High pressure die casting of Fe-based metallic glass

Science.gov (United States)

Ramasamy, Parthiban; Szabo, Attila; Borzel, Stefan; Eckert, Jürgen; Stoica, Mihai; Bárdos, András

2016-01-01

Soft ferromagnetic Fe-based bulk metallic glass key-shaped specimens with a maximum and minimum width of 25.4 and 5 mm, respectively, were successfully produced using a high pressure die casting (HPDC) method, The influence of die material, alloy temperature and flow rate on the microstructure, thermal stability and soft ferromagnetic properties has been studied. The results suggest that a steel die in which the molten metal flows at low rate and high temperature can be used to produce completely glassy samples. This can be attributed to the laminar filling of the mold and to a lower heat transfer coefficient, which avoids the skin effect in the steel mold. In addition, magnetic measurements reveal that the amorphous structure of the material is maintained throughout the key-shaped samples. Although it is difficult to control the flow and cooling rate of the molten metal in the corners of the key due to different cross sections, this can be overcome by proper tool geometry. The present results confirm that HPDC is a suitable method for the casting of Fe-based bulk glassy alloys even with complex geometries for a broad range of applications. PMID:27725780

High pressure die casting of Fe-based metallic glass.

Science.gov (United States)

Ramasamy, Parthiban; Szabo, Attila; Borzel, Stefan; Eckert, Jürgen; Stoica, Mihai; Bárdos, András

2016-10-11

Soft ferromagnetic Fe-based bulk metallic glass key-shaped specimens with a maximum and minimum width of 25.4 and 5 mm, respectively, were successfully produced using a high pressure die casting (HPDC) method, The influence of die material, alloy temperature and flow rate on the microstructure, thermal stability and soft ferromagnetic properties has been studied. The results suggest that a steel die in which the molten metal flows at low rate and high temperature can be used to produce completely glassy samples. This can be attributed to the laminar filling of the mold and to a lower heat transfer coefficient, which avoids the skin effect in the steel mold. In addition, magnetic measurements reveal that the amorphous structure of the material is maintained throughout the key-shaped samples. Although it is difficult to control the flow and cooling rate of the molten metal in the corners of the key due to different cross sections, this can be overcome by proper tool geometry. The present results confirm that HPDC is a suitable method for the casting of Fe-based bulk glassy alloys even with complex geometries for a broad range of applications.

High pressure die casting of Fe-based metallic glass

Science.gov (United States)

Ramasamy, Parthiban; Szabo, Attila; Borzel, Stefan; Eckert, Jürgen; Stoica, Mihai; Bárdos, András

2016-10-01

Soft ferromagnetic Fe-based bulk metallic glass key-shaped specimens with a maximum and minimum width of 25.4 and 5 mm, respectively, were successfully produced using a high pressure die casting (HPDC) method, The influence of die material, alloy temperature and flow rate on the microstructure, thermal stability and soft ferromagnetic properties has been studied. The results suggest that a steel die in which the molten metal flows at low rate and high temperature can be used to produce completely glassy samples. This can be attributed to the laminar filling of the mold and to a lower heat transfer coefficient, which avoids the skin effect in the steel mold. In addition, magnetic measurements reveal that the amorphous structure of the material is maintained throughout the key-shaped samples. Although it is difficult to control the flow and cooling rate of the molten metal in the corners of the key due to different cross sections, this can be overcome by proper tool geometry. The present results confirm that HPDC is a suitable method for the casting of Fe-based bulk glassy alloys even with complex geometries for a broad range of applications.

The effects of Ni substitution on the magnetic properties of as-cast and annealed Fe-Co amorphous alloy wires

International Nuclear Information System (INIS)

Pinitsoontorn, S.; Badini Confalonieri, G.A..; Davies, H.A.; Gibbs, M.R.J.

2005-01-01

Amorphous alloy wires of composition (Co x Fe y Ni z ) 72.5 Si 12.5 B 15 , with Ni substituted for both Co and Fe, were prepared by the rotating water bath chill cast technique. The maximum Ni content that can be substituted in order to cast amorphous wire is reported. The effects of Ni addition on the hysteresis loop parameters and the major magnetic properties of the as-cast wire are reported

Microstructures and mechanical properties of heat-treated Al–5.0Cu–0.5Fe squeeze cast alloys with different Mn/Fe ratio

Energy Technology Data Exchange (ETDEWEB)

Zhang, Weiwen, E-mail: mewzhang@scut.edu.cn; Lin, Bo; Fan, Jianlei; Zhang, Datong; Li, Yuanyuan

2013-12-20

The Al–5.0 wt% Cu–0.5 wt% Fe alloys with different Mn/Fe ratio were prepared by squeeze casting. Various test techniques, including tensile test, image analysis, scanning electron microscope (SEM), X-ray diffraction (XRD), electron probe micro-analyzer (EPMA) and transmission electron microscopy (TEM) were used to examine the microstructures and mechanical properties of the alloys in T5 heat-treated condition. The results show that the β-Fe (Al{sub 7}Cu{sub 2}Fe) is stable and its needle-like morphology is maintained after T5 heat treatment. However, the Chinese script Al{sub m}Fe, α-Fe or Al{sub 6}(FeMn) partially transform to a new Chinese script Cu-rich α(CuFe) (Al{sub 7}Cu{sub 2}Fe or Al{sub 7}Cu{sub 2}(FeMn)), which is harmful to the mechanical properties of the alloys due to the decrease of the Cu content in α(Al) matrix. The optimal Mn/Fe ratio is determined by the morphology of Fe-rich intermetallics, volume fraction of θ′ and T (Al{sub 20}Cu{sub 2}Mn{sub 3}), size of α(Al) dendrite and porosity. Excessive Mn/Fe ratio will deteriorate the mechanical properties of the alloys due to the increase of the total amount of porosity and the Fe-rich intermetallics. When the Mn/Fe ratio is 1.6 and 1.2 for the applied pressure of 0 MPa and 75 MPa, respectively, the needle-like β-Fe phase is completely converted to the Chinese script Fe-rich intermetallics. The ultimate tensile strength, yield strength and elongation of the T5 heat-treated alloy with the Mn/Fe ratio of 1.2 and applied pressure of 75 MPa reach 395 MPa, 335 MPa and 14%, respectively.

Microstructures and mechanical properties of heat-treated Al–5.0Cu–0.5Fe squeeze cast alloys with different Mn/Fe ratio

International Nuclear Information System (INIS)

Zhang, Weiwen; Lin, Bo; Fan, Jianlei; Zhang, Datong; Li, Yuanyuan

2013-01-01

The Al–5.0 wt% Cu–0.5 wt% Fe alloys with different Mn/Fe ratio were prepared by squeeze casting. Various test techniques, including tensile test, image analysis, scanning electron microscope (SEM), X-ray diffraction (XRD), electron probe micro-analyzer (EPMA) and transmission electron microscopy (TEM) were used to examine the microstructures and mechanical properties of the alloys in T5 heat-treated condition. The results show that the β-Fe (Al 7 Cu 2 Fe) is stable and its needle-like morphology is maintained after T5 heat treatment. However, the Chinese script Al m Fe, α-Fe or Al 6 (FeMn) partially transform to a new Chinese script Cu-rich α(CuFe) (Al 7 Cu 2 Fe or Al 7 Cu 2 (FeMn)), which is harmful to the mechanical properties of the alloys due to the decrease of the Cu content in α(Al) matrix. The optimal Mn/Fe ratio is determined by the morphology of Fe-rich intermetallics, volume fraction of θ′ and T (Al 20 Cu 2 Mn 3 ), size of α(Al) dendrite and porosity. Excessive Mn/Fe ratio will deteriorate the mechanical properties of the alloys due to the increase of the total amount of porosity and the Fe-rich intermetallics. When the Mn/Fe ratio is 1.6 and 1.2 for the applied pressure of 0 MPa and 75 MPa, respectively, the needle-like β-Fe phase is completely converted to the Chinese script Fe-rich intermetallics. The ultimate tensile strength, yield strength and elongation of the T5 heat-treated alloy with the Mn/Fe ratio of 1.2 and applied pressure of 75 MPa reach 395 MPa, 335 MPa and 14%, respectively

Characteristics of Fe-28Mn-6Si-5Cr shape memory alloy produced by centrifugal casting

International Nuclear Information System (INIS)

Otsuka, H.; Maruyama, T.; Kubo, H.

2000-01-01

Recent application of ferrous shape memory alloys, particularly Fe-Mn-Si alloys as pipe joints used for a tunnel driving technique in the field of civil engineering, requires efficient production of alloy pipes. Centrifugal casting is one of the efficient manufacturing techniques which can produce suitable sizes of pipes of approximately 4 to 14 inches in outside diameter. The mechanical properties of the centrifugally cast Fe-Mn-Si shape memory alloy were investigated to have 700 MPa in tensile strength and shape recovery of ∝3% of the initial deformation. The shape recovery achieved by the centrifugally cast materials proved to be comparable to that of the rolled materials. The TEM microstructure of the centrifugally cast materials deformed necessarily in the process of shape recovery reveals random distribution of ε (hcp) bands containing many dislocations inside, whereas the structure of the rolled materials shows ε phases containing fewer dislocations. (orig.)

Structural and magnetic properties of rapidly quenched and as-cast bulk NdFeBCu alloys

International Nuclear Information System (INIS)

Sanchez Ll, J.L.; Bustamante S, R.; Barthem, V.M.T.S.; Miranda, P.E.V. de

2005-01-01

A study of the structural and magnetic properties of as-cast and melt spun (x)Nd 2 Fe 14 B(100-x)Nd 70 Cu 30 alloys (x=10, 50 and 75%wt.) is presented. In as-cast alloys for x=10wt%. the formation of a high coercivity phase, referred to as N (T C =240 deg. C, i H C =4.9kOe) is found. N is a (Nd-Fe)-based phase with a Fe/Nd ratio lower than that of phase Nd 2 Fe 14 B (φ). It is suggested that this phase is related to the A 1 phase found in binary Nd-Fe alloys. In melt-spun alloys, at the same x value of 10wt%, another hard phase is found which is suggested to be the Nd 6 Fe 13 Cu δ-phase (T C =192 deg. C, i H C =4.8kOe). Transmission electron microscope (TEM) micrographs of the ribbons with x=10wt% shows the formation of nanograins with a non-uniform grain size distribution. In cast alloys with x=50 and 75wt% large slab-like grains of φ are formed, in the inter-granular region a Nd-Cu eutectic phase and Nd grains, are observed. High coercivities are obtained in ribbons with x=50wt% ( i H C =19.7kOe) and 75wt% ( i H C =13.0kOe). A slight reduction in the Curie temperature of the φ-phase with respect to the bulk value is found in these ribbons

Structure and mechanical properties of as-cast Ti-5Nb-xFe alloys

International Nuclear Information System (INIS)

Hsu, Hsueh-Chuan; Hsu, Shih-Kuang; Wu, Shih-Ching; Lee, Chih-Jhan; Ho, Wen-Fu

2010-01-01

In this study, as-cast Ti-5Nb and a series of Ti-5Nb-xFe alloys were investigated and compared with commercially pure titanium (c.p. Ti) in order to determine their structure and mechanical properties. The series of Ti-5Nb-xFe alloys contained an iron content ranging from 1 to 5 mass% and were prepared by using a commercial arc-melting vacuum-pressure casting system. Additionally, X-ray diffraction (XRD) for phase analysis was conducted with a diffractometer, and three-point bending tests were performed to evaluate the mechanical properties of all specimens. The fractured surfaces were observed by using scanning electron microscopy (SEM). The experimental results indicated that these alloys possessed a range of different structures and mechanical properties dependent upon the various additions of Fe. With an addition of 1 mass% Fe, retention of the metastable β phase began. However, when 4 mass% Fe or greater was added, the β phase was entirely retained with a bcc crystal structure. Moreover, the ω phase was only detected in the Ti-5Nb-2Fe, Ti-5Nb-3Fe and Ti-5Nb-4Fe alloys. The largest quantity of ω phase and the highest bending modulus were found in the Ti-5Nb-3Fe alloy. The Ti-5Nb-2Fe alloy had the lowest bending modulus, which was lower than that of c.p. Ti by 20%. This alloy exhibited the highest bending strength/modulus ratio of 26.7, which was higher than that of c.p. Ti by 214%, and of the Ti-5Nb alloy (14.4 ) by 85%. Additionally, the elastically recoverable angles of the ductile Ti-5Nb-1Fe (19.9 o ) and Ti-5Nb-5Fe (29.5 o ) alloys were greater than that of c.p. Ti (2.7 o ) by as much as 637% and 993%, respectively. Furthermore, the preliminary cell culturing results revealed that the Ti-5Nb-xFe alloys were not only biocompatible, but also supported cell attachment.

Structure and mechanical properties of as-cast Ti-5Nb-xFe alloys

Energy Technology Data Exchange (ETDEWEB)

Hsu, Hsueh-Chuan; Hsu, Shih-Kuang; Wu, Shih-Ching [Department of Dental Laboratory Technology, Central Taiwan University of Science and Technology, Taichung 40605, Taiwan (China); Institute of Biomedical Engineering and Material Science, Central Taiwan University of Science and Technology, Changhua 51591, Taiwan (China); Lee, Chih-Jhan [Department of Materials Science and Engineering, Da-Yeh University, Changhua 51591, Taiwan (China); Ho, Wen-Fu, E-mail: fujii@mail.dyu.edu.tw [Department of Materials Science and Engineering, Da-Yeh University, Changhua 51591, Taiwan (China)

2010-09-15

In this study, as-cast Ti-5Nb and a series of Ti-5Nb-xFe alloys were investigated and compared with commercially pure titanium (c.p. Ti) in order to determine their structure and mechanical properties. The series of Ti-5Nb-xFe alloys contained an iron content ranging from 1 to 5 mass% and were prepared by using a commercial arc-melting vacuum-pressure casting system. Additionally, X-ray diffraction (XRD) for phase analysis was conducted with a diffractometer, and three-point bending tests were performed to evaluate the mechanical properties of all specimens. The fractured surfaces were observed by using scanning electron microscopy (SEM). The experimental results indicated that these alloys possessed a range of different structures and mechanical properties dependent upon the various additions of Fe. With an addition of 1 mass% Fe, retention of the metastable {beta} phase began. However, when 4 mass% Fe or greater was added, the {beta} phase was entirely retained with a bcc crystal structure. Moreover, the {omega} phase was only detected in the Ti-5Nb-2Fe, Ti-5Nb-3Fe and Ti-5Nb-4Fe alloys. The largest quantity of {omega} phase and the highest bending modulus were found in the Ti-5Nb-3Fe alloy. The Ti-5Nb-2Fe alloy had the lowest bending modulus, which was lower than that of c.p. Ti by 20%. This alloy exhibited the highest bending strength/modulus ratio of 26.7, which was higher than that of c.p. Ti by 214%, and of the Ti-5Nb alloy (14.4 ) by 85%. Additionally, the elastically recoverable angles of the ductile Ti-5Nb-1Fe (19.9{sup o}) and Ti-5Nb-5Fe (29.5{sup o}) alloys were greater than that of c.p. Ti (2.7{sup o}) by as much as 637% and 993%, respectively. Furthermore, the preliminary cell culturing results revealed that the Ti-5Nb-xFe alloys were not only biocompatible, but also supported cell attachment.

