary Ni-Cr-Gd alloy was also examined. The Gd level of each alloy was ∼2 wt-%. All the alloys initiated solidification by formation of primary austenite and terminated solidification by a Liquid γ + Ni 5 Gd eutectic-type reaction at ∼1270 C. The solidification temperature ranges of the alloys varied from ∼100 to 130 C (depending on alloy composition). This is a substantial reduction compared to the solidification temperature range to Gd-enriched stainless steels (360 to 400 C) that terminate solidification by a peritectic reaction at ∼1060 C. The higher-temperature eutectic reaction that occurs in the Ni-based alloys is accompanied by significant improvements in hot ductility and solidification cracking resistance. The results of this research demonstrate that Gd-enriched Ni-based alloys are excellent candidate materials for nuclear criticality control in spent nuclear fuel storage applications that require production and fabrication of large amounts of material through conventional ingot metallurgy and fusion welding techniques

  15. Charge transfer in chromium-transition metal alloys

    International Nuclear Information System (INIS)

    Kulakowski, K.; Maksymowicz, A.

    1984-07-01

    The average T-matrix approximation is applied for calculations of charge transfer of 3d-electrons in transition metal alloys. The role of concentration, long-range and short-range atomic order is investigated. The results are in reasonable agreement with experimental data. (author)

  16. Microstructure and damage behavior of W-Cr alloy under He irradiation

    Science.gov (United States)

    Huang, Ke; Luo, Lai-Ma; Zan, Xiang; Xu, Qiu; Liu, Dong-Guang; Zhu, Xiao-Yong; Cheng, Ji-Gui; Wu, Yu-Cheng

    2018-04-01

    In this study, a large-power inductively coupled plasma source was designed to perform the continuous helium ion irradiations of W-Cr binary alloy (W-20 wt%Cr) under relevant conditions of the International Thermonuclear Experimental Reactor. Surface damages and microstructures of irradiated W-20Cr were observed by using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. The addition of Cr dramatically enhanced the micro-hardness of the obtained bulk materials, and the interface between the W matrix and the second phase Cr-O is a semi-coherent interface. After irradiation, the doping of Cr element effectively reduces the damage of the W matrix during the irradiation process. The semi-coherent interface between the second phase and the W matrix improves the anti-irradiation performance of the W-20Cr alloy.

  17. Determination of crystalline texture in aluminium - uranium alloys by neutron diffraction

    International Nuclear Information System (INIS)

    Azevedo, A.M.V. de.

    1978-01-01

    Textures of hot-rolled aluminum-uranium alloys and of aluminum were determined by neutron diffraction. Sheets of alloys containing 8.0, 21.5 and 23.7 wt pct U, as well as pure aluminum, were obtained in a stepped rolling process, 15% reduction each step, 75% total reduction. During the rolling the temperature was 600 0 C. Alloys with low uranium contents are two phase systems in which an intermetallic compound UAl 4 , orthorhombic, is dispersed in a pure aluminum matrix. The addition of a few percent of Si in such alloys leads to the formation of UAl 3 , simple cubic, instead of UAl 4 . The Al -- 23.7 wt pct U alloy was prepared with 2,2 wt pct of Si. The results indicate that the texture of the matrix is more dependent on the uranium concentration than on the texture of the intermetallic phases. An improvement in the technique applied to texture measurements by using a sample fully bathed in the neutron beam is also presented. The method takes advantage of the low neutron absorption of the studied materials as well as of the neglibible variation in the multiple scattering which occurs in a conveniently shaped sample having a weakly developed texture. (Author) [pt

  18. Effects of Yb on the mechanical properties and microstructures of an Al-Mg alloy

    International Nuclear Information System (INIS)

    Song Min; Wu Zhenggang; He Yuehui

    2008-01-01

    This paper reported a first study of the effects of Yb on the microstructures and mechanical properties of an extruded Al-Mg alloy. It has been shown that the addition of 0.3 wt.% Yb decreases the mechanical properties of the alloy since Mg- and Yb-containing constituents decrease the concentration of Mg solute atoms in Al matrix, and thus the solution strengthening effect. However, the addition of 1 wt.% Yb substantially improves the mechanical behavior of the alloy because the concentration of Yb solute atoms in Al matrix is high enough to generate solution strengthening effect. The improvement in the mechanical properties is due to the large work-hardening and high dislocation density caused by the interaction between dislocations and Yb and Mg solute atoms. The Yb and Mg atoms inhibit the dynamic recovery and recrystallization of the alloy, thus provide a uniformly distributed dislocation structure with high density

  19. Effect of milling time and CNT concentration on hardness of CNT/Al2024 composites produced by mechanical alloying

    International Nuclear Information System (INIS)

    Pérez-Bustamante, R.; Pérez-Bustamante, F.; Estrada-Guel, I.; Licea-Jiménez, L.; Miki-Yoshida, M.; Martínez-Sánchez, R.

    2013-01-01

    Carbon nanotube/2024 aluminum alloy (CNT/Al 2024 ) composites were fabricated with a combination of mechanical alloying (MA) and powder metallurgy routes. Composites were microstructurally and mechanically evaluated at sintering condition. A homogeneous dispersion of CNTs in the Al matrix was observed by a field emission scanning electron microscopy. High-resolution transmission electron microscopy confirmed not only the presence of well dispersed CNTs but also needle-like shape aluminum carbide (Al 4 C 3 ) crystals in the Al matrix. The formation of Al 4 C 3 was suggested as the interaction between the outer shells of CNTs and the Al matrix during MA process in which crystallization took place after the sintering process. The mechanical behavior of composites was evaluated by Vickers microhardness measurements indicating a significant improvement in hardness as function of the CNT content. This improvement was associated to a homogeneous dispersion of CNTs and the presence of Al 4 C 3 in the aluminum alloy matrix. - Highlights: ► The 2024 aluminum alloy was reinforced by CNTs by mechanical alloying process. ► Composites were microstructural and mechanically evaluated after sintering condition. ► The greater the CNT concentration, the greater the hardness of the composites. ► Higher hardness in composites is achieved at 20 h of milling. ► The formation of Al 4 C 3 does not present a direct relationship with the milling time.

  20. Microstructure and Mechanical Properties of MWCNTs Reinforced A356 Aluminum Alloys Cast Nanocomposites Fabricated by Using a Combination of Rheocasting and Squeeze Casting Techniques

    Directory of Open Access Journals (Sweden)

    Abou Bakr Elshalakany

    2014-01-01

    Full Text Available A356 hypoeutectic aluminum-silicon alloys matrix composites reinforced by different contents of multiwalled carbon nanotubes (MWCNTs were fabricated using a combination of rheocasting and squeeze casting techniques. A novel approach by adding MWCNTs into A356 aluminum alloy matrix with CNTs has been performed. This method is significant in debundling and preventing flotation of the CNTs within the molten alloy. The microstructures of nanocomposites and the interface between the aluminum alloy matrix and the MWCNTs were examined by using an optical microscopy (OM and scanning electron microscopy (SEM equipped with an energy dispersive X-ray analysis (EDX. This method remarkably facilitated a uniform dispersion of nanotubes within A356 aluminum alloy matrix as well as a refinement of grain size. In addition, the effects of weight fraction (0.5, 1.0, 1.5, 2.0, and 2.5 wt% of the CNT-blended matrix on mechanical properties were evaluated. The results have indicated that a significant improvement in ultimate tensile strength and elongation percentage of nanocomposite occurred at the optimal amount of 1.5 wt% MWCNTs which represents an increase in their values by a ratio of about 50% and 280%, respectively, compared to their corresponding values of monolithic alloy. Hardness of the samples was also significantly increased by the addition of CNTs.

  1. Mechanical properties and fracture mechanism of as-cast Mg77TM12Zn5Y6 (TM = Cu, Ni) bulk amorphous matrix composites

    International Nuclear Information System (INIS)

    Qiu, K.Q.; Hu, N.N.; Zhang, H.B.; Jiang, W.H.; Ren, Y.L.; Liaw, P.K.

    2009-01-01

    Comparative investigations on the microstructures, thermal stability and mechanical properties of Mg 77 Cu 12 Zn 5 Y 6 and Mg 77 Ni 12 Zn 5 Y 6 bulk metallic glass matrix composites were carried out by using scanning electron microscopy (SEM), DSC and compressive tester. The results show that the microstructure of as-cast samples with 3 mm in diameter for Cu-containing alloy is consisted of Mg flakes and dotted Mg 2 Cu phase in the amorphous matrix, while the as-cast Ni-containing alloy with the same diameter is mainly consisted of Mg flakes in the amorphous matrix. The glass transition temperature and supercooled liquid region are 413 K and 27 K for the Cu-containing, 443 K and 32 K for the Ni-containing amorphous matrix composites, respectively. The fracture strength, yield strength and plastic strain are 532 MPa, 390 MPa and 2.4% for the Cu-containing alloy, 667 MPa, 412 MPa and 7% for the Ni-containing alloy, respectively. Furthermore, the fracture mechanism for the amorphous matrix composites was discussed according to both the fracture surfaces and the stress-strain curves.

  2. Tiny intracranial aneurysms: Endovascular treatment by coil embolisation or sole stent deployment

    International Nuclear Information System (INIS)

    Lu Jun; Liu Jiachun; Wang Lijun; Qi Peng; Wang Daming

    2012-01-01

    Purpose: Tiny intracranial aneurysms pose a significant therapeutic challenge for interventional neuroradiologists. The authors report their preliminary results of endovascular treatment of these aneurysms. Methods: Between January 2002 and December 2009, 52 tiny intracranial aneurysms (defined as ≤3 mm in maximum diameter) in 46 patients (22 men; mean age, 57.9 years) were treated by endosaccular coil embolisation or sole stent deployment in the parent artery. Of 52 aneurysms, 29 had ruptured and 23 remained unruptured. The initial angiographic results, procedural complications, and clinical outcomes were assessed at discharge. Imaging follow-up was performed with cerebral angiography. Results: One aneurysm coiling procedure failed because of unsuccessful micro-catheterization. Forty-three aneurysms were successfully coil embolized, of which complete occlusion was obtained in 14, subtotal occlusion in 18 and incomplete occlusion in 11. The other 8 aneurysms were treated by sole stent deployment in the parent artery. Procedural complications (2 intraprocedural ruptures and 3 thromboembolic events) occurred in 5 (9.6%) of 52 aneurysms, resulting in permanent morbidity in only 1 (2.2%, 1/46) patient. No rebleeding occurred during clinical follow-up (mean duration, 46.7 months). Of the 16 coiled aneurysms that receiving repetitive angiography, 6 initially completely and 3 subtotally occluded aneurysms remained unchanged, 4 initially subtotally and 3 incompletely occluded aneurysms progressed to total occlusion. Five sole stent deployed aneurysms received angiographic follow-up (mean duration, 10.0 months), of which 3 remained unchanged, 1 became smaller and 1 progressed to total occlusion. Conclusion: Endovascular treatment of tiny intracranial aneurysms is technical feasible and relatively safe. Coil embolisation seems to be effective in preventing early recanalisation, whereas sole stenting technique needs further investigation to determine its effectiveness.

  3. Evaluation of HEBM Mechanical Alloying of Al2O3— 356/7075 Powder Mixture

    CSIR Research Space (South Africa)

    Govender, G

    2012-04-01

    Full Text Available Particle reinforced aluminium alloy metal matrix composites (MMC) have proven to be one of the advanced materials capable of replacing conventional structural alloys. However, the demand for such materials has been confined to high cost applications...

  4. Effects of Surface Dipole Lengths on Evaporation of Tiny Water Aggregation

    International Nuclear Information System (INIS)

    Wang Shen; Wan Rongzheng; Fang Haiping; Tu Yusong

    2013-01-01

    Using molecular dynamics simulation, we compared evaporation behavior of a tiny amount of water molecules adsorbed on solid surfaces with different dipole lengths, including surface dipole lengths of 1 fold, 2 folds, 4 folds, 6 folds and 8 folds of 0.14 nm and different charges from 0.1e to 0.9e. Surfaces with short dipole lengths (1-fold system) can always maintain hydrophobic character and the evaporation speeds are not influenced, whether the surface charges are enhanced or weakened; but when surface dipole lengths get to 8 folds, surfaces become more hydrophilic as the surface charge increases, and the evaporation speeds increase gradually and monotonically. By tuning dipole lengths from 1-fold to 8-fold systems, we confirmed non-monotonic variation of the evaporation flux (first increases, then decreases) in 4 fold system with charges (0.1e–0.7e), reported in our previous paper [S. Wang, et al., J. Phys. Chem. B 116 (2012) 13863], and also show the process from the enhancement of this unexpected non-monotonic variation to its vanishment with surface dipole lengths increasing. Herein, we demonstrated two key factors to influence the evaporation flux of a tiny amount of water molecules adsorbed on solid surfaces: the exposed surficial area of water aggregation from where the water molecules can evaporate directly and the attraction potential from the substrate hindering the evaporation. In addition, more interestingly, we showed extra steric effect of surface dipoles on further increase of evaporation flux for 2-folds, 4-folds, 6-folds and 8-folds systems with charges around larger than 0.7e. (The steric effect is first reported by parts of our authors [C. Wang, et al., Sci. Rep. 2 (2012) 358]). This study presents a complete physical picture of the influence of surface dipole lengths on the evaporation behavior of the adsorbed tiny amount of water. (condensed matter: structural, mechanical, and thermal properties)

  5. Radiochemical neutron activation analysis of zirconium and zirconium-niobium alloys

    International Nuclear Information System (INIS)

    Tashimova, F.A.; Sadikov, I.I.; Salimov, M.

    2004-01-01

    Full text: Zirconium and zirconium-niobium alloys are used on nuclear technology, as fuel cladding of nuclear reactors. Their nuclear-physical, mechanical and thermophysical properties are influenced them matrix and impurity composition, therefore determination of matrix and impurity content of these materials is a very important task. Neutron activation analysis is one from multielemental and high sensible techniques that are widely applied in analysis of high purity materials. Investigation of nuclear-physical characteristics of zirconium has shown that instrumental variant NAA is unusable for analysis due to high radioactivity of a matrix. Therefore it is necessary carrying out radiochemical separation of impurity radionuclides from matrix. Study of the literature datum have shown, that zirconium and niobium are very well extracted from muriatic solution with 5% tributyl phosphineoxide (TBPO) solution in toluene and 0,75 M solution of di-2-ethyl hexyl phosphoric acid (HDEHP) in cyclohexanone. Investigation of these elements extraction in these systems has shown that more effective and selective separation of matrix radionuclides is achieved in HDEHP-3M HCI system. This system is also extracted and hafnium, witch is an accompanying element of zirconium and its high content prevented determination of other impurity elements in sample. Therefore we used extraction system HDEHP-3M HCl for analysis of zirconium and zirconium-niobium alloys in chromatographic variant. By measurement of distribution profile of a matrix and of elution curve of determined elements is established, that for effective separation of impurity and matrix radionuclides there is enough chromatographic column with diameter 1 cm and height of a sorbent layer 7 cm, thus volume of elute, necessary for complete elution of determinate elements is 35-40 ml. On the basis of the carried out researches the technique of radiochemical NAA of high purity zirconium and zirconium-niobium alloy, which allows to

  6. An augmented space formulation of the optical conductivity of random semiconducting alloys

    International Nuclear Information System (INIS)

    Mookerjee, A.

    1984-08-01

    A formalism has been developed for the study of optical conductivity of disordered semiconducting alloys effect of off-diagonal disorder, clustering and randomness in the electron-photon interaction matrix may be incorporated within this. The aim is to finally study GaAssub(x)Sbsub(1-x) as well as deep levels in this alloy. (author)

  7. Microstructure and high temperature oxidation resistance of Ti-Ni gradient coating on TA2 titanium alloy fabricated by laser cladding

    Science.gov (United States)

    Liu, Fencheng; Mao, Yuqing; Lin, Xin; Zhou, Baosheng; Qian, Tao

    2016-09-01

    To improve the high temperature oxidation resistance of TA2 titanium alloy, a gradient Ni-Ti coating was laser cladded on the surface of the TA2 titanium alloy substrate, and the microstructure and oxidation behavior of the laser cladded coating were investigated experimentally. The gradient coating with a thickness of about 420-490 μm contains two different layers, e.g. a bright layer with coarse equiaxed grain and a dark layer with fine and columnar dendrites, and a transition layer with a thickness of about 10 μm exists between the substrate and the cladded coating. NiTi, NiTi2 and Ni3Ti intermetallic compounds are the main constructive phases of the laser cladded coating. The appearance of these phases enhances the microhardness, and the dense structure of the coating improves its oxidation resistance. The solidification procedure of the gradient coating is analyzed and different kinds of solidification processes occur due to the heat dissipation during the laser cladding process.

  8. Thermal and microstructural analysis of alloys of Al-Mg-Li system

    International Nuclear Information System (INIS)

    Ovsyannikov, B.V.; Zamaytin, V.M.; Smirnov, V.L.; Mushnikov, V.S.

    2008-01-01

    By means of the thermal analysis one investigated into melting and solidification of Al-Mg-Li system 1420, 1421 and 1424 aluminum-lithium alloys. One determined the temperature values of the nonequilibrium and the equilibrium solidus, the initiation of the liquidus linear shrinkage of the listed alloys. Making use of a scanning electron microscope with a microanalyser unit one studied the microstructure of the alloys and determined the local chemical composition of the phases unsoluble under homogenization of ingots along the aluminum matrix grain boundaries [ru

  9. Ultrahigh Sensitivity Piezoresistive Pressure Sensors for Detection of Tiny Pressure.

    Science.gov (United States)

    Li, Hongwei; Wu, Kunjie; Xu, Zeyang; Wang, Zhongwu; Meng, Yancheng; Li, Liqiang

    2018-05-31

    High sensitivity pressure sensors are crucial for the ultra-sensitive touch technology and E-skin, especially at the tiny pressure range below 100 Pa. However, it is highly challenging to substantially promote sensitivity beyond the current level at several to two hundred kPa -1 , and to improve the detection limit lower than 0.1 Pa, which is significant for the development of pressure sensors toward ultrasensitive and highly precise detection. Here, we develop an efficient strategy to greatly improve the sensitivity near to 2000 kPa -1 by using short channel coplanar device structure and sharp microstructure, which is systematically proposed for the first time and rationalized by the mathematic calculation and analysis. Significantly, benefiting from the ultrahigh sensitivity, the detection limit is improved to be as small as 0.075 Pa. The sensitivity and detection limit are both superior to the current levels, and far surpass the function of human skin. Furthermore, the sensor shows fast response time (50 μs), excellent reproducibility and stability, and low power consumption. Remarkably, the sensor shows excellent detection capacity in the tiny pressure range including LED switching with a pressure of 7 Pa, ringtone (2-20 Pa) recognition, and ultrasensitive (0.1 Pa) electronic glove. This work represents a performance and strategic progress in the field of pressure sensing.

  10. Tensile Flow Behavior of Tungsten Heavy Alloys Produced by CIPing and Gelcasting Routes

    Science.gov (United States)

    Panchal, Ashutosh; Ravi Kiran, U.; Nandy, T. K.; Singh, A. K.

    2018-06-01

    Present work describes the flow behavior of tungsten heavy alloys with nominal compositions 90W-7Ni-3Fe, 93W-4.9Ni-2.1Fe, and 95W-3.5Ni-1.5Fe (wt pct) produced by CIPing and gelcasting routes. The overall microstructural features of gelcasting are finer than those of CIPing alloys. Both the grain size of W and corresponding contiguity values increase with increase in W content in the present alloys. The volume fraction of matrix phase decreases with increase in W content in both the alloys. The lattice parameter values of the matrix phase also increase with increase in W content. The yield strength ( σ YS) continuously increases with increase in W content in both the alloys. The σ YS values of CIPing alloys are marginally higher than those of gelcasting at constant W. The ultimate tensile strength ( σ UTS) and elongation values are maximum at intermediate W content. Present alloys exhibit two slopes in true stress-true plastic strain curves in low and high strain regimes and follow a characteristic Ludwigson relation. The two slopes are associated with two deformation mechanisms that are occurring during tensile deformation. The overall nature of differential curves of all the alloys is different and these curves contain three distinctive stages of work hardening (I, II, and III). This suggests varying deformation mechanisms during tensile testing due to different volume fractions of constituent phases. The slip is the predominant deformation mechanism of the present alloys during tensile testing.

  11. Relationship between Microstructure and Properties of Cu-Cr-Ag-(Ce) Alloy Using Microscopic Investigation.

    Science.gov (United States)

    Chen, Huiming; Yuan, Dawei; Wu, Shanjiang; Wang, Hang; Xie, Weibin; Yang, Bin

    2017-01-01

    Microstructure, precipitation hardening response, and mechanical and physical properties of Cu-Cr-Ag alloy and Cu-Cr-Ag-Ce alloy have been investigated using transmission electron microscopy, scanning electron microscope, optical microscope, electrical conductivity analysis, and tensile test. The influence of element Ce on the matrix refinement, impurity removal, and precipitation in the Cu-Cr-Ag alloys has been analyzed. The experimental results show that the strength and electrical conductivity of Ce containing alloys are greater than those of Ce-free alloys after each processing step. Improvement of strength and electrical conductivity of the Cu-Cr-Ag alloy by adding Ce element is attributed to removing oxygen and sulfur from as-cast alloy.

  12. Oxidation behavior of U-2wt%Nb, Ti, and Ni alloys in air

    International Nuclear Information System (INIS)

    Ju, J. S.; Yoo, K. S.; Jo, I. J.; Gug, D. H.; Su, H. S.; Lee, E. P.; Bang, K. S.; Kim, H. D.

    2003-01-01

    For the long term storage safety study of the metallic spent fuel, U-Nb, U-Ti, U-Ni, U-Zr, and U-Hf simulated metallic uranium alloys, known as corrosion resistant alloys, were fabricated and oxidized in oxygen gas at 200 .deg. C-300 .deg. C. Simulated metallic uranium alloys were more corrosion resistant than pure uranium metal, and corrosion resistance increases Nb, Ni, Ti in that order. The oxidation rates of uranium alloys determined and activation energy was calculated for each alloy. The matrix microstructure of the test specimens were analyzed using OM, SEM, and EPMA. It was concluded that Nb was the best acceptable alloying elements for reducing corrosion of uranium metal considered to suitable as candidate

  13. Corrosion and protection of magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ghali, E. [Laval Univ., Quebec City, PQ (Canada). Dept. of Mining and Metallurgy

    2000-07-01

    The oxide film on magnesium offers considerable surface protection in rural and some industrial environments and the corrosion rate lies between that of aluminum and low carbon steels. Galvanic coupling of magnesium alloys, high impurity content such as Ni, Fe, Cu and surface contamination are detrimental for corrosion resistance of magnesium alloys. Alloying elements can form secondary particles which are noble to the Mg matrix, thereby facilitating corrosion, or enrich the corrosion product thereby possibly inhibiting the corrosion rate. Bimetallic corrosion resistance can be increased by fluxless melt protection, choice of compatible alloys, insulating materials, and new high-purity alloys. Magnesium is relatively insensible to oxygen concentration. Pitting, corrosion in the crevices, filiform corrosion are observed. Granular corrosion of magnesium alloys is possible due to the cathodic grain-boundary constituent. More homogeneous microstructures tend to improve corrosion resistance. Under fatigue loading conditions, microcrack initiation in Mg alloys is related to slip in preferentially oriented grains. Coating that exclude the corrosive environments can provide the primary defense against corrosion fatigue. Magnesium alloys that contain neither aluminum nor zinc are the most SCC resistant. Compressive surface residual stresses as that created by short peening increase SCC resistance. Cathodic polarization or cladding with a SCC resistant sheet alloy are good alternatives. Effective corrosion prevention for magnesium alloy components and assemblies should start at the design stage. Selective surface preparation, chemical treatment and coatings are recommended. Oil application, wax coating, anodizing, electroplating, and painting are possible alternatives. Recently, it is found that a magnesium hydride layer, created on the magnesium surface by cathodic charging in aqueous solution is a good base for painting. (orig.)

  14. Is Cu60Ti10Zr30 a bulk glass-forming alloy?

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Saida, J.; Kato, H.

    2003-01-01

    . Nanocrystals with a significant volume fraction are randomly distributed in the amorphous matrix. The copper element is enriched in nanocrystals while a slightly high zirconium content is found in the matrix. We classify that the Cu60Ti10Zr30 alloy prepared by both of the aforementioned methods...