Microstructure and magnetocaloric effect in cast LaFe11.5Si1.5Bx (x=0.5, 1.0)

International Nuclear Information System (INIS)

Zhang, H.; Long, Y.; Cao, Q.; Mudryk, Ya.; Zou, M.; Gschneidner, K.A.; Pecharsky, V.K.

2010-01-01

Phase formation, structure, and the magnetocaloric effect (MCE) in as-cast LaFe 11.5 Si 1.5 B x (x=0.5, 1.0) compounds have been studied. The Curie temperatures, T C , are ∼211 and 230 K for x=0.5 and 1.0, respectively, which are higher than that of annealed LaFe 11.5 Si 1.5 (T C =183 K), while the maximum magnetic entropy changes at the respective T C under a magnetic field change of 0-5 T are 7.8 and 5.8 J/(kg K). Wavelength dispersive spectrometry (WDS) analysis shows that only a small fraction of boron atoms is dissolved in the NaZn 13 -type structure phase, and that the compositions of the as-cast LaFe 11.5 Si 1.5 B x (x=0.5, 1.0) alloys are much different from the intended nominal compositions. These as-cast alloys exhibit second-order magnetic phase transitions and low MCEs. However, based on the relative cooling power, the as-cast LaFe 11.5 Si 1.5 B x alloys are promising candidates for magnetic refrigerants over a wide temperature range.

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.

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.

Anisotropic bonded Sm{sub 2.3}Fe{sub 16.8}Zr{sub 0.2}N{sub y} magnets prepared by milling of as cast material

Energy Technology Data Exchange (ETDEWEB)

Gebel, B.; Kubis, M.; Roessler, U.K.; Mueller, K.H. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany). Inst. fuer Metallische Werkstoffe

2001-07-01

As cast Sm{sub 2.3}Fe{sub 16.8}Zr{sub 0.2} material was milled for 100 min {<=} t {<=} 900 min. After annealing at 800 C for 1 h and subsequent nitrogenation, the samples were cold compacted in a magnetic field and resin bonded. The coercivity {mu}{sub 0J}H{sub C} of the samples increased from 0.59 T (t = 100 min) to 2.18 T (t = 900 min). On the other hand, the remanence along the texture axis decreased monotonically with increasing milling time due to the decrease of the degree of texture of the aligned powders. Prolonged milling leads finally to the formation of a soft magnetic phase as indicated by a shoulder in the demagnetization curve for t > 600 min. The highest energy product (BH){sub max} of 50 kJm{sup -3} (136 kJm{sup -3} for the theoretical density of 7.7 gcm{sup -3}) was obtained for an intermediate milling time of 400 min. Zn bonding of the powders resulted in magnets with lower energy products but improved coercivities. (orig.)

The Role of Carbon in Grain Refinement of Cast CrFeCoNi High-Entropy Alloys

Science.gov (United States)

Liu, X. W.; Liu, L.; Liu, G.; Wu, X. X.; Lu, D. H.; Yao, J. Q.; Jiang, W. M.; Fan, Z. T.; Zhang, W. B.

2018-06-01

As a promising engineering material, high-entropy alloys (HEAs) CrFeCoNi system has attracted extensive attention worldwide. Their cast alloys are of great importance because of their great formability of complex components, which can be further improved through the transition of the columnar to equiaxed grains and grain refinement. In the current work, the influence of C contents on the grain structures and mechanical properties of the as-cast high-entropy alloy CrFeCoNi was chosen as the target and systematically studied via a hybrid approach of the experiments and thermodynamic calculations. The alloys with various C additions were prepared by arc melting and drop cast. The as-cast macrostructure and microstructure were characterized using optical microscopy, scanning electron microscopy, and transmission electron microscopy. The cast HEAs transform from coarse columnar grains into equiaxed grains with the C level increased to ≥ 2 at. pct and the size of equiaxed grains is further decreased with the increasing C addition. It is revealed that the interdendritic segregation of Cr and C results in grain boundary precipitation of M23C6 carbides. The grain refinement is attributed to the additional constitutional supercoiling from the C addition. The yield stress and tensile strength at room temperature are improved due to the transition of columnar to equiaxed grains and grain refinement.

Evaluation of cast Ti-Fe-O-N alloys for dental applications

International Nuclear Information System (INIS)

Koike, Marie; Ohkubo, Chikahiro; Sato, Hideki; Fujii, Hideki; Okabe, Toru

2005-01-01

Good mechanical properties, biocompatibility and corrosion resistance make titanium an excellent material for biomedical applications. However, when better mechanical properties than those offered by commercially pure titanium (CPTi) are needed, Ti-6Al-4V is sometimes a good alternative. Some new titanium alloys, developed as industrial structural materials, aim at an intermediate range of strength between that of CP Ti and Ti-6Al-4V. Two of these alloys are Super-TIX800TM (Ti-1% Fe-0.35% O-0.01% N) and Super-TIX800NTM (Ti-1% Fe-0.3% O-0.04% N) (both produced by Nippon Steel Corp., Japan). Besides being stronger than CP Ti, the cost of manufacturing these alloys is reportedly lower than for Ti-6Al-4V since they do not contain any expensive elements. In addition, they are not composed of elements such as aluminum or vanadium, which have caused biocompatibility concerns in medical and dental appliances. To evaluate these alloys as candidates for dental use, it is helpful to compare them to CP Ti (ASTM Grade 2) and Ti-6Al-4V (ASTM Grade 5), which have already been employed in dentistry. We evaluated the tensile properties, mold filling capacity, corrosion characteristics and grindability of these industrial alloys prepared by investment casting. Compared to the strengths of cast CPTi, the yield strength and tensile strength of these cast alloys were more than 20% and approximately 30% higher, respectively. On the other hand, both of these properties were 30% lower than for Ti-6Al-4V. Better grindability and wear resistance were additional benefits of these new alloys for dental applications

Epitaxial Fe16N2 thin film on nonmagnetic seed layer

Science.gov (United States)

Hang, Xudong; Zhang, Xiaowei; Ma, Bin; Lauter, Valeria; Wang, Jian-Ping

2018-05-01

Metastable α″ -Fe16N2 has attracted much interest as a candidate for rare-earth-free hard magnetic materials. We demonstrate that Fe16N2 thin films were grown epitaxially on Cr seed layers with MgO (001) substrates by facing-target sputtering. Good crystallinity with the epitaxial relation MgO (001 )[110 ] ∥ Cr (001 )[100 ] ∥ Fe16N2 (001 )[100 ] was obtained. The chemical order parameter, which quantifies the degree of N ordering in the Fe16N2 (the N-disordered phase is α' -Fe8N martensite), reaches 0.75 for Cr-seeded samples. Cr has a perfect lattice constant match with Fe16N2, and no noticeable strain can be assigned to Fe16N2. The intrinsic saturation magnetization of this non-strained Fe16N2 thin film at room temperature is determined to be 2.31 T by polarized neutron reflectometry and confirmed with vibrating sample magnetometry. Our work provides a platform to directly study the magnetic properties of high purity Fe16N2 films with a high order parameter.

Production of an Amorphous Fe_<75>Si_<10>B_<15> Sheet by a Metallic Mold Casting Method and its Properties

OpenAIRE

Inoue, Akihisa; Yamamoto, Hirokazu; Saito, Takanobu; Masumoto, Tsuyosi

1993-01-01

The application of a metallic mold casting method to an Fe_Si_B_ alloy with the largest glass-forming ability in (Fe, Co, Ni)-Si-B system was found to cause the formation of a mostly single amorphous phase in a sheet form with a thickness of 0.1 mm. No distinct difference in thermal stability (crystallization temperature and heat of crystallization), hardness, Curie temperature and magnetization is detected between the as-cast sheet and the melt-spun amorphous ribbon with a thickness of 0.02 ...

Hardness and Wear Resistance of TiC-Fe-Cr Locally Reinforcement Produced in Cast Steel

Directory of Open Access Journals (Sweden)

Olejnik E.

2016-06-01

Full Text Available In order to increase wear resistance cast steel casting the TiC-Fe-Cr type composite zones were fabricated. These zones were obtained by means of in situ synthesis of substrates of the reaction TiC with a moderator of a chemical composition of white cast iron with nickel of the Ni-Hard type 4. The synthesis was carried out directly in the mould cavity. The moderator was applied to control the reactive infiltration occurring during the TiC synthesis. The microstructure of composite zones was investigated by electron scanning microscopy, using the backscattered electron mode. The structure of composite zones was verified by the X-ray diffraction method. The hardness of composite zones, cast steel base alloy and the reference samples such as white chromium cast iron with 14 % Cr and 20 % Cr, manganese cast steel 18 % Mn was measured by Vickers test. The wear resistance of the composite zone and the reference samples examined by ball-on-disc wear test. Dimensionally stable composite zones were obtained containing submicron sizes TiC particles uniformly distributed in the matrix. The macro and microstructure of the composite zone ensured three times hardness increase in comparison to the cast steel base alloy and one and a half times increase in comparison to the white chromium cast iron 20 % Cr. Finally ball-on-disc wear rate of the composite zone was five times lower than chromium white cast iron containing 20 % Cr.

Multi-layers castings

Directory of Open Access Journals (Sweden)

J. Szajnar

2010-01-01

Full Text Available In paper is presented the possibility of making of multi-layers cast steel castings in result of connection of casting and welding coating technologies. First layer was composite surface layer on the basis of Fe-Cr-C alloy, which was put directly in founding process of cast carbon steel 200–450 with use of preparation of mould cavity method. Second layer were padding welds, which were put with use of TIG – Tungsten Inert Gas surfacing by welding technology with filler on Ni matrix, Ni and Co matrix with wolfram carbides WC and on the basis on Fe-Cr-C alloy, which has the same chemical composition with alloy, which was used for making of composite surface layer. Usability for industrial applications of surface layers of castings were estimated by criterion of hardness and abrasive wear resistance of type metal-mineral.

Evolution of Fe based intermetallic phases in Al–Si hypoeutectic casting alloys: Influence of the Si and Fe concentrations, and solidification rate

International Nuclear Information System (INIS)

Gorny, Anton; Manickaraj, Jeyakumar; Cai, Zhonghou; Shankar, Sumanth

2013-01-01

Highlights: •Anomalous evolution of Fe based intermetallic phases in Al–Si–Fe alloys. •XRF coupled with nano-diffraction to confirm the nano-size Fe intermetallic phases. •Crystallography of the θ-Al 13 Fe 4 , τ 5 -Al 8 Fe 2 Si and τ 6 -Al 9 Fe 2 Si 2 phases. •Peritectic reactions involving the Fe intermetallic phases in Al–Si–Fe alloys. -- Abstract: Al–Si–Fe hypoeutectic cast alloy system is very complex and reported to produce numerous Fe based intermetallic phases in conjunction with Al and Si. This publication will address the anomalies of phase evolution in the Al–Si–Fe hypoeutectic casting alloy system; the anomaly lies in the peculiarities in the evolution and nature of the intermetallic phases when compared to the thermodynamic phase diagram predictions and past publications of the same. The influence of the following parameters, in various combinations, on the evolution and nature of the intermetallic phases were analyzed and reported: concentration of Si between 2 and 12.6 wt%, Fe between 0.05 and 0.5 wt% and solidification rates of 0.1, 1, 5 and 50 K s −1 . Two intermetallic phases are observed to evolve in these alloys under these solidification conditions: the τ 5 -Al 8 SiFe 2 and τ 6 -Al 9 Fe 2 Si 2 . The τ 5 -Al 8 SiFe 2 phase evolves at all levels of the parameters during solidification and subsequently transforms into the τ 6 -Al 9 Fe 2 Si 2 through a peritectic reaction when promoted by certain combinations of solidification parameters such as higher Fe level, lower Si level and slower solidification rates. Further, it is also hypothesized from experimental evidences that the θ-Al 13 Fe 4 binary phase precludes the evolution of the τ 5 during solidification and subsequently transforms into the τ 6 phase during solidification. These observations are anomalous to the publications as prior art and simulation predictions of thermodynamic phase diagrams of these alloys, wherein, only one intermetallic phases in the �

Dependence Of The Structure And Magnetic Properties Of Cast Plate-Shaped Nd60Fe30Al10 Samples On Their Thickness

Directory of Open Access Journals (Sweden)

Michalski B.

2015-09-01

Full Text Available The hard magnetic Nd-Fe-Al alloys are inferior to Nd-Fe-B magnets as far as the magnetic properties are concerned, but their great advantage is that they need no additional annealing to achieve good magnetic properties. These properties depend on the cooling rate from the melting state, and on the thickness of the sample - the best values are achieved at the quenching rates at which the samples have a thickness of 0.3-2 mm. The present study is concerned with the correlation between the magnetic properties of the plate-shaped Nd60Fe30Al10 samples and their size - thickness. Two casting ways: with the melt stream perpendicular direction and parallel to the surface of the plates were used. The plates were produced by pressure casting and suction casting. The studies have shown that the cooling rates depends on local propagation on liquid metal in the mold resulting in heterogeneity of structure and properties.

Effect of Fe content, cooling rate and porosity on the tensile properties of cast 319 and 356 aluminum alloys

International Nuclear Information System (INIS)

Ma, Z.; Samuel, A.M.; Samuel, F.H.; Doty, H.W.; Valtierra, S.

2002-01-01

The present study was carried out to investigate the effects of Fe content, cooling rate and porosity on the tensile properties of cast 319 and 356 alloys. Both experimental and industrial 319 alloys (containing 0.1 and 0.4 wt% Mg) and industrial 356 alloys were used, with 200-300 ppm strontium additions to study the modification effect. The Fe content was varied from 0.2 to 0.8 wt% in the 319 alloys, and from 0.1 to 0.6 wt% in the 356 alloy in keeping with Fe levels observed in industry. An end-chilled mold was employed to obtain directionally solidified castings, where the cooling rate varied with the height of the casting. Tensile and microstructural samples were sectioned at heights corresponding to dendrite arm spacings of ∼23 to ∼83 μm. The microstructures were examined using optical- and scanning electron microscopy. The effect of Fe content and cooling rate was investigated through measurements of the β-Al 5 FeSi platelets, using image analysis. Porosity measurements were also made. Phase identification was done using EPMA, EDX and XRD. The results show that the β-Al 5 FeSi platelet size has a significant effect on ductility and tensile strength up to sizes of ∼100 μm in the 319 alloys and ∼70 μm in the 356 alloy, but has no significant effect on the yield strength. While tensile properties are interpreted by means of UTS vs. log Elongation plots (after the Quality index concept of Drouzy et al. (5)), in the present study, the properties for all sample conditions were best interpreted by means of log UTS vs. log Elongation plots, where the properties increased linearly within low cooling rate-high Fe and high cooling rate-low Fe condition extremities. The results are explained in terms of the β-Al 5 FeSi platelet size and porosity values obtained. (author)

Influence of Sr, Fe and Mn content and casting process on the microstructures and mechanical properties of AlSi7Cu3 alloy

Energy Technology Data Exchange (ETDEWEB)

Li, Zaidao [Laboratoire de Mécanique de Lille (LML), FRE 3723, Ecole Centrale de Lille, 59651 Villeneuve d' Ascq (France); Unité Matériaux et Transformations, UMR CNRS 8207, Univ. Lille 1, 59655 Villeneuve d' Ascq (France); Limodin, Nathalie; Tandjaoui, Amina; Quaegebeur, Philippe [Laboratoire de Mécanique de Lille (LML), FRE 3723, Ecole Centrale de Lille, 59651 Villeneuve d' Ascq (France); Osmond, Pierre [PSA Peugeot Citröen, Direction de la Recherche et de l' Innovation Automobile, Route de Gisy-78943, Vélizy-Villacoublay Cedex (France); Balloy, David [Unité Matériaux et Transformations, UMR CNRS 8207, Univ. Lille 1, 59655 Villeneuve d' Ascq (France)

2017-03-24

The effects of Strontium (Sr), Iron (Fe) and Manganese (Mn) additions, casting process (i.e., cooling rate) on the microstructures and mechanical properties of AlSi7Cu3 alloy were investigated. 2D and 3D metallographic and image analysis have been performed to measure the microstructural changes occurring at different Sr, Fe and Mn levels and casting process. The evolution of mechanical properties of the alloys has been monitored by Brinell and Vickers hardness measurement and tensile tests. Addition of Sr slightly refines the eutectic silicon particles but it also introduces more pores. The combined addition of Fe and Mn induces an increase of Fe-rich intermetallic compounds which include both α-Al{sub 15}(Fe,Mn){sub 3}Si{sub 2} and β-Al{sub 5}FeSi phase, while the volume fraction of porosity decreases with the Fe and Mn content increase. The secondary dendrite arm spacing slightly decreases with the addition of Sr, Fe and Mn alloying elements.