  15. Cu-segregation at the Q'/α-Al interface in Al-Mg-Si-Cu alloy

    International Nuclear Information System (INIS)

    Matsuda, Kenji; Teguri, Daisuke; Uetani, Yasuhiro; Sato, Tatsuo; Ikeno, Susumu

    2002-01-01

    Cu segregation was detected at the Q ' /α-Al interface in an Al-Mg-Si-Cu alloy by energy-filtered transmission electron microscopy. By contrast, in a Cu-free Al-Mg-Si alloy no segregation was observed at the interface between the matrix and Type-C precipitate

  16. Simultaneous increase in strength and ductility by decreasing interface energy between Zn and Al phases in cast Al-Zn-Cu alloy.

    Science.gov (United States)

    Han, Seung Zeon; Choi, Eun-Ae; Park, Hyun Woong; Lim, Sung Hwan; Lee, Jehyun; Ahn, Jee Hyuk; Hwang, Nong-Moon; Kim, Kwangho

    2017-09-22

    Cast-Al alloys that include a high amount of the second element in their matrix have comparatively high strength but low ductility because of the high volume fraction of strengthening phases or undesirable inclusions. Al-Zn alloys that have more than 30 wt% Zn have a tensile strength below 300 MPa, with elongation under 5% in the as-cast state. However, we found that after substitution of 2% Zn by Cu, the tensile strength of as-cast Al-Zn-Cu alloys was 25% higher and ductility was four times higher than for the corresponding Al-35% Zn alloy. Additionally, for the Al-43% Zn alloy with 2% Cu after 1 h solution treatment at 400 °C and water quenching, the tensile strength unexpectedly reached values close to 600 MPa. For the Al-33% Zn alloy with 2% Cu, the tensile strength was 500 MPa with 8% ductility. The unusual trends of the mechanical properties of Al-Zn alloys with Cu addition observed during processing from casting to the subsequent solution treatment were attributed to the precipitation of Zn in the Al matrix. The interface energy between the Zn particles and the Al matrix decreased when using a solution of Cu in Zn.

  17. Effect Of Milling Time On Microstructure Of AA6061 Composites Fabricated Via Mechanical Alloying

    Directory of Open Access Journals (Sweden)

    Tomiczek B.

    2015-06-01

    Full Text Available The aim of this work is to determine the effect of manufacturing conditions, especially milling time, on the microstructure and crystallite size of a newly developed nanostructural composite material with the aluminium alloy matrix reinforced with halloysite nanotubes. Halloysite, being a clayey mineral of volcanic origin, is characterized by high porosity and large specific surface area. Thus it can be used as an alternative reinforcement in metal matrix composite materials. In order to obtain this goal, composite powders with fine microstructures were fabricated using high-energy mechanical alloying, cold compacting and hot extrusion techniques. The obtained composite powders of aluminium alloy reinforced with 5, 10 and 15 wt% of halloysite nanotubes were characterized with SEM, TEM and XRD analysis. It has been proven that the use of mechanical alloying leads to a high degree of deformation, which, coupled with a decreased grain size below 100 nm and the dispersion of the refined reinforcing particles–reinforces the material very well.

  18. Effective and Environmentally Friendly Nickel Coating on the Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    Ivana Škugor Rončević

    2016-12-01

    Full Text Available The low density and good mechanical properties make magnesium and its alloys attractive construction materials in the electronics, automotive, and aerospace industry, together with application in medicine due to their biocompatibility. Magnesium AZ91D alloy is an alloy with a high content of aluminum, whose mechanical properties overshadow the low corrosion resistance caused by the composition of the alloy and the existence of two phases: α magnesium matrix and β magnesium aluminum intermetallic compound. To improve the corrosion resistance, it is necessary to find an effective protection method for the alloy surface. Knowing and predicting electrochemical processes is an essential for the design and optimization of protective coatings on magnesium and its alloys. In this work, the formations of nickel protective coatings on the magnesium AZ91D alloy surface by electrodeposition and chemical deposition, are presented. For this purpose, environmentally friendly electrolytes were used. The corrosion resistance of the protected alloy was determined in chloride medium using appropriate electrochemical techniques. Characterization of the surface was performed with highly sophisticated surface-analytical methods.

  19. Mechanical characterization of SiC particulate & E-glass fiber reinforced Al 3003 hybrid metal matrix composites

    Science.gov (United States)

    Narayana, K. S. Lakshmi; Shivanand, H. K.

    2018-04-01

    Metal matrix composites constitute a class of low cost high quality materials which offer high performance for various industrial applications. The orientation of this research is towards the study of mechanical properties of as cast silicon carbide (SiC) particulates and Short E-Glass fibers reinforced Aluminum matrix composites (AMCs). The Hybrid metal matrix composite is developed by reinforcing SiC particulates of 100 microns and short E-Glass fibers of 2-3 mm length with Al 3003 in different compositions. The vortex method of stir casting was employed, in which the reinforcements were introduced into the vortex created by the molten metal by means of mechanical stirrer. The mechanical properties of the prepared metal matrix composites were analyzed. From the studies it was noticed that an improvement in mechanical properties of the reinforced alloys compared to unreinforced alloys.

  20. Research on aging precipitation in a Cu-Cr-Zr-Mg alloy

    International Nuclear Information System (INIS)

    Su Juanhua; Dong Qiming; Liu Ping; Li Hejun; Kang Buxi

    2005-01-01

    The effects of aging processes on the properties and microstructure of Cu-0.3Cr-0.15Zr-0.05Mg lead frame alloy were investigated. Aging precipitation phase was dealt with by transmission electronic microscope (TEM). After solid solution was treated at 920 deg. C and aged at 470 deg. C for 4 h, the fine precipitation of an ordered compound CrCu 2 (Zr, Mg) is found in copper matrix as well as fine Cr and Cu 4 Zr. Along the grain boundary, there are larger chromium. The hardness and electrical conductivity can reach 109 HV and 80% IACS, respectively. Sixty percent cold-rolled deformation prior to aging at 470 deg. C enhances the hardness of the alloy. The coherent precipitates Cr in copper matrix and the dislocations pinned by the fine precipitates are responsible for maximum strengthening of the alloy. So the hardness 165 HV and electrical conductivity 79.2% IACS are available

  1. Application of mathematical experimental planning in the investigation of thermodynamic properties of three- component alloys

    International Nuclear Information System (INIS)

    Sokolovskaya, E.M.; Guzej, L.S.; Tikhankin, G.A.; Meshkov, L.L.

    1977-01-01

    Thermodynamic properties of solid solutions of niobium and tungsten in nickel have been investigated by the method of electromotive forces with the use of simplex-matrix experiment planning techniques. The planning matrix and the results of investigating the thermodynamic properties of alloys of the nickel-niobium-tungsten system at 1250 deg are presented. The application of experiment planning has made it possible to obtain sufficient information concerning the thermodynamics of solid solutions of niobium and tungsten in nickel from the experimental data for six ternary alloys only

  2. Microstructure and martensitic transformation of Ni-Ti-Pr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chunwang [Inner Mongolia University of Technology, College of Science, Hohhot (China); Shanghai Maritime University, College of Arts and Sciences, Shanghai (China); Zhao, Shilei; Jin, Yongjun; Hou, Qingyu [Inner Mongolia University of Technology, College of Science, Hohhot (China); Guo, Shaoqiang [Beihang University, Key Laboratory of Micro-nano Measurement, Manipulation and Physics (Ministry of Education), Department of Physics, Beijing (China)

    2017-09-15

    The effect of Pr addition on the microstructure and martensitic transformation behavior of Ni{sub 50}Ti{sub 50-x}Pr{sub x} (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9) alloys were investigated experimentally. Results show that the microstructures of Ni-Ti-Pr alloys consist of the NiTi matrix and the NiPr precipitate with the Ti solute. The martensitic transformation start temperature decreases gradually with the increase in Pr fraction. The stress around NiPr precipitates is responsible for the decrease in martensitic transformation temperature with the increase in Pr fraction in Ni-Ti-Pr alloys. (orig.)

  3. The science of tiny things: physics at the nanoscale

    Energy Technology Data Exchange (ETDEWEB)

    Copp, Stacy Marla [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-07

    Nanoscience is the study of tiny objects that are only a billionth of a meter in size, or about 1,000 to 10,000 times smaller than a human hair. From the electronics in your smartphone to the molecular motors that are in your body’s cells, nanoscientists study and design materials that span a huge range of subjects, from physics to chemistry to biology. I will talk about some of what we do at LANL’s Center for Integrated Technologies, as well as how I first got interested in nanoscience and how I became a nanoscientist at LANL.

  4. Microstructure and Aging Behavior of Nonflammable AZ91D Mg Alloy

    OpenAIRE

    Seok Hong Min; Tae Kwon Ha

    2014-01-01

    Phase equilibria of AZ91D Mg alloys for nonflammable use, containing Ca and Y, were carried out by using FactSage® and FTLite database, which revealed that solid solution treatment could be performed at temperatures from 400 to 450oC. Solid solution treatment of AZ91D Mg alloy without Ca and Y was successfully conducted at 420oC and supersaturated microstructure with all beta phase resolved into matrix was obtained. In the case of AZ91D Mg alloy with some Ca and Y; howeve...

  5. Oxidation kinetics and auger microprobe analysis of some oxidized zirconium alloys

    International Nuclear Information System (INIS)

    Ploc, R.A.

    1989-01-01

    Oxidation kinetics at 300 o C in dry oxygen of 0.5 wt% binary alloys of iron, nickel, and chromium in zirconium were determined for several surface preparations. Further, chemical profiles of the oxides as they existed on the matrix and on the precipitates were obtained by sputtering and Auger electron analysis. The appearance of 'breakaway' oxidation was controlled by the surface finish of the alloy, a variable that could be used to eliminate the phenomenon for all alloys except the Zr/Ni binary, which required β-quenching to accomplish the same purpose. (author)

  6. Laser direct marking applied to rasterizing miniature Data Matrix Code on aluminum alloy

    Science.gov (United States)

    Li, Xia-Shuang; He, Wei-Ping; Lei, Lei; Wang, Jian; Guo, Gai-Fang; Zhang, Teng-Yun; Yue, Ting

    2016-03-01

    Precise miniaturization of 2D Data Matrix (DM) Codes on Aluminum alloy formed by raster mode laser direct part marking is demonstrated. The characteristic edge over-burn effects, which render vector mode laser direct part marking inadequate for producing precise and readable miniature codes, are minimized with raster mode laser marking. To obtain the control mechanism for the contrast and print growth of miniature DM code by raster laser marking process, the temperature field model of long pulse laser interaction with material is established. From the experimental results, laser average power and Q frequency have an important effect on the contrast and print growth of miniature DM code, and the threshold of laser average power and Q frequency for an identifiable miniature DM code are respectively 3.6 W and 110 kHz, which matches the model well within normal operating conditions. In addition, the empirical model of correlation occurring between laser marking parameters and module size is also obtained, and the optimal processing parameter values for an identifiable miniature DM code of different but certain data size are given. It is also found that an increase of the repeat scanning number effectively improves the surface finish of bore, the appearance consistency of modules, which has benefit to reading. The reading quality of miniature DM code is greatly improved using ultrasonic cleaning in water by avoiding the interference of color speckles surrounding modules.

  7. New X-Ray Technique to Characterize Nanoscale Precipitates in Aged Aluminum Alloys

    Science.gov (United States)

    Sitdikov, V. D.; Murashkin, M. Yu.; Valiev, R. Z.

    2017-10-01

    This paper puts forward a new technique for measurement of x-ray patterns, which enables to solve the problem of identification and determination of precipitates (nanoscale phases) in metallic alloys of the matrix type. The minimum detection limit of precipitates in the matrix of the base material provided by this technique constitutes as little as 1%. The identification of precipitates in x-ray patterns and their analysis are implemented through a transmission mode with a larger radiation area, longer holding time and higher diffractometer resolution as compared to the conventional reflection mode. The presented technique has been successfully employed to identify and quantitatively describe precipitates formed in the Al alloy of the Al-Mg-Si system as a result of artificial aging. For the first time, the x-ray phase analysis has been used to identify and measure precipitates formed during the alloy artificial aging.

  8. Indentation creep behaviors of amorphous Cu-based composite alloys

    Science.gov (United States)

    Song, Defeng; Ma, Xiangdong; Qian, Linfang

    2018-04-01

    This work reports the indentation creep behaviors of two Si2Zr3/amorphous Cu-based composite alloys utilizing nanoindentation technique. By analysis with Kelvin model, the retardation spectra of alloys at different positions, detached and attached regions to the intermetallics, were deduced. For the indentation of detached regions to Si2Zr3 intermetallics in both alloys, very similarity in creep displacement can be observed and retardation spectra show a distinct disparity in the second retardation peak. For the indentation of detached regions, the second retardation spectra also display distinct disparity. At both positions, the retardation spectra suggest that Si elements may lead to the relatively dense structure in the amorphous matrix and to form excessive Si2Zr3 intermetallics which may deteriorate the plastic deformation of current Cu-based composite alloys.

  9. Effects of Eutectic Si Particles on Mechanical Properties and Fracture Toughness of Cast A356 Aluminum Alloys

    International Nuclear Information System (INIS)

    Lee, Kyu Hong; Lee, Sung Hak; Kwon, Yong Nam

    2007-01-01

    The present study aims at investigating the effects of eutectic Si particles on mechanical properties and fracture toughness of three A356 aluminum alloys. These A356 alloys were fabricated by casting processes such as rheo-casting, squeeze-casting, and casting-forging, and their mechanical properties and fracture toughness were analyzed in relation with microfracture mechanism study. All the cast A356 alloys contained eutectic Si particles mainly segregated along solidification cells, and the distribution of Si particles was modified by squeeze-casting and casting-forging processes. Microfracture observation results showed that eutectic Si particles segregated along cells were cracked first, but that aluminum matrix played a role in blocking crack propagation. Tensile properties and fracture toughness of the squeeze cast and cast-forged alloys having homogeneous distribution of eutectic Si particles were superior to those of the rheo-cast alloy. In particular, the cast-forged alloy had excellent hardness, strength, ductility, and fracture toughness because of the matrix strengthening and homogeneous distribution of eutectic Si particles due to forging process

  10. Application research of ferrous matrix composites in roller ring used in high-speed wire/bar rolling mill

    International Nuclear Information System (INIS)

    Song Yanpei; Li Xiuqing; Bi Shuangxu

    2010-01-01

    Research highlights: → A composite structure roller rings was fabricated by centrifugal casting. → The roller rings consisted of outer WCP/Fe-C composites layer and inner Fe-C alloy matrix. → Hardness attained to HRA80-85 in the composites layer, and HRA73-76 in inner Fe-C alloy matrix where the toughness was over 8 J/cm 2 . → The wear resistance of the roller rings excelled that of high-speed steel, and approached to that of the WC hard alloy roll. → The production cost of the WCP/Fe-C composites roller ring decreased by 50%. - Abstract: Tungsten carbide particle (WC P ) reinforced ferrous matrix composites roller rings were fabricated by centrifugal casting. The microstructures, properties and application effect of the composites roller rings were investigated by SEM, TEM and various property testers. The experimental results show that the WC P were uniformly distributed in outer reinforced-layer (working-layer) of 20-50 mm in thickness and their volume fraction reached 60-80 vol.%; there was a good interface bonding between WC P and Fe-C alloy without any reaction products; hardness attained to HRA80-85 in working-layer, and HRA73-76 in inner ferrous matrix where the toughness was over 8 J/cm 2 ; the wear resistance of the composites roller rings excels that of high-speed steel; service life of the composites parts approached to that of the WC hard alloy roll when the same WC P -volume-fraction in working-layer were obtained for both of them, but the production cost of the WC P /Fe-C composites roller ring decreased by 50%.

  11. Investigation of americium-241 metal alloys for target applications

    International Nuclear Information System (INIS)

    Conner, W.V.; Rockwell International Corp., Golden, CO

    1982-01-01

    Several 241 Am metal alloys have been investigated for possible use in the Lawrence Livermore National Laboratory Radiochemical Diagnostic Tracer Program. Several properties were desired for an alloy to be useful for tracer program applications. A suitable alloy would have a fairly high density, be ductile, homogeneous and easy to prepare. Alloys investigated have included uranium-americium, aluminium-americium, and cerium-americium. Uranium-americium alloys with the desired properties proved to be difficult to prepare, and work with this alloy was discontinued. Aluminium-americium alloys were much easier to prepare, but the alloy consisted of an aluminium-americium intermetallic compound (AmAl 4 ) in an aluminum matrix. This alloy could be cast and formed into shapes, but the low density of aluminum, and other problems, made the alloy unsuitable for the intended application. Americium metal was found to have a high solid solubility in cerium and alloys prepared from these two elements exhibited all of the properties desired for the tracer program application. Cerium-americium alloys containing up to 34 wt% americium have been prepared using both co-melting and co-reduction techniques. The latter technique involves co-reduction of cerium tetrafluoride and americium tetrafluoride with calcium metal in a sealed reduction vessel. Casting techniques have been developed for preparing up to eight 2.2 cm (0.87 in) diameter disks in a single casting, and cerium-americium metal alloy disks containing from 10 to 25 wt% 241 Am have been prepared using these techniques. (orig.)

  12. Converting hcp Mg-Al-Zn alloy into bcc Mg-Li-Al-Zn alloy by electrolytic deposition and diffusion of reduced lithium atoms in a molten salt electrolyte LiCl-KCl

    International Nuclear Information System (INIS)

    Lin, M.C.; Tsai, C.Y.; Uan, J.Y.

    2007-01-01

    A body-centered cubic (bcc) Mg-12Li-9Al-1Zn (wt.%) alloy was fabricated in air by electrolysis from LiCl-KCl molten salt at 500 deg. C. Electrolytic deposition of Li atoms on cathode (Mg-Al-Zn alloy) and diffusion of the Li atoms formed the bcc Mg-Li-Al-Zn alloy with 12 wt.% Li and only 0.264 wt.% K. Low K concentration in the bcc Mg alloy strip after the electrolysis process resulted from 47% atomic size misfit between K and Mg atoms and low solubility of K in Mg matrix

  13. The irradiation induced microstructural development and the role of γ' on void formation in Ni-based alloys

    International Nuclear Information System (INIS)

    Kato, T.; Nakata, K.; Masaoka, I.; Takahashi, H.; Takeyama, T.; Ohnuki, S.; Osanai, H.

    1984-01-01

    The microstructural development for Inconel X-750, Ni-13 at% Al, and Ni-11.5 at% Si alloys during irradiation was investigated. These alloys were previously heat-treated at temperatures of 723-1073 K, and γ' precipitates were produced. Irradiation was performed in a high voltage electron microscope in the temperature range 627-823 K. In the case of solution-treated Inconel, interstitial dislocation loops were formed initially, while voids were nucleated after longer times. When the Inconel specimen containing a high number density of small γ' was irradiated, dislocation loops were formed in both the matrix and precipitate-matrix interface. The loops formed on the interface scarcely grew during irradiation. On the other hand, for the Ni-Al alloy fine γ' nucleated during irradiation, the large γ' precipitated by pre-aging, dissolved. A similar resolution process was also observed in Ni-Si alloy. Furthermore, in the Ni-Si alloy precipitates of γ' formed preferentially at interstitial dislocation loops and both specimen surfaces. (orig.)

  14. Discontinuous precipitation in copper base alloys

    Indian Academy of Sciences (India)

    Discontinuous precipitation (DP) is associated with grain boundary migration in the wake of which alternate plates of the precipitate and the depleted matrix form. Some copper base alloys show DP while others do not. In this paper the misfit strain parameter, , has been calculated and predicted that if 100 > ± 0.1, DP is ...

  15. Micromechanical characteristics of an Al/sub 2/O/sub 3/-TiNi ceramic produced in a high-pressure chamber

    Energy Technology Data Exchange (ETDEWEB)

    Barashkov, G.A.; Neshpor, V.S.; Berdikov, V.F.; Pushkarev, O.I.; Lavrenova, E. A.

    1987-03-01

    The micromechanical characteristics of an Al/sub 2/O/sub 3/-TiNi ceramic produced in high-pressure chambers under conditions of forced mass transfer are investigated experimentally using the microindentation method. The objective of the study is to use micromechanical characteristics to determine the time required for producing an Al/sub 2/O/sub 3/-TiNi ceramic with a fully formed structure. It is found that the process of forced mass transfer and crystallization is completed within 60-120 s.

  16. Influence of in situ formed ZrB2 particles on microstructure and mechanical properties of AA6061 metal matrix composites

    International Nuclear Information System (INIS)

    Dinaharan, I.; Murugan, N.; Parameswaran, Siva

    2011-01-01

    Highlights: → In situ fabrication of aluminium metal matrix composite reinforced ZrB 2 particles. → Colour metallography of composites. → Improvement of matrix properties by ZrB 2 particles. → Sliding wear behaviour of in situ composites. - Abstract: Particulate reinforced metal matrix composites (PMMCs) have gained considerable amount of research emphasis and attention in the present era. Research is being carried out across the globe to produce new combination of PMMCs. PMMCs are prepared by adding a variety of ceramic particles with monolithic alloys using several techniques. An attempt has been made to produce aluminium metal matrix composites reinforced with zirconium boride (ZrB 2 ) particles by the in situ reaction of K 2 ZrF 6 and KBF 4 salts with molten aluminium. The influence of in situ formed ZrB 2 particles on the microstructure and mechanical properties of AA6061 alloy was studied in this work. The in situ formed ZrB 2 particles significantly refined the microstructure and enhanced the mechanical properties of AA6061 alloy. The weight percentage of ZrB 2 was varied from 0 to 10 in steps of 2.5. Improvement of hardness, ultimate tensile strength and wear resistance of AA6061 alloy was observed with the increase in ZrB 2 content.

  17. A study of microstructure and wear behaviour of TiB2/Al metal matrix composites

    Directory of Open Access Journals (Sweden)

    A. Sreenivasan

    Full Text Available The present paper deals with the study of microstructure and wear characteristics of TiB2 reinforced aluminium metal matrix composites (MMCs. Matrix alloys with 5, 10 and 15% of TiB2 were made using stir casting technique. Effect of sliding velocity on the wear behaviour and tribo-chemistry of the worn surfaces of both matrix and composites sliding against a EN24 steel disc has been investigated under dry conditions. A pin-on-disc wear testing machine was used to find the wear rate, in which EN24 steel disc was used as the counter face, loads of 10-60N in steps of 10N and speeds of 100, 200, 300, 400 and 500 rpm were employed. The results showed that the wear rate was increased with an increase in load and sliding speed for both the materials. However, a lower wear rate was obtained for MMCs when compared to the matrix alloys. The wear transition from slight to severe was presented at the critical applied loads. The transition loads for the MMCs were much higher than that of the matrix alloy. The transition loads were increased with increase in TiB2 and the same was decreased with the increase of sliding speeds. The SEM and EDS analyses were undertaken to demonstrate the effect of TiB2 particles on the wear mechanism for each conditions.

  18. Grindability of cast Ti-Cu alloys.

    Science.gov (United States)

    Kikuchi, Masafumi; Takada, Yukyo; Kiyosue, Seigo; Yoda, Masanobu; Woldu, Margaret; Cai, Zhuo; Okuno, Osamu; Okabe, Toru

    2003-07-01

    The purpose of the present study was to evaluate the grindability of a series of cast Ti-Cu alloys in order to develop a titanium alloy with better grindability than commercially pure titanium (CP Ti), which is considered to be one of the most difficult metals to machine. Experimental Ti-Cu alloys (0.5, 1.0, 2.0, 5.0, and 10.0 mass% Cu) were made in an argon-arc melting furnace. Each alloy was cast into a magnesia mold using a centrifugal casting machine. Cast alloy slabs (3.5 mm x 8.5 mm x 30.5 mm), from which the hardened surface layer (250 microm) was removed, were ground using a SiC abrasive wheel on an electric handpiece at four circumferential speeds (500, 750, 1000, or 1250 m/min) at 0.98 N (100 gf). Grindability was evaluated by measuring the amount of metal volume removed after grinding for 1min. Data were compared to those for CP Ti and Ti-6Al-4V. For all speeds, Ti-10% Cu alloy exhibited the highest grindability. For the Ti-Cu alloys with a Cu content of 2% or less, the highest grindability corresponded to an intermediate speed. It was observed that the grindability increased with an increase in the Cu concentration compared to CP Ti, particularly for the 5 or 10% Cu alloys at a circumferential speed of 1000 m/min or above. By alloying with copper, the cast titanium exhibited better grindability at high speed. The continuous precipitation of Ti(2)Cu among the alpha-matrix grains made this material less ductile and facilitated more effective grinding because small broken segments more readily formed.

  19. Solute redistribution studies in oxidised zirconium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Khera, S K; Kale, G B; Gadiyar, H S [Bhabha Atomic Research Centre, Bombay (India). Metallurgy Div.

    1977-01-01

    Electron microprobe studies on solute distribution in oxide layers and in the regions near oxide metal interface have been carried out in the case of zircaloy-2 and zirconium binary alloys containing niobium, tin, iron, copper, chromium and nickel and oxidised in steam at 550 deg C. In the case of alloys having higher oxidation rates, the oxide of solute element was found to dissolve in ZrO/sub 2/ without any composition variation. However, for solute addition with limited solubility like Cr, Cu and Fe, solute enrichment at metal/oxide interface and depletion of the same matrix has been observed. The intensity profiles for nickel distribution were also found to be identical to Fe or Cr distribution. The mode of solute distribution has been discussed in relation to oxidation behaviour of these alloys.

  20. Positron annihilation characterization of nanostructured ferritic alloys

    International Nuclear Information System (INIS)

    Alinger, M.J.; Glade, S.C.; Wirth, B.D.; Odette, G.R.; Toyama, T.; Nagai, Y.; Hasegawa, M.

    2009-01-01

    Nanostructured ferritic alloys (NFAs) were produced by mechanically alloying Fe-14Cr-3W-0.4Ti and 0.25Y 2 O 3 (wt%) powders followed by hot isostatic pressing consolidation at 850, 1000 and 1150 deg. C. Positron annihilation lifetime and orbital momentum spectroscopy measurements are in qualitative agreement with small angle neutron scattering, transmission electron microscopy and atom probe tomography observations, indicating that up to 50% of the annihilations occur at high densities of Y-Ti-O enriched nm-scale features (NFs). Some annihilations may also occur in small cavities. In Y-free control alloys, that do not contain NFs, positrons primarily annihilate in the Fe-Cr matrix and at features such as dislocations, while a small fraction annihilate in large cavities or Ar bubbles.

  1. Wear Characterization of Aluminium/Basalt Fiber Reinforced Metal Matrix Composites - A Novel Material

    Directory of Open Access Journals (Sweden)

    P. Amuthakkannan

    2017-06-01

    Full Text Available Aluminum alloy based metal matrix composite participate have a wider applications in wear resistance applications. Attempt made in current study is that, basalt fiber reinforced aluminum metal matrix composite have been prepared using stir casting method. Different weight percentage of basalt fiber reinforced with Al (6061 metal matrix composites are used to study the wear resistance of the composites. For wear study, percentage of reinforcement, normal load and sliding velocity are the considered as important parameters. To study the effect of basalt fiber reinforcement on the dry sliding wear of Al6061 alloy composites the Pin On wear tester is used. Initially hardness of the composites was tested, it was found that increasing reinforcement in the composite hardness value of the composites also increased. Based on the Grey relation analysis (GRA the effects of wear resistance of the composites were studied.

  2. Aqueous electrochemistry of precipitation-hardened nickel base alloys

    International Nuclear Information System (INIS)

    Hosoya, K.; Ballinger, R.; Prybylowski, J.; Hwang, I.S.

    1990-11-01

    An investigation has been conducted to explore the importance of local crack tip electrochemical processes in precipitation-hardened Ni-Cr-Fe alloys driven by galvanic couples between grain boundary precipitates and the local matrix. The electrochemical behavior of γ' [Ni 3 (Al,Ti)] has been determined as a function of titanium concentration, temperature, and solution pH. The electrochemical behavior of Ni-Cr-Fe solid solution alloys has been investigated as a function of chromium content for a series of 10 Fe-variable Cr (6--18%)-balance Ni alloys, temperature, and pH. The investigation was conducted in neutral and pH3 solutions over the temperature range 25--300 degree C. The results of the investigation show that the electrochemical behavior of these systems is a strong function of temperature and composition. This is especially true for the γ' [Ni 3 (Al,Ti)] system where a transition from active/passive behavior to purely active behavior and back again occurs over a narrow temperature range near 100 degree C. Behavior of this system was also found to be a strong function of titanium concentration. In all cases, the Ni 3 (Al,Ti) phase was active with respect to the matrix. The peak in activity near 100 degree C correlates well with accelerated crack growth in this temperature range, observed in nickel-base alloy X-750 heat treated to precipitate γ' on the grain boundaries. 20 refs., 23 figs., 3 tabs

  3. Features of film growth during plasma anodizing of Al 2024/SiC metal matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Xue Wenbin [Key Laboratory for Radiation Beam Technology and Materials Modification, Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China)]. E-mail: xuewb@bnu.edu.cn

    2006-07-15

    Plasma anodizing is a novel promising process to fabricate corrosion-resistant protective films on metal matrix composites. The corrosion-resistant films were prepared by plasma anodizing on SiC reinforced aluminum matrix composite. The morphology and microstructure of films were analyzed by scanning electron microscopy. Specifically, the morphology of residual SiC reinforcement particles in the film was observed. It is found that the most SiC reinforcement particles have been molten to become silicon oxide, but a few tiny SiC particles still remain in the film close to the composite/film interface. This interface is irregular due to the hindering effect of SiC particles on the film growth. Morphology and distribution of residual SiC particles in film provide direct evidence to identify the local melt occurs in the interior of plasma anodizing film even near the composite/film interface. A model of film growth by plasma anodizing on metal matrix composites was proposed.

  4. Features of film growth during plasma anodizing of Al 2024/SiC metal matrix composite

    International Nuclear Information System (INIS)

    Xue Wenbin

    2006-01-01

    Plasma anodizing is a novel promising process to fabricate corrosion-resistant protective films on metal matrix composites. The corrosion-resistant films were prepared by plasma anodizing on SiC reinforced aluminum matrix composite. The morphology and microstructure of films were analyzed by scanning electron microscopy. Specifically, the morphology of residual SiC reinforcement particles in the film was observed. It is found that the most SiC reinforcement particles have been molten to become silicon oxide, but a few tiny SiC particles still remain in the film close to the composite/film interface. This interface is irregular due to the hindering effect of SiC particles on the film growth. Morphology and distribution of residual SiC particles in film provide direct evidence to identify the local melt occurs in the interior of plasma anodizing film even near the composite/film interface. A model of film growth by plasma anodizing on metal matrix composites was proposed

  5. Effect of matrix constitution on interface of aluminium/δ-Al2O3 and strength of metal matrix composites

    International Nuclear Information System (INIS)

    Johansson, P.; Hutchinson, B.; Savage, S.J.

    1992-06-01

    Aluminium based fiber composites have been made by squeeze casting. The 'saffil' pre-forms used in the work employed aluminium oxide binder or silica binder. Two families of alloys have been used based either on high purity aluminium or 3% copper containing alloys. These were both alloyed with a range of magnesium contents from 0.1% to 5% with the aim of varying the degree of reaction and bonding between the matrix and the reinforcing fibres. Studies of macro- and micro structures have been performed as well as non-destructive testing by X-ray radiography. Tensile testing, three point bend tests on notched bars and wetting studies in a wetting balance are also included in the investigation. The structure of the squeeze cast products shows different zones. The extension and appearance of the zones are dependent on the alloy constitution. In general the surface of the casting have small equiaxed grains. This surface zone is replaced by a columnar grain zone which, in the center, transforms to an equiaxed crystal zone. Defects such as pores, fibre-free zones, and 'pockets' in the interface matrix/fiber have been found. Of these defects, only pores can be detected by X-ray radiography. Evaluation of tensile testing shows a relatively large scatter of results. The results reveal a dominant role of matrix composition on strength level. For the 20 vol% reinforced metals, with performs with silica binder, the maximum measured elongation was 3.5%. With alumina binder approximately half of the above mentioned ductility is obtained. The use of grain-refiner, Al-5Ti-B, decreases the ductility of the composite below 2%, independent of the type of binder. From 3-point bend tests fracture energies are estimated to vary between 0.3 and 0.6 Joule. The toughness is low. Studies of the wetting between pieces of ceramic pre-forms and molten Al-2Mg show that generally the wetting is poor. At the same time, the wettability of d-alumina with silicon oxide as binding medium was slightly

  6. Mechanical spectroscopy study on the Cu54Zr40Al6 amorphous matrix alloy at low temperature

    International Nuclear Information System (INIS)

    Marques, P.W.B.; Chaves, J.M.; Silva, P.S.; Florêncio, O.; Moreno-Gobbi, A.; Aliaga, L.C.R.; Botta, W.J.

    2015-01-01

    Highlights: • Cu 54 Zr 40 Al 6 alloy was characterized by mechanical spectroscopy at low temperature. • Flexural and ultrasonic methods showed peaks associated to rearrangement of clusters. • The peaks less stable were associated with annihilation of Zr or Cu clusters. • MHz range can be favors the formation of Cu an Al-centered icosahedral structures. • TEM images show an increase in the size and number of crystal in amorphous matrix. - Abstract: A mechanical spectroscopy study of Cu 54 Zr 40 Al 6 bulk metallic glasses composites was carried out in the kHz and MHz frequency ranges, by means of flexural and ultrasonic methods, respectively, in the temperature interval 150–300 K. In internal friction and attenuation curves at low temperature were observed peaks which were associated with distortions in the configuration of atomic clusters, which absorbed different quantities of energy due to short and medium order rearrangements. Changes within the clusters or atomic jumps between clusters occurring in the specimen induced the onset of polyamorphic peaks, since electronic interactions and bonding changed abruptly

  7. Microstructure and properties of Cu–Al–Fe high-temperature shape memory alloys

    International Nuclear Information System (INIS)

    Yang, Shuiyuan; Su, Yu; Wang, Cuiping; Liu, Xingjun

    2014-01-01

    Highlights: • Three-phase microstructure is observed for x = 0 both under the quenched and aged states. • Two-phase microstructure is observed for x = 1 both under the quenched and aged states. • Only martensite exists for x = 2 after quenching, whereas γ 1 (Cu 9 Al 4 ) phase appears after aging. • High martensitic transformation temperatures (>450 °C) are obtained for all studied alloys. • The alloy for x = 1 after aging still remains relatively good recovery strain and ratio. - Abstract: The microstructure, martensitic transformation, mechanical and shape memory properties of Cu 84−x Al 11+x Fe 5 (x = 0, 1, 2) alloys under the quenched and aged states were investigated. The results show that x = 0 and 1 under the quenched state exhibit a mixture of primary β ′ 1 and little γ ′ 1 martensites, and x = 2 only shows dominant γ ′ 1 martensite. Small amounts of α(Cu) and Fe(Al,Cu) phases are observed for x = 0, whereas only tiny Fe(Al,Cu) phase exists for x = 1. After aging, all alloys have a mixture of β ′ 1 and γ ′ 1 martensites, and the snowflake-shaped γ 1 (Cu 9 Al 4 ) precipitate is present for x = 2. The recovery strain and ratio for x = 0 and 2 remarkably decrease after aging due to the precipitations. However, the recovery strain of x = 1 after aging still linearly increases with the increase of the pre-strain, up to a maximum value of 1.6%

  8. The role of minor alloying elements on the stability and dispersion of yttria nanoclusters in nanostructured ferritic alloys: An ab initio study

    International Nuclear Information System (INIS)

    Murali, D.; Panigrahi, B.K.; Valsakumar, M.C.; Chandra, Sharat; Sundar, C.S.; Raj, Baldev

    2010-01-01

    Nanostructured ferritic alloys derive their strength from the dispersion of oxide nanoclusters in the ferritic matrix. We have explored the relative role of minor alloying elements like Ti and Zr on the stability of nanoclusters of vacancy-Y-Ti-O by density functional theory calculations and shown that the binding energy of these clusters increases when we replace Ti with Zr. This could imply faster nucleation of the nanoclusters which, in turn, may lead to finer dispersion of nanoclusters resulting in improved performance of ferritic alloys. Further, we show a core/shell structure for these nanoclusters in which the core is enriched in Y, O, Ti while the shell is enriched in Cr.

  9. Effect of thermal cycling on the microstructure of a directionally solidified Fe, Cr, Al-TaC eutectic alloy

    Science.gov (United States)

    Harf, F. H.; Tewari, S. N.

    1977-01-01

    Cylindrical bars (1.2 cm diameter) of Fe-13.6Cr-3.7Al-9TaC (wt %) eutectic alloy were directionally solidified in a modified Bridgman type furnace at 1 cm/h. The alloy microstructure consisted of aligned TaC fibers imbedded in a bcc Fe-Cr-Al matrix. Specimens of the alloy were thermally cycled from 1100 to 425 C in a burner rig. The effects of 1800 thermal cycles on the microstructure was examined by scanning electron microscopy, revealing a zig-zag shape of TaC fibers aligned parallel to the growth direction. The mechanism of carbide solution and reprecipitation on the (111) easy growth planes, suggested previously to account for the development of irregular serrations in Co-Cr-Ni matrix alloys, is believed to be responsible for these zig-zag surfaces.

  10. Fabrication of tungsten wire reinforced nickel-base alloy composites

    Science.gov (United States)

    Brentnall, W. D.; Toth, I. J.

    1974-01-01

    Fabrication methods for tungsten fiber reinforced nickel-base superalloy composites were investigated. Three matrix alloys in pre-alloyed powder or rolled sheet form were evaluated in terms of fabricability into composite monotape and multi-ply forms. The utility of monotapes for fabricating more complex shapes was demonstrated. Preliminary 1093C (2000F) stress rupture tests indicated that efficient utilization of fiber strength was achieved in composites fabricated by diffusion bonding processes. The fabrication of thermal fatigue specimens is also described.

  11. α′ precipitation in neutron-irradiated Fe–Cr alloys

    International Nuclear Information System (INIS)

    Bachhav, Mukesh; Robert Odette, G.; Marquis, Emmanuelle A.

    2014-01-01

    Graphical abstract: -- A series of model Fe–Cr alloys containing 3–18 at.% Cr was neutron irradiated at a nominal temperature of 563 K to 1.82 dpa. Solute distributions were analyzed by atom probe tomography, which revealed α′ precipitation for alloys containing more than 9 at.% Cr. Both the Cr concentration dependence of α′ precipitation and the measured matrix compositions are in agreement with the recently published Fe–Cr phase diagrams. An irradiation-accelerated precipitation process is strongly suggested

  12. Characterization of low alloy ferritic steel–Ni base alloy dissimilar metal weld interface by SPM techniques, SEM/EDS, TEM/EDS and SVET

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Siyan; Ding, Jie; Ming, Hongliang; Zhang, Zhiming; Wang, Jianqiu, E-mail: wangjianqiu@imr.ac.cn

    2015-02-15

    The interface region of welded A508–Alloy 52 M is characterized by scanning probe microscope (SPM) techniques, scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM)/Energy Dispersive Spectroscopy (EDS) and scanning vibrate electrode technique (SVET). The regions along the welded A508–Alloy 52 M interface can be categorized into two types according to their different microstructures. In the type-I interface region, A508 and Alloy 52 M are separated by the fusion boundary, while in the type-II interface region, A508 and Alloy 52 M are separated by a martensite zone. A508, martensite zone and grain boundaries in Alloy 52 M are ferromagnetic while the Alloy 52 M matrix is paramagnetic. The Volta potentials measured by scanning Kelvin probe force microscopy (SKPFM) of A508, martensite zone and Alloy 52 M follow the order: V{sub 52} {sub M} > V{sub A508} > V{sub martensite}. The corrosion behavior of A508–Alloy 52 M interface region is galvanic corrosion, in which Alloy 52 M is cathode while A508 is anode. The martensite dissolves faster than Alloy 52 M, but slower than A508 in the test solution. - Highlights: • The A508–Alloy 52 M interface regions can be categorized into two types. • The chromium depleted region is observed along the Alloy 52 M grain boundary. • The Alloy 52 M grain boundaries which are close to the interface are ferromagnetic. • Martensite zone has lower Volta potential but higher corrosion resistance than A508.

  13. Crystallographic study of grain refinement in aluminum alloys using the edge-to-edge matching model

    International Nuclear Information System (INIS)

    Zhang, M.-X.; Kelly, P.M.; Easton, M.A.; Taylor, J.A.

    2005-01-01

    The edge-to-edge matching model for describing the interfacial crystallographic characteristics between two phases that are related by reproducible orientation relationships has been applied to the typical grain refiners in aluminum alloys. Excellent atomic matching between Al 3 Ti nucleating substrates, known to be effective nucleation sites for primary Al, and the Al matrix in both close packed directions and close packed planes containing these directions have been identified. The crystallographic features of the grain refiner and the Al matrix are very consistent with the edge-to-edge matching model. For three other typical grain refiners for Al alloys, TiC (when a = 0.4328 nm), TiB 2 and AlB 2 , the matching only occurs between the close packed directions in both phases and between the second close packed plane of the Al matrix and the second close packed plane of the refiners. According to the model, it is predicted that Al 3 Ti is a more powerful nucleating substrate for Al alloy than TiC, TiB 2 and AlB 2 . This agrees with the previous experimental results. The present work shows that the edge-to-edge matching model has the potential to be a powerful tool in discovering new and more powerful grain refiners for Al alloys

  14. TEM study of β′ precipitate interaction mechanisms with dislocations and β′ interfaces with the aluminium matrix in Al–Mg–Si alloys

    International Nuclear Information System (INIS)

    Teichmann, Katharina; Marioara, Calin D.; Andersen, Sigmund J.; Marthinsen, Knut

    2013-01-01

    The interaction mechanisms between dislocations and semi-coherent, needle-shaped β′ precipitates in Al–Mg–Si alloys have been studied by High Resolution Transmission Electron Microscopy (HRTEM). Dislocation loops appearing as broad contrast rings around the precipitate cross-sections were identified in the Al matrix. A size dependency of the interaction mechanism was observed; the precipitates were sheared when the longest dimension of their cross-section was shorter than approximately 15 nm, and looped otherwise. A more narrow ring located between the Al matrix and bulk β′ indicates the presence of a transition interface layer. Together with the bulk β′ structure, this was further investigated by High Angle Annular Dark Field Scanning TEM (HAADF-STEM). In the bulk β′ a higher intensity could be correlated with a third of the Si-columns, as predicted from the published structure. The transition layer incorporates Si columns in the same arrangement as in bulk β′, although it is structurally distinct from it. The Z-contrast information and arrangement of these Si-columns demonstrate that they are an extension of the Si-network known to structurally connect all the precipitate phases in the Al–Mg–Si(–Cu) system. The width of the interface layer was estimated to about 1 nm. - Highlights: ► β′ is found to be looped at sizes larger than 15 nm (cross section diameter). ► β′ is found to be sheared at sizes smaller than 15 nm (cross section diameter). ► The recently determined crystal structure of β′ is confirmed by HAADF-STEM. ► Between β′ and the Al-matrix a transition layer of about 1 nm is existent. ► The β′/matrix layer is structurally distinct from bulk β′ and the aluminium matrix.

  15. Tungsten wire--nickel base alloy composite development. Contractor report, 1 Jun 1974--29 Feb 1976

    International Nuclear Information System (INIS)

    Brentnall, W.D.; Moracz, D.J.

    1976-03-01

    Further development and evaluation of refractory wire reinforced nickel-base alloy composites is described. Emphasis was placed on evaluating thermal fatigue resistance as a function of matrix alloy composition, fabrication variables and reinforcement level and distribution. Tests for up to 1,000 cycles were performed, and the best system identified in this current work was 50v/o W/NiCrAlY. Improved resistance to thermal fatigue damage would be anticipated for specimens fabricated via optimized processing schedules. Other properties investigated included 1,093 C (2,000 F) stress rupture strength, impact resistance and static air oxidation. A composite consisting of 30v/o W--Hf--C alloy fibers in a NiCrAlY alloy matrix was shown to have a 100-hour stress rupture strength at 1,093 C (2,000 F) of 365 MN/m 2 (53 ksi) or a specific strength advantage of about 3:1 over typical D.S. eutectics

  16. Life cycle assessment of metal alloys for structural applications

    Science.gov (United States)

    Malovrh Rebec, K.; Markoli, B.; Leskovar, B.

    2018-03-01

    The study compared environmental footprints of two types of Al-alloys: well-known 5083 aluminium alloy with magnesium and traces of manganese and chromium in its composition. This material is highly resistant to seawater corrosion and the influence of industrial chemicals. Furthermore, it retains exceptional strength after welding. The comparisons were made to an innovative alloy where the aluminium based matrix is reinforced by metastable quasicrystals (QC), thus avoiding magnesium in its composition. Furthermore, we checked other aluminium ingots’ footprints and compared European average and Germany country specific production data. Environmental footprints were assessed via cradle to gate life cycle assessment. Our findings normalized to 1 m2 plate suggest, that newly proposed alloy could save around 50 % in value of parameters abiotic resources depletion of fossil fuels, acidification, eutrophication, global warming potential and photochemical ozone creation potential if we compare Qc5 to 6 mm 5083 alloy plate. Only abiotic resources depletion of elements and ozone depletion parameters increase for Qc5 compared to 6 mm 5083 alloy plate.

  17. Development of shear bands in amorphous-crystalline metallic alloys

    International Nuclear Information System (INIS)

    Pozdnyakov, V.A.

    2004-01-01

    A theoretical study is made into conditions of shear band evolution in amorphous-crystalline alloys with various morphological types of structural constituents. The condition of shear band evolution in thin amorphous alloys in the interior of the crystalline matrix is obtained. It is shown that a scale effect exists which manifests itself in suppression of the process of localized plastic flow with amorphous alloy thickness decreasing down to the limit. The analysis of the condition for shear band evolution in an amorphous alloy with nanocrystalline inclusions is accomplished. The relationship of a critical stress of shear band evolution to a volume fraction of disperse crystal inclusions is obtained. A consideration is also given to the evolution of shear bands in the material containing amorphous and crystalline areas of micro meter size. For the alloy with the structure of this type conditions for propagation of localized flows by a relay race type mechanism are determined [ru

  18. Low gravity containerless processing of immiscible gold rhodium alloys

    Science.gov (United States)

    Andrews, J. Barry

    1986-01-01

    Under normal one-g conditions immiscible alloys segregate extensively during solidification due to sedementation of the more dense of the immiscible liquid phases. However, under low-g conditions it should be possible to form a dispersion of the two immiscible liquids and maintain this dispersed structure during solidification. Immiscible (hypermonotectic) gold-rhodium alloys were processed in the Marshall Space Flight Center 105 meter drop tube in order to investigate the influence of low gravity, containerless solidification on their microstructure. Hypermonotectic alloys composed of 65 atomic % rhodium exhibited a tendency for the gold rich liquid to wet the outer surface of the containerless processed samples. This tendency led to extensive segregation in several cases. However, well dispersed microstructures consisting of 2 to 3 micron diameter rhodium-rich spheres in a gold-rich matrix were produced in 23.4 atomic % rhodium alloys. This is one of the best dispersions obtained in research on immiscible alloy-systems to data.

  19. Effect of aluminium on formation of metastable phases in titanium-niobium alloys

    International Nuclear Information System (INIS)

    Trenogina, T.L.; Derevyanko, V.N.; Vozilkin, V.A.

    2001-01-01

    Specific features of phase transformations in the alloy of Ti-20Nb-29Al (at.%) are investigated in comparison with those in the aluminium-free Ti-21Nb alloy. It is states that in the alloy Ti-20Nb-29Al on quenching the ordering of β-solid solution takes place with B2-structure formation. The B2-matrix experiences decomposition with the formation of ordered Ω 0 -phase which field ranges up to 700 deg C. The investigation results show that the sequence of phase formation in Ti-Nb-Al and aluminium-free alloys is much the same. The only difference between them is the formation of ordered phases in the alloy Ti-20Nb-29Al [ru

  20. Microstructure and properties of Mg-Al binary alloys

    Directory of Open Access Journals (Sweden)

    ZHENG Wei-chao

    2006-11-01

    Full Text Available The effects of different amounts of added Al, ranging from 1 % to 9 %, on the microstructure and properties of Mg-Al binary alloys were investigated. The results showed that when the amount of added Al is less than 5%, the grain size of the Mg-Al binary alloys decreases dramatically from 3 097 μm to 151 μm with increasing addition of Al. Further addition of Al up to 9% makes the grain size decrease slowly to 111 μm. The α-Mg dendrite arms are also refined. Increasing the amount of added Al decreases the hot cracking susceptibility of the Mg-Al binary alloys remarkably, and enhances the micro-hardness of the α-Mg matrix.