Effect of boron addition on the magnetic properties of the Fe-Nd-Al alloys prepared by suction casting

International Nuclear Information System (INIS)

Bai, Q.; Xu, H.; Tan, X.H.; Zhang, S.Y.

2007-01-01

The microstructure and magnetic properties of the Fe-Nd-Al alloys prepared by suction casting with boron addition have been investigated. The increasing boron content in the Fe-Nd-Al alloys significantly increases the intrinsic coercivity ( i H c ) and decreases the proportion of the amorphous phase. The magnetization at the maximum applied field (σ ' s ) of the Fe-Nd-Al-B alloys decreases, while the coercivity increases markedly after annealing. The high intrinsic coercivity is due to the presence of the Nd 2 Fe 14 B phase

Microstructure Formation in Strip-Cast RE-Fe-B Alloys for Magnets

Science.gov (United States)

Yamamoto, Kazuhiko; Matsuura, Masashi; Sugimoto, Satoshi

2017-07-01

During the manufacturing of sintered NdFeB magnets, it is well known that the microstructure of the starting alloy has a strong influence on the processing and the magnetic properties of the product. In this study, we clarify the microstructure formation in strip-cast rare earth (R)-Fe-B alloys used to produce magnets. The microstructure of the alloy surface in contact with the cooling roll and its cross-section were observed using laser microscopy, field emission electron microprobe analysis, and transmission electron microscopy. The orientations of crystal grains were determined by X-ray diffraction and electron backscatter diffraction analyses. Petal-shaped structures were found to cover the alloy surface in contact with the cooling roll, each consisting of a central nucleation region and radially grown Nd2Fe14B dendritic structures. The nucleation region, consisting of a "disc" and "predendrites", occurs in the super-cooled region of the contact area between the cooling roll and melt. In the disc region, spherical Nd2Fe14B particles in the thickness direction increase in volume. These discs and predendrites observed in the super-cooled area negatively influence the magnetic orientation and sinterability in the produced magnets. Therefore, it is important to avoid excessive super-cooling to obtain optimum magnetic properties.

Effect of oxide films, inclusions and Fe on reproducibility of tensile properties in cast Al–Si–Mg alloys: Statistical and image analysis

International Nuclear Information System (INIS)

Eisaabadi B, G.; Davami, P.; Kim, S.K.; Varahram, N.; Yoon, Y.O.; Yeom, G.Y.

2012-01-01

Double oxide films (hereafter: oxides), inclusions and Fe-rich phases are known to be the most detrimental defects in cast Al–Si–Mg alloys. The effects of these defects on reproducibility of tensile properties in Al–7Si–0.35Mg alloy have been investigated in this study. Four different casting conditions (low oxide—low Fe, high oxide—low Fe, low oxide—high Fe and high oxide—high Fe) were studied. In each case, 30 tensile test samples were prepared by casting in a metallic mold and machining (total of 120 tensile test samples). Results of tensile test were analyzed by Weibull three-parameter and mixture analyses. The microstructure and fracture surface of samples were studied by optical and scanning electron microscopes. Total of 800 metallography images (200 images for each experiment) were taken and analyzed by image analysis software. Finally, the relationship between tensile properties and defects characteristics was discussed. According to the results, Fe (Fe-related phases) had larger negative impact on tensile properties of the alloy compared to oxides. On the other hand, Weibull analysis revealed that the scattering of tensile properties was mainly due to the presence of oxides in microstructure. Results of image analysis showed that the shape factor and number of pores were mainly controlled by oxides and Fe, respectively. Also, there was a clear relationship between Weibull modules of UTS and El% and shape factor of pores. Furthermore, tensile properties of the examined alloy showed strong dependence to the number of pores.

Evolution of Fe based intermetallic phases in Al–Si hypoeutectic casting alloys: Influence of the Si and Fe concentrations, and solidification rate

Energy Technology Data Exchange (ETDEWEB)

Gorny, Anton; Manickaraj, Jeyakumar [Light Metal Casting Research Centre (LMCRC), Department of Mechanical Engineering, McMaster University, 1280 Main Street W, Hamilton, ON, Canada L8S 4L7 (Canada); Cai, Zhonghou [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Shankar, Sumanth, E-mail: shankar@mcmaster.ca [Light Metal Casting Research Centre (LMCRC), Department of Mechanical Engineering, McMaster University, 1280 Main Street W, Hamilton, ON, Canada L8S 4L7 (Canada)

2013-11-15

Highlights: •Anomalous evolution of Fe based intermetallic phases in Al–Si–Fe alloys. •XRF coupled with nano-diffraction to confirm the nano-size Fe intermetallic phases. •Crystallography of the θ-Al{sub 13}Fe{sub 4}, τ{sub 5}-Al{sub 8}Fe{sub 2}Si and τ{sub 6}-Al{sub 9}Fe{sub 2}Si{sub 2} phases. •Peritectic reactions involving the Fe intermetallic phases in Al–Si–Fe alloys. -- Abstract: Al–Si–Fe hypoeutectic cast alloy system is very complex and reported to produce numerous Fe based intermetallic phases in conjunction with Al and Si. This publication will address the anomalies of phase evolution in the Al–Si–Fe hypoeutectic casting alloy system; the anomaly lies in the peculiarities in the evolution and nature of the intermetallic phases when compared to the thermodynamic phase diagram predictions and past publications of the same. The influence of the following parameters, in various combinations, on the evolution and nature of the intermetallic phases were analyzed and reported: concentration of Si between 2 and 12.6 wt%, Fe between 0.05 and 0.5 wt% and solidification rates of 0.1, 1, 5 and 50 K s{sup −1}. Two intermetallic phases are observed to evolve in these alloys under these solidification conditions: the τ{sub 5}-Al{sub 8}SiFe{sub 2} and τ{sub 6}-Al{sub 9}Fe{sub 2}Si{sub 2}. The τ{sub 5}-Al{sub 8}SiFe{sub 2} phase evolves at all levels of the parameters during solidification and subsequently transforms into the τ{sub 6}-Al{sub 9}Fe{sub 2}Si{sub 2} through a peritectic reaction when promoted by certain combinations of solidification parameters such as higher Fe level, lower Si level and slower solidification rates. Further, it is also hypothesized from experimental evidences that the θ-Al{sub 13}Fe{sub 4} binary phase precludes the evolution of the τ{sub 5} during solidification and subsequently transforms into the τ{sub 6} phase during solidification. These observations are anomalous to the publications as prior art and

Diffusion of C and Cr During Creation of Surface Layer on Cast Steel Casting

Directory of Open Access Journals (Sweden)

Szajnar J.

2014-10-01

Full Text Available In paper a method of improvement in utility properties of unalloyed cast steel casting in result of diffusion of C and Cr in process of creation of surface layer is presented. The aim of paper was determination of diffusion range of basic elements of alloyed surface layer. Moreover a quantitative analysis of carbides phase strengthens alloyed surface layer of casting was carried out. The results of studies shown that important factors of surface layer creation are maximal temperature Tmax on granular insert – cast steel boundary dependent of pouring temperature, granularity Zw of Fe-Cr-C alloy insert and thickness of casting wall gśo. On the basis of obtained results was affirmed that with increase of thickness of casting wall increases range of diffusion in solid state in Fe-Cr-C grains and in liquid state. Moreover the range of Tmax = 13001500oC favours creation of the proper alloyed surface layers on cast steel.

Solid-state transformation of Fe-rich intermetallic phases in Al–5.0Cu–0.6Mn squeeze cast alloy with variable Fe contents during solution heat treatment

International Nuclear Information System (INIS)

Lin, Bo; Zhang, Weiwen; Zhao, Yuliang; Li, Yuanyuan

2015-01-01

The Al–5.0 wt.% Cu–0.6 wt.% Mn alloys with a variable Fe content were prepared by squeeze casting. Optical microscopy (OM), Deep etching technique, scanning electron microscopy(SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to examine the solid-state transformation of Fe-rich intermetallics during the solution heat treatment. The results showed that the Chinese script-like α-Fe, Al 6 (FeMn) and needle-like Al 3 (FeMn) phases transform to a new Cu-rich β-Fe (Al 7 Cu 2 (FeMn)) phase during solution heat treatment. The possible reaction and overall transformation kinetics of the solid-state phase transformation for the Fe-rich intermetallics were investigated. - Graphical abstract: Display Omitted - Highlights: • The α-Fe, Al 6 (FeMn) and Al 3 (FeMn) phases change to the β-Fe phases. • Possible reactions of Fe phases during solution heat treatment are discussed. • The overall fractional transformation rate follows an Avrami curve

The structure of high-quality aluminium cast iron

Directory of Open Access Journals (Sweden)

D. Kopyciński

2012-01-01

Full Text Available In this study presents the analyse of aluminium iron cast structure (as-cast condition which are used in high temperature. While producing the casts of aluminium iron major influence has been preserve the structure of technological process parameters. The addition to Fe-C-Al alloy V, Ti, Cr leads to the improvement of functional and mechanical cast qualities. In this study, a method was investigated to eliminate the presence of undesirable Al4C3 phases in a aluminium cast iron structure and thus improve the production process. V and Ti additions in aluminium cast iron allows to development of FeAl - VC or TiC alloys. In particular, V or Ti contents above 5 wt.% were found to totally eliminate the presence of Al4C3. In addition, preliminary work indicates that the alloy with the FeAl - VC or TiC structure reveals high oxidation resistance. The introduction of 5 wt.% chromium to aluminium cast iron strengthened Al4C3 precipitate. Thus, the resultant alloy can be considered an intermetallic FeAl matrix strengthened by VC and TiC or modified Al4C3 reinforcements.

Influence of Cu on modifying the beta phase and enhancing the mechanical properties of recycled Al-Si-Fe cast alloys.

Science.gov (United States)

Basak, C B; Babu, N Hari

2017-07-18

High iron impurity affects the castability and the tensile properties of the recycled Al-Si alloys due to the presence of the Fe containing intermetallic β-Al 9 Fe 2 Si 2 phase. To date only Mn addition is known to transform the β-Al 9 Fe 2 Si 2 phase in the Al-Si-Fe system. However, for the first time, as reported here, it is shown that β-phase transforms to the ω-Al 7 Cu 2 Fe phase in the presence of Cu, after solutionization at 793 K. The ω-phase decomposes below 673 K resulting into the formation of θ-Al 2 Cu phase. However, the present thermodynamic description of the Al-Si-Fe-Cu system needs finer tuning to accurately predict the stability of the ω-phase in these alloys. In the present study, an attempt was made to enhance the strength of Al-6wt%Si-2wt%Fe model recycled cast alloy with different amount of Cu addition. Microstructural and XRD analysis were carried out in detail to show the influence of Cu and the stability range of the ω-phase. Tensile properties and micro-hardness values are also reported for both as-cast and solutionized alloys with different amount of Cu without and with ageing treatment at 473 K. The increase in strength due to addition of Cu, in Fe-rich Al-Si alloys is promising from the alloy recyclability point of view.

Solid-state transformation of Fe-rich intermetallic phases in Al–5.0Cu–0.6Mn squeeze cast alloy with variable Fe contents during solution heat treatment

Energy Technology Data Exchange (ETDEWEB)

Lin, Bo [School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640 (China); School of Mechanical Engineering, Gui Zhou University, Guiyang 550000 (China); Zhang, Weiwen, E-mail: mewzhang@scut.edu.cn [School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640 (China); Zhao, Yuliang; Li, Yuanyuan [School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640 (China)

2015-06-15

The Al–5.0 wt.% Cu–0.6 wt.% Mn alloys with a variable Fe content were prepared by squeeze casting. Optical microscopy (OM), Deep etching technique, scanning electron microscopy(SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to examine the solid-state transformation of Fe-rich intermetallics during the solution heat treatment. The results showed that the Chinese script-like α-Fe, Al{sub 6}(FeMn) and needle-like Al{sub 3}(FeMn) phases transform to a new Cu-rich β-Fe (Al{sub 7}Cu{sub 2}(FeMn)) phase during solution heat treatment. The possible reaction and overall transformation kinetics of the solid-state phase transformation for the Fe-rich intermetallics were investigated. - Graphical abstract: Display Omitted - Highlights: • The α-Fe, Al{sub 6}(FeMn) and Al{sub 3}(FeMn) phases change to the β-Fe phases. • Possible reactions of Fe phases during solution heat treatment are discussed. • The overall fractional transformation rate follows an Avrami curve.

CALPHAD simulation of the Mg–(Mn, Zr)–Fe system and experimental comparison with as-cast alloy microstructures as relevant to impurity driven corrosion of Mg-alloys

Energy Technology Data Exchange (ETDEWEB)

Gandel, D.S., E-mail: darren.gandel@monash.edu [CAST Cooperative Research Centre (Australia); Department of Materials Engineering, Monash University, Clayton, VIC 3800 (Australia); Easton, M.A. [CAST Cooperative Research Centre (Australia); Department of Materials Engineering, Monash University, Clayton, VIC 3800 (Australia); Gibson, M.A. [CAST Cooperative Research Centre (Australia); CSIRO Process Science and Engineering, Clayton, VIC 3168 (Australia); Birbilis, N. [CAST Cooperative Research Centre (Australia); Department of Materials Engineering, Monash University, Clayton, VIC 3800 (Australia)

2014-02-14

Four Mg alloys with variations in the ratio of Mn, Zr and Fe additions were cast and their microstructures analysed via electron microscopy. Thermodynamic calculations of the expected phases using PANDAT were evaluated with actual as-cast microstructures. Some of the as-cast alloys did appear to form phases similar to those anticipated from the PANDAT calculations. Furthermore, there was a new Mn–Fe particle interaction observed that was not predicted, but which is posited to be responsible for the increase in corrosion resistance among Mn containing Mg alloys with Fe impurities. The experimental work herein has been shown to be invaluable in the understanding of this practically important system with sparingly soluble Fe and its potential influence on the corrosion of Mg alloys. - Highlights: • Alloy microstructure of the Mg-(Mn,Zr, Fe) system was analysed and reported. • CALPHAD analysis was used in conjunction with traditional SEM analysis techniques in this study. • A proposed Mn–Fe interaction within Mg has been observed for the first time. • Experimental validation of calculated phases is required to understand the effect of Mn and Zr on Mg.