  1. Critically designing today’s melt processed bulk magnesium alloys using boron rich nanoparticles

    International Nuclear Information System (INIS)

    Paramsothy, Muralidharan; Gupta, Manoj

    2015-01-01

    Highlights: • B 4 C nanoparticles increased the tensile ductility of Mg–Al alloy to about 25%. • SiB 6 nanoparticles increased the tensile ductility of Mg–Zn alloy to about 23%. • ZrB 2 nanoparticles increased the tensile strength of Mg–RE alloy to above 400 MPa. • Hypothetically, 5–10% cold working could significantly increase tensile strength. • Hypothetically, 5–10% cold working could maintain tensile ductility above 10%. - Abstract: In this work, boron rich nanoparticles (B 4 C, SiB 6 and ZrB 2 ) were added to bulk melt processed Mg–Al, Mg–Zn and Mg–RE (Rare Earth) series contemporary magnesium alloys, respectively. The most obvious positive effect when adding B 4 C nanoparticles to the Mg–Al alloy was the significant increase in tensile ductility (to about 25%). Here, there was no significant change in grain size or crystallographic texture due to nanoparticle addition. However, it was observed that stacking faults formed more easily in the magnesium matrix due to nanoparticle addition. Also, it was observed that coarser nanoparticles broke down high strain zones (HSZs) during tensile deformation. The addition of SiB 6 to Mg–Zn alloy also resulted in similar significant increase in tensile ductility (to about 23%). Tensile deformation induced alignment of more rounded and spherical nanoparticles was observed. Stacking faults forming more easily in the alloy matrix was also observed. However, the formation of nanograins (nanoscale recrystallization) during room temperature tensile deformation was observed in this system. This implied that nanograin rotation during deformation was also responsible for the observed enhanced tensile ductility. When ZrB 2 was added to Mg–RE alloy, the tensile strength was significantly enhanced (yield strength >400 MPa) after thermal ageing. Here, the ZrB 2 nanoparticles induced the formation of thermal ageing resistant long period stacking/ordered (LPSO) nanograins and nanolayers in the Mg

  2. High-strength shape memory steels alloyed with nitrogen

    International Nuclear Information System (INIS)

    Ullakko, K.; Jakovenko, P.T.; Gavriljuk, V.G.

    1996-01-01

    Since shape memory effect in Fe-Mn-Si systems was observed, increasing attention has been paid to iron based shape memory alloys due to their great technological potential. Properties of Fe-Mn-Si shape memory alloys have been improved by alloying with Cr, Ni, Co and C. A significant improvement on shape memory, mechanical and corrosion properties is attained by introducing nitrogen in Fe-Mn-Si based systems. By increasing the nitrogen content, strength of the matrix increases and the stacking fault energy decreases, which promote the formation of stress induced martensite and decrease permanent slip. The present authors have shown that nitrogen alloyed shape memory steels exhibit recoverable strains of 2.5--4.2% and recovery stresses of 330 MPa. In some cases, stresses over 700 MPa were attained at room temperature after cooling a constrained sample. Yield strengths of these steels can be as high as 1,100 MPa and tensile strengths over 1,500 MPa with elongations of 30%. In the present study, effect of nitrogen alloying on shape memory and mechanical properties of Fe-Mn-Si, Fe-Mn-Si-Cr-Ni and Fe-Mn-Cr-Ni-V alloys is studied. Nitrogen alloying is shown to exhibit a beneficial effect on shape memory properties and strength of these steels

  3. Powder metallurgical low-modulus Ti-Mg alloys for biomedical applications.

    Science.gov (United States)

    Liu, Yong; Li, Kaiyang; Luo, Tao; Song, Min; Wu, Hong; Xiao, Jian; Tan, Yanni; Cheng, Ming; Chen, Bing; Niu, Xinrui; Hu, Rong; Li, Xiaohui; Tang, Huiping

    2015-11-01

    In this work, powder metallurgical (PM) Ti-Mg alloys were prepared using combined techniques of mechanical alloying and spark plasma sintering. The alloys mainly consist of super saturations of Mg in Ti matrix, and some laminar structured Ti- and Mg-rich phases. The PM Ti-Mg alloys contain a homogeneous mixtures of nanocrystalline Mg and Ti phases. The novel microstructures result in unconventional mechanical and biological properties. It has been shown that the PM Ti-Mg alloys have a much lower compression modulus (36-50GPa) compared to other Ti alloys, but still remain a very high compressive strength (1500-1800MPa). In addition, the PM Ti-Mg alloys show good biocompatibility and bioactivity. Mg can dissolve in the simulated body fluids, and induce the formation of the calcium phosphate layer. The compression modulus of PM Ti-Mg alloys decreases with the amount of Mg, while the bioactivity increases. Although the corrosion resistance of Ti-Mg alloys decreases with the content of Mg, the alloys still show good stability in simulated body fluid under electrochemical conditions. The indirect and direct cytotoxicity results show that PM Ti-Mg alloys have a good biocompatibility to NIH-3T3 cells. Therefore, the PM Ti-Mg alloys are promising candidates in biomedical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Growth of permanganate conversion coating on 2024-Al alloy

    International Nuclear Information System (INIS)

    Kulinich, S.A.; Akhtar, A.S.; Wong, P.C.; Wong, K.C.; Mitchell, K.A.R.

    2007-01-01

    The growth of permanganate conversion coating on aluminum 2024-T3 alloy has been studied by characterizing, with scanning Auger microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy, the coatings formed by immersion of the alloy in the coating bath (containing KMnO 4 and Na 2 B 4 O 7 , pH 9.1) for different periods of time and at different temperatures. At room temperature, during the first 1-5 min of immersion, MnO 2 deposits are formed only on the second-phase intermetallic particles (of Al-Cu-Mg and Al-Cu-Fe-Mn types), but the coating starts to develop on the Al matrix surface after 5-10 min. The coating slows down and stops after about 150 min, with a thinner deposit over the alloy matrix. The process is accelerated at higher temperatures, for example at 68 deg. C it self-limits after about 3 min. The electrochemical growth process appears to follow that established for the chromate conversion coatings, although XPS does not detect significant MnO 4 - incorporation into the permanganate coatings

  5. (Updated) Nanotechnology: Understanding the Tiny Particles That May Save a Life | Poster

    Science.gov (United States)

    By Nathalie Walker, Guest Writer Could nanotechnology—the study of tiny matter ranging in size from 1 to 200 nanometers—be the future of cancer treatment? Although it is a relatively new field in cancer research, nanotechnology is not new to everyday life. Have you ever thought about the tennis ball you’ve thrown with your dog at the park and wondered what it is made of?

  6. High power X-ray welding of metal-matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, Richard A.; Goeppner, George A.; Noonan, John R.; Farrell, William J.; Ma, Qing

    1997-12-01

    A method for joining metal-matrix composites (MMCs) by using high power x-rays as a volumetric heat source is provided. The method involves directing an x-ray to the weld line between two adjacent MMCs materials to create an irradiated region or melt zone. The x-rays have a power density greater than about 10{sup 4} watts/cm{sup 2} and provide the volumetric heat required to join the MMC materials. Importantly, the reinforcing material of the metal-matrix composites remains uniformly distributed in the melt zone, and the strength of the MMCs are not diminished. In an alternate embodiment, high power x-rays are used to provide the volumetric heat required to weld metal elements, including metal elements comprised of metal alloys. In an alternate embodiment, high power x-rays are used to provide the volumetric heat required to weld metal elements, including metal elements comprised of metal alloys.

  7. Influence of Al7Cu2Fe intermetallic particles on the localized corrosion of high strength aluminum alloys

    International Nuclear Information System (INIS)

    Chemin, Aline; Marques, Denys; Bisanha, Leandro; Motheo, Artur de Jesus; Bose Filho, Waldek Wladimir; Ruchert, Cassius Olivio Figueiredo

    2014-01-01

    Highlights: • The corrosion on new aerospace aluminum alloy is studied. • Al 7 Cu 2 Fe precipitate was detected in the 7475-T7351 and 7081 T73511 alloy by scanning electron microscopy. • Al 7 Cu 2 Fe particles have different morphologies depending on the forming process. • Corrosion pitting occurs around Al 7 Cu 2 Fe precipitates in 7475-T7351 and 7081-T73511 alloys. - Abstract: The development of aluminum alloys of the Al–Zn–Mg–Cu system is the primary factor that enabled the evolution of aircraft. However, it has been shown that these alloys tend to undergo pitting corrosion due to the presence of elements such as iron, copper and silicon. Thus, the purpose of this study is to evaluate the behavior of the Al 7 Cu 2 Fe precipitate in 7475-T7351 and 7081-T73511 alloys based on microstructural characterization and polarization tests. The corrosion and pitting potentials were found to be very similar, and matrix dissolution occurred around the Al 7 Cu 2 Fe precipitate in both alloys, revealing the anodic behavior of the matrix

  8. Effect of elastic interphase strains on extinction in aging nimonic type alloys

    International Nuclear Information System (INIS)

    Gitgarts, M.I.; Ivashin, V.V.

    1977-01-01

    The effect of νsup(')-phase separation processes on the variation of (3) CuKsub(α) diffraction line integral intensity in KhN67VMTYu alloy ageing has been investigated, the alloy being characterized by various degrees of volumetric inconsistency between the separation phase and matrix. The ageing of KhN67VMTYu alloy, in which the separation of the νsup(')-phase does not cause interphase strains, is not accompanied by abatement of extinction: the diffraction line intensity is practically the same for both aged and tempered specimens

  9. Deformation behaviors of aluminum alloys for automobile parts studied by neutron diffraction

    International Nuclear Information System (INIS)

    Katayanagi, Kazue; Morita, Kensuke; Tomota, Yo; Kamiyama, Takashi; Terakado, Katsuyoshi

    2008-01-01

    In situ time of flight neutron diffraction measurements during tension test were performed for three Al-Si alloys with different microstructures including hot-forged (AHS 2), T 6 heat-treated (AHS 2-T 6) and die-cast (ACD 12) specimens. Strength and work-hardening behaviors of these specimens are investigated by evaluating phase stresses, i.e., stress partitioning between Si and the Al matrix as well as intergranular stresses of [hkl] oriented family grains in the component phases. It is revealed that Si particles embedded in the Al matrix play a role of the hard second phase. The size and shape of the Si particles affect work hardening and fracture of the alloys. (author)

  10. Evolution of microstructure of U-Mo alloys in as cast and sintered forms

    International Nuclear Information System (INIS)

    Sinha, V.P.; Hegde, P.V.; Prasad, G.J.; Kamath, H.S.; Dey, G.K.

    2009-01-01

    Over the years U 3 Si 2 compound dispersed in aluminium matrix has been successfully used as potential Low Enriched Uranium (LEU 235 ) base dispersion fuel in new research and test reactors and also for converting High Enriched Uranium (HEU > 85% U 235 ) cores to LEU in most of the existing research and test reactors. The maximum density achievable with U 3 Si 2 -AI dispersion fuel is around 4.8 g U cm -3 . To achieve a uranium density of 8.0 to 9.0 g U cm -3 in dispersion fuel with aluminium as matrix material, it is required to use γ-stabilized uranium metal powders. At Metallic Fuels Division, R and D efforts are on to develop these high density uranium alloys. Molybdenum plays a crucial role in metastabilising the γ-phase of uranium at room temperature which is very much evident when we see the microstructures of different U-Mo alloys with varying molybdenum concentration as solute atom. The paper describes the role of molybdenum in imparting metastability in U-Mo alloys from their microstructures in as cast and sintered forms. The paper also covers the role of tailored microstructure in U-Mo alloy for the purpose of hydriding and dehydriding treatment to generate alloy powders. (author)

  11. The Effect of Si Morphology on Machinability of Al-Si Alloys

    Directory of Open Access Journals (Sweden)

    Muhammet Uludağ

    2015-12-01

    Full Text Available Many of the cast parts require some sort of machining like milling, drilling to be used as a finished product. In order to improve the wear properties of Al alloys, Si is added. The solubility of Si in Al is quite low and it has a crystallite type structure. It behaves as particulate metal matrix composite which makes it an attractive element. Thus, the wear and machinability properties of these type of alloys depend on the morphology of Si in the matrix. In this work, Sr was added to alter the morphology of Si in Al-7Si and Al-12Si. Cylindrical shaped samples were cast and machinability characteristics of Sr addition was studied. The relationship between microstructure and machinability was evaluated.

  12. Corrosion behaviour of electrodeposited nanocrystalline Ni-W and Ni-Fe-W alloys

    International Nuclear Information System (INIS)

    Sriraman, K.R.; Ganesh Sundara Raman, S.; Seshadri, S.K.

    2007-01-01

    The present work deals with evaluation of corrosion behaviour of electrodeposited nanocrystalline Ni-W and Ni-Fe-W alloys. Corrosion behaviour of the coatings deposited on steel substrates was studied using polarization and electrochemical impedance spectroscopy techniques in 3.5% NaCl solution while their passivation behaviour was studied in 1N sulphuric acid solution. The corrosion resistance of Ni-W alloys increased with tungsten content up to 7.54 at.% and then decreased. In case of Ni-Fe-W alloys it increased with tungsten content up to 9.20 at.% and then decreased. The ternary alloy coatings exhibited poor corrosion resistance compared to binary alloy coatings due to preferential dissolution of iron from the matrix. Regardless of composition all the alloys exhibited passivation behaviour over a wide range of potentials due to the formation of tungsten rich film on the surface

  13. Analysis of the transformations temperatures of helicoidal Ti-Ni actuators using computational numerical methods

    Directory of Open Access Journals (Sweden)

    Carlos Augusto do N. Oliveira

    2013-01-01

    Full Text Available The development of shape memory actuators has enabled noteworthy applications in the mechanical engineering, robotics, aerospace, and oil industries and in medicine. These applications have been targeted on miniaturization and taking full advantage of spaces. This article analyses a Ti-Ni shape memory actuator used as part of a flow control system. A Ti-Ni spring actuator is subjected to thermomechanical training and parameters such as transformation temperature, thermal hysteresis and shape memory effect performance were investigated. These parameters were important for understanding the behavior of the actuator related to martensitic phase transformation during the heating and cooling cycles which it undergoes when in service. The multiple regression methodology was used as a computational tool for analysing data in order to simulate and predict the results for stress and cycles where the experimental data was not developed. The results obtained using the training cycles enable actuators to be characterized and the numerical simulation to be validated.

  14. Disintegration of the net-shaped grain-boundary phase by multi-directional forging and its influence on the microstructure and properties of Cu-Ni-Si alloy

    Science.gov (United States)

    Zhang, Jinlong; Lu, Zhenlin; Zhao, Yuntao; Jia, Lei; Xie, Hui; Tao, Shiping

    2017-09-01

    Cu-Ni-Si alloys with 90% Cu content and Ni to Si ratios of 5:1 were fabricated by fusion casting, and severe plastic deformation of the Cu-Ni-Si alloy was carried out by multi-direction forging (MDF). The results showed that the as-cast and homogenized Cu-Ni-Si alloys consisted of three phases, namely the matrix phase α-Cu (Ni, Si), the reticular grain boundary phase Ni31Si12 and the precipitated phase Ni2Si. MDF significantly destroyed the net-shaped grain boundary phase, the Ni31Si12 phase and refined the grain size of the Cu matrix, and also resulted in the dissolving of Ni2Si precipitates into the Cu matrix. The effect of MDF on the conductivity of the solid solution Cu-Ni-Si alloy was very significant, with an average increase of 165.16%, and the hardness of the Cu-Ni-Si alloy also increased obviously.

  15. Mechanical properties and grindability of dental cast Ti-Nb alloys.

    Science.gov (United States)

    Kikuchi, Masafumi; Takahashi, Masatoshi; Okuno, Osamu

    2003-09-01

    Aiming at developing a dental titanium alloy with better mechanical properties and machinability than unalloyed titanium, a series of Ti-Nb alloys with Nb concentrations up to 30% was made. They were cast into magnesia-based molds using a dental casting machine and the mechanical properties and grindability of the castings were examined. The hardness of the alloys with Nb concentrations of 5% and above was significantly higher than that of titanium. The yield strength and tensile strength of the alloys with Nb concentrations of 10% and above were significantly higher than those of titanium, while the elongation was significantly lower. A small addition of niobium to titanium did not contribute to improving the grindability of titanium. The Ti-30% Nb alloy exhibited significantly better grindability at low grinding speed with higher hardness, strength, and Young's modulus than titanium, presumably due to precipitation of the omega phase in the beta matrix.

  16. Effect of two-stage sintering process on microstructure and mechanical properties of ODS tungsten heavy alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyong H. [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong, Yusong-gu, Taejon 305-701 (Korea, Republic of); Cha, Seung I. [International Center for Young Scientists, National Institute for Materials Science 1-1, Namiki, Tsukuba 305-0044 (Japan); Ryu, Ho J. [DUPIC, Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yusong-gu, Taejon 305-353 (Korea, Republic of); Hong, Soon H. [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong, Yusong-gu, Taejon 305-701 (Korea, Republic of)], E-mail: shhong@kaist.ac.kr

    2007-06-15

    Oxide dispersion strengthened (ODS) tungsten heavy alloys have been considered as promising candidates for advanced kinetic energy penetrator due to their characteristic fracture mode compared to conventional tungsten heavy alloy. In order to obtain high relative density, the ODS tungsten heavy alloy needs to be sintered at higher temperature for longer time, however, induces growth of tungsten grains. Therefore, it is very difficult to obtain controlled microstructure of ODS tungsten heavy alloy having fine tungsten grains with full densification. In this study, two-stage sintering process, consisted of primary solid-state sintering and followed by secondary liquid phase sintering, was introduced for ODS tungsten heavy alloys. The mechanically alloyed 94W-4.56Ni-1.14Fe-0.3Y{sub 2}O{sub 3} powders are solid-state sintered at 1300-1450 deg. C for 1 h in hydrogen atmosphere, and followed by liquid phase sintering temperature at 1465-1485 deg. C for 0-60 min. The microstructure of ODS tungsten heavy alloys showed high relative density above 97%, with contiguous tungsten grains after primary solid-state sintering. The microstructure of solid-state sintered ODS tungsten heavy alloy was changed into spherical tungsten grains embedded in W-Ni-Fe matrix during secondary liquid phase sintering. The two-stage sintered ODS tungsten heavy alloy from mechanically alloyed powders showed finer microstructure and higher mechanical properties than conventional liquid phase sintered alloy. The mechanical properties of ODS tungsten heavy alloys are dependent on the microstructural parameters such as tungsten grain size, matrix volume fraction and tungsten/tungsten contiguity, which can be controlled through the two-stage sintering process.

  17. Tensile behaviour at room and high temperatures of novel metal matrix composites based on hyper eutectic Al-Si alloys

    International Nuclear Information System (INIS)

    Valer, J.; Rodriguez, J.M.; Urcola, J.J.

    1997-01-01

    This work shows the improvement obtained on tensile stress at room and high temperatures of hyper eutectic Al-Si alloys. These alloys are produced by a combination of spray-forming, extrusion and thixoforming process, in comparison with conventional casting alloys.Al-25% Si-5%Cu. Al-25%Si-5%Cu-2%Mg and Al-30%Si-5%Cu alloys have been studied relating their microstructural parameters with tensile stress obtained and comparing them with conventional Al-20%Si. Al-36%Si and Al-50%Si alloys. Al-25%Si-5%Cu alloy-was tested before and after semi-solid forming, in order to distinguish the different behaviour of this alloy due to the different microstructure. The properties obtained with these alloys were also related to Al-SiC composites formed by similar processes. (Author) 20 refs

  18. Microstructural and microchemical evolution in vanadium alloys by heavy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Sekimura, Naoto; Kakiuchi, Hironori; Shirao, Yasuyuki; Iwai, Takeo [Tokyo Univ. (Japan)

    1996-10-01

    Microstructural and microchemical evolution in vanadium alloys were investigated using heavy ion irradiation. No cavities were observed in V-5Cr-5Ti alloys irradiated to 30 dpa at 520 and 600degC. Energy dispersive X-ray spectroscopy analyses showed that Ti peaks around grain boundaries. Segregation of Cr atoms was not clearly detected. Co-implanted helium was also found to enhance dislocation evolution in V-5Cr-5Ti. High density of matrix cavities were observed in V-5Fe alloys irradiated with dual ions, whereas cavities were formed only around grain boundaries in single ion irradiated V-5Fe. (author)

  19. Investigations on Mechanical Behaviour of Micro Graphite Particulates Reinforced Al-7Si Alloy Composites

    Science.gov (United States)

    Nagaraj, N.; Mahendra, K. V.; Nagaral, Madeva

    2018-02-01

    Micro particulates reinforced metal matrix composites are finding wide range of applications in automotive and sports equipment manufacturing industries. In the present study, an attempt has been made to develop Al-7Si-micro graphite particulates reinforced composites by using liquid melt method. 3 and 6 wt. % of micro graphite particulates were added to the Al-7Si base matrix. Microstructural characterization was done by using scanning electron microscope and energy dispersive spectroscope. Mechanical behaviour of Al-7Si-3 and 6 wt. % composites were evaluated as per ASTM standards. Scanning electron micrographs revealed the uniform distribution of micro graphite particulates in the Al-7Si alloy matrix. EDS analysis confirmed the presence of B and C elements in graphite reinforced composites. Further, it was noted that ultimate tensile and yield strength of Al-7Si alloy increased with the addition of 3 and 6wt. % of graphite particulates. Hardness of graphite reinforced composites was lesser than the base matrix.

  20. Studies of alloy structures and properties. Annual summary report, December 1, 1976--December 1, 1977

    International Nuclear Information System (INIS)

    Duwez, P.

    1977-01-01

    Brief summaries of research activities in the following areas are given: superconductivity to ferromagnetism in amorphous Gd--La--Au alloys; magnetic regimes in amorphous Ni--Fe--P--B alloys; electronic and magnetic properties of amorphous Fe--P--B alloys; critical phenomena and magnetic properties of amorphous gadolinium based ferromagnets; Kondo effect, spin correlations, and superconductivity in amorphous alloys doped with magnetic impurities; flux pinning by crystalline phase precipitates embedded in an amorphous superconducting matrix; kinetics of crystallization of amorphous alloys; properties of the flux lattice in amorphous superconductors; low temperature calorimeter; low temperature heat capacity of metastable superconductors; thermal relaxation effects and crystallization of amorphous alloys; fundamental studies of amorphous superconductors using superconductive tunneling; low temperature calorimetry of bulk amorphous metals; and mictomagnetism in amorphous alloys

  1. Chromium surface alloying of structural steels during laser treatment

    International Nuclear Information System (INIS)

    Kurov, I.E.; Nagornykh, S.N.; Sivukhin, G.A.; Solenov, S.V.

    1987-01-01

    Results of matrix alloying from the surface layer and creation of considerably increased chromium concentration in the depth which permits to increase the efficiency of laser treatment of steels (12Kh18N10T and 38KhN3M) in the process of their further mechanical polishing, are presented. The treatment was realized by continuous CO 2 -laser at different power densities and scanning rates are presented. A model describing the creation of anomalous distributions of the alloying element in steels is plotted

  2. Mechanical properties and fracture mechanism of as-cast Mg{sub 77}TM{sub 12}Zn{sub 5}Y{sub 6} (TM = Cu, Ni) bulk amorphous matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, K.Q. [School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110178 (China)], E-mail: kqqiu@yahoo.com.cn; Hu, N.N.; Zhang, H.B. [School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110178 (China); Jiang, W.H. [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37990 (United States); Ren, Y.L. [School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110178 (China); Liaw, P.K. [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37990 (United States)

    2009-06-10

    Comparative investigations on the microstructures, thermal stability and mechanical properties of Mg{sub 77}Cu{sub 12}Zn{sub 5}Y{sub 6} and Mg{sub 77}Ni{sub 12}Zn{sub 5}Y{sub 6} bulk metallic glass matrix composites were carried out by using scanning electron microscopy (SEM), DSC and compressive tester. The results show that the microstructure of as-cast samples with 3 mm in diameter for Cu-containing alloy is consisted of Mg flakes and dotted Mg{sub 2}Cu phase in the amorphous matrix, while the as-cast Ni-containing alloy with the same diameter is mainly consisted of Mg flakes in the amorphous matrix. The glass transition temperature and supercooled liquid region are 413 K and 27 K for the Cu-containing, 443 K and 32 K for the Ni-containing amorphous matrix composites, respectively. The fracture strength, yield strength and plastic strain are 532 MPa, 390 MPa and 2.4% for the Cu-containing alloy, 667 MPa, 412 MPa and 7% for the Ni-containing alloy, respectively. Furthermore, the fracture mechanism for the amorphous matrix composites was discussed according to both the fracture surfaces and the stress-strain curves.

  3. Influence of cold rolling and fatigue on the residual stress state of a metal matrix composite

    International Nuclear Information System (INIS)

    Hanus, E.; Ericsson, T.; Lu, J.; Decomps, F.

    1993-01-01

    The large difference in the coefficient of thermal expansion between the matrix alloy and the particle in a metal matrix composite gives rise to residual stresses in the material. In the present work the effect of cold rolling and four-point bending fatigue on the residual stress state of a silicon carbide particle reinforced aluminium alloy (AA 2014) has been investigated. The three dimensional stress state measured in both phases: matrix and reinforcement, has been determined by using an X-ray diffraction technique. It was found that cold rolling induces surface compressive macrostresses of about -250 MPa, with a penetration depth around 2 mm. The absolute values of the pseudomacrostresses in both phases are significantly reduced due to the single track rolling. Stress relaxation occurs during four-point bending fatigue. (orig.)

  4. Microstructure and mechanical properties of stir cast ZX51/Al2O3p magnesium matrix composites

    International Nuclear Information System (INIS)

    Rahmany-Gorji, Reza; Alizadeh, Ali; Jafari, Hassan

    2016-01-01

    Magnesium matrix composites can overcome the limitations of magnesium and its alloys. This paper investigates the effect of adding Al 2 O 3 microparticles on microstructure and mechanical response of ZX51 alloy-matrix composites. Stir casting process was chosen due largely to its low cost to fabricate the novel ZX51/Al 2 O 3 p composites. Scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffractometry were used in order to analyze the microstructure of as-cast composites. Tension, compression, and Brinell hardness tests were performed to determine mechanical properties of the composites. It was revealed that the microstructure of matrix alloy is composed of α-Mg grains and (α-Mg+Ca 2 Mg 6 Zn 3 ) eutectic mixture distributed predominantly along grain boundaries. The addition of Al 2 O 3 p brought about a marked grain refinement and also introduced slight amounts of porosity. The results showed that with increasing volume percentage of Al 2 O 3 p, hardness and yield strength increase while tensile strength, compressive strength, and ductility decrease; in consequence, toughness decreases as well.

  5. Unexpected formation of hydrides in heavy rare earth containing magnesium alloys

    Directory of Open Access Journals (Sweden)

    Yuanding Huang

    2016-09-01

    Full Text Available Mg–RE (Dy, Gd, Y alloys show promising for being developed as biodegradable medical applications. It is found that the hydride REH2 could be formed on the surface of samples during their preparations with water cleaning. The amount of formed hydrides in Mg–RE alloys is affected by the content of RE and heat treatments. It increases with the increment of RE content. On the surface of the alloy with T4 treatment the amount of formed hydride REH2 is higher. In contrast, the amount of REH2 is lower on the surfaces of as-cast and T6-treated alloys. Their formation mechanism is attributed to the surface reaction of Mg–RE alloys with water. The part of RE in solid solution in Mg matrix plays an important role in influencing the formation of hydrides.

  6. Titanium–35niobium alloy as a potential material for biomedical implants: In vitro study

    International Nuclear Information System (INIS)

    Perez de Andrade, Dennia; Marotta Reis de Vasconcellos, Luana; Chaves Silva Carvalho, Isabel; Ferraz de Brito Penna Forte, Lilibeth; Souza Santos, Evelyn Luzia de; Falchete do Prado, Renata; Santos, Dalcy Roberto dos; Alves Cairo, Carlos Alberto; Rodarte Carvalho, Yasmin

    2015-01-01

    Research on new titanium alloys and different surface topographies aims to improve osseointegration. The objective of this study is to analyze the behavior of osteogenic cells cultivated on porous and dense samples of titanium–niobium alloys, and to compare them with the behavior of such type of cells on commercial pure titanium. Samples prepared using powder metallurgy were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and metallographic and profilometer analyses. Osteogenic cells from newborn rat calvaria were plated over different groups: dense or porous samples composed of Ti or Ti–35niobium (Nb). Cell adhesion, cell proliferation, MTT assay, cell morphology, protein total content, alkaline phosphatase activity, and mineralization nodules were assessed. Results from XRD and EDS analysis confirmed the presence of Ti and Nb in the test alloy. Metallographic analysis revealed interconnected pores, with pore size ranging from 138 to 150 μm. The profilometer analysis detected the greatest rugosity within the dense alloy samples. In vitro tests revealed similar biocompatibility between Ti–35Nb and Ti; furthermore, it was possible to verify that the association of porous surface topography and the Ti–35Nb alloy positively influenced mineralized matrix formation. We propose that the Ti–35Nb alloy with porous topography constitutes a biocompatible material with great potential for use in biomedical implants. - Highlights: • Powder metallurgy is effective in producing porous biomaterials. • Ti–35Nb alloy improved mineralized matrix formation. • Porous surface favored a multidirectional pattern of cell spreading. • Porous surface Ti–35Nb alloy appears to be more favorable to bone formation than existing alloys

  7. Titanium–35niobium alloy as a potential material for biomedical implants: In vitro study

    Energy Technology Data Exchange (ETDEWEB)

    Perez de Andrade, Dennia; Marotta Reis de Vasconcellos, Luana; Chaves Silva Carvalho, Isabel; Ferraz de Brito Penna Forte, Lilibeth; Souza Santos, Evelyn Luzia de [Department of Bioscience and Oral Diagnosis, Institute of Science and Technology, UNESP — Univ Estadual Paulista, State University of São Paulo (UNESP), Av. Engenheiro Francisco José Longo, 777, São José dos Campos 12245-000, SP (Brazil); Falchete do Prado, Renata, E-mail: renatafalchete@hotmail.com [Department of Bioscience and Oral Diagnosis, Institute of Science and Technology, UNESP — Univ Estadual Paulista, State University of São Paulo (UNESP), Av. Engenheiro Francisco José Longo, 777, São José dos Campos 12245-000, SP (Brazil); Santos, Dalcy Roberto dos; Alves Cairo, Carlos Alberto [Division of Materials, Air and Space Institute, CTA, Praça Mal. do Ar Eduardo Gomes, 14, São José dos Campos 12904-000, SP (Brazil); Rodarte Carvalho, Yasmin [Department of Bioscience and Oral Diagnosis, Institute of Science and Technology, UNESP — Univ Estadual Paulista, State University of São Paulo (UNESP), Av. Engenheiro Francisco José Longo, 777, São José dos Campos 12245-000, SP (Brazil)

    2015-11-01

    Research on new titanium alloys and different surface topographies aims to improve osseointegration. The objective of this study is to analyze the behavior of osteogenic cells cultivated on porous and dense samples of titanium–niobium alloys, and to compare them with the behavior of such type of cells on commercial pure titanium. Samples prepared using powder metallurgy were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and metallographic and profilometer analyses. Osteogenic cells from newborn rat calvaria were plated over different groups: dense or porous samples composed of Ti or Ti–35niobium (Nb). Cell adhesion, cell proliferation, MTT assay, cell morphology, protein total content, alkaline phosphatase activity, and mineralization nodules were assessed. Results from XRD and EDS analysis confirmed the presence of Ti and Nb in the test alloy. Metallographic analysis revealed interconnected pores, with pore size ranging from 138 to 150 μm. The profilometer analysis detected the greatest rugosity within the dense alloy samples. In vitro tests revealed similar biocompatibility between Ti–35Nb and Ti; furthermore, it was possible to verify that the association of porous surface topography and the Ti–35Nb alloy positively influenced mineralized matrix formation. We propose that the Ti–35Nb alloy with porous topography constitutes a biocompatible material with great potential for use in biomedical implants. - Highlights: • Powder metallurgy is effective in producing porous biomaterials. • Ti–35Nb alloy improved mineralized matrix formation. • Porous surface favored a multidirectional pattern of cell spreading. • Porous surface Ti–35Nb alloy appears to be more favorable to bone formation than existing alloys.

  8. Structure and grindability of dental Ti-Cr alloys

    International Nuclear Information System (INIS)

    Hsu, H.-C.; Wu, S.-C.; Chiang, T.-Y.; Ho, W.-F.

    2009-01-01

    The purpose of this study was to investigate the structure and microhardness of a series of binary Ti-Cr alloys with Cr contents up to 30 wt%. In addition, the grindability was also evaluated using an electric dental handpiece with SiC wheels, with the goal of developing a titanium alloy with better mechanical properties and machinability than commercially pure titanium (c.p. Ti), a metal generally considered to be difficult to machine. This study evaluated the phase and structure of Ti-Cr alloys, using an X-ray diffraction (XRD) for phase analysis and optical microscope for microstructure of the etched alloys. Grindability was evaluated by measuring the amount of metal volume removed after grinding for 1 min. Results indicated that the structure of Ti-Cr alloys is sensitive to the Cr content. The cast c.p. Ti has a hexagonal α phase. With 5 wt% Cr, metastable β phase starts to be retained. With Cr contents higher than 10 wt%, the equi-axed β phase is almost entirely retained. In addition, athermal ω phase was found in the Ti-5Cr and Ti-10Cr alloys. The largest quantity of ω phase and highest microhardness were found in Ti-10Cr alloy. The grinding rate of the Ti-Cr alloys showed a similar tendency to the microhardness. The Ti-10Cr alloy exhibited the best grindability, especially at 1000 m/min, which presumably due to the brittle nature of the alloy containing the ω phase in the β matrix.

  9. Compaction study of particulate iron-chromium matrix composite reinforced with alumina

    International Nuclear Information System (INIS)

    Saidatulakmar Shamsuddin; Shamsul Baharin Jamaludin; Zuhailawati Hussain; Zainal Arifin Ahmad

    2007-01-01

    Recently, a sharper focus on cost reduction in producing advanced composites systems has increased and leads to an interest in ferrous matrix composite which is cheaper compared to Cobalt, Nickel and their alloys that are scarce, expensive and their dust is especially harmful. In the present investigation, Fe-Cr-Al 2 O 3 composite was prepared using conventional powder metallurgy technique; mixing, compaction and sintering. Consolidation of particulate materials is dependent on the compaction process. As load is increased, the number of contacting asperities increases and they flatten and grow to form a planar contact surface. These asperities eventually merge to form bonding surfaces between particles. This paper focused on finding the optimum compaction parameter in a uniaxial pressing. Six different pressure were studied; (250, 375, 500, 625, 750 and 875)MPa. experimental results show that the optimum compaction parameter is 750 MPa that produced highest linear shrinkage, highest bulk density, lowest porosity and highest hardness value. Every sample has formed binary alloy of Fe-Cr alloy, confirmed by XRD and alumina are homogeneously distributed in the Fe-Cr matrix revealed by optical micrograph and SEM. from EDX, the composites consist of iron, chromium and alumina. (author)

  10. Hot mechanical behaviour of dispersion strengthened Cu alloys

    International Nuclear Information System (INIS)

    Garcia G, Jose; Espinoza G, Rodrigo; Palma H, Rodrigo; Sepulveda O, Aquiles

    2003-01-01

    This work is part of a research project which objective is the improvement of the high-temperature mechanical properties of copper, without an important decrease of the electrical or thermal conduction properties. The general hypothesis is that this will be done by the incorporation of nanometric ceramic dispersoids for hindering the dislocation and grain boundaries movement. In this context, the object of the present work is the study of the resistance to hot deformation of dispersion-strengthened copper alloys which have prepared by reactive milling. Two different alloys, Cu-2,39wt.%Ti-0.56wt.%C and Cu-1.18wt.%Al, were prepared so as obtain a copper matrix reinforced with nanometric TiC y Al 2 O 3 particles with a nominal total amount of 5 vol.%. The particles were developed by an in-situ formation process during milling. The materials were prepared in an attritor mill, and consolidated by extrusion at 750 o C, with an area reduction rate of 10:1. The resistance to hot deformation was evaluated by hot compression tests at 500 and 850 o C, at initial strain rates of 10 -3 and 10 -4 s-1. To evaluate the material softening due temperature, annealing at 400, 650 y 900 o C during 1h were applied; after that, hardness was measured at room temperature. Both studies alloys presented a higher resistance to hot deformation than pure copper, with or without milling. Moreover, the Cu-Ti-C alloy presented a mechanical resistance higher than that of the Cu-Al one. Both alloys presented strain-stress compression curves with a typical hot-work shape: an initial maximum followed by a stationary plateau. The Cu-Ti-C alloy had a higher hardness and did not present a hardness decay even after annealings at the higher temperature imposed (900 o C), while the Cu-Al alloy did exhibit a strong decay of hardness after the annealing at 900 o C. The best behaviour exhibited by the Cu-Ti C alloy, was attributed to the formation of a major quantity of dispersoids that in the Cu-Al alloy. In

  11. Wear behaviour of A356 aluminium alloy reinforced with micron and nano size SiC particles

    CSIR Research Space (South Africa)

    Camagu, ST

    2013-07-01

    Full Text Available A method for producing metal matrix composites MMC was successfully implemented for mixing nano and low micron (“Hybrid”) sized SiC reinforcing particles in an aluminium alloy matrix. Due to the improved specific modulus and strength, MMC...

  12. Microstructure and mechanical properties of spray deposited hypoeutectic Al-Si alloy

    International Nuclear Information System (INIS)

    Ferrarini, C.F.; Bolfarini, C.; Kiminami, C.S.; Botta F, W.J.

    2004-01-01

    The microstructure and the tensile properties of an Al-8.9 wt.% Si-3.2 wt.% Cu-0.9 wt.% Fe-0.8% Zn alloy processed by spray forming was investigated. The alloy was gas atomized with argon and deposited onto a copper substrate. The microstructure was evaluated by optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Small faceted dispersoids observed surrounding equiaxial α-Al matrix were identified by SEM-EDS as silicon particles. Sand cast samples with the same composition showed a columnar dendritic α-Al matrix, Al-Si eutectic, polyhedric α-AlFeSi and needle-like β-AlFeSi intermetallics. In the spray formed material the formation of the Al-Si eutetic was suppressed, and the formation of the α-AlFeSi and β-AlFeSi intermetallics was strongly reduced. The fine and homogeneous microstructure showed an aluminium matrix with grain size ranging from 30 to 40 μm, and particle size of the silicon dispersoids having a mean size of 12 μm. Room temperature tensile tests of the spray formed alloy showed relative increasing of strength and elongation when compared with the values observed for the conventionally cast counterparts. These results can be ascribed to the refined microstructure and the scarce presence of intermetallics of the spray formed material

  13. Structure and properties of porous TiNi(Co, Mo)-based alloy produced by the reaction sintering

    Science.gov (United States)

    Artyukhova, Nadezda; Yasenchuk, Yuriy; Chekalkin, Timofey; Gunther, Victor; Kim, Ji-Soon; Kang, Ji-Hoon

    2016-10-01

    Modern medical technologies have developed many new devices that can be implanted into humans to repair, assist or take the place of diseased or defective bones, arteries and even organs. The materials, especially porous ones, used for these devices have evolved steadily over the past twenty years with TiNi-based alloys replacing stainless steels and titanium. The aim of the paper is to presents results for examination of porous TiNi(Co,Mo)-based alloys intended further to be used in clinical practice. The structure and properties of porous TiNi-based alloys obtained by reaction sintering of Ti and Ni powders with additions of Co and Mo have been studied. It has been shown that alloying additions both Co and Mo inhibit the compaction of nickel powders in the initial stage of sintering. The maximum irreversible strain of porous samples under loading in the austenitic state is fixed with the Co addition, and the minimum one is fixed with the Mo addition. The Co addition leads to the fact that the martensite transformation in the TiNi phase becomes close to a one-step, and the Mo addition leads to the fact that the martensite transformation becomes more uniform. Both Co and Mo lead to an increase in the maximum accumulated strain as a result of the formation of temperature martensite. The additional increase in the maximum accumulated strain of the Ti50Ni49Co1 alloy is caused by decreased resistance of the porous Ni γ -based mass during the load.

  14. Physical and Mechanical Properties of LoVAR: A New Lightweight Particle-Reinforced Fe-36Ni Alloy

    Science.gov (United States)

    Stephenson, Timothy; Tricker, David; Tarrant, Andrew; Michel, Robert; Clune, Jason

    2015-01-01

    Fe-36Ni is an alloy of choice for low thermal expansion coefficient (CTE) for optical, instrument and electrical applications in particular where dimensional stability is critical. This paper outlines the development of a particle-reinforced Fe-36Ni alloy that offers reduced density and lower CTE compared to the matrix alloy. A summary of processing capability will be given relating the composition and microstructure to mechanical and physical properties.

  15. Part I. Corrosion studies of continuous alumina fiber reinforced aluminum-matrix composites. Part II. Galvanic corrosion between continuous alumina fiber reinforced aluminum-matrix composites and 4340 steel

    Science.gov (United States)

    Zhu, Jun

    Part I. The corrosion performance of continuous alumina fiber reinforced aluminum-matrix composites (CF-AMCs) was investigated in both the laboratory and field environments by comparing them with their respective monolithic matrix alloys, i.e., pure Al, A1-2wt%Cu T6, and Al 6061 T6. The corrosion initiation sites were identified by monitoring the changes in the surface morphology. Corrosion current densities and pH profiles at localized corrosion sites were measured using the scanning-vibrating electrode technique and the scanning ion-selective electrode technique, respectively. The corrosion damage of the materials immersed in various electrolytes, as well as those exposed in a humidity chamber and outdoor environments, was evaluated. Potentiodynamic polarization behavior was also studied. The corrosion initiation for the composites in 3.15 wt% NaCl occurred primarily around the Fe-rich intermetallic particles, which preferentially existed around the fiber/matrix interface on the composites. The corrosion initiation sites were also caused by physical damage (e.g., localized deformation) to the composite surface. At localized corrosion sites, the buildup of acidity was enhanced by the formation of micro-crevices resulting from fibers left in relief as the matrix corroded. The composites that were tested in exposure experiments exhibited higher corrosion rates than their monolithic alloys. The composites and their monolithic alloys were subjected to pitting corrosion when anodically polarized in the 3.15 wt% NaCl, while they passivated when anodically polarized in 0.5 M Na2SO4. The experimental results indicated that the composites exhibited inferior corrosion resistance compared to their monolithic matrix alloys. Part II. Galvanic corrosion studies were conducted on CF-AMCs coupled to 4340 steel since CF-AMCs have low density and excellent mechanical properties and are being considered as potential jacketing materials for reinforcing steel gun barrels. Coupled and

  16. The irradiation-induced microstructural development and the role of γ' on void formation in Ni-based alloys

    Science.gov (United States)

    Kato, Takahiko; Nakata, Kiyotomo; Masaoka, Isao; Takahashi, Heishichiro; Takeyama, Taro; Ohnuki, Soumei; Osanai, Hisashi

    1984-05-01

    The microstructural development for Inconel X-750, N1-13 at%A1, and Ni-11.5 at%Si alloys during irradiation was investigated. These alloys were previously heat-treated at temperatures of 723-1073 K, and γ' precipitates were produced. Irradiation was performed in a high voltage electron microscope (1000 kV) in the temperature range 673-823 K. In the case of solution-treated Inconel, interstitial dislocation loops were formed initially, while voids were nucleated after longer times. When the Inconel specimen containing a high number density of small γ' was irradiated, dislocation loops were formed in both the matrix and precipitate-matrix interface. The loops formed on the interface scarcely grew during irradiation. On the other hand, for the Ni-Al alloy fine γ' nucleated during irradiation, the large γ' precipitated by pre-aging, dissolved. A similar resolution process was also observed in Ni-Si alloy. Furthermore, in the Ni-Si alloy precipitates of γ' formed preferentially at interstitial dislocation loops and both specimen surfaces.

  17. Microstructural evolution and creep of Fe-Al-Ta alloys

    Energy Technology Data Exchange (ETDEWEB)

    Prokopcakova, Petra; Svec, Martin [Technical University of Liberec (Czech Republic). Dept. of Material Science; Palm, Martin [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany). Structure and Nano-/Micromechanics of Materials

    2016-05-15

    The microstructural evolution in Fe-Al-Ta alloys containing 23 - 31 at.% Al and 1.5 - 2.2 at.% Ta has been studied in the temperature range 650 - 750 C by annealing for 1, 10, 100 and 1 000 h. The experiments confirm that in this temperature range the precipitation of the stable hexagonal C14 Laves phase is preceded by formation of coherent, metastable L2{sub 1} Heusler phase precipitates within the Fe-Al matrix. However, precipitates of C14 are observed after much shorter annealing times than previously assumed. Creep strength increases substantially with increasing Al content of the alloys because the solid solubility for Ta in the Fe-Al matrix increases with increasing Al content and solid-solution hardening contributes substantially to the observed high creep strength. It may therefore be that the microstructural changes during creep have no noticeable effect on creep strength.

  18. Microstructural evolution and creep of Fe-Al-Ta alloys

    International Nuclear Information System (INIS)

    Prokopcakova, Petra; Svec, Martin; Palm, Martin

    2016-01-01

    The microstructural evolution in Fe-Al-Ta alloys containing 23 - 31 at.% Al and 1.5 - 2.2 at.% Ta has been studied in the temperature range 650 - 750 C by annealing for 1, 10, 100 and 1 000 h. The experiments confirm that in this temperature range the precipitation of the stable hexagonal C14 Laves phase is preceded by formation of coherent, metastable L2 1 Heusler phase precipitates within the Fe-Al matrix. However, precipitates of C14 are observed after much shorter annealing times than previously assumed. Creep strength increases substantially with increasing Al content of the alloys because the solid solubility for Ta in the Fe-Al matrix increases with increasing Al content and solid-solution hardening contributes substantially to the observed high creep strength. It may therefore be that the microstructural changes during creep have no noticeable effect on creep strength.

  19. Effect of mechanical and thermal loading on boron carbide particles reinforced Al-6061 alloy

    International Nuclear Information System (INIS)

    Manjunatha, B.; Niranjan, H.B.; Satyanarayana, K.G.

    2015-01-01

    Metal Matrix Composites (MMC) considered as one of the ‘advanced materials’ have evoked growing interest during the last three decades due to their high performance and applications in strategic sectors. These composites exhibit unique and attractive properties over the monolithic alloys, but suffer from low ductility, which makes them not so attractive for some of the applications where high toughness is one of the design criteria. This limitation of MMCs has been overcome by resorting to various treatments such as mechanical and thermal loading. Considering very limited reports available on Al alloy reinforced with boron carbide (B 4 C) particles, this paper presents (i) preparation of Al-6061 alloy reinforced with 1.5–10 wt% B 4 C, (ii) subjecting them to mechanical and thermal treatments and (iii) characterization of all the above samples. Specific ultimate tensile strength and hardness of all the composites were higher than those of matrix. Also, these values increased with increasing amount of particles, with composites containing 8 wt% B 4 C showing the maximum values in all the three conditions. These observations are supported by the uniform distribution of particles in the matrix as observed in their microstructure

  20. Phase equilibria and thermodynamic properties of high-alloy tool steels : theoretical and experimental approach

    OpenAIRE

    Bratberg, Johan

    2005-01-01

    The recent development of tool steels and high-speed steels has led to a significant increase in alloy additions, such as Co, Cr, Mo, N, V, and W. Knowledge about the phase relations in these multicomponent alloys, that is, the relative stability between different carbides or the solubility of different elements in the carbides and in the matrix phase, is essential for understanding the behaviour of these alloys in heat treatments. This information is also the basis for improving the properti...

  1. Exogenously applied D-pinitol and D-chiro-inositol modifies the accumulation of α-D-galactosides in developing tiny vetch (Vicia hirsuta [L.] S.F. Gray seeds

    Directory of Open Access Journals (Sweden)

    Lesław B. Lahuta

    2011-01-01

    Full Text Available In the present study we have investigated the effect of exogenous cyclitols on the accumulation of their galactosides and raffinose family oligosaccharides (RFOs, as well as on some enzymes important for their biosynthesis in seeds of tiny vetch (Vicia hirsuta [L.] S.F. Gray. Immature seeds during 6-day incubation with D-chiro-inositol (naturally does not appear in seeds of tiny vetch were accumulated cyclitol and its galactosides (fagopyritols: B1 and B2. Short 4-hour incubation with D-chiro-inositol, and subsequent slow desiccation process caused accumulation of free cyclitol only, without biosynthesis of its galactosides. Feeding D-chiro-inositol to pods of tiny vetch induced accumulation of high levels of its galactosides (fagopyritol B1, B2 and B3 in maturing seeds. Similarly, feeding D-pinitol increased accumulation of its mono-, di- and tri-galactosides: GPA, GPB, DGPA and TGPA in tiny vetch seed. Accumulation of both cyclitols and their galactosides drastically reduced accumulation of verbascose. Inhibition of RFOs biosynthesis by elevated levels of free cyclitols suggests some competition between formation of both types of galactosides and similarity of both biosynthetic routes in tiny vetch seeds. Galactinol synthase (GolS from tiny vetch seeds demonstrated ability to utilize D-chiro-inositol as galactosyl acceptor, instead of myo-inositol. Presence of both cyclitols, as substrates for GolS, caused synthesis of their galactosides: fagopyritol B1 and galactinol. However, formation of galactinol was more efficient than fagopyritol B1. D-chiro-Inositol and D-pinitol at concentrations several-fold higher than myo-inositol had inhibitory effect on GolS. Thus, we suggest that a level of free cyclitols can have an influence on the rate of galactinol biosynthesis and further accumulation of RFOs and galactosyl cyclitols in tiny vetch seeds.