Methods of improvement in hardness of composite surface layer on cast steel

Directory of Open Access Journals (Sweden)

J. Szajnar

2008-08-01

Full Text Available The paper presents a method of usable properties of surface layers improvement of cast carbon steel 200–450, by put directly in founding process a composite surface layer on the basis of Fe-Cr-C alloy and next its remelting with use of welding technology TIG – Tungsten Inert Gas. Technology of composite surface layer guarantee mainly increase in hardness and abrasive wear resistance of cast steel castings on machine elements. This technology can be competition for generally applied welding technology (surfacing by welding and thermal spraying. However the results of studies show, that is possible to connection of both methods founding and welding of surface hardening of cast steel castings. In range of experimental plan was made test castings with composite surface layer, which next were remelted with energy 0,8 and 1,6 kJ/cm. Usability for industrial applications of test castings was estimated by criterion of hardness and abrasive wear resistance of type metal-mineral.

Search for 14.4 keV solar axions emitted in the M1-transition of $^{57}$Fe nuclei with CAST

CERN Document Server

Andriamonje, S; Autiero, D; Barth, K; Belov, A; Beltrán, B; Bräuninger, H; Carmona, J M; Cebrián, S; Collar, J I; Dafni, T; Davenport, M; Di Lella, L; Eleftheriadis, C; Englhauser, J; Fanourakis, G K; Ferrer-Ribas, E; Fischer, H; Franz, J; Friedrich, P; Geralis, T; Giomataris, Yu; Gninenko, S; Gómez, H; Hasinoff, M; Heinsius, F H; Hoffmann, D H H; Irastorza, I G; Jacoby, J; Jakovčić, K; Kang, D; Königsmann, K C; Kotthaus, R; Krčmar, M; Kousouris, K; Kuster, M; Lakić, B; Lasseur, C; Liolios, A; Ljubičić, A; Lutz, G; Luzón, G; Miller, D; Morales, J; Ortiz, A; Papaevangelou, T; Placci, A; Raffelt, G; Riege, H; Rodríguez, A; Ruz, J; Savvidis, I; Semertzidis, Y; Serpico, P; Stewart, L; Vieira, J; Villar, J; Vogel, J; Walckiers, L; Zioutas, K

2009-01-01

We have searched for 14.4 keV solar axions or more general axion-like particles (ALPs), that may be emitted in the M1 nuclear transition of 57Fe, by using the axion-to-photon conversion in the CERN Axion Solar Telescope (CAST) with evacuated magnet bores (Phase I). From the absence of excess of the monoenergetic X-rays when the magnet was pointing to the Sun, we set model-independent constraints on the coupling constants of pseudoscalar particles that couple to two photons and to a nucleon g_{a\\gamma} |-1.19 g_{aN}^{0}+g_{aN}^{3}|<1.36\\times 10^{-16} GeV^{-1} for m_{a}<0.03 eV at the 95% confidence level.

Compound cast product and method for producing a compound cast product

Science.gov (United States)

Meyer, Thomas N.; Viswanathan, Srinath

2002-09-17

A compound cast product is formed in a casting mold (14) having a mold cavity (16) sized and shaped to form the cast product. A plurality of injectors (24) is supported from a bottom side (26) of the casting mold (14). The injectors (24) are in fluid communication with the mold cavity (16) through the bottom side (26) of the casting mold (14). A molten material holder furnace (12) is located beneath the casting mold (14). The holder furnace (12) defines molten material receiving chambers (36) configured to separately contain supplies of two different molten materials (37, 38). The holder furnace (12) is positioned such that the injectors (24) extend downward into the receiving chamber (36). The receiving chamber (36) is separated into at least two different flow circuits (51, 52). A first molten material (37) is received in a first flow circuit (51), and a second molten material (38) is received into a second flow circuit (52). The first and second molten materials (37, 38) are injected into the mold cavity (16) by the injectors (24) acting against the force of gravity. The injectors (24) are positioned such that the first and second molten materials (37, 38) are injected into different areas of the mold cavity (16). The molten materials (37, 38) are allowed to solidify and the resulting compound cast product is removed from the mold cavity (16).

Economical surface treatment of die casting dies to prevent soldering in high pressure casting

International Nuclear Information System (INIS)

Fraser, D.T.; Jahedi, M.Z.

2001-01-01

This paper describes the use of a gas oxidation treatment of H13 tool steel to develop a compact iron oxide layer at the surface of core pins to prevent soldering in high pressure die casting. The performance of oxide layers in the protection of die steel against soldering during high pressure die casting was tested in a specially designed die using removable core pins and Al-11 Si-3 Cu casting alloy. The gas oxidation treatment can be applied at low temperatures and to large areas of the die surface. In addition this process is very cost effective compared to other coating processes such as physical vapour deposition (PVD), or thermo-reactive diffusion (TRD) coatings. This work demonstrated that surface treatment producing pure magnetite (Fe 3 O 4 ) layers are more protective than oxide layers containing a combination of Fe 3 O 4 (magnetite) and Fe 3 O 3 (haematite). The magnetite layer acts as a barrier between the die steel/casting alloy interface and prevents the formation of inter-metallic phases. Optical microscopy and scanning electron microscope were used to determine the thickness of the oxide layer, while X-ray diffraction was performed to determine the oxide phase structure

Effect of cerium addition on microstructure and mechanical properties of high-strength Fe85Cr4Mo8V2C1 cast steel

Energy Technology Data Exchange (ETDEWEB)

Hufenbach, J., E-mail: j.k.hufenbach@ifw-dresden.de [IFW Dresden, Institute for Complex Materials, P.O. Box 270116, D-01171 Dresden (Germany); Helth, A. [IFW Dresden, Institute for Complex Materials, P.O. Box 270116, D-01171 Dresden (Germany); Lee, M.-H. [Korea Institute of Industrial Technology, Gaetbeol-ro 156, Yeonsu-gu, Incheon 406-840 (Korea, Republic of); Wendrock, H.; Giebeler, L. [IFW Dresden, Institute for Complex Materials, P.O. Box 270116, D-01171 Dresden (Germany); Choe, C.-Y.; Kim, K.-H. [Korea Institute of Industrial Technology, Gaetbeol-ro 156, Yeonsu-gu, Incheon 406-840 (Korea, Republic of); Kühn, U. [IFW Dresden, Institute for Complex Materials, P.O. Box 270116, D-01171 Dresden (Germany); Kim, T.-S. [Korea Institute of Industrial Technology, Gaetbeol-ro 156, Yeonsu-gu, Incheon 406-840 (Korea, Republic of); Eckert, J. [IFW Dresden, Institute for Complex Materials, P.O. Box 270116, D-01171 Dresden (Germany); TU Dresden, Institute of Materials Science, D-01062 Dresden (Germany)

2016-09-30

This work presents an investigation on the influence of rare earth additions (Ce) on the microstructure and mechanical properties of a cast Fe85Cr4Mo8V2C1 (element contents in wt%) tool steel. The applied relatively high solidification rate during the casting process promotes the formation of non-equilibrium phases such as martensite, retained austenite as well as a fine network-like structure of complex carbides. This combination of phases and their morphology results in excellent mechanical properties already in the as-cast state. Cerium additions induce a change in phase formation and resulting mechanical properties. Besides morphological and quantitative changes of the main constituent phases, novel carbo-oxide and carbide phases are formed. To investigate this microstructural phenomenon, X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) combined with energy dispersive X-ray spectroscopy (EDX) were applied. Altogether, the addition of small amounts of the rare earth element cerium together with a tailored casting process results in enhanced mechanical properties compared to the Fe85Cr4Mo8V2C1 alloy and offers new possibilities to obtain high-strength and simultaneously adequate ductile cast steels for advanced tool design.

Determining casting defects in near-net shape casting aluminum parts by computed tomography

Science.gov (United States)

Li, Jiehua; Oberdorfer, Bernd; Habe, Daniel; Schumacher, Peter

2018-03-01

Three types of near-net shape casting aluminum parts were investigated by computed tomography to determine casting defects and evaluate quality. The first, second, and third parts were produced by low-pressure die casting (Al-12Si-0.8Cu-0.5Fe-0.9Mg-0.7Ni-0.2Zn alloy), die casting (A356, Al-7Si-0.3Mg), and semi-solid casting (A356, Al-7Si-0.3Mg), respectively. Unlike die casting (second part), low-pressure die casting (first part) significantly reduced the formation of casting defects (i.e., porosity) due to its smooth filling and solidification under pressure. No significant casting defect was observed in the third part, and this absence of defects indicates that semi-solid casting could produce high-quality near-net shape casting aluminum parts. Moreover, casting defects were mostly distributed along the eutectic grain boundaries. This finding reveals that refinement of eutectic grains is necessary to optimize the distribution of casting defects and reduce their size. This investigation demonstrated that computed tomography is an efficient method to determine casting defects in near-net shape casting aluminum parts.

The structure of abrasion-resisting castings made of chromium cast iron

Directory of Open Access Journals (Sweden)

D. Kopyciński

2011-01-01

Full Text Available In this study presents the analyse of chrome iron cast structure (as-cast condition which are used in rugged conditions abrasion-percussive and high temperature. While producing the casts of chrome iron major influence has been preserve the structure of technologi cal process parameters. The addition to Fe-C-Cr alloy Ni, Mo or Cu and then proper heat treatment leads to the improvement of functional and mechanical cast qualities. Then it is possible to develop high mechanical properties which are recommended by PN-EN12513. As can it be seen from the above research silicon is an adverse chemical element in this kind of alloy cast iron. However, the reason of cracksappearing in chrome iron casts are phosphorus eutectic microareas. When the compound of Si and P reach the critical point, described inPN-88/H-83144 outdated standard, the microareas might appear.

Control of chilling tendency in grey cast iron reuse

Directory of Open Access Journals (Sweden)

Saliu Ojo Seidu

2013-02-01

Full Text Available In grey cast iron remelt and recycling, white iron can result in the cast product if careful control of the chilling tendency is not ensured. Many jobbing foundries are constrained in furnace types and available foundry additives that the operation always results in white irons. This study is towards ensuring grey iron is reproduced from cast iron scrap auto engine blocks, when using a diesel fired rotary furnace and a FeSi alloy for structural modification (inoculation. With varying addition rate of the FeSi alloy to the tapped molten metal, chill wedge tests were performed on two different wedge samples of type W (according to ASTM A367- wedge test with cooling modulus of 0.45 cm (W3½ and 0.54 cm (W4. The carbon equivalents for the test casts were within hypoeutectic range (3.85 wt. (% to 4.11 wt. (%. In the W4 wedge sample, at 2.0 wt. (% addition rate of the FeSi alloy, the relative clear chill was totally reduced to zero from 19.76%, while the relative mottled chill was brought down to 9.59% from 33.71%. The microstructure from the cast at this level of addition was free of carbidic phases; it shows randomly oriented graphite flakes evenly distributed in the iron matrix. Hardness assessment shows that increasing rate of FeSi addition results in decreasing hardness, with maximum effect at 2.0 wt. (% addition. With equivalent aspect ratio (cooling modulus in a target cast product, this addition rate for this FeSi alloy under this furnace condition will attain graphitized microstructure in the cast product.

Control of chilling tendency in grey cast iron reuse

Directory of Open Access Journals (Sweden)

Saliu Ojo Seidu

2012-01-01

Full Text Available In grey cast iron remelt and recycling, white iron can result in the cast product if careful control of the chilling tendency is not ensured. Many jobbing foundries are constrained in furnace types and available foundry additives that the operation always results in white irons. This study is towards ensuring grey iron is reproduced from cast iron scrap auto engine blocks, when using a diesel fired rotary furnace and a FeSi alloy for structural modification (inoculation. With varying addition rate of the FeSi alloy to the tapped molten metal, chill wedge tests were performed on two different wedge samples of type W (according to ASTM A367- wedge test with cooling modulus of 0.45 cm (W3½ and 0.54 cm (W4. The carbon equivalents for the test casts were within hypoeutectic range (3.85 wt. (% to 4.11 wt. (%. In the W4 wedge sample, at 2.0 wt. (% addition rate of the FeSi alloy, the relative clear chill was totally reduced to zero from 19.76%, while the relative mottled chill was brought down to 9.59% from 33.71%. The microstructure from the cast at this level of addition was free of carbidic phases; it shows randomly oriented graphite flakes evenly distributed in the iron matrix. Hardness assessment shows that increasing rate of FeSi addition results in decreasing hardness, with maximum effect at 2.0 wt. (% addition. With equivalent aspect ratio (cooling modulus in a target cast product, this addition rate for this FeSi alloy under this furnace condition will attain graphitized microstructure in the cast product.

Wear and Corrosion Resistance of Fe Based Coatings by HVOF Sprayed on Gray Cast-Iron for Automotive Application

Directory of Open Access Journals (Sweden)

M.S. Priyan

2014-12-01

Full Text Available In this study, commercially available FeSiNiCr and FeBCr alloy powders were designed with suitable compositions, gas atomized and then coated on gray cast-iron substrate. The microstructures of the feed stock Fe based alloy powders and the coatings were investigated by means of optical microscopy (OM, X-Ray diffraction (XRD, Thermogravimetric analysis (TGA and Scanning Electron Microscopy (SEM. In the present study, both the coating materials experienced two-body wear mechanisms. The results showed that for loads of 0.05 N, 0.1 N and 0.2 N, the wear resistance of FeBCr coating was less than FeSiNiCr by 44 %, 40 % and 31 %, respectively. The results indicated that the coated substrates exhibited lower corrosion current densities and lower corrosion rates, when placed in 20 wt.% H2SO4 solutions. In addition, the use of optimal spraying parameters/conditions gave improvements to the corrosion resistance of the substrates that had been treated with the crystalline coating.

Rapid Assessment of the Ce-Co-Fe-Cu System for Permanent Magnetic Applications

Science.gov (United States)

Meng, F.; Chaudhary, R. P.; Gandha, K.; Nlebedim, I. C.; Palasyuk, A.; Simsek, E.; Kramer, M. J.; Ott, R. T.

2018-04-01

This work focuses on the rapid synthesis and characterization of quaternary Ce(CoFeCu)5 alloy libraries to assess their potential viability as permanent magnets. Arrays of bulk specimens with controlled compositions were synthesized via laser engineered net shaping (LENS) by feeding different ratios of alloy powders into a melt pool created by a laser. Based on the assessment of the magnetic properties of the LENS printed samples, arc-melted and cast ingots were prepared with varying Fe (5-20 at.%) and Co (60-45 at.%) compositions while maintaining constant Ce (16 at.%) and Cu (19 at.%) content. The evolution of the microstructure and phases with varying chemical compositions and their dependence on magnetic properties are analyzed in as-cast and heat-treated samples. In both the LENS printed and cast samples, we find the best magnetic properties correspond to a predominantly single-phase Ce(CoFeCu)5 microstructure in which high coercivity (H c > 10 kOe) can be achieved without any microstructural refinement.