  2. Characterization of B4C-composite-reinforced aluminum alloy composites

    Science.gov (United States)

    Singh, Ram; Rai, R. N.

    2018-04-01

    Dry sliding wear tests conducted on Pin-on-disk wear test machine. The rotational speed of disc is ranging from (400-600rpm) and under loads ranging from (30-70 N) the contact time between the disc and pin is constant for each pin specimen of composites is 15 minute. In all manufacturing industries the uses of composite materials has been increasing globally, In the present study, an aluminum 5083 alloy is used as the matrix and 5% of weight percentage of Boron Carbide (B4C) as the reinforcing material. The composite is produced using stir casting technique. This is cost effective method. The aluminum 5083 matrix can be strengthened by reinforcing with hard ceramic particles like silicon carbide and boron carbide. In this experiment, aluminum 5083 alloy is selected as one of main material for making parts of the ship it has good mechanical properties, good corrosion resistance and it is can welded very easily and does have good strength. The samples are tested for hardness and tensile strength. The mechanical properties like Hardness can be increased by reinforcing aluminum 5083alloy 5% boron carbide (B4C) particles and tensile strength. Finally the Scanning Electron Microscope (SEM) analysis and EDS is done, which helps to study topography of composites and it produces images of a sample by scanning it with a focused beam of electrons and the presence of composition found in the matrix.

  3. Corrosion behavior of Zr-x(Nb, Sn and Cu) binary alloys

    International Nuclear Information System (INIS)

    Kim, M. H.; Lee, M. H.; Park, S. Y.; Jung, Y. H.; We, M. Y.

    1999-01-01

    For the development of advanced zirconium alloys for nuclear fuel cladding, the corrosion behaviors of zirconium binary alloys were studied on the Zr-xNb, Zr-xSn, and Zr-xCu alloys. The corrosion test were performed in water at 360 deg C, steam at 400 deg C and LiOH at 360 deg C for 45 days. The corrosion behaviors of Zr-xNb was similar to that of Zr-xCu alloys. However, the corrosion behavior of Zr-xSn was different from Zr-xNb and Zr-xCu. The weight gain of Zr-xNb and Zr-xCu was increased with addition of alloying elements. When Sn is added to Zr matrix in range below the solubility limit, the corrosion resistance decrease with increasing Sn-content, while in the range over solubility limit, Sn has an adverse effect on the corrosion resistance. Especially, Zr-xSn alloys showed higher corrosion resistance than Zr-xNb and Zr-xCu alloys in LiOH solution

  4. A simple stir casting technique for the preparation of in situ Fe-aluminides reinforced Al-matrix composites

    Directory of Open Access Journals (Sweden)

    Susanta K. Pradhan

    2016-09-01

    Full Text Available This article presents a simple stir casting technique for the development of Fe-aluminides particulate reinforced Al-matrix composites. It has been demonstrated that stirring of super-heated Al-melt by a mild steel plate followed by conventional casting and hot rolled results in uniform dispersion of in situ Al13Fe4 particles in the Al matrix; the amount of reinforcement is found to increase with increasing melt temperature. With reference to base alloy, the developed composite exhibits higher hardness and improved tensile strength without much loss of ductility; since, composite like base alloy undergoes ductile mode of fracture.

  5. Phase transformations behavior in a Cu-8.0Ni-1.8Si alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Q. [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Li, Z., E-mail: lizhou6931@163.com [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China) and Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha, 410083 (China); Wang, M.P. [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha, 410083 (China); Zhang, L.; Gong, S. [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Xiao, Z. [Department of Engineering, University of Liverpool, Liverpool, L693 GH (United Kingdom); Pan, Z.Y. [Hunan Nonferrous Metals Holding Group Co., Ltd., Changsha, 410015 (China)

    2011-02-24

    Research highlights: > High solute concentrations Cu-Ni-Si alloy with super high strength and high conductivity has a good prospect for replacing Cu-Be alloys. At least four different kinds of precipitation products (DO{sub 22} ordered structure, {beta}-Ni{sub 3}Si precipitate, {delta}-Ni{sub 2}Si precipitate and {gamma}-Ni{sub 5}Si{sub 2} precipitate) have been observed in previous investigation. Therefore, the overall phase transformation behavior of Cu-Ni-Si alloy appears to be very complex. And most previous studies on the phase transformation usually investigated the precipitation process at only one temperature or at most a few temperatures, which is far away to establish a time-temperature-transformation (TTT) diagram for Cu-Ni-Si alloy. > The phase transformation behavior of Cu-8.0Ni-1.8Si alloy has been studied systematically at wide temperature range in this paper. The results we have gained are that: after solution treatment, followed by different conditions of isothermal treatment, DO{sub 22} ordering, discontinuous precipitation and continuous precipitation were observed in the alloy; discontinuous precipitates of {beta}-Ni{sub 3}Si phase appeared when the alloy isothermal treated at 550 deg. C for short time, which had not been reported by the previous Cu-Ni-Si system alloy's researchers in their papers; two kinds of precipitates of {beta}-Ni{sub 3}Si and {delta}-Ni{sub 2}Si were determined by the TEM characterization; the orientation relationship between the two kinds of precipitates and Cu-matrix is that: (1 1 0){sub Cu}//(1 1 0){sub {beta}}//(211-bar){sub {delta}}, [112-bar]{sub Cu}//[11-bar 2]{sub {beta}}//[3 2 4]{sub {delta}}; during overaging treatment, Cu-matrix, {beta}-Ni{sub 3}Si, {delta}-Ni{sub 2}Si and {delta}'-Ni{sub 2}Si were distinguished in the samples and the orientation relationship between the precipitates and Cu-matrix can be expressed as that: (0 2 2){sub Cu}//(0 2 2){sub {beta}}//(1 0 0){sub {delta}}, (02-bar 2){sub Cu

  6. Corrosion characteristics of Hastelloy N alloy after He+ ion irradiation

    International Nuclear Information System (INIS)

    Lin Jianbo; Yu Xiaohan; Li Aiguo; He Shangming; Cao Xingzhong; Wang Baoyi; Li Zhuoxin

    2014-01-01

    With the goal of understanding the invalidation problem of irradiated Hastelloy N alloy under the condition of intense irradiation and severe corrosion, the corrosion behavior of the alloy after He + ion irradiation was investigated in molten fluoride salt at 700 °C for 500 h. The virgin samples were irradiated by 4.5 MeV He + ions at room temperature. First, the virgin and irradiated samples were studied using positron annihilation lifetime spectroscopy (PALS) to analyze the influence of irradiation dose on the vacancies. The PALS results showed that He + ion irradiation changed the size and concentration of the vacancies which seriously affected the corrosion resistance of the alloy. Second, the corroded samples were analyzed using synchrotron radiation micro-focused X-ray fluorescence, which indicated that the corrosion was mainly due to the dealloying of alloying element Cr in the matrix. Results from weight-loss measurement showed that the corrosion generally correlated with the irradiation dose of the alloy. (author)

  7. Growth and surface morphology of ion-beam sputtered Ti-Ni thin films

    International Nuclear Information System (INIS)

    Rao, Ambati Pulla; Sunandana, C.S.

    2008-01-01

    Titanium-nickel thin films have been deposited on float glass substrates by ion beam sputtering in 100% pure argon atmosphere. Sputtering is predominant at energy region of incident ions, 1000 eV to 100 keV. The as-deposited films were investigated by X-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM). In this paper we attempted to study the surface morphology and elemental composition through AFM and XPS, respectively. Core level as well as valence band spectra of ion-beam sputtered Ti-Ni thin films at various Ar gas rates (5, 7 and 12 sccm) show that the thin film deposited at 3 sccm possess two distinct peaks at binding energies 458.55 eV and 464.36 eV mainly due to TiO 2 . Upon increasing Ar rate oxidation of Ti-Ni is reduced and the Ti-2p peaks begin approaching those of pure elemental Ti. Here Ti-2p peaks are observed at binding energy positions of 454.7 eV and 460.5 eV. AFM results show that the average grain size and roughness decrease, upon increasing Ar gas rate, from 2.90 μm to 0.096 μm and from 16.285 nm to 1.169 nm, respectively

  8. Wear resistance of laser-deposited boride reinforced Ti-Nb-Zr-Ta alloy composites for orthopedic implants

    International Nuclear Information System (INIS)

    Samuel, Sonia; Nag, Soumya; Scharf, Thomas W.; Banerjee, Rajarshi

    2008-01-01

    The inherently poor wear resistance of titanium alloys limits their application as femoral heads in femoral (hip) implants. Reinforcing the soft matrix of titanium alloys (including new generation β-Ti alloys) with hard ceramic precipitates such as borides offers the possibility of substantially enhancing the wear resistance of these composites. The present study discusses the microstructure and wear resistance of laser-deposited boride reinforced composites based on Ti-Nb-Zr-Ta alloys. These composites have been deposited using the LENS TM process from a blend of elemental Ti, Nb, Zr, Ta, and boron powders and consist of complex borides dispersed in a matrix of β-Ti. The wear resistance of these composites has been compared with that of Ti-6Al-4V ELI, the current material of choice for orthopedic femoral implants, against two types of counterfaces, hard Si 3 N 4 and softer SS440C stainless steel. Results suggest a substantial improvement in the wear resistance of the boride reinforced Ti-Nb-Zr-Ta alloys as compared with Ti-6Al-4V ELI against the softer counterface of SS440. The presence of an oxide layer on the surface of these alloys and composites also appears to have a substantial effect in terms of enhanced wear resistance

  9. Microstructure and properties of Cu–Al–Fe high-temperature shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shuiyuan, E-mail: yangshuiyuan@xmu.edu.cn; Su, Yu; Wang, Cuiping; Liu, Xingjun, E-mail: lxj@xmu.edu.cn

    2014-07-01

    Highlights: • Three-phase microstructure is observed for x = 0 both under the quenched and aged states. • Two-phase microstructure is observed for x = 1 both under the quenched and aged states. • Only martensite exists for x = 2 after quenching, whereas γ{sub 1}(Cu{sub 9}Al{sub 4}) phase appears after aging. • High martensitic transformation temperatures (>450 °C) are obtained for all studied alloys. • The alloy for x = 1 after aging still remains relatively good recovery strain and ratio. - Abstract: The microstructure, martensitic transformation, mechanical and shape memory properties of Cu{sub 84−x}Al{sub 11+x}Fe{sub 5} (x = 0, 1, 2) alloys under the quenched and aged states were investigated. The results show that x = 0 and 1 under the quenched state exhibit a mixture of primary β{sup ′}{sub 1} and little γ{sup ′}{sub 1} martensites, and x = 2 only shows dominant γ{sup ′}{sub 1} martensite. Small amounts of α(Cu) and Fe(Al,Cu) phases are observed for x = 0, whereas only tiny Fe(Al,Cu) phase exists for x = 1. After aging, all alloys have a mixture of β{sup ′}{sub 1} and γ{sup ′}{sub 1} martensites, and the snowflake-shaped γ{sub 1} (Cu{sub 9}Al{sub 4}) precipitate is present for x = 2. The recovery strain and ratio for x = 0 and 2 remarkably decrease after aging due to the precipitations. However, the recovery strain of x = 1 after aging still linearly increases with the increase of the pre-strain, up to a maximum value of 1.6%.

  10. Wear behavioral study of as cast and 7 hr homogenized Al25Mg2Si2Cu4Ni alloy at constant load

    Science.gov (United States)

    Harlapur, M. D.; Sondur, D. G.; Akkimardi, V. G.; Mallapur, D. G.

    2018-04-01

    In the current study, the wear behavior of as cast and 7 hr homogenized Al25Mg2Si2Cu4Ni alloy has been investigated. Microstructure, SEM and EDS results confirm the presence of different intermetallic and their effects on wear properties of Al25Mg2Si2Cu4Ni alloy in as cast as well as aged condition. Alloying main elements like Si, Cu, Mg and Ni partly dissolve in the primary α-Al matrix and to some amount present in the form of intermetallic phases. SEM structure of as cast alloy shows blocks of Mg2Si which is at random distributed in the aluminium matrix. Precipitates of Al2Cu in the form of Chinese script are also observed. Also `Q' phase (Al-Si-Cu-Mg) be distributed uniformly into the aluminium matrix. Few coarsened platelets of Ni are seen. In case of 7 hr homogenized samples blocks of Mg2Si get rounded at the corners, Platelets of Ni get fragmented and distributed uniformly in the aluminium matrix. Results show improved volumetric wear resistance and reduced coefficient of friction after homogenizing heat treatment.

  11. A surface-analytical examination of stringer particles in aluminum-lithium-copper alloys

    Science.gov (United States)

    Larson, L. A.; Avalos-Borja, M.; Pizzo, P. P.

    1984-01-01

    A surface analytical examination of powder metallurgy processed Al-Li-Cu alloys was conducted. The oxide stringer particles often found in these alloys are characterized. Particle characterization is important to more fully understand their impact on the stress corrosion and fracture properties of the alloy. The techniques used where SIMS (Secondary Ion Mass Spectroscopy) and SAM (Scanning Auger Microscopy). The results indicate that the oxide stringer particles contain both Al and LI with relatively high Li content and the Li compounds may be associated with the stringer particles, thereby locally depleting the adjacent matrix of Li solute.

  12. Electron backscatter diffraction as a useful method for alloys microstructure characterization

    Energy Technology Data Exchange (ETDEWEB)

    Klimek, Leszek; Pietrzyk, Bozena

    2004-11-17

    Microstructure examination of cast Co-Cr-Mo alloy is presented in this paper. The surface morphology and chemical composition of the alloy were investigated by means of scanning electron microscopy (SEM) and energy dispersive X-ray microanalysis (EDX). An identification of alloy phases was carried out using electron backscatter diffraction (EBSD). Two different kinds of precipitates in metallic matrix were found. They were identified as MC and M{sub 23}C{sub 6} type of carbides in Co-lattice solid solution. The advantages and limits of the EBSD method are described. It is presented that EBSD, as excellent tool for phase identification, is a valuable supplementary method for materials research.

  13. Repassivation Potential of Alloy 22 in Sodium and Calcium Chloride Brines

    International Nuclear Information System (INIS)

    Rebak, R B; Ilevbare, G O; Carranza, R M

    2007-01-01

    A comprehensive matrix of 60 tests was designed to explore the effect of calcium chloride vs. sodium chloride and the ratio R of nitrate concentration over chloride concentration on the repassivation potential of Alloy 22. Tests were conducted using the cyclic potentiodynamic polarization (CPP) technique at 75 C and at 90 C. Results show that at a ratio R of 0.18 and higher nitrate was able to inhibit the crevice corrosion in Alloy 22 induced by chloride. Current results fail to show in a consistent way a different effect on the repassivation potential of Alloy 22 for calcium chloride solutions than for sodium chloride solutions

  14. Effects of Al-Mn-Ti-P-Cu master alloy on microstructure and properties of Al-25Si alloy

    Directory of Open Access Journals (Sweden)

    Xu Chunxiang

    2013-09-01

    Full Text Available To obtain a higher microstructural refining efficiency, and improve the properties and processing ability of hypereutectic Al-25Si alloy, a new environmentally friendly Al-20.6Mn-12Ti-0.9P-6.1Cu (by wt.% master alloy was fabricated; and its modification and strengthening mechanisms on the Al-25Si alloy were studied. The mechanical properties of the unmodified, modified and heat treated alloys were investigated. Results show that the optimal addition amount of the Al-20.6Mn-12Ti-0.9P-6.1Cu master alloy is 4wt.%. In this case, primary Si and eutectic Si as well as メ-Al phase were clearly refined, and this refining effect shows an excellent long residual action as it can be heat-retained for at least 5 h. After being T6 heat treated, the morphology of primary and eutectic Si in the Al-25Si alloys with the addition of 4wt.% Al-20.6Mn-12Ti-0.9P-6.1Cu alloy changes into particles and short rods. The average grain size of the primary and eutectic Si decreases from 250 レm (unmodified to 13.83 レm and 35 レm (unmodified to 7 レm; the メ-Al becomes obviously finer and the distribution of Si phases tends to be uniform and dispersed. Meanwhile, the tensile properties are improved obviously; the tensile strengths at room temperature and 300 ìC reach 241 MPa and 127 MPa, increased by 153.7% and 67.1%, respectively. In addition, the tensile fracture mechanism changes from brittle fracture for the alloy without modification to ductile fracture after modification. Modifying the morphology of Si phase and strengthening the matrix can effectively block the initiation and propagation of cracks, thus improving the strength of the hypereutectic Al-25Si alloy.

  15. Production and properties of light-metal base amorphous alloys

    International Nuclear Information System (INIS)

    Inoue, Akihisa; Masumoto, Tsuyoshi

    1993-01-01

    Light-metal base alloys with high specific strength and good corrosion resistance were produced through amorphization of Al and Mg-based alloys. The amorphous phase is formed in rapidly solidified Al-TM-Ln and Mg-TM-Ln (TM=transition metal, Ln=lanthanide metal) alloys. The highest tensile strength (σ f ) reaches 1,330 MPa for the Al base and 830 MPa for the Mg base. Furthermore, the Mg-based alloys have a large glass-forming capacity which enables to produce an amorphous phase by a metallic mold casting method. The extrusion of the Al-based amorphous powders at temperatures above crystallization temperature caused the formation of high strength materials with finely mixed structure consisting of dispersed intermetallic compounds in an Al matrix. The highest values of σ f and fatigue limit are as high as 940 and 313 MPa, respectively, at room temperature and 520 and 165 MPa at 473 K. The extruded Al-Ni-Mm alloy has already been used as machine parts and subsequent further development as practical materials is expected by taking these advantages

  16. Effect of hot rolling on the microstructure and mechanical properties of Ti3Al based dual phase alloys

    International Nuclear Information System (INIS)

    Wu, J.; Zhang, L.; Hua, W.; Qiu, G.

    1999-01-01

    Development of α 2 -Ti 3 Al based dual phase alloys have shown some promising potentials in property improvement by introducing Ti 5 Si 3 silicide phase into the matrix via Si alloying. However, the presence of coarse network of Ti 5 Si 3 phase formed by eutectic reaction in the as-cast state also embrittles the alloy. Both hot rolling and powder metallurgy are considered to be the possible ways to refine the Ti 5 Si 3 phase in the matrix. Two Ti-Al-Si-Nb alloys whose Si contents are 2 and 5 at.% respectively were arc melted into ingots and then hot rolled to sheets in this investigation. Optical metallographic examination correlates the microstructures of the as-cast and as-rolled alloys with the different rolling amounts, showing that the coarse silicide network is broken into small particles after hot rolling. Mechanical property testing from room temperature to 800 C indicates that the strength and plastic elongation of the hot-rolled alloys are much higher than those of the as-cast ones. The data obtained in this investigation are comparable with those obtained in the P/M processed specimens. Fracture surfaces of the alloys are also examined

  17. Synthetic osteogenic extracellular matrix formed by coated silicon dioxide nanosprings

    Directory of Open Access Journals (Sweden)

    Hass Jamie L

    2012-01-01

    Full Text Available Abstract Background The design of biomimetic materials that parallel the morphology and biology of extracellular matrixes is key to the ability to grow functional tissues in vitro and to enhance the integration of biomaterial implants into existing tissues in vivo. Special attention has been put into mimicking the nanostructures of the extracellular matrix of bone, as there is a need to find biomaterials that can enhance the bonding between orthopedic devices and this tissue. Methods We have tested the ability of normal human osteoblasts to propagate and differentiate on silicon dioxide nanosprings, which can be easily grown on practically any surface. In addition, we tested different metals and metal alloys as coats for the nanosprings in tissue culture experiments with bone cells. Results Normal human osteoblasts grown on coated nanosprings exhibited an enhanced rate of propagation, differentiation into bone forming cells and mineralization. While osteoblasts did not attach effectively to bare nanowires grown on glass, these cells propagated successfully on nanosprings coated with titanium oxide and gold. We observed a 270 fold increase in the division rate of osteoblasts when grow on titanium/gold coated nanosprings. This effect was shown to be dependent on the nanosprings, as the coating by themselves did not alter the growth rate of osteoblast. We also observed that titanium/zinc/gold coated nanosprings increased the levels of osteoblast production of alkaline phosphatase seven folds. This result indicates that osteoblasts grown on this metal alloy coated nanosprings are differentiating to mature bone making cells. Consistent with this hypothesis, we showed that osteoblasts grown on the same metal alloy coated nanosprings have an enhanced ability to deposit calcium salt. Conclusion We have established that metal/metal alloy coated silicon dioxide nanosprings can be used as a biomimetic material paralleling the morphology and biology of

  18. Topology Optimization of Shape Memory Alloy Actuators using Element Connectivity Parameterization

    DEFF Research Database (Denmark)

    Langelaar, Matthijs; Yoon, Gil Ho; Kim, Yoon Young

    2005-01-01

    This paper presents the first application of topology optimization to the design of shape memory alloy actuators. Shape memory alloys (SMA’s) exhibit strongly nonlinear, temperature-dependent material behavior. The complexity in the constitutive behavior makes the topology design of SMA structure......) stiffness matrix of continuum finite elements. Therefore, any finite element code, including commercial codes, can be readily used for the ECP implementation. The key ideas and characteristics of these methods will be presented in this paper....

  19. Optical and vibrational properties of sulfur and selenium versus halogens in hydrogenated amorphous silicon matrix

    International Nuclear Information System (INIS)

    Al-Alawi, S.M.; Al-Dallal, S.

    1999-01-01

    The infrared spectra of a compositional variation series of alpha-Si,S:H; alpha-Si,Se:H, alpha-Si:Cl, H and alpha-Si:F,H thin films were deposited by r.f. glow discharge were compared. It was shown that S, Se, Cl and F can be bonded to the silicon matrix. The stretching mode bands at 2000 cm/sup -1/. and 2100 cm/sup -1/ in the infrared spectra of the above alloys shifts systematically to higher wave numbers when incorporated S,Se or halogen atoms are increases. This observation was attributed to the larger electronegativity of these atoms with respect to the host matrix. Optical transmission spectroscopy and photothermal deflection experiments reveal an increase in the band gap when the content of any of the above elements is increased. However, the highest band gap was obtained for sulfur alloys. This result was interpreted in terms of the S-Si bond strength as compared to other elements. It was found that alpha-Si, S:H was interpreted in terms of the S-Si alloys exhibit the highest structural stability among the four alloys for moderate amount of incorporated sulfur atoms. (author)

  20. Niobium Carbide-Reinforced Al Matrix Composites Produced by High-Energy Ball Milling

    Science.gov (United States)

    Travessa, Dilermando Nagle; Silva, Marina Judice; Cardoso, Kátia Regina

    2017-06-01

    Aluminum and its alloys are key materials for the transportation industry as they contribute to the development of lightweight structures. The dispersion of hard ceramic particles in the Al soft matrix can lead to a substantial strengthening effect, resulting in composite materials exhibiting interesting mechanical properties and inspiring their technological use in sectors like the automotive and aerospace industries. Powder metallurgy techniques are attractive to design metal matrix composites, achieving a homogeneous distribution of the reinforcement into the metal matrix. In this work, pure aluminum has been reinforced with particles of niobium carbide (NbC), an extremely hard and stable refractory ceramic. Its use as a reinforcing phase in metal matrix composites has not been deeply explored. Composite powders produced after different milling times, with 10 and 20 vol pct of NbC were produced by high-energy ball milling and characterized by scanning electron microscopy and by X-ray diffraction to establish a relationship between the milling time and size, morphology, and distribution of the particles in the composite powder. Subsequently, an Al/10 pct NbC composite powder was hot extruded into cylindrical bars. The strength of the obtained composite bars is comparable to the commercial high-strength, aeronautical-grade aluminum alloys.

  1. Lost foam casting of aluminum alloy-SiCp composite material

    International Nuclear Information System (INIS)

    Baalasuburamaniam, R.; Cvetnic, C.; Ravindran, C.

    2002-01-01

    Metal matrix composites are a viable alternative to cast irons in automotive components with possible increase in strength-to-weight ratio. Lost foam casting of aluminum alloy matrix composite containing 20 volume percent SiC was carried out at 690, 730, and 770 o C with a view to determining the effects of cooling rate on microstructure, particle distribution, microporosity and mechanical properties. These results were compared with those for the matrix material cast under similar conditions. The results and the correlations are of particular interest as there is no published literature on lost foam casting of composite materials. (author)

  2. Precipitation Behavior of Magnesium Alloys Containing Neodymium and Yttrium

    Science.gov (United States)

    Solomon, Ellen L. S.

    Magnesium is the lightest of the structural metals and has great potential for reducing the weight of transportation systems, which in turn reduces harmful emissions and improves fuel economy. Due to the inherent softness of Mg, other elements are typically added in order to form a fine distribution of precipitates during aging, which improves the strength by acting as barriers to moving dislocations. Mg-RE alloys are unique among other Mg alloys because they form precipitates that lie parallel to the prismatic planes of the Mg matrix, which is an ideal orientation to hinder dislocation slip. However, RE elements are expensive and impractical for many commercial applications, motivating the rapid design of alternative alloy compositions with comparable mechanical properties. Yet in order to design new alloys reproducing some of the beneficial properties of Mg-RE alloys, we must first fully understand precipitation in these systems. Therefore, the main objectives of this thesis are to identify the roles of specific RE elements (Nd and Y) on precipitation and to relate the precipitate microstructure to the alloy strength. The alloys investigated in this thesis are the Mg-Nd, Mg-Y, and Mg-Y-Nd systems, which contain the main alloying elements of commercial WE series alloys (Y and Nd). In all three alloy systems, a sequence of metastable phases forms upon aging. Precipitate composition, atomic structure, morphology, and spatial distribution are strongly controlled by the elastic strain energy originating from the misfitting coherent precipitates. The dominating role that strain energy plays in these alloy systems gives rise to very unique microstructures. The evolution of the hardness and precipitate microstructure with aging revealed that metastable phases are the primary strengthening phases of these alloys, and interact with dislocations by shearing. Our understanding of precipitation mechanisms and commonalities among the Mg-RE alloys provide future avenues to

  3. Research on Zr50Al15-xNi10Cu25Yx amorphous alloys prepared by mechanical alloying with commercial pure element powders

    International Nuclear Information System (INIS)

    Long Woyun; Ouyang Xueqiong; Luo Zhiwei; Li Jing; Lu Anxian

    2011-01-01

    Amorphous Zr 50 Al 15-x Ni 10 Cu 25 Y x alloy powders were fabricated by mechanical alloying at low vacuum with commercial pure element powders. The effects on glass forming ability of Al partial substituted by Y in Zr 50 Al 15 Ni 10 Cu 25 and thermal stability of Si 3 N 4 powders addition were investigated. The as-milled powders were characterized by X-ray diffraction, scanning electron microscopy and differential scanning calorimeter. The results show that partial substitution of Al can improve the glass forming ability of Zr 50 Al 15 Ni 10 Cu 25 alloy. Minor Si 3 N 4 additions raise the crystallization activation energy of the amorphous phase and thus improve its thermal stability. -- Research Highlights: → ZrAlNiCu amorphous alloys can be synthesized by MA in low cost. → Appropriate amount of Al substituted by Y in ZrAlNiCu alloy can improve its glass forming ability. → A second phase particle addition helps to improve the thermal stability of the amorphous matrix.

  4. The role of intermetallic phases in the corrosion of magnesium-rare earth alloys

    Energy Technology Data Exchange (ETDEWEB)

    Silva Campos, Maria del Rosario

    2016-07-25

    A new concept to develop a RE based Mg alloy with improved corrosion resistance was followed in the current work. Based on subsequent characterisation steps to eliminate less suitable RE elements the best microstructure for improved corrosion resistance was identified. At first, the corrosion properties of selected RE elements were determined. Based on these results RE elements that have a potential to enhance the corrosion resistance of Mg-RE alloys were selected. Two aspects of RE elements were important for the selection: the electrochemical properties and the solid solubility in Mg. If the solubility limit of RE elements in the Mg matrix is exceeded, they form intermetallic phases with Mg. By performing galvanic coupling measurements the compatibility between Mg matrix and intermetallic phases were estimated. At that point three binary Mg-RE alloys systems remained (Mg-Ce, Mg-La, and Mg-Gd). To evaluate the influence of composition (amount of intermetallic phases) on the corrosion behaviour, four concentrations were cast with 1, 5, 10 and 15 wt. % of RE. Ce and La have a lower solid solubility in Mg matrix generating higher volume fraction of the secondary phases, thus higher dissolution rates in the binary Mg-RE alloys. While Gd with higher solid solubility shows a different behaviour. Additions of up to 10 wt. % Gd resulted in similar behaviour compared to 1 wt. % Gd addition. The most promising results were obtained for the Mg-Gd system with 10 wt. % Gd. Thus, the microstructure of this alloy was further modified by heat treatments to understand the influence of microstructural changes on corrosion behaviour. A ternary element was used to attempt further optimisation of the corrosion performance. Additions of Al, Zn, Ga and Y did not show any improvement in the corrosion resistance of Mg10Gd. This is due to increasing volume fractions of critical more noble phases and the microstructure dominated by eutectic phase formation. Thus galvanic effects became much

  5. The role of intermetallic phases in the corrosion of magnesium-rare earth alloys

    International Nuclear Information System (INIS)

    Silva Campos, Maria del Rosario

    2016-01-01

    A new concept to develop a RE based Mg alloy with improved corrosion resistance was followed in the current work. Based on subsequent characterisation steps to eliminate less suitable RE elements the best microstructure for improved corrosion resistance was identified. At first, the corrosion properties of selected RE elements were determined. Based on these results RE elements that have a potential to enhance the corrosion resistance of Mg-RE alloys were selected. Two aspects of RE elements were important for the selection: the electrochemical properties and the solid solubility in Mg. If the solubility limit of RE elements in the Mg matrix is exceeded, they form intermetallic phases with Mg. By performing galvanic coupling measurements the compatibility between Mg matrix and intermetallic phases were estimated. At that point three binary Mg-RE alloys systems remained (Mg-Ce, Mg-La, and Mg-Gd). To evaluate the influence of composition (amount of intermetallic phases) on the corrosion behaviour, four concentrations were cast with 1, 5, 10 and 15 wt. % of RE. Ce and La have a lower solid solubility in Mg matrix generating higher volume fraction of the secondary phases, thus higher dissolution rates in the binary Mg-RE alloys. While Gd with higher solid solubility shows a different behaviour. Additions of up to 10 wt. % Gd resulted in similar behaviour compared to 1 wt. % Gd addition. The most promising results were obtained for the Mg-Gd system with 10 wt. % Gd. Thus, the microstructure of this alloy was further modified by heat treatments to understand the influence of microstructural changes on corrosion behaviour. A ternary element was used to attempt further optimisation of the corrosion performance. Additions of Al, Zn, Ga and Y did not show any improvement in the corrosion resistance of Mg10Gd. This is due to increasing volume fractions of critical more noble phases and the microstructure dominated by eutectic phase formation. Thus galvanic effects became much

  6. The development and mechanical characterization of aluminium copper-carbon fiber metal matrix hybrid composite

    Science.gov (United States)

    Manzoor, M. U.; Feroze, M.; Ahmad, T.; Kamran, M.; Butt, M. T. Z.

    2018-04-01

    Metal matrix composites (MMCs) come under advanced materials that can be used for a wide range of industrial applications. MMCs contain a non-metallic reinforcement incorporated into a metallic matrix which can enhance properties over base metal alloys. Copper-Carbon fiber reinforced aluminium based hybrid composites were prepared by compo casting method. 4 weight % copper was used as alloying element with Al because of its precipitation hardened properties. Different weight compositions of composites were developed and characterized by mechanical testing. A significant improvement in tensile strength and micro hardness were found, before and after heat treatment of the composite. The SEM analysis of the fractured surfaces showed dispersed and embedded Carbon fibers within the network leading to the enhanced strength.

  7. Quantifying the stress fields due to a delta-hydride precipitate in alpha-Zr matrix

    Energy Technology Data Exchange (ETDEWEB)

    Tummala, Hareesh [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Capolungo, Laurent [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tome, Carlos N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-19

    This report is a preliminary study on δ-hydride precipitate in zirconium alloy performed using 3D discrete dislocation dynamics simulations. The ability of dislocations in modifying the largely anisotropic stress fields developed by the hydride particle in a matrix phase is addressed for a specific dimension of the hydride. The influential role of probable dislocation nucleation at the hydride-matrix interface is reported. Dislocation nucleation around a hydride was found to decrease the shear stress (S13) and also increase the normal stresses inside the hydride. We derive conclusions on the formation of stacks of hydrides in zirconium alloys. The contribution of mechanical fields due to dislocations was found to have a non-negligible effect on such process.

  8. Metal matrix composites. Part 1. Types, properties, applications

    International Nuclear Information System (INIS)

    Edil da Costa, C.; Velasco Lopez, F.; Torralba Castello, M.

    2000-01-01

    An overview on the state of the art of metal matrix composites used in the automotive and aerospace industries is made. These materials usually are based on light alloys (Al, Ti and Mg) and reinforced with fibres or particles. In this review, it is presented a general scope on the different MMCs families, about their properties and their main applications. (Author) 61 refs

  9. KevlarTM Fiber-Reinforced Polybenzoxazine Alloys for Ballistic Impact Application

    Directory of Open Access Journals (Sweden)

    Chanchira Jubsilp

    2011-10-01

    Full Text Available A light weight ballistic composites from KevlarTM-reinforcing fiber having polybenzoxazine (BA/urethane prepolymer (PU alloys as a matrix were investigated in this work. The effect of alloy compositions on the ballistic composite properties was determined. The results revealed that the enhancement in the glass transition temperature (Tg of the KevlarTM-reinforced BA/PU composites compared to that of the KevlarTM-reinforced polybenzoxazine composite was observed. The increase of the elastomeric PU content in the BA/PU alloy resulted in samples with tougher characteristics. The storage modulus of the KevlarTM-reinforced BA/PU composites increased with increasing the mass fraction of polybenzoxazine. A ballistic impact test was also performed on the KevlarTM-reinforced BA/PU composites using a 9 mm handgun. It was found that the optimal contents of PU in the BA/PU alloys should be approximately 20wt%. The extent of the delaminated area and interfacial fracture were observed to change with the varied compositions of the matrix alloys. The appropriate thickness of KevlarTM-reinforced 80/20 BA/PU composite panel was 30 plies and 50 plies to resist the penetration from the ballistic impact equivalent to levels II-A and III-A of NIJ standard. The arrangement of composite panels with the higher stiffness panel at the front side also showed the best efficiency of ballistic penetration resistance.

  10. Effects of solution heat treatment on the microstructure and hardness of Mg-5Li-3Al-2Zn-2Cu alloy

    Energy Technology Data Exchange (ETDEWEB)

    Li Jiqing; An Jiangmin; Qu Zhikun [Key Laboratory of Superlight Materials and Surface Technology (Harbin Engineering University), Ministry of Education, Harbin 150001 (China); Wu Ruizhi, E-mail: Ruizhiwu2006@yahoo.com [Key Laboratory of Superlight Materials and Surface Technology (Harbin Engineering University), Ministry of Education, Harbin 150001 (China); Zhang Jinghuai; Zhang Milin [Key Laboratory of Superlight Materials and Surface Technology (Harbin Engineering University), Ministry of Education, Harbin 150001 (China)

    2010-10-15

    The microstructure and hardness of Mg-5Li-3Al-2Zn-2Cu alloy were investigated both in the as-cast condition and after solution heat treatment at 330-390 deg. C for 5 h. The as-cast alloy contains a microstructure consisting of {alpha}-Mg matrix, AlLi phase, AlCuMg phase and Al{sub 2}Cu phase. After the solution heat treament, the AlLi phase was dissolved into the matrix, however, the AlCuMg and Al{sub 2}Cu phases were not dissolved. With the increase of solution temperature, almost all the AlLi phase was dissolved, and the effects of solution strengthening of Al and Li atoms in the alloy increase, which results in the gradual increase of the Brinell hardness of the solution-treated alloy.

  11. Comparison of the irradiation effects on swelling and microstructure in commercial alloy A-286 and a simple Fe--25 Ni--15Cr gamma prime hardened alloy

    International Nuclear Information System (INIS)

    Chickering, R.W.; Bajaj, R.; Lally, J.S.

    1977-01-01

    The irradiation behaviors of alloy A-286 as well as experimental gamma prime hardened alloys are being studied in the National Alloy Development Program for application of gamma prime hardened alloys in the liquid metal fast breeder reactor. The principal direction of the studies concerns the high temperature strength and swelling resistance of the alloys. Minor element compositions may affect the phase stability and void swelling. A high Ti to Al ratio indicates a tendency for the gamma prime Ni 3 (Ti,Al) to transform into eta phase (Ni 3 Ti) after long term thermal aging and irradiation enhances the tendency for transformation. Another minor element, Si, as a constituent of G-phase, and irradiation may enhance G-phase formation. The Ti, Al, and Si contents affect the swelling of Fe-Cr-Ni alloys. The swelling resistance generally increases with increasing amounts of these three elements in the matrix. In the study the effects of Ti to Al ratio, Ti content, Al content, and Si content on swelling and phase stability were analyzed after Ni-ion irradiation

  12. Application of a dynamic-nanoindentation method to analyze the local structure of an Fe-18 at.% Gd cast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong; Baik, Youl [Dept. of Materials Science and Technology, Dankook University, Cheonan(Korea, Republic of); Moon, Byung M. [Liquid Processing and Casting Technology R and D Group, KITECH, Incheon (Korea, Republic of); Sohn, Dong Seong [Nuclear Engineering Department, UNIST, Ulsan (Korea, Republic of)

    2017-04-15

    A dynamic nanoindentation method was applied to study an Fe-18 at.% Gd alloy as a neutron-absorbing material prepared by vacuum arc-melting and cast in a mold. The Fe-18 at.% Gd cast alloy had a microstructure with matrix phases and an Fe-rich primary dendrite of Fe9Gd. Rietveld refinement of the X-ray spectra showed that the Fe-18 at.% Gd cast alloy consisted of 35.84 at.% Fe3Gd, 6.58 at.% Fe5Gd, 16.22 at.% Fe9Gd, 1.87 at.% Fe2Gd, and 39.49 at.% β-Fe17Gd2. The average nanohardness of the primary dendrite phase and the matrix phases were 8.7 GPa and 9.3 GPa, respectively. The fatigue limit of the matrix phase was approximately 37% higher than that of the primary dendrite phase. The dynamic nanoindentation method is useful for identifying local phases and for analyzing local mechanical properties.

  13. Morphology, microstructure, and mechanical properties of laser-welded joints in GH909 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chunming; Cai, Yuanzheng; Hu, Chongjing; Zhang, Xiong; Yan, Fei; Hu, Xiyuan [Huazhong University of Science and Technology, Wuhan (China)

    2017-05-15

    The experimental laser welding of GH909 alloy was conducted in this study. The morphology, microstructure, and mechanical properties of laser-welded joints were analyzed by scanning electron microscopy, energy diffraction spectroscopy, and other techniques. Results revealed that the microstructure of the welded joints mainly consisted of tiny cellular structures, dendritic structures, and equiaxed crystals. Pores appeared in the interdendritic regions because of the insufficient local feeding of molten metal during solidification. Nb segregation in the heat-affected zone caused liquation cracking, whereas C segregation further induced the formation of carbide precipitates along the grain boundaries during the welding thermal cycle. The instability of the keyhole significantly promoted the escape of the metal vapor/plasma from the hole; as a result, porosity defects formed in the weld. The average tensile strength of the test joints was 756 MPa, which is 93.1 % of that of the base metal. The average microhardness of the weld zone (250 HV) was higher than that of the GH909 alloy substrate (208 HV), peaking at 267 HV. Microcracks appeared along the grain boundaries, proving that the grain boundaries were the weakest areas in the joint.

  14. The dissimilar brazing of Kovar alloy to SiCp/Al composites using silver-based filler metal foil

    Science.gov (United States)

    Wang, Peng; Xu, Dongxia; Zhai, Yahong; Niu, Jitai

    2017-09-01

    Aluminum metal matrix composites with high SiC content (60 vol.% SiCp/Al MMCs) were surface metallized with a Ni-P alloy coating, and vacuum brazing between the composites and Kovar alloy were performed using rapidly cooled Ag-22.0Cu-15.9In-10.86Sn-1.84Ti (wt%) foil. The effects of Ni-P alloy coating and brazing parameters on the joint microstructures and properties were researched by SEM, EDS, and single lap shear test, respectively. Results show that Ag-Al intermetallic strips were formed in the 6063Al matrix and filler metal layer because of diffusion, and they were arranged regularly and accumulated gradually as the brazing temperature was increased ( T/°C = 550-600) or the soaking time was prolonged ( t/min = 10-50). However, excessive strips would destroy the uniformity of seams and lead to a reduced bonding strength (at most 70 MPa). Using a Ni-P alloy coating, void free joints without those strips were obtained at 560 °C after 20 min soaking time, and a higher shear strength of 90 MPa was achieved. The appropriate interface reaction ( 2 μm transition layer) that occurred along the Ni-P alloy coating/filler metal/Kovar alloy interfaces resulted in better metallurgical bonding. In this research, the developed Ag-based filler metal was suitable for brazing the dissimilar materials of Ni-P alloy-coated SiCp/Al MMCs and Kovar alloy, and capable welding parameters were also broadened.

  15. The characteristics of aluminum-scandium alloys processed by ECAP

    International Nuclear Information System (INIS)

    Venkateswarlu, K.; Rajinikanth, V.; Ray, Ajoy Kumar; Xu Cheng; Langdon, Terence G.

    2010-01-01

    Aluminum-scandium alloys were prepared having different scandium additions of 0.2, 1.0 and 2.0 wt.% and these alloys were processed by equal-channel angular pressing (ECAP) at 473 K. The results show the grain refinement of the aluminum matrix and the morphology of the Al 3 Sc precipitates depends strongly on the scandium concentration. The tensile properties were evaluated after ECAP by pulling to failure at initial strain rates from 1.0 x 10 -3 to 1.0 x 10 -1 s -1 . The Al-1% Sc alloy exhibited the highest tensile strength of ∼250 MPa at a strain rate of 1.0 x 10 -1 s -1 . This alloy also exhibited a superior grain refinement of ∼0.4 μm after ECAP where this is attributed to a smaller initial grain size and an optimum volume fraction of dispersed Al 3 Sc precipitates having both micrometer and nanometer sizes.

  16. Effect of Cr and Mn addition and heat treatment on AlSi3Mg casting alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tocci, Marialaura, E-mail: m.tocci@unibs.it [Department of Mechanical and Industrial Engineering, University of Brescia, Via Branze 38, 25123 Brescia (Italy); Donnini, Riccardo, E-mail: riccardo.donnini@cnr.it [National Research Council of Italy (CNR), Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), Via R. Cozzi 53, 20125 Milan (Italy); Angella, Giuliano, E-mail: giuliano.angella@cnr.it [National Research Council of Italy (CNR), Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), Via R. Cozzi 53, 20125 Milan (Italy); Pola, Annalisa, E-mail: annalisa.pola@unibs.it [Department of Mechanical and Industrial Engineering, University of Brescia, Via Branze 38, 25123 Brescia (Italy)

    2017-01-15

    In the present paper the effect of heat treatment on an AlSi3Mg alloy with and without Cr and Mn addition was investigated. Beside the well-known modification of the morphology of Fe-containing intermetallics, it was found that Cr and Mn allowed the formation of dispersoids in the aluminium matrix after solution heat treatment at 545 °C, as shown by scanning transmission electron microscope observations. These particles were responsible of the enhanced Vickers microhardness of the aluminium matrix in comparison with the base alloy after solution treatment and quenching, according to dispersion hardening mechanism. The presence of these particles was not affected by ageing treatment, which instead allowed the precipitation of β-Mg{sub 2}Si, as shown by the elaboration of differential scanning calorimeter curves. The formation of dispersoids and the study of their effect on mechanical properties can represent an interesting development for applications at high temperatures of casting alloys due to their thermal stability compared to other strengthening phases as β-Mg{sub 2}Si. - Highlights: •Cr and Mn successfully modified the morphology of Fe-containing intermetallics. •Cr- and Mn-dispersoids formed in the aluminium matrix during solution treatment. •Dispersion hardening was detected after solution treatment for Cr-containing alloy. •The dispersion hardening effect was maintained after ageing treatment.

  17. Three body abrasion of laser surface alloyed aluminium AA1200

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2012-06-01

    Full Text Available Laser surface alloying of aluminium AA1200 was performed with a 4 kW Nd:YAG laser to improve the abrasion wear resistance. Aluminium surfaces reinforced with metal matrix composites and intermetallic phases were achieved. The phases present depended...

  18. Atomic displacements in dilute alloys of Cr, Nb and Mo

    Indian Academy of Sciences (India)

    physics pp. 497–514. Atomic displacements in dilute alloys of Cr, Nb and Mo ... used to calculate dynamical matrix and the impurity-induced forces up to second nearest ... origin, the lattice is strained, and the host atoms get displaced to new ...

  19. High Temperature Deformation Mechanism in Hierarchical and Single Precipitate Strengthened Ferritic Alloys by In Situ Neutron Diffraction Studies.

    Science.gov (United States)

    Song, Gian; Sun, Zhiqian; Li, Lin; Clausen, Bjørn; Zhang, Shu Yan; Gao, Yanfei; Liaw, Peter K

    2017-04-07

    The ferritic Fe-Cr-Ni-Al-Ti alloys strengthened by hierarchical-Ni 2 TiAl/NiAl or single-Ni 2 TiAl precipitates have been developed and received great attentions due to their superior creep resistance, as compared to conventional ferritic steels. Although the significant improvement of the creep resistance is achieved in the hierarchical-precipitate-strengthened ferritic alloy, the in-depth understanding of its high-temperature deformation mechanisms is essential to further optimize the microstructure and mechanical properties, and advance the development of the creep resistant materials. In the present study, in-situ neutron diffraction has been used to investigate the evolution of elastic strain of constitutive phases and their interactions, such as load-transfer/load-relaxation behavior between the precipitate and matrix, during tensile deformation and stress relaxation at 973 K, which provide the key features in understanding the governing deformation mechanisms. Crystal-plasticity finite-element simulations were employed to qualitatively compare the experimental evolution of the elastic strain during tensile deformation at 973 K. It was found that the coherent elastic strain field in the matrix, created by the lattice misfit between the matrix and precipitate phases for the hierarchical-precipitate-strengthened ferritic alloy, is effective in reducing the diffusional relaxation along the interface between the precipitate and matrix phases, which leads to the strong load-transfer capability from the matrix to precipitate.

  20. Microstructure and erosive wear behaviors of Ti6Al4V alloy treated by plasma Ni alloying

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.X.; Wu, H.R.; Shan, X.L.; Lin, N.M.; He, Z.Y., E-mail: tyuthzy@126.com; Liu, X.P.

    2016-12-01

    Graphical abstract: The Ni modified layers were prepared on the surface of Ti6Al4V substrate by the plasma surface alloying technique. The surface and cross-section morphology, element concentration and phase composition were investigated by thermal field emission scanning electron microscopy (SEM), and glow discharge optical emission spectroscopy (GDOES), X-ray diffraction (XRD), respectively. The cross-section nano-scale hardness of Ni modified layer was measured by nano indenter. The results showed that Ni modified layers exhibited triple layers structure and continuous gradient distribution of the concentration. From the surface to the matrix, they were 2 μm Ni deposition layer, 8 μm Ni-rich alloying layer including the phases of Ni{sub 3}Ti, NiTi, Ti{sub 2}Ni, AlNi{sub 3} and 24 μm Ni-poor alloying layer forming the solid solution of nickel. With increasing of the thickness of Ni modified layer, the microhardness increased first, reached the climax, then gradient decreased. The erosion tests were performed on the surface of the untreated and treated Ti6Al4V sample using MSE (Micro-slurry-jet Erosion) method. The experiment results showed that the wear rate of every layer showed different value, and the Ni-rich alloying layer was the lowest. The strengthening mechanism of Ni modified layer was also discussed. - Highlights: • The Ni modified layers were prepared by the plasma surface alloying technique. • Triple layers structure was prepared. • Using Micro-slurry-jet Erosion method. • The erosion rate of Ni modified layer experienced the process of descending first and then ascending. • Improvement of erosion resistance performance of Ni-rich alloying layer was prominent. The wear mechanism of Ni modified layer showed micro-cutting wearing. - Abstract: The Ni modified layers were prepared on the surface of Ti6Al4V substrate by the plasma surface alloying technique. The surface and cross-section morphology, element concentration and phase composition

  1. Kinetics of radiation-induced precipitation at the alloy surface

    Science.gov (United States)

    Lam, N. Q.; Nguyen, T.; Leaf, G. K.; Yip, S.