Rapid Assessment of the Ce-Co-Fe-Cu System for Permanent Magnetic Applications

Science.gov (United States)

Meng, F.; Chaudhary, R. P.; Gandha, K.; Nlebedim, I. C.; Palasyuk, A.; Simsek, E.; Kramer, M. J.; Ott, R. T.

2018-06-01

This work focuses on the rapid synthesis and characterization of quaternary Ce(CoFeCu)5 alloy libraries to assess their potential viability as permanent magnets. Arrays of bulk specimens with controlled compositions were synthesized via laser engineered net shaping (LENS) by feeding different ratios of alloy powders into a melt pool created by a laser. Based on the assessment of the magnetic properties of the LENS printed samples, arc-melted and cast ingots were prepared with varying Fe (5-20 at.%) and Co (60-45 at.%) compositions while maintaining constant Ce (16 at.%) and Cu (19 at.%) content. The evolution of the microstructure and phases with varying chemical compositions and their dependence on magnetic properties are analyzed in as-cast and heat-treated samples. In both the LENS printed and cast samples, we find the best magnetic properties correspond to a predominantly single-phase Ce(CoFeCu)5 microstructure in which high coercivity ( H c > 10 kOe) can be achieved without any microstructural refinement.

Mossbauer and XRD characterization of the phase transformations in a Fe-Mn-Al-C-Mo-Si-Cu as cast alloy during tribology test

Science.gov (United States)

Ramos, J.; Piamba, J. F.; Sánchez, H.; Alcazar, G. A. Pérez

2015-06-01

In present study Fe-29.0Mn-6Al-0.9C-1.8Mo-1.6Si-0.4Cu (%w) alloy was obtained after melted in an induction furnace, and then molded as an ingot. From the as cast ingot it were cut samples for the different characterization measurements. The microstructure of the as-cast sample is of dendritic type and its XRD pattern was refined with the lines of the austenite, with a big volumetric fraction, and the lines of the martensite, with small volumetric fraction. The Mössbauer spectrum of the sample was fitted with a broad singlet which corresponds to disordered austenite. After the tribology test, its XRD pattern was refined with the lines of two austenite phases, one similar to the previous one and other with bigger lattice parameter. The total volumetric fraction of the austenite is smaller than that obtained for sample without wear. It was added the lines of the martensite phase with bigger volumetric fraction than that of the previous sample. The Mössbauer spectrum of the weared sample was fitted with two paramagnetic sites which correspond to the two Fe austenite phases and a hyperfine magnetic field distribution which is associated to the disordered original martensite and the new one which appears in the surface as a consequence of the wear process. These results show that during wear process the original austenite phase is transformed in martensite and in a new austenite phase. The increases of the martensitic phase improves mechanical properties and wear behavior.

Mossbauer and XRD characterization of the phase transformations in a Fe-Mn-Al-C-Mo-Si-Cu as cast alloy during tribology test

Energy Technology Data Exchange (ETDEWEB)

Ramos, J. [Universidad Autónoma de Occidente (Colombia); Piamba, J. F. [Universidad del Valle, Departamento Física (Colombia); Sánchez, H. [Universidad del Valle, Escuela de Materiales (Colombia); Alcazar, G. A. Pérez, E-mail: gpgeperez@gmail.com [Universidad del Valle, Departamento Física (Colombia)

2015-06-15

In present study Fe-29.0Mn-6Al–0.9C-1.8Mo-1.6Si-0.4Cu (%w) alloy was obtained after melted in an induction furnace, and then molded as an ingot. From the as cast ingot it were cut samples for the different characterization measurements. The microstructure of the as-cast sample is of dendritic type and its XRD pattern was refined with the lines of the austenite, with a big volumetric fraction, and the lines of the martensite, with small volumetric fraction. The Mössbauer spectrum of the sample was fitted with a broad singlet which corresponds to disordered austenite. After the tribology test, its XRD pattern was refined with the lines of two austenite phases, one similar to the previous one and other with bigger lattice parameter. The total volumetric fraction of the austenite is smaller than that obtained for sample without wear. It was added the lines of the martensite phase with bigger volumetric fraction than that of the previous sample. The Mössbauer spectrum of the weared sample was fitted with two paramagnetic sites which correspond to the two Fe austenite phases and a hyperfine magnetic field distribution which is associated to the disordered original martensite and the new one which appears in the surface as a consequence of the wear process. These results show that during wear process the original austenite phase is transformed in martensite and in a new austenite phase. The increases of the martensitic phase improves mechanical properties and wear behavior.

On the cooling rate of strip cast ingots for sintered NdFeB magnets

Energy Technology Data Exchange (ETDEWEB)

Yu, L.Q. [State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Yan, M. [State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027 (China)]. E-mail: mse_yanmi@dial.zju.edu.cn; Wu, J.M. [State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Luo, W. [State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Cui, X.G. [State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027 (China); Ying, H.G. [State Key Lab of Silicon Materials, Zhejiang University, Hangzhou 310027 (China)

2007-04-30

Effects of the cooling rate of strip cast ingots on magnetic properties of sintered NdFeB magnets were studied. It is found that the magnetic properties greatly depend on wheel speed due to different alloy microstructures, which affect readily the particle size distribution of powders obtained after the subsequent jet milling. At higher cooling rate, interlamellar spacing between Nd-rich platelets of the alloy was small, resulting in a lower saturated magnetization due to increased amounts of small particles after jet milling. With further decreasing cooling rate, the resultant larger interlamellar spacing led to too large particle sizes as well as a more irregular shape; thus deteriorated the magnetic properties of the final magnet. A model was developed to disclose the effects of particle sizes on the magnetic alignment process. In the current investigation, optimum magnetic properties of the final magnets were obtained with a cooling rate of 2.6 m/s for preparing the strip. The magnets made by conventionally cast ingot technique exhibited the lowest magnetic properties because of the slowest cooling rate.

Thermal Expansion Properties of Fe-42Ni-Si Alloy Strips Fabricated by Melt Drag Casting Process

International Nuclear Information System (INIS)

Kim, Moo Kyum; Ahn, Yong Sik; Namkung, Jeong; Kim, Moon Chul; Kim, Yong Chan

2007-01-01

Thermal expansion property was investigated on Fe-42% Ni alloy strip added by alloying element of Si of 0∼1.5wt.%. The strip was fabricated by a melt drag casting process. Addition of Si enlarged the solid-liquid region and reduced the melting point which leads to the increase of the formability of a strip. The alloy containing 0.6 wt.% Si showed the lowest thermal expansion ratio in the temperature range between 20 to 350 .deg. C. The grain size was increased with reduction ratio and annealing temperature, which resulted in the decrease of the thermal expansion coefficient of strip. Because of grain refining by precipitation of Ni 3 Fe, the alloy strip containing 1.5 wt.% Si showed higher thermal expansion ratio compared with the alloy containing 0.6 wt.% Si

Fabrication of aligned porous LaNi0.6Fe0.4O3 perovskite by water based freeze casting

Science.gov (United States)

Soltani, Niloofar; Martínez-Bautista, Rubén; Bahrami, Amin; Huerta Arcos, Lázaro; Cassir, Michel; Chávez Carvayar, José

2018-05-01

A novel porous cathode of LaNi0.6Fe0.4O3 perovskite with aligned porosities was engineered for solid oxide fuel cells. LaNi0.6Fe0.4O3 was produced through metal nitrate and acid citric combustion method and calcined at different temperatures. The synthesized LNF at 600 °C shows specific surface area (SBET) of 24.4 m2 g-1 and an average pore size of 12.2 nm. The chemical composition and structure of LaNi0.6Fe0.4O3 synthesized at temperature 600-1400 °C, were analyzed by XRD, XPS and HRTEM. SEM observations of freeze cast nano-sized LNF showed the vertically aligned hexagonal walls. These walls contain a great value of fine pores which accelerate the gas transportation.

Rapidly cast crystalline thin sheet materials

International Nuclear Information System (INIS)

Warlimont, H.; Emmerich, K.

1986-01-01

The current state and progress of casting thin sheet and ribbons directly from the melt are reviewed. First, the solidification phenomena pertinent to the process are outlined. Subsequently, Fe-Si,l Fe-Si-Al, Fe-Nd-B, Ag-Cu-Ti, alloy steels, Ni superalloys and Si are treated as examples. Finally, the information available on process development is critically assessed

Effect of trace yttrium addition on the microstructure and tensile properties of recycled Al–7Si–0.3Mg–1.0Fe casting alloys

Energy Technology Data Exchange (ETDEWEB)

Wan, Bingbing [Guangdong Key Laboratory for Advanced Metallic Materials Processing, South China University of Technology, Guangzhou, Guangdong 510640 (China); School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou, Guangdong 510640 (China); Chen, Weiping, E-mail: mewpchen@scut.edu.cn [Guangdong Key Laboratory for Advanced Metallic Materials Processing, South China University of Technology, Guangzhou, Guangdong 510640 (China); School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou, Guangdong 510640 (China); Liu, Lusheng; Cao, Xueyang; Zhou, Li [Guangdong Key Laboratory for Advanced Metallic Materials Processing, South China University of Technology, Guangzhou, Guangdong 510640 (China); School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou, Guangdong 510640 (China); Fu, Zhiqiang, E-mail: kopyhit@163.com [Guangdong Key Laboratory for Advanced Metallic Materials Processing, South China University of Technology, Guangzhou, Guangdong 510640 (China)

2016-06-01

In the present work, the effect of yttrium (Y) addition (0, 0.15, 0.3, 0.5 and 0.7 wt%) on the microstructure and tensile properties of recycled A356 cast alloys containing 1.0 wt% Fe has been studied systematically. With the addition of Y, despite no transformations of β-Fe (Al{sub 5}FeSi) phases into α-Fe phases, the acicular β-Fe phases were refined remarkably, and the volume fraction of β-Fe phases were decreased evidently. With addition of 0.3 wt% Y, the average length of β-Fe phase decreased from ~78 µm to ~20 µm and the finest β-Fe phases were obtained, in the meantime, the eutectic silicon particles were present in fully modified form, and the secondary dendrite arm spacing (SDAS) reached the lowest value. In addition, it was proposed that according to the microstructural analysis, the Al{sub 2}Si{sub 2}Y intermetallic phases might be responsible for the refinement of the β-Fe phases. With addition of 0.3 wt% Y, the maximum improvement of quality index was achieved, approximately 32% in both as-cast and T6 heat treated alloys, and the corresponding Y-modified alloys in T6 heat treated condition obtained the best tensile properties compared with other experimental alloys, with the corresponding ultimate tensile strength (UTS) and elongation (EL) values being 383.86 MPa and 4.85%, respectively. Furthermore, the tensile properties of 0.3 wt% Y modified recycled Al–7Si–0.3Mg–1.0Fe alloys (T6) exceed the minimum properties standard for ZL101A alloy (JB, T6), approximately 30.12% for UTS value and 61.67% for EL value, suggesting it can be a good candidate for the commercial applications.

Effect of microstructure and surface features on wetting angle of a Fe-3.2 wt%C.E. cast iron with water

Science.gov (United States)

Riahi, Samira; Niroumand, Behzad; Dorri Moghadam, Afsaneh; Rohatgi, Pradeep K.

2018-05-01

In the present study, variation in surface wetting behavior of a hypoeutectic cast iron with its microstructural features and surface roughness was investigated. Samples with an identical composition, i.e. Fe-3.2 wt%C.E., and different microstructures (a gray cast iron with A-type flake graphite and a white cast iron) were fabricated by gravity casting of molten cast iron in a chill mold at different cooling rates. A variation of surface roughness was also developed by polishing, a four-stage electroetching and a four-stage mechanical abrading on the samples. Roughness and water contact angles of all surfaces were then measured. The surface roughness factor and the solid fraction in contact with water by the Wenzel and Cassie-Baxter contact models were also calculated and compared with the corresponding measured contact angles to find out which regime was active. Results indicated that the surface microstructure and the type of constituents present at the surface influenced the cast iron surface wettability and that it was possible to change the surface contact angle by modification of the surface microstructure. The mechanically abraded gray cast iron followed the Wenzel-type regime while the electroetched surfaces of gray cast iron exhibited a transition from Wenzel to Cassie-Baxter type regime. In white cast iron, the results indicated Wenzel type behavior in the electroetched samples while for the mechanically abraded samples, none of these two models could predict the wetting behavior. Furthermore, the wetting angles of both gray and white cast irons were measured after 1, 2, 3 and 4 weeks of air exposure. The results showed that the wetting angles of both samples increased to above 90° after one week of air exposure which was likely due to adsorption of low surface energy hydrocarbons on the surfaces.

High Ms Fe16N2 thin film with Ag under layer on GaAs substrate

Energy Technology Data Exchange (ETDEWEB)

Allard Jr, Lawrence Frederick [ORNL

2016-01-01

(001) textured Fe16N2 thin film with Ag under layer is successfully grown on GaAs substrate using a facing target sputtering (FTS) system. After post annealing, chemically ordered Fe16N2 phase is formed and detected by X-ray diffraction (XRD). High saturation magnetization (Ms) is measured by a vibrating sample magnetometer (VSM). In comparison with Fe16N2 with Ag under layer on MgO substrate and Fe16N2 with Fe under layer on GaAs substrate, the current layer structure shows a higher Ms value, with a magnetically softer feature in contrast to the above cases. In addition, X-ray photoelectron spectroscopy (XPS) is performed to characterize the binding energy of N atoms. To verify the role of strain that the FeN layer experiences in the above three structures, Grazing Incidence X-ray Diffraction (GIXRD) is conducted to reveal a large in-plane lattice constant due to the in-plane biaxial tensile strain. INTRODUCTION

Preparation and evaluation of magnetic nanocomposite fibers containing α″-Fe16N2 and α-Fe nanoparticles in polyvinylpyrrolidone via magneto-electrospinning

Science.gov (United States)

Kartikowati, Christina W.; Suhendi, Asep; Zulhijah, Rizka; Ogi, Takashi; Iwaki, Toru; Okuyama, Kikuo

2016-01-01

Two kinds of ferromagnetic nanocomposite fiber comprising α″-Fe16N2 and α-Fe nanoparticles (NPs), which have the highest magnetic moments as hard and soft magnetic materials, respectively, embedded in polyvinylpyrrolidone (PVP) have been synthesized via the magneto-electrospinning method. Both α″-Fe16N2 and α-Fe were single-domain core-shell NPs with an average outer diameter of 50 nm and Al2O3 as the shell. Ferrofluid precursors used for the electrospinning were prepared by dispersing these NPs in a PVP-toluene-methanol solution. The results show that applying the magnetic field in the same direction as the electric field resulted in smaller and more uniform fiber diameters. Nanocomposite fibers containing α″-Fe16N2 had smaller diameters than those containing α-Fe NPs. These magnetic-field effects on the fiber formation were explained by referring to the kinetic energy of the moving jet in the electrospinning process. In addition, magnetic hysteresis curves showed an enhancement of the magnetic coercivity (H c) and remanence (M r) by 22.9% and 22.25%, respectively. These results imply a promising possibility of constructing bulk magnetic materials using α″-Fe16N2 NPs, which furthermore reveals attractive features for many other magnetic applications, such as magnetic sensors.

Temperature and salinity profile data from CTD casts from NOAA Ship RAINIER west of Prince of Wales Island, Alaska, from 2008-05-16 to 2008-06-16 (NODC Accession 0043264)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Physical oceanographic data were collected from NOAA Ship RAINIER west of Prince of Wales Island from 16 May 2008 to 16 June 2008. Data were collected from CTD casts...

Fabrication of Ti-0.48Al Alloy by Centrifugal Casting.

Science.gov (United States)

Park, Jong Bum; Lee, Jung-Il; Ryu, Jeong Ho

2018-09-01

Many of the unique properties of TiAl alloys that make are attractive for use in high-temperature structural applications also make it challenging to process them into useful products. Cast TiAl is rapidly nearing commercialization, particularly in the vehicle industry, owing to its low production cost. In this study, the centrifugal casting of a TiAl (Ti-48%Al, mole fraction) turbocharger was simulated and an experimental casting was created in vacuum using an induction melting furnace coupled to a ceramic composite mold. Numerical simulation results agreed with the experiment. The crystal structure, microstructure, and chemical composition of the TiAl prepared by centrifugal casting were studied by X-ray diffractometry, optical microscopy, field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS). FE-SEM and EDS examinations of the TiAl casting revealed that the thickness of the oxide layer (α-case) was typically less than 35 μm.

Impact of as-cast structure on structure and properties of twin-roll cast AA8006 alloy

Energy Technology Data Exchange (ETDEWEB)

Slamova, M.; Ocenasek, V. [Vyzkumny Ustav Kovu, Panenske Brezany (Czechoslovakia); Juricek, Z.

2000-07-01

Sheet production by twin-roll casting (TRC) process is a well established practice in the aluminium industry because it offers several advantages in comparison with DC casting and hot rolling, esp. lower production and investment costs. Thin strips exhibiting a combination of good strength and high ductility are required for various applications and for this reason alloys with higher Fe and Mn content such as AA 8006 displace AA 1xxx or AA 8011 alloys. However, TRC of AA 8006 strips involves several problems, e.g. casting conditions and subsequent treatment procedures need fine tuning. The results of an investigation of the effect of casting conditions on structure and properties of AA 8006 strips are presented. The influence of casting speed, grain refiner addition, molten metal level in the tundish, tip setback and roll separating force was investigated. The impact of imperfect as-cast structure on structure and properties of thin strips in H22 and O tempers was evaluated and compared with strips from good as-cast material. (orig.)

Spatial Bimetallic Castings Manufactured from Iron Alloys

Directory of Open Access Journals (Sweden)

M. Cholewa

2007-07-01

Full Text Available In this paper a conception for manufacturing method of skeleton castings with composite features was shown. Main application of such castings are the working organs of machines subjected to intensive abrasive and erosive wear. Skeleton geometry was based on three-dimensional cubic net consisting of circular connectors and nodes joining 6 connectors according to Cartesian co-ordinate system. Dimension of an elementary cell was equal to 10 mm and diameter of single connector was equal to 5 mm. For bimetallic castings preparation two Fe based alloys were used: L25SHMN cast steel for skeleton substrate and ZlCr15NiMo cast iron for working part of the casting. In presented work obtained structure was analyzed with indication of characteristic regions. Authors described phenomena occurring at the alloys interface and phases in transition zone. A thesis was formulated concerning localization of transition zone at the cast iron matrix – cast steel reinforcement interface. Direction of further studies were indicated.

Hydrogenation-disproportionation-desorption-recombination in Sm2Fe16M (M=Al, Ga and Si) and magnetic properties of their carburized powders

International Nuclear Information System (INIS)

Kubis, M.; Rave, W.; Cao, L.; Gebel, B.; Mueller, K.-H.; Schultz, L.

1998-01-01

The application of the hydrogenation-disproportionation-desorption-recombination (HDDR) process in Sm 2 Fe 16 M (M=Al,Ga and Si) was investigated. The hydrogen absorption behaviour was studied by temperature-pressure analysis (TPA). In the temperature range between 500 and 800 C, Sm 2 Fe 16 M samples with M=Ga and Si show a weaker hydrogen absorption than Sm 2 Fe 16 Al. This was confirmed by X-ray diffraction which showed a complete disproportionation of Sm 2 Fe 16 Al into SmH z (1.9 2 Fe 16 Ga and Sm 2 Fe 16 Si exhibit a fraction of undecomposed material with the Th 2 Zn 17 -type structure after the disproportionation procedure. These results point to a stabilization of Sm 2 Fe 16 M against disproportionation by hydrogen for M=Ga and Si. The magnetization processes of carburized HDDR powders were studied by VSM measurements and Kerr microscopy. The demagnetization curve of our HDDR processed Sm 2 Fe 16 AlC y is well shaped, whereas those of Sm 2 Fe 16 GaC y and Sm 2 Fe 16 SiC y show a large decrease of the polarization at low fields. The favourable behaviour of Sm 2 Fe 16 AlC y is due to a homogeneous submicron grain structure. In Sm 2 Fe 16 GaC y and Sm 2 Fe 16 SiC y samples, an additional, magnetically soft phase with larger domains was observed which causes the low coercivity. As a consequence, HDDR was only favourable for the preparation of Sm 2 Fe 16 MC y hard magnets with M=Al but not for M=Ga and Si. Optimization of the HDDR process in Sm 2 Fe 16 Al and subsequent nitrogenation or carburization led to coercivities of μ 0j H c =2.9 and 2.5 T, respectively. (orig.)

Effect of Welding Parameters on Microstructure and Mechanical Properties of Cast Fe-40Al Alloy

Directory of Open Access Journals (Sweden)

Osman Torun

2016-09-01

Full Text Available Friction welding of cast Fe-40Al alloy was carried out at 1000 rmp for various friction times, friction pressures, and forging pressures. The microstructures of the interface of welded samples were analyzed by optical and scanning electron microscopy (SEM. Micrographs demonstrated that excellent welding formed continuously along the interface, except for samples welded for 3 s. Chemical compositions of the interface of the friction welded samples and of the fractured surface of all the specimens were determined using energy dispersive spectroscopy (EDS. After the welding process, shear tests were applied to the welded samples to determine the shear strength of joints. Test results indicated that the maximum shear strength was 469.5 MPa.

Permanent magnets prepared from Sm10.5Fe88.5Zr1.0Ny without homogenization

International Nuclear Information System (INIS)

Gebel, B.; Kubis, M.; Mueller, K.-H.

1997-01-01

In as-cast Sm 2 Fe 17 the high amount of α-Fe caused by a peritectic reaction can be considerably reduced by a small addition of about 1 at% Zr. X-ray diffraction showed that as-cast Sm 10.5 Fe 88.5 Zr 1.0 mainly consists of a phase with the Th 2 Zn 17 -type structure and SmFe 3 . Non-homogenized Sm 10.5 Fe 88.5 Zr 1.0 was milled and (i) annealed in vacuum or (ii) treated with a hydrogenation-disproportionation-desorp tion-recombination (HDDR) process. The annealed and subsequently nitrogenated powder is magnetically anisotropic and has a coercivity μ 0J H C up to 2.0 T and an energy product (BH) max up to 136 kJ/m 3 . HDDR-treated and nitrogenated powder is isotropic and exhibits values of μ 0J H C = 3.1 T and (BH) max 103 kJ/m 3 . Consequently, Sm 10.5 Fe 88.5 Zr 1.0 N y (y ∼ 16) permanent magnets with very good properties can be prepared without the time-consuming homogenization procedure. (orig.)

Microstructural studies of suck cast (Zr-SS)-3 and 5 AI alloys for nuclear metallic waste form

International Nuclear Information System (INIS)

Kumar, P.; Das, N.; Sengupta, P.; Arya, A.; Dey, G.K.

2015-01-01

Management of radioactive metallic waste using 'alloy melting route' is currently being investigated. For disposal of Zr and SS base nuclear metallic wastes, Zr-stainless steel (SS) hybrid alloys are being considered as baseline alloys for developing metallic-waste-form (MWF) alloys. In this context Zr-16 wt. %55 has been selected for MWF alloy in our previous study. In present study, to include amorphous phase in this alloy, 3 and 5 wt. % Al has been added in order to improve desirable properties and useful features of MWF and the two alloys have been prepared by suck casting techniques. Microstructure of these alloys have been investigated by optical and electron microscopy which shows occurrence of two different phases, e.g. dark grey and white phases, in (Zr-16 SS)-3 Al and three different phases, e.g. grey, dark grey and white phases in (Zr-16 SS)-5 AI. Electron diffraction and X-ray diffraction (XRD) analyses of these two alloy specimens revealed the occurrence of Zr (Fe, Cr, AI) (dark grey) and Zr 2 (Fe, Cr, AI) (white) phases in (Zr-16 SS)-3 Al whereas, Zr (Fe, Cr, AI) (dark grey), Zr 2 (Fe, Cr, AI) (grey) and Zr 3 (Fe, Cr, AI) (white) phases were found in (Zr-16 SS)-5 AI. In addition, presence of amorphous phase was indicated by XRD analysis that could be confirmed by transmission electron microscopy of these two alloys. (author)

Modelling the solidification of ductile cast iron parts with varying wall thicknesses

DEFF Research Database (Denmark)

Bjerre, Mathias Karsten; Tiedje, Niels Skat; Thorborg, Jesper

2015-01-01

] with a 2D FE solution of the heat conduction equation is developed in an in-house code and model parameters are calibrated using experimental data from representative castings made of ductile cast iron. The main focus is on the influence of casting thickness and resulting local cooling conditions...

Microstructure and Mechanical Properties of Al-5Mg-0.8Mn Alloys with Various Contents of Fe and Si Cast under Near-Rapid Cooling

Directory of Open Access Journals (Sweden)

Yulin Liu

2017-10-01

Full Text Available Al-5Mg-0.8Mn alloys (AA5083 with various iron and silicon contents were cast under near-rapid cooling and rolled into sheets. The aim was to study the feasibility of minimizing the deteriorating level of the harmful Fe-rich phases on the mechanical properties through refining the intermetallics by significantly increasing the casting rate. The results showed that the size and density of the intermetallic particles that remained in the hot bands and the cold rolled sheets increased as the contents of iron and silicon in the alloys were increased. However, the increment of the particle sizes was limited due to the significant refinement of the intermetallics formed during casting under near-rapid cooling. The mechanical properties of the alloys reduced as the contents of iron and silicon in the alloys increased. However, the decrement of tensile strengths and ductility was quite small. Therefore, higher contents of iron and silicon could be used in the Al-5Mg-0.8Mn alloy (AA5083 alloy when the material is cast under near-rapid cooling, such as in the continuous strip casting process.

The effect of Fe-rich intermetallics on the microstructure, hardness and tensile properties of Al–Mg2Si die-cast composite

International Nuclear Information System (INIS)

Emamy, M.; Emami, A.R.; Khorshidi, R.; Ghorbani, M.R.

2013-01-01

Highlights: ► Effect of Fe on the microstructure and mechanical properties of Al–Mg 2 Si composite. ► Fe changed the size of primary Mg 2 Si from 33 μm to 15 μm. ► Higher hardness, YS, UTS and Quality Index values obtained from Fe addition. ► Different morphologies of Fe-intermetallics were found with higher Fe contents. - Abstract: In present paper, an attempt was made to examine the effect of different concentrations of Fe (0.5, 1, 1.5, 2 and 3 wt.%) on the microstructure and tensile properties of an in situ Al–15wt.%Mg 2 Si metal matrix composite (MMC). The composite was made by casting process and characterized by optical microscope, scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy. The results depicted that the addition of 2 wt.% Fe to the MMC changes the morphology of primary Mg 2 Si from irregular to polyhedral shape and reduces its average particle size from 33 μm to 15 μm. The microstructural studies also showed that the addition of Fe leads to the formation of Fe-rich intermetallics with polyhedral, plate-like and star-like morphology. Hardness results demonstrated that Fe addition to Al–15%Mg 2 Si composite has a positive effect on the hardness improvement. Further investigations on tensile tests revealed optimum Fe (1 wt.%) level for improving tensile properties. In the point of fracture behavior of the composite, Fe-containing specimens showed a brittle mode of failure

The Structure of the Silumin Coat on Alloy Cast Steels

Directory of Open Access Journals (Sweden)

T. Szymczak

2012-04-01

Full Text Available The work presents the analysis results of the structure of the coat obtained by dipping in silumin AlSi5 of two grades of alloy cast steel: GX6CrNiTi18-10 (LH18N9T and GX39Cr13 (LH14. The temperature of the silumin bath was 750±5°C, and the hold-up time of the cast steel element τ = 180 s. The absolute thickness of the coat obtained in the given conditions was g = 104 μm on cast steel GX6CrNiTi18-10 and g = 132 μm on GX39Cr13. The obtained coat consisted of three layers of different phase structure. The first layer from the base “g1`” was constructed of the phase AlFe including Si and alloy additives of the tested cast steel grades: Cr and Ni (GX6CrNiTi18-10 and Cr (GX39Cr13. The second layer “g1``” of intermetallic phases AlFe which also contains Si and Cr crystallizes on it. The last, external layer “g2” of the coat consists of the silumin containing the intermetallic phases AlFeSi which additionally can contain alloy additives of the cast steel. It was shown that there were no carbides on the coat of the tested cast steels which are the component of their microstructure, as it took place in the case of the coat on the high speed steels.

Exchange correlation length and magnetoresistance in Fe-Cu and Fe-Cu-Ni melt-spun ribbons

International Nuclear Information System (INIS)

El Ghannami, M.; Gomez-Polo, C.; Rivero, G.; Hernando, A.

1994-01-01

The magnetic properties of Fe 30 Cu 70 melt-spun ribbons are reported for the first time. In the as-cast state, the microstructure consists of b.c.c.-Fe grains immersed in a Cu-rich matrix. However, the addition of a small percentage of Ni gives rise to the appearance of new Cu-Fe-Ni phases. Under suitable thermal treatments, the microstructure of both alloys evolves towards a complete phase segregation in b.c.c-Fe and f.c.c.-Cu immiscibles phases. The temperature dependence of the magnetic properties is analysed and related to the microstructural changes produced during the thermal treatments. Remarkable magneto-resistance effects have been observed in both as-cast alloys, with maximum values of the order of 6% at low measuring temperatures. (orig.)

Repairs of Damaged Castings Made of Graphitic Cast Iron by Means of Brazing

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Mičian M.

2017-09-01

Full Text Available The article summarizes the theoretical knowledge from the field of brazing of graphitic cast iron, especially by means of conventional flame brazing using a filler metal based on CuZn (CuZn40SnSi – brass alloy. The experimental part of the thesis presents the results of performance assessment of brazed joints on other than CuZn basis using silicone (CuSi3Mn1 or aluminium bronze (CuAl10Fe. TIG electrical arc was used as a source of heat to melt these filler materials. The results show satisfactory brazed joints with a CuAl10Fe filler metal, while pre-heating is not necessary, which favours this method greatly while repairing sizeable castings. The technological procedure recommends the use of AC current with an increased frequency and a modified balance between positive and negative electric arc polarity to focus the heat on a filler metal without melting the base material. The suitability of the joint is evaluated on the basis of visual inspection, mechanic and metallographic testing.

Mechanical properties of Fe-Ni-Cr-Si-B bulk glassy alloy

International Nuclear Information System (INIS)

Lee, Kee Ahn; Kim, Yong Chan; Kim, Jung Han; Lee, Chong Soo; Namkung, Jung; Kim, Moon Chul

2007-01-01

The mechanical properties and crystallization behavior of new Fe-Ni-Cr-Si-B-based bulk glassy alloys were investigated. The suitability of the continuous roll casting method for the production of bulk metallic glass (BMG) sheets in such alloy systems was also examined. BMG samples (Fe-Ni-Cr-Si-B, Fe-Ni-Zr-Cr-Si-B, Fe-Ni-Zr-Cr-W-Si-B) in amorphous strip, cylindrical, and sheet forms were prepared through melt spinning, copper mold casting, and twin roll strip casting, respectively. Fe-Ni-Cr-Si-B alloy exhibited compressive strength of up to 2.93 GPa and plastic strain of about 1.51%. On the other hand, the Fe-Ni-Zr-Cr-Si-B, composite-type bulk sample with diameter of 2.0 mm showed remarkable compressive plastic strain of about 4.03%. The addition of zirconium was found to enhance the homogeneous precipitation of nanocrystalline less than 7 nm and to develop a hybrid-composite microstructure with increasing sample thickness. Twin roll strip casting was successfully applied to the fabrication of sheets in Fe-Ni-Cr-Si-B-based BMGs. The combined characteristics of high mechanical properties and ease of microstructure control proved to be promising in terms of the future progress of structural bulk amorphous alloys

Mechanical properties of Fe-Ni-Cr-Si-B bulk glassy alloy

Energy Technology Data Exchange (ETDEWEB)

Lee, Kee Ahn [School of Advanced Materials Engineering, Andong National University, Andong 760-749 (Korea, Republic of)]. E-mail: keeahn@andong.ac.kr; Kim, Yong Chan [New Metals Research Team, RIST, Pohang 790-330 (Korea, Republic of); Kim, Jung Han [Center for Advanced Aerospace materials, POSTECH, Pohang 790-784 (Korea, Republic of); Lee, Chong Soo [Center for Advanced Aerospace materials, POSTECH, Pohang 790-784 (Korea, Republic of); Namkung, Jung [New Metals Research Team, RIST, Pohang 790-330 (Korea, Republic of); Kim, Moon Chul [New Metals Research Team, RIST, Pohang 790-330 (Korea, Republic of)

2007-03-25

The mechanical properties and crystallization behavior of new Fe-Ni-Cr-Si-B-based bulk glassy alloys were investigated. The suitability of the continuous roll casting method for the production of bulk metallic glass (BMG) sheets in such alloy systems was also examined. BMG samples (Fe-Ni-Cr-Si-B, Fe-Ni-Zr-Cr-Si-B, Fe-Ni-Zr-Cr-W-Si-B) in amorphous strip, cylindrical, and sheet forms were prepared through melt spinning, copper mold casting, and twin roll strip casting, respectively. Fe-Ni-Cr-Si-B alloy exhibited compressive strength of up to 2.93 GPa and plastic strain of about 1.51%. On the other hand, the Fe-Ni-Zr-Cr-Si-B, composite-type bulk sample with diameter of 2.0 mm showed remarkable compressive plastic strain of about 4.03%. The addition of zirconium was found to enhance the homogeneous precipitation of nanocrystalline less than 7 nm and to develop a hybrid-composite microstructure with increasing sample thickness. Twin roll strip casting was successfully applied to the fabrication of sheets in Fe-Ni-Cr-Si-B-based BMGs. The combined characteristics of high mechanical properties and ease of microstructure control proved to be promising in terms of the future progress of structural bulk amorphous alloys.

Changes in Structural Characteristics of Hypoeutectic Al-Si Cast Alloy after Age Hardening

OpenAIRE

Lenka HURTALOVÁ; Juraj BELAN; Eva TILLOVÁ; Mária CHALUPOVÁ

2012-01-01

The contribution describes influence of the age-hardening consist of solution treatment at 515 °C with holding time 4 hours, water quenching at 40 °C and artificial aging at different temperature 150 °C, 170 °C and 190 °C with different holding time 2, 4, 8, 16 and 32 hours on mechanical properties (tensile strength and Brinell hardness) and changes in morphology of eutectic Si, Fe-rich and Cu-rich intermetallic phases in secondary (recycled) AlSi9Cu3 cast alloy. A combination of different an...

Hydrogenation-disproportionation-desorption-recombination in Sm{sub 2}Fe{sub 16}M (M=Al, Ga and Si) and magnetic properties of their carburized powders

Energy Technology Data Exchange (ETDEWEB)

Kubis, M.; Rave, W.; Cao, L.; Gebel, B.; Mueller, K.-H.; Schultz, L. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany)

1998-11-20

The application of the hydrogenation-disproportionation-desorption-recombination (HDDR) process in Sm{sub 2}Fe{sub 16}M (M=Al,Ga and Si) was investigated. The hydrogen absorption behaviour was studied by temperature-pressure analysis (TPA). In the temperature range between 500 and 800 C, Sm{sub 2}Fe{sub 16}M samples with M=Ga and Si show a weaker hydrogen absorption than Sm{sub 2}Fe{sub 16}Al. This was confirmed by X-ray diffraction which showed a complete disproportionation of Sm{sub 2}Fe{sub 16}Al into SmH{sub z} (1.9Fe,Al), while Sm{sub 2}Fe{sub 16}Ga and Sm{sub 2}Fe{sub 16}Si exhibit a fraction of undecomposed material with the Th{sub 2}Zn{sub 17}-type structure after the disproportionation procedure. These results point to a stabilization of Sm{sub 2}Fe{sub 16}M against disproportionation by hydrogen for M=Ga and Si. The magnetization processes of carburized HDDR powders were studied by VSM measurements and Kerr microscopy. The demagnetization curve of our HDDR processed Sm{sub 2}Fe{sub 16}AlC{sub y} is well shaped, whereas those of Sm{sub 2}Fe{sub 16}GaC{sub y} and Sm{sub 2}Fe{sub 16}SiC{sub y} show a large decrease of the polarization at low fields. The favourable behaviour of Sm{sub 2}Fe{sub 16}AlC{sub y} is due to a homogeneous submicron grain structure. In Sm{sub 2}Fe{sub 16}GaC{sub y} and Sm{sub 2}Fe{sub 16}SiC{sub y} samples, an additional, magnetically soft phase with larger domains was observed which causes the low coercivity. As a consequence, HDDR was only favourable for the preparation of Sm{sub 2}Fe{sub 16}MC{sub y} hard magnets with M=Al but not for M=Ga and Si. Optimization of the HDDR process in Sm{sub 2}Fe{sub 16}Al and subsequent nitrogenation or carburization led to coercivities of {mu}{sub 0j}H{sub c}=2.9 and 2.5 T, respectively. (orig.) 11 refs.

Application of complex inoculants in improving the process-ability of grey cast iron for cylinder blocks

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LIU Wei-ming

2006-05-01

Full Text Available Effect of several complex inoculants on mechanical properties, process-ability and sensibility of grey cast iron used in cylinder block were investigated. The experimental results showed that the grey cast iron treated with 60%FeSi75+40%RE complex inoculants has tensile strength consistently at about 295 MPa along with good hardness and improved metallurgy quality. While the grey cast iron inoculated with 20%FeSi75+80%Sr compound inoculants has the best process-ability, the lowest cross-section sensibility and the least microhardness difference. The wear amount of the drill increases correspondingly with the increase of the microhardness difference of matrix structure, indicating the great effect of homogeneousness of matrix structure in the grey cast iron on the machinability of the grey cast iron.

Influence of cooling rate on the microstructure and corrosion behavior of Al–Fe alloys

International Nuclear Information System (INIS)

Dorin, T.; Stanford, N.; Birbilis, N.; Gupta, R.K.

2015-01-01

Highlights: • Increasing the cooling rate from 0.1 to 500 °C/s, mass loss rate decreased by 6 times. • Increase in corrosion resistance was attributed to the refined Fe-intermetallics. • Increased cooling rate resulted in increased Fe content in solid solution. • Direct strip casting can produce alloys with higher acceptable content of impurities. • Direct Strip Casting is a potential candidate to improve recyclability of Al alloys - Abstract: The effect of Fe in Al is technologically important for commercial Al-alloys, and in recycled Al. This work explores the use of the novel rapid solidification technology, known as direct strip casting, to improve the recyclability of Al-alloys. We provide a comparison between the corrosion and microstructure of Al–Fe alloys prepared with wide-ranging cooling rates (0.1 °C/s to 500 °C/s). Rapid cooling was achieved via direct strip casting, while slow cooling was achieved using sand casting. Corrosion was studied via polarisation and immersion tests, followed by surface analysis using scanning electron microscopy and optical profilometry. It was shown that the corrosion resistance of Al–Fe alloys is improved with increased cooling rates, attributed to the reduced size and number of Fe-containing intermetallics.

One-step production of optimized Fe-Ga particles by spark erosion

International Nuclear Information System (INIS)

Hong, J. I.; Solomon, V. C.; Smith, David J.; Parker, F. T.; Summers, E. M.; Berkowitz, A. E.

2006-01-01

Spherical Fe-Ga particles were prepared by spark erosion in liquid Ar, which directly incorporated the desirable rapid quench from high temperatures. The compositions of the particles investigated were 15.0, 16.3, and 18.9 at. % Ga, respectively, as determined from electron-probe microanalysis, x-ray diffraction, and Moessbauer spectra. Composites for magnetostriction measurements were prepared by mixing particles with epoxy at the volume fraction of 48% and curing in a magnetic field. Magnetostriction values of the composites were comparable to those of polycrystalline chill-cast alloys of the same compositions. Composites with particles having Ga concentrations of 18.9 at. % had the highest magnetostriction, similar to results reported for bulk Fe-Ga alloys

High coercivity in Fe-Nb-B-Dy bulk nanocrystalline magnets

Energy Technology Data Exchange (ETDEWEB)

Ziolkowski, Grzegorz; Chrobak, Artur; Klimontko, Joanna [Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007, Katowice (Poland); Chrobak, Dariusz; Rak, Jan [Institute of Materials Science, University of Silesia, 75 Pulku Piechoty 1, 41-500, Chorzow (Poland); Zivotsky, Ondrej; Hendrych, Ales [Department of Physics, VSB-TU Ostrava, Ostrava (Czech Republic)

2016-11-15

The paper refers to structural and magnetic properties of the (Fe{sub 80}Nb{sub 6}B{sub 14}){sub 1-x}Dy{sub x} (x = 0.08, 0.10, 0.12, 0.16) bulk nanocrystalline alloys prepared by making use of the vacuum suction casting technique. The samples are in a form of rods with different diameters d = 1.5, 1, and 0.5 mm. The phase structure was investigated by XRD technique and reveals an occurrence of magnetically hard Dy{sub 2}Fe{sub 14}B as well as other relatively soft Dy-Fe, Fe-B, and Fe phases dependently on the Dy content. The alloys show hard magnetic properties with high coercive field up to 5.5 T (for x = 0.12 and d = 0.5 mm). The observed magnetic hardening effect with the increase of cooling rate (decrease of sample diameter d) can be attributed to a formation of ultra-hard magnetic objects as well as increasing role of low dimensional microstructure. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The microstructure of steels and cast irons. History and interpretation

International Nuclear Information System (INIS)

Durand-Charre, M.

2003-01-01

The microstructure of steels and cast irons is a monograph on the history and interpretation of the microstructure of steels and iron alloys. Its 400 pages are illustrated by a lot of micrographies of commercial alloys or model alloys at each the available scales with the modern investigations means of electronic microscopy and the optical macro/microscopy. The first part of this book is an historical introduction on the development of the metallurgical structures manually forged for the iron knowledge, in particular the famous structures called damask. The second part of this book deals with the fundamental notions in order to give all the reasoning bases required on the phases equilibria and the transformations kinetics. Concerning the phases equilibria, a lot of diagrams are included. The reading of ternary systems is analyzed for six systems representative of the reactions encountered in steels, Fe-Cr-C, Fe-Ni-Cr, Fe-Mn-S, Fe-Co-Cu, Fe-Mo-Cr and Fe-C-V. The solidification structures are studied through all the classical cases but in others too as the markings of peritectic or metatectic reactions or transformations in series. Solid phases transformations are illustrated and commented with recent interpretations, in particular in the case of bainitic structures. A lot of references allow to deepen the non developed aspects. The third part is a guide to understand and discuss on scientific bases the role of alloy elements and those of different specific treatments resulting to the optimisation of steels and iron casts, to define the micrographic characteristics in relation with the use properties. Steels are classified in series for the very low alloy steels to steels with high amounts in alloy elements resulting of a very fine composition adjustment. Cast irons are presented naturally according to their microstructure, classified in white irons, lamellar grey and nodular irons. (O.M.)

Microstructure and Hot Deformation Behavior of Fe-20Cr-5Al Alloy

OpenAIRE

Jung-Ho Moon; Tae Kwon Ha

2014-01-01

High temperature deformation behavior of cast Fe-20Cr-5Al alloy has been investigated in this study by performing tensile and compression tests at temperatures from 1100 to 1200oC. Rectangular ingots of which the dimensions were 300×300×100 in millimeter were cast using vacuum induction melting. Phase equilibrium was calculated using the FactSage®, thermodynamic software and database. Tensile strength of cast Fe-20Cr-5Al alloy was 4 MPa at 1200oC. With temperature decreas...

Permanent magnets prepared from Sm{sub 10.5}Fe{sub 88.5}Zr{sub 1.0}N{sub y} without homogenization

Energy Technology Data Exchange (ETDEWEB)

Gebel, B.; Kubis, M.; Mueller, K.-H. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany). Inst. fuer Metallische Werkstoffe

1997-10-01

In as-cast Sm{sub 2}Fe{sub 17} the high amount of {alpha}-Fe caused by a peritectic reaction can be considerably reduced by a small addition of about 1 at% Zr. X-ray diffraction showed that as-cast Sm{sub 10.5}Fe{sub 88.5}Zr{sub 1.0} mainly consists of a phase with the Th{sub 2}Zn{sub 17}-type structure and SmFe{sub 3}. Non-homogenized Sm{sub 10.5}Fe{sub 88.5}Zr{sub 1.0} was milled and (i) annealed in vacuum or (ii) treated with a hydrogenation-disproportionation-desorp tion-recombination (HDDR) process. The annealed and subsequently nitrogenated powder is magnetically anisotropic and has a coercivity {mu}{sub 0J}H{sub C} up to 2.0 T and an energy product (BH){sub max} up to 136 kJ/m{sup 3}. HDDR-treated and nitrogenated powder is isotropic and exhibits values of {mu}{sub 0J}H{sub C} = 3.1 T and (BH){sub max} 103 kJ/m{sup 3}. Consequently, Sm{sub 10.5}Fe{sub 88.5}Zr{sub 1.0}N{sub y} (y {approx} 16) permanent magnets with very good properties can be prepared without the time-consuming homogenization procedure. (orig.). 11 refs.

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

Science.gov (United States)

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

2010-03-01

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

Possibilities of Pelletizing and Briquetting of Dusts from Castings Grinding

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A. Pribulová

2010-04-01

Full Text Available Foundry dust can be divided into three groups: metallic dust with Fe content over 70%, mixed dust with Fe or SiO2 content between 10 –70% and sand wastes with minimum content of SiO2 about 70%. Dust from castings grinding with high Fe content (87.9% is still landfillin Slovakia. The aim of experiments with dust from grinding has been to find the cheapest way of dust agglomeration with minimumamount of binder because of melting in the electric induction furnace. The dust was pelletized and briquetted and as binders bentonite, water glass and cement were used. Briquettes made from dust from grinding with addition of water glass got compression strength after three months on the air about 82 kPa. Briquettes with addition of water glass were melted together with cast iron in electric induction furnace. Yield of metal from briquettes was around 80% and slag quantity around 4% (without briquettes the slag quantity was 1.4%.

Microstructure evolution and large magnetocaloric effect of La0.8Ce0.2(Fe0.95Co0.05)11.8Si1.2 alloy prepared by strip-casting and annealing

Science.gov (United States)

Zhong, X. C.; Feng, X. L.; Huang, J. H.; Zhang, H.; Huang, Y. L.; Liu, Z. W.; Jiao, D. L.

2018-04-01

The microstructure and magnetocaloric effect of the La0.8Ce0.2(Fe0.95Co0.05)11.8Si1.2 strip-cast flakes annealed between 1273K and 1423K for different time have been investigated. For the flakes annealed for 2h from 1273K to 1423K, the shape and distribution of α-Fe, La-rich and NaZn13-type 1:13 phases are quite sensitive to the annealing temperature. Especially, at a high annealing temperature of 1423K, the 1:13 phase began to decompose into macroscopic α-Fe conglomerations and La-rich dendrites. With the increase of annealing time from 0 to 12h at 1323K, the amount of 1:13 phase increased significantly and reached ˜93.50 wt.% at 12h. However, an overlong annealing time also led to 1:13 phase decomposition and influenced the magnetic performance. For the flakes annealed at 1323K for 12h, large magnetic entropy change value of 18.12Jkg-1K-1 at 5T has been obtained. The present results indicate that strip casting method can potentially be used in mass production of high performance magnetocaloric materials.

Effects of high temperature surface oxides on room temperature aqueous corrosion and environmental embrittlement of iron aluminides

Energy Technology Data Exchange (ETDEWEB)

Buchanan, R.A.; Perrin, R.L.

1996-09-01

Studies were conducted to determine the effects of high-temperature surface oxides, produced during thermomechanical processing, heat treatment (750 {degrees}C in air, one hour) or simulated in-service-type oxidation (1000{degrees}C in air, 24 hours) on the room-temperature aqueous-corrosion and environmental-embrittlement characteristics of iron aluminides. Materials evaluated included the Fe{sub 3}Al-based iron aluminides, FA-84, FA-129, FAL and FAL-Mo, a FeAl-based iron aluminide, FA-385, and a disordered low-aluminum Fe-Al alloy, FAPY. Tests were performed in a mild acid-chloride solution to simulate aggressive atmospheric corrosion. Cyclic-anodic-polarization tests were employed to evaluate resistances to localized aqueous corrosion. The high-temperature oxide surfaces consistently produced detrimental results relative to mechanically or chemically cleaned surfaces. Specifically, the pitting corrosion resistances were much lower for the as-processed and 750{degrees} C surfaces, relative to the cleaned surfaces, for FA-84, FA-129, FAL-Mo, FA-385 and FAPY. Furthermore, the pitting corrosion resistances were much lower for the 1000{degrees}C surfaces, relative to cleaned surfaces, for FA-129, FAL and FAL-Mo.

Fatigue Life of Cast Titanium Alloys Under Simulated Denture Framework Displacements

Science.gov (United States)

Koike, Mari; Chan, Kwai S.; Hummel, Susan K.; Mason, Robert L.; Okabe, Toru

2013-02-01

The objective of the study was to evaluate the hypothesis that the mechanical properties and fatigue behavior of removable partial dentures (RPD) made from cast titanium alloys can be improved by alloying with low-cost, low-melting elements such as Cu, Al, and Fe using commercially pure Ti (CP-Ti) and Ti-6Al-4V as controls. RPD specimens in the form of rest-shaped, clasp, rectangular-shaped specimens and round-bar tensile specimens were cast using an experimental Ti-5Al-5Cu alloy, Ti-5Al-1Fe, and Ti-1Fe in an Al2O3-based investment with a centrifugal-casting machine. The mechanical properties of the alloys were determined by performing tensile tests under a controlled displacement rate. The fatigue life of the RPD specimens was tested by the three-point bending in an MTS testing machine under a cyclic displacement of 0.5 mm. Fatigue tests were performed at 10 Hz at ambient temperature until the specimens failed into two pieces. The tensile data were statistically analyzed using one-way ANOVA (α = 0.05) and the fatigue life data were analyzed using the Kaplan-Meier survival analysis (α = 0.05). The experimental Ti-5Al-5Cu alloy showed a significantly higher average fatigue life than that of either CP-Ti or Ti-5Al-1Fe alloy ( p < 0.05). SEM fractography showed that the fatigue cracks initiated from surface grains, surface pores, or hard particles in surface grains instead of the internal casting pores. Among the alloys tested, the Ti-5Al-5Cu alloy exhibited favorable results in fabricating dental appliances with an excellent fatigue behavior compared with other commercial alloys.

Effect of Cr, Ti, V, and Zr Micro-additions on Microstructure and Mechanical Properties of the Al-Si-Cu-Mg Cast Alloy

Science.gov (United States)

Shaha, S. K.; Czerwinski, F.; Kasprzak, W.; Friedman, J.; Chen, D. L.

2016-05-01

Uniaxial static and cyclic tests were used to assess the role of Cr, Ti, V, and Zr additions on properties of the Al-7Si-1Cu-0.5Mg (wt pct) alloy in as-cast and T6 heat-treated conditions. The microstructure of the as-cast alloy consisted of α-Al, eutectic Si, and Cu-, Mg-, and Fe-rich phases Al2.1Cu, Al8.5Si2.4Cu, Al5.2CuMg4Si5.1, and Al14Si7.1FeMg3.3. In addition, the micro-sized Cr/Zr/Ti/V-rich phases Al10.7SiTi3.6, Al6.7Si1.2TiZr1.8, Al21.4Si3.4Ti4.7VZr1.8, Al18.5Si7.3Cr2.6V, Al7.9Si8.5Cr6.8V4.1Ti, Al6.3Si23.2FeCr9.2V1.6Ti1.3, Al92.2Si16.7Fe7.6Cr8.3V1.8, and Al8.2Si30.1Fe1.6Cr18.8V3.3Ti2.9Zr were present. During solution treatment, Cu-rich phases were completely dissolved, while the eutectic silicon, Fe-, and Cr/Zr/Ti/V-rich intermetallics experienced only partial dissolution. Micro-additions of Cr, Zr, Ti, and V positively affected the alloy strength. The modified alloy in the T6 temper during uniaxial tensile tests exhibited yield strength of 289 MPa and ultimate tensile strength of 342 MPa, being significantly higher than that for the Al-Si-Cu-Mg base. Besides, the cyclic yield stress of the modified alloy in the T6 state increased by 23 pct over that of the base alloy. The fatigue life of the modified alloy was substantially longer than that of the base alloy tested using the same parameters. The role of Cr, Ti, V, and Zr containing phases in controlling the alloy fracture during static and cyclic loading is discussed.

Locally Reinforcement TiC-Fe Type Produced in Situ in Castings

Directory of Open Access Journals (Sweden)

Olejnik E.

2016-09-01

Full Text Available Refinement is one of the most energy consuming technological process, aimed at obtaining mineral raw materials of the proper grain size. Cast structural elements such as jaws or hammers in crushing machines operate under conditions of an intensive wear. The data indicate that 80 % of failures of machines and devices is caused by wearing of rubbing surfaces. This problem became the subject of several scientific and industrial investigations carried out in the whole world in order to produce materials ultra- wear resistant. Methods allowing to obtain wear resistant composite castings are discussed in the hereby paper. Within the performed research microstructures of the produced composite zones were presented and the comparative analysis with regard to mechanical and functional properties of local composite reinforcements in relation to the commercial alloys of increased wear resistance was performed. The results show almost twenty five times increase in wear resistance compared to manganese cast steel containing 18 % Mn.

Study of Bending Fatigue Properties of Al-Si Cast Alloy

Directory of Open Access Journals (Sweden)

Tillová E.

2017-09-01

Full Text Available Fatigue properties of casting Al-alloys are very sensitive to the microstructural features of the alloy (e.g. size and morphology of the eutectic Si, secondary dendrite arm spacing - SDAS, intermetallics, grain size and casting defects (porosity and oxides. Experimental study of bending fatigue properties of secondary cast alloys have shown that: fatigue tests up to 106-107cycles show mean fatigue limits of approx. 30-49 MPa (AlSi9Cu3 alloy - as cast state, approx. 65-76 MPa (AlSi9Cu3 alloy after solution treatment and 60-70 MPa (self-hardened AlZn10Si8Mg alloy in the tested casting condition; whenever large pore is present at or near the specimen’s surface, it will be the dominant cause of fatigue crack initiation; in the absence of large casting defects, the influence of microstructural features (Si morphology; Fe-rich phases on the fatigue performance becomes more pronounced.

Method for casting thin metal objects

Science.gov (United States)

Pehrson, Brandon P; Moore, Alan F

2015-04-14

Provided herein are various embodiments of systems for casting thin metal plates and sheets. Typical embodiments include layers of mold cavities that are oriented vertically for casting the metal plates. In some embodiments, the mold cavities include a beveled edge such that the plates that are cast have a beveled edge. In some embodiments, the mold cavities are filled with a molten metal through an open horizontal edge of the cavity. In some embodiments, the mold cavities are filled through one or more vertical feed orifices. Further disclosed are methods for forming a thin cast metal plate or sheet where the thickness of the cast part is in a range from 0.005 inches to 0.2 inches, and the surface area of the cast part is in a range from 16 square inches to 144 square inches.

Conductivity enhancement induced by casting of polymer electrolytes under a magnetic field

International Nuclear Information System (INIS)

Kovarsky, R.; Golodnitsky, D.; Peled, E.; Khatun, S.; Stallworth, P.E.; Greenbaum, S.; Greenbaum, A.

2011-01-01

Highlights: ► Ordering of polymer electrolytes under applied magnetic field. ► Positive effect of nanosize ferromagnetic filler. ► Structure-ion conductivity interrelationship. - Abstract: We recently presented a procedure for orienting the polyethylene-oxide (PEO) helices in a direction perpendicular to the film plane by casting the polymer electrolytes (PE) under a magnetic field (MF). Here we study the influence of magnetic fields of different strengths and configurations on the structural properties and ionic conductivity of concentrated LiCF 3 SO 3 (LiTf) and LiAsF 6 :P(EO) pristine and composite polymer electrolytes containing γ-Fe 2 O 3 nanoparticles. Some data of LiI:P(EO) system are shown for comparison. We suggest that the effect of type of salt (LiI, LiTf and LiAsF 6 ) on the structure–conductivity relationship of the polymer electrolytes cast under magnetic field is closely connected to the crystallinity of the PEO–LiX system. It was found that the higher the content of the crystalline phase and the size of spherulites in the typically cast salt-polymer system, the stronger the influence of the magnetic field on the conductivity enhancement when the electrolyte is cast and dried under MF. Casting of the PE from a high-dielectric-constant solvent results in disentanglement of the PEO chains, which facilitates even more the perpendicular orientation of helices under applied MF. The enhancement of ionic conductivity was appreciably higher in the PEs cast under strong NdFeB magnets than under SmCo. Both bulk (intrachain) and grain-boundary conductivities increase when a MF is applied, but the improvement in the grain-boundary conductivity – associated with ion-hopping between polymer chains – is more pronounced. For LiAsF 6 :(PEO) 3 at 65 °C, the interchain conductivity increased by a factor of 75, while the intrachain conductivity increased by a factor of 11–14. At room temperature, the SEI resistance of these PEs, cast under NdFeB HMF

Effects of heat treatment on the microstructure and mechanical properties of AA2618 DC cast alloy

International Nuclear Information System (INIS)

Elgallad, E.M.; Shen, P.; Zhang, Z.; Chen, X.-G.

2014-01-01

Highlights: • The microstructure and mechanical properties of AA2618 DC cast alloy were studied. • The Al 2 CuMg, Al 2 Cu, Al 7 Cu 4 Ni, Al 7 Cu 2 (Fe,Ni) and Al 9 FeNi phases were identified. • Solution treatment at 530 °C for 5 h is the optimum solution treatment. • Different combinations of strength and ductility can be achieved. • The strengthening of AA2618 DC cast alloy was caused by GPB zones and S′ phase. - Abstract: Direct chill (DC) cast ingot plates of AA2618 alloy have been increasingly used for large-mold applications in the plastics and automotive industries. The effects of different heat treatments on the microstructure and mechanical properties of AA2618 DC cast alloy were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and hardness and tensile testing. The as-cast microstructure contained a considerable amount of coarse intermetallic phases, including Al 2 CuMg, Al 2 Cu, Al 7 Cu 4 Ni, Al 7 Cu 2 (Fe,Ni) and Al 9 FeNi, resulting in poor mechanical properties. Solution treatment at 530 °C for 5 h dissolved the first three phases into the solid solution and consequently improved the mechanical properties of the alloy. By utilizing the appropriate aging temperature and time, different combinations of strength and ductility could be obtained to fulfill the design requirements of large-mold applications. The strengthening of AA2618 DC cast alloy under the aging conditions studied was caused by GPB zones and S′ precipitates. The evolution of both precipitates in terms of their size and density was observed to have a significant effect on the mechanical properties of the alloy

Effect of Titanium Inoculation on Tribological Properties of High Chromium Cast Iron

Directory of Open Access Journals (Sweden)

Siekaniec D.

2017-12-01

Full Text Available The present investigation focuses on the study of the influence of titanium inoculation on tribological properties of High Chromium Cast Iron. Studies of tribological properties of High Chromium Cast Iron, in particularly the wear resistance are important because of the special application of this material. High Chromium Cast Iron is widely used for parts that require high wear resistance for example the slurry pumps, brick dies, several pieces of mine drilling equipment, rock machining equipment, and similar ones. Presented research described the effects of various amounts of Fe-Ti as an inoculant for wear resistance. The results of wear resistance were collated with microstructural analysis. The melts were conducted in industrial conditions. The inoculation was carried out on the stream of liquid metal. The following amount of inoculants have been used; 0.17% Fe-Ti, 0.33% Fe-Ti and 0.66% Fe-Ti. The tests were performed on the machine type MAN. The assessment of wear resistance was made on the basis of the weight loss. The experimental results indicate that inoculation improve the wear resistance. In every sample after inoculation the wear resistance was at least 20% higher than the reference sample. The best result, thus the smallest wear loss was achieved for inoculation by 0.66% Fe-Ti. There is the correlation between the changing in microstructure and wear resistance. With greater amount of titanium the microstructure is finer. More fine carbides do not crumbling so quickly from the matrix, improving the wear resistance.

Glass forming ability and magnetic properties of Co(40.2−x)Fe(20.1+x)Ni6.7B22.7Si5.3Nb5 (x=0–10) bulk metallic glasses produced by suction casting

International Nuclear Information System (INIS)

Sarlar, Kagan; Kucuk, Ilker

2015-01-01

The effect of Fe concentration on the glass forming ability (GFA) and magnetic properties in Co (40.2−x) Fe (20.1+x) Ni 6.7 B 22.7 Si 5.3 Nb 5 (x=0–10) bulk metallic glasses were investigated. By suction casting method, the bulk metallic glasses with diameters up to 2 mm were produced. We try to find out which Fe