    1988-05-01

    Radiation-induced precipitation of a new phase at the surface of an alloy during irradiation at elevated temperatures was studied with the aid of a kinetic model of segregation. The preferential coupling of solute atoms with the defect fluxes gives rise to a strong solute enrichment at the surface, which, if surpassing the solute solubility limit, leads to the formation of a precipitate layer. The moving precipitate/matrix interface was accommodated by means of a mathematical scheme that transforms spatial coordinates into a reference frame in which the boundaries are immobile. Sample calculations were performed for precipitation of the γ'-Ni 3Si layer on Ni-Si alloys undergoing electron irradiation. The dependences of the precipitation kinetics on the defect-production rate, irradiation temperature, internal defect sink concentration and alloy composition were investigated systematically.

  2. Evolution of Fe environments in mechanically alloyed Fe–Nb–(B) compositions

    Energy Technology Data Exchange (ETDEWEB)

    Blázquez, J.S., E-mail: jsebas@us.es; Ipus, J.J.; Conde, C.F.; Conde, A.

    2014-12-05

    Highlights: • Nb is rapidly incorporated to the nanocrystalline FeNb(B) matrix. • B inclusions remains even after long milling times. • B is helpful to enhance the comminuting of crystallites. - Abstract: Nanocrystalline alloys of nominal composition Fe{sub 85}Nb{sub 5}B{sub 10} were produced by mechanical alloying from a mixture of elemental powders. Two commercial boron structures were used: amorphous and crystalline. In addition, a third composition Fe{sub 94.4}Nb{sub 5.6} was prepared for comparison. X-ray diffraction and Mössbauer spectroscopy were used to describe the evolution of the microstructure and Fe environments as a function of the milling time. Whereas Nb is rapidly incorporated into the nanocrystalline matrix, boron inclusions remain even after long milling times. The presence of boron is found to enhance the comminuting of crystallites.

  3. Thermal creep properties of alloy D9 stainless steel and 316 stainless steel fuel clad tubes

    International Nuclear Information System (INIS)

    Latha, S.; Mathew, M.D.; Parameswaran, P.; Bhanu Sankara Rao, K.; Mannan, S.L.

    2008-01-01

    Uniaxial thermal creep rupture properties of 20% cold worked alloy D9 stainless steel (alloy D9 SS) fuel clad tubes for fast breeder reactors have been evaluated at 973 K in the stress range 125-250 MPa. The rupture lives were in the range 90-8100 h. The results are compared with the properties of 20% cold worked type 316 stainless steel (316 SS) clad tubes. Alloy D9 SS were found to have higher creep rupture strengths, lower creep rates and lower rupture ductility than 316 SS. The deformation and damage processes were related through Monkman Grant relationship and modified Monkman Grant relationship. The creep damage tolerance parameter indicates that creep fracture takes place by intergranular cavitation. Precipitation of titanium carbides in the matrix and chromium carbides on the grain boundaries, dislocation substructure and twins were observed in transmission electron microscopic investigations of alloy D9 SS. The improvement in strength is attributed to the precipitation of fine titanium carbides in the matrix which prevents the recovery and recrystallisation of the cold worked microstructure

  4. Microstructure and mechanical properties of Al-Si-X alloys fabricated by gas atomization and extrusion process

    International Nuclear Information System (INIS)

    Lee, T.H.; Hong, S.J.

    2009-01-01

    In order to develop good wear resistant and high-strength alloys, Al 81 Si 19 alloy was reinforced with transition elements such as Ni and Ce. The solubility of Si in aluminum was amplified, with increasing the Ni and Ce content in the rapidly solidified powders. The extruded bars consist of homogeneously dispersed fine Si particles along with Al 3 Ni and Al 3 Ce compounds (30-120 nm) in aluminum matrix (grain size below 500 nm). The tensile strength at room temperature for Al 81 Si 19 , Al 78 Si 19 Ni 2 Ce 0.5 and Al 76 Si 19 Ni 4 Ce 1 bars extruded at 400 deg. C was estimated as 281, 521, and 668 MPa, respectively. In addition, the maximum tensile strength of 730 MPa was attained in Al 73 Si 19 Ni 7 Ce 1 bulk alloy. The uniform dispersion of precipitates (Si, Al 3 Ni and Al 3 Ce particles) from the supersaturated Al matrix of ternary and quaternary alloys after extrusion was effective for enhanced mechanical properties.

  5. Production and Characterization of WC-Reinforced Co-Based Superalloy Matrix Composites

    Science.gov (United States)

    Özgün, Özgür; Dinler, İlyas

    2018-05-01

    Cobalt-based superalloy matrix composite materials were produced through the powder metallurgy technique using element powders at high purity and nano-sized wolfram carbide (WC) reinforcement in this study. An alloy that had the same chemical composition as the Stellite 6 alloy but not containing carbon was selected as the matrix alloy. The powder mixtures obtained as a result of mixing WC reinforcing member and element powders at the determined ratio were shaped by applying 300 MPa of pressure. The green components were sintered under argon atmosphere at 1240 °C for 120 minutes. The densities of the sintered components were determined by the Archimedes' principle. Microstructural characterization was performed via X-ray diffraction analysis, scanning electron microscope examinations, and energy-dispersive spectrometry. Hardness measurements and tensile tests were performed for determining mechanical characteristics. The relative density values of the sintered components increased by increasing the WC reinforcement ratio and they could almost reach the theoretical density. It was determined from the microstructural examinations that the composite materials consisted of fine and equiaxed grains and coarse carbides demonstrating a homogeneous dispersion along the microstructure at the grain boundaries. As it was the case in the density values, the hardness and strength values of the composites increased by increasing the WC ratio.

  6. Analytical model of radiation-induced precipitation at the surface of dilute binary alloy

    Science.gov (United States)

    Pechenkin, V. A.; Stepanov, I. A.; Konobeev, Yu. V.

    2002-12-01

    Growth of precipitate layer at the foil surface of an undersaturated binary alloy under uniform irradiation is treated analytically. Analytical expressions for the layer growth rate, layer thickness limit and final component concentrations in the matrix are derived for coherent and incoherent precipitate-matrix interfaces. It is shown that the high temperature limit of radiation-induced precipitation is the same for both types of interfaces, whereas layer thickness limits are different. A parabolic law of the layer growth predicted for both types of interfaces is in agreement with experimental data on γ '-phase precipitation at the surface of Ni-Si dilute alloys under ion irradiation. Effect of sputtering on the precipitation rate and on the low temperature limit of precipitation under ion irradiation is discussed.

  7. Vacuum brazing of electroless Ni-P alloy-coated SiCp/Al composites using aluminum-based filler metal foil

    Science.gov (United States)

    Wang, Peng; Xu, Dongxia; Niu, Jitai

    2016-12-01

    Using rapidly cooled (Al-10Si-20Cu-0.05Ce)-1Ti (wt%) foil as filler metal, the research obtained high-performance joints of electroless Ni-P alloy-coated aluminum matrix composites with high SiC particle content (60 vol%, SiCp/Al-MMCs). The effect of brazing process on joint properties and the formation of Al-Ni and Al-Cu-Ni intermetallic compounds were investigated, respectively. Due to the presence of Ni-P alloy coating, the wettability of liquid filler metal on the composites was improved obviously and its contact angle was only 21°. The formation of Al3Ni2 and Al3(CuNi)2 intermetallic compounds indicated that well metallurgical bonding occurred along the 6063Al matrix alloy/Ni-P alloy layer/filler metal foil interfaces by mutual diffusion and dissolution. And the joint shear strength increased with increasing the brazing temperature from 838 to 843 K or prolonging the soaking time from 15 to 35 min, while it decreased a lot because of corrosion occurring in the 6063Al matrix at high brazing temperature of 848 K. Sound joints with maximum shear strength of 112.5 MPa were obtained at 843 K for soaking time of 35 min. In this research, the beneficial effect of surface metallization by Ni-P alloy deposits on improving wettability on SiCp/Al-MMCs was demonstrated, and capable welding parameters were broadened as well.

  8. High strength tungsten heavy alloys with molybdenum additions

    International Nuclear Information System (INIS)

    Bose, A.; Sims, D.M.; German, R.M.

    1987-01-01

    Tungsten heavy alloys are candidates for numerous applications based on the unique combination of high density, high strength, and high ductility coupled with excellent machinability. Though there has been considerable research on heavy alloys, the primary focus has been on the ductility. These alloys are well suited for ballistic uses due to their high densities and it is expected that for superior ballistic performance, a high hardness, high strength and moderate ductility alloy would be ideal. The major goal of this investigation was to obtain heavy alloys with hardness greater than HRA 72. It is evident from the phase diagrams that molybdenum, which goes into solution in tungsten, nickel and iron, could act as a potential strengthening addition. With this in view, tungsten heavy alloys with molybdenum additions were fabricated from mixed elemental powders. A baseline composition of 90W-7Ni-3Fe was chosen to its good elongation and moderate strength. The molybdenum additions were made by replacing the tungsten. Compared to the baseline properties with no molybdenum addition, the strength and hardness showed a continuous increase with molybdenum addition. The ductility of the alloy continued to decrease with increasing molybdenum content, but even with 16% wt. % molybdenum of the elongation was still around 6%. An interesting facet of these alloying additions is the grain refinement that is brought about by adding to molybdenum to the system. The grain refinement is related to the lower solubility of tunbsten in the matrix due to partial displacement by molybdenum

  9. Influence of Thin-Film Adhesives in Pullout Tests Between Nickel-Titanium Shape Memory Alloy and Carbon Fiber-Reinforced Polymer Matrix Composites

    Science.gov (United States)

    Quade, Derek J.; Jana, Sadhan; McCorkle, Linda S.

    2018-01-01

    Strips of nickel-titanium (NiTi) shape memory alloy (SMA) and carbon fiber-reinforced polymer matrix composite (PMC) were bonded together using multiple thin film adhesives and their mechanical strengths were evaluated under pullout test configuration. Tensile and lap shear tests were conducted to confirm the deformation of SMAs at room temperature and to evaluate the adhesive strength between the NiTi strips and the PMC. Optical and scanning electron microscopy techniques were used to examine the interfacial bonding after failure. Simple equations on composite tensile elongation were used to fit the experimental data on tensile properties. ABAQUS models were generated to show the effects of enhanced bond strength and the distribution of stress in SMA and PMC. The results revealed that the addition of thin film adhesives increased the average adhesive strength between SMA and PMC while halting the room temperature shape memory effect within the pullout specimen.

  10. Precipitation behavior and grain refinement of burnishing Al-Zn-Mg alloy

    Directory of Open Access Journals (Sweden)

    Ce Pang

    2018-02-01

    Full Text Available Burnishing is a unique strengthening approach to improve the strength of surface layer and remains the ductility of the interior of metallic materials. In this work, burnishing treatment was employed to improve the surface microstructure of naturally aged Al-Zn-Mg alloys after solid solution. Transmission electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction and nano-indentation were used to characterize the effects of the burnishing on the microstructures of surface layer and Guinier-Preston (GP zones. It was indicated that GP zones uniformly distributed and dispersed in the matrix before burnishing, and the amount of GP zones decreased dramatically after burnishing processing. Additionally, the grains in the surficial layer were refined into nano-crystals with an average grain size of 78 nm. Burnishing treatment not only led to formation of large number of dislocation substructures in the sub-surface and near-matrix surface, but also promoted the precipitation of metastable η' phase at grain boundaries. The synergistic effects of the grain refinement, dislocation multiplication and the precipitation of η' phase strengthen the burnished layer of Al-Zn-Mg alloy. Keywords: Al-Zn-Mg alloy, Burnishing, Nano-crystal, Precipitation, Grain refinement

  11. The thermochemical behavior of some binary shape memory alloys by high temperature direct synthesis calorimetry

    International Nuclear Information System (INIS)

    Meschel, S.V.; Pavlu, J.; Nash, P.

    2011-01-01

    Research highlights: → We studied 14 shape memory alloys. → The enthalpies of formation and structure characteristics are summarized. → Theoretical predictions by ab initio calculations compare better with experimental measurements than Miedema's semi empirical model. - Abstract: The standard enthalpies of formation of some shape memory alloys have been measured by high temperature direct synthesis calorimetry at 1373 K. The following results (in kJ/mol of atoms) are reported: CoCr (-0.3 ± 2.9); CuMn (-3.7 ± 3.2); Cu 3 Sn (-10.4 ± 3.1); Fe 2 Tb (-5.5 ± 2.4); Fe 2 Dy (-1.6 ± 2.9); Fe 17 Tb 2 (-2.1 ± 3.1); Fe 17 Dy 2 (-5.3 ± 1.7); FePd 3 (-16.0 ± 2.7); FePt (-23.0 ± 1.9); FePt 3 (-20.7 ± 2.3); NiMn (-24.9 ± 2.6); TiNi (-32.7 ± 1.0); TiPd (-60.3 ± 2.5). The results are compared with some earlier experimental values obtained by calorimetry and by EMF technique. They are also compared with predicted values on the basis of the semi empirical model of Miedema and co-workers and with ab initio calculations when available. We will also assess the available information regarding the structures of these alloys.

  12. Fabrication and Characterization of FeNiCr Matrix-TiC Composite for Polishing CVD Diamond Film

    Institute of Scientific and Technical Information of China (English)

    Zhuji Jin; Zewei Yuan; Renke Kang; Boxian Dong

    2009-01-01

    Dynamic friction polishing (DFP) is one of the most promising methods appropriate for polishing CVD diamond film with high efficiency and low cost.By this method CVD diamond film is polished through being simply pressed against a metal disc rotating at a high speed utilizing the thermochemical reaction occurring as a result of dynamic friction between them in the atmosphere.However, the relatively soft materials such as stainless steel, cast iron and nickel alloy widely used for polishing CVD diamond film are easy to wear and adhere to diamond film surface, which may further lead to low efficiency and poor polishing quality.In this paper, FeNiCr matrix-TiC composite used as grinding wheel for polishing CVD diamond film was obtained by combination of mechanical alloying (MA) and spark plasma sintering (SPS).The process of ball milling,composition, density, hardness, high-temperature oxidation resistance and wear resistance of the sintered piece were analyzed.The results show that TiC was introduced in MA-SPS process and had good combination with FeNiCr matrix and even distribution in the matrix.The density of composite can be improved by mechanical alloying.The FeNiCr matrix-TiC composite obtained at 1273 K was found to be superior to at 1173 K sintering in hardness, high-temperature oxidation resistance and wearability.These properties are more favorable than SUS304 for the preparation of high-performance grinding wheel for polishing CVD diamond film.

  13. Fatigue characteristics of sand-cast AZ91D magnesium alloy

    Directory of Open Access Journals (Sweden)

    Zhenming Li

    2017-03-01

    Full Text Available The fatigue characteristics of the AZ91D-T6 alloy samples taken from engine blocks have been investigated at 20 °C and elevated temperature (150 °C. The fatigue strength and cyclic stress amplitude of the alloy significantly decrease with the increase of the test temperature, although cyclic hardening occurs continuously until failure for both temperatures. With the increase of the temperature, the decreased fatigue life of the alloy tested at the same stress amplitude is mainly attributed to the decreased matrix strength and the increased hysteresis energies. Fatigue failure of the engine blocks made of AZ91D-T6 alloy is mainly controlled by casting defects. For the defect-free specimens, the crack initiation behavior is determined by the single-slip (20 °C and by environment-assisted cyclic slip (150 °C during fatigue, respectively. The low-cycle fatigue lives of the alloy can be predicted using the Coffin-Manson relation and Basquin laws, the three-parameter equation and the energy-based concepts, while the high-cycle fatigue lives of the alloy fitted well with the developed long crack life model and MSF life models.

  14. Pseudo-elasticity and shape memory effect on the TiNiCoV alloy

    International Nuclear Information System (INIS)

    Hsu, S.E.; Yeh, M.T.; Hsu, I.C.; Chang, S.K.; Dai, Y.C.; Wang, J.Y.

    2000-01-01

    Unlike most of the structural intermetallic compound, TiNi is an exceptional case of inherent ductility. Besides its amusing behavior of high damping capacity due to martensitic transformation, the duel properties of shape memory and pseudo-elasticity co-exhibited in the same V and Co-modified TiNi-SMA at various temperature will attract another attention in modern manufacturing technology. The objective of this paper is to investigate the pseudo-elasticity and strain rate effect on TiNiCoV-SMA. The presence of dual behavior of super-elasticity and shape memory effect is technological significant for application of advanced materials on the structural component. An illustration of application of TiNiCoV shape memory alloy on the face of golf club head will be presented in this paper. (orig.)

  15. Corrosion behaviors of Mg and its alloys with different Al contents in a modified simulated body fluid

    International Nuclear Information System (INIS)

    Wen Zhaohui; Wu Changjun; Dai Changsong; Yang Feixia

    2009-01-01

    The corrosion behaviors of pure magnesium (Mg) and three Mg alloys with different Al contents were investigated in a modified simulated body fluid (m-SBF) through immersion tests, Tafel experiments, and electrochemical impedance spectroscopic (EIS) experiments. The immersion results show that the corrosion rates (CRs) of the four samples were in an order of AZ91D ct ) of the three magnesium alloys initially increased and then decreased while the R ct of pure Mg was kept lower within 24 h. The results of a scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) show that pure Mg and three alloys were heterogeneously corroded in the m-SBF. The corrosion of pure Mg, which showed a more uniform corrosion appearance, resulted from localized corrosion over the entire surface. Alloy AZ91D (of 8.5-9.5 wt.% Al) showed relatively uniform corrosion morphology and the β-Mg 12 Al 17 precipitates in alloy AZ91D were more homogeneously and continuously distributed along the grain boundaries. Obvious corrosion pits were found on the surface of alloy AZ61 and AZ31. The corrosion pits of alloy AZ61 were shallower than those of alloy AZ31. Alloy AZ61 (of 5.8-7.2 wt.% Al) possessed more Al 8 Mn 5 and a little β-Mg 12 Al 17 presented along the grain boundary heterogeneously and discontinuously. Al 8 Mn 5 was the main phase of the AZ31 alloy (of 2.5-3.5 wt.% Al) dispersed into the matrix. In conclusion, the microstructure and the Al content in the α-Mg (Al) matrix significantly affected the corrosion properties of the alloys in the m-SBF. With the increase in Al content, the corrosion resistances of the samples were improved.

  16. Effect of heat treatments on the microstructure and mechanical properties of an extruded Mg{sub 95.5}Y{sub 3}Zn{sub 1.5} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Huan; Xue, Feng, E-mail: xuefeng@seu.edu.cn; Bai, Jing; Sun, Yangshan

    2013-11-15

    The microstructure and mechanical properties of the extruded Mg{sub 95.5}Y{sub 3}Zn{sub 1.5} alloy under different heat treatment were systematically investigated by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and an electronic universal testing machine. The results show that the as-extruded alloy is composed of 18R LPSO stripes and α-Mg matrix with stacking faults (SFs) in it. The fine 14H LPSO lamellas are formed in α-Mg matrix near the areas of SFs during solution treatment at 500 °C for 8 h. A great number of fine β′ phases are precipitated in the α-Mg matrix of T6-treated (aging of the T4-treated alloy at 225 °C for 24 h) and T5-treated (aging of the as-extruded alloy at 225 °C for 32 h) alloys. Moreover, the SFs which were first observed in extruded alloy are retained in T5-staged specimen, and exhibit a cross arrangement with β′ precipitates. The absence of 14H LPSO phase in T5-treated alloy indicates that the 14H structure cannot be formed during aging at 225 °C. Tensile tests reveal that the presence of 14H lamellas improves the ductility of the alloy, but decreases the strength, suggesting that the 18R LPSO stripes are more effective in strengthening the alloy than 14H LPSO lamellas. The T6-staged alloy exhibits superior comprehensive mechanical properties with ultimate tensile strength of 358 MPa, tensile yield strength of 226 MPa and elongation of 6.1% at room temperature.

  17. Application of feal intermetallic phase matrix based alloys in the turbine components of a turbocharger

    Directory of Open Access Journals (Sweden)

    J. Cebulski

    2015-01-01

    Full Text Available This paper presents a possible application of the state-of-the-art alloys based on the FeAl intermetallic phases as materials for the manufacture of heat-proof turbine components in an automobile turbocharger. The research was aimed at determining the resistance to corrosion of Fe40Al5CrTiB alloy in a gaseous environment containing 9 % O2 + 0,2 % HCl + 0,08 % SO2 + N2. First the kinetics of corrosion processes for the considered alloy were determined at the temperatures of 900 °C, 1 000 °C and 1 100 °C, which was followed by validation under operating conditions. To do so, the tests were carried out over a distance of 20 000 km. The last stage involved examination of the surfaces after the test drive. The obtained results are the basis for further research in this field.

  18. Transmission electron microscopy of aged Ti-10Mo-20Nb alloy after hot swaging; Microscopia eletronica de transmissao da liga Ti-10Mo-20Nb envelhecida apos forjamento a quente

    Energy Technology Data Exchange (ETDEWEB)

    Gabriel, Sinara Borborema, E-mail: sinarab@msn.com [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Baldan, Renato, E-mail: renatobaldan@gmail.com [Universidade de Sao Paulo (EEL/USP), Lorena, SP (Brazil). Escola de Engenharia; Torres, Juliana; Oliveira, Nathalia Rodrigues, E-mail: juliana_torres_5@hotmail.com, E-mail: nathalia_roliveira@yahoo.com.br [Centro Universitario de Volta Redonda (UNIFOA), Volta Redonda, RJ (Brazil); Nunes, Carlos Angelo; Mei, Paulo Roberto, E-mail: cnunes@demar.eel.usp.br, E-mail: pmei@fem.unicamp.br [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil)

    2014-08-15

    Ti alloys are widely used in biomedical applications. Within this class, metastable β -Ti alloys stand, because through thermomechanical processing it is possible to obtain mechanical properties and in particular one suitable Young's modulus for biomedical applications. These alloys require high mechanical strength and a low Young's modulus to avoid stress shielding. Preliminary studies showed that the microstructure of the Ti-10Mo- 20Nb alloy after cold forging and aging 500 °C/24 h consisted in bimodal distribution of α phase in the β matrix. The aim of this study was to characterize the microstructure of Ti-10Mo-20Nb alloy after hot forging and aging at 500 °C for 24 hours. Microstructural characterization consisted of analyzes by X-ray diffraction and transmission electron microscopy. According to the results, while the cold forging resulted in a bimodal α distribution in the β matrix, hot forging resulted in a thin and homogeneous α precipitation in the β matrix. (author)

  19. exploration the extrudability of aluminum matrix composite (lm6/tic)

    African Journals Online (AJOL)

    lanez

    2017-11-24

    Nov 24, 2017 ... Aluminum matrix composites (LM6/TiC) is a mix of excellent properties of aluminum casting alloy (LM6), and particles of (TiC) which make it the first choice in many applications like airplane and marine industries. During this research the extrudability and mechanical specifications of this composite ...

  20. High-temperature mechanical properties and fracture mechanisms of Al–Si piston alloy reinforced with in situ TiB{sub 2} particles

    Energy Technology Data Exchange (ETDEWEB)

    Han, Gang [School of Mechanical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081 (China); Zhang, Weizheng, E-mail: zhangwz@bit.edu.cn [School of Mechanical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081 (China); Zhang, Guohua; Feng, Zengjian; Wang, Yanjun [Shandong Binzhou Bohai Piston Co., Ltd., Binzhou 256602 (China)

    2015-05-01

    In order to assess the high-temperature performance of aluminum–silicon alloy reinforced with titanium diboride particles as potential piston material, the tensile behaviors and fracture mechanisms of in situ 4 wt% TiB{sub 2}/Al–Si composite were investigated in the temperature range 25–350 °C. The tensile results revealed that the composite exhibited higher modulus than the matrix alloy at all testing temperatures, but both the matrix alloy and the composite presented similar strength levels above 200 °C. The ductility of the composite was found to be lower than that of the unreinforced matrix alloy at 25 and 200 °C, but no obvious distinction was observed at 350 °C. The effects of temperature and the presence of TiB{sub 2} particles on tensile properties of the composite had been evaluated. Fractographic morphology studies were done using scanning electron microscope, which indicated that the fracture of the composite altered from brittle to ductile mode with temperature increasing. At 25 and 200 °C, fracture was dominated by cracked silicon particles and separated TiB{sub 2} particles, while decohesion at particle–matrix interface was prevalent at 350 °C. Analysis of the fracture surfaces also showed that regions of clustered TiB{sub 2} particles were found to be the locations prone to damage in the composite at both room and high temperatures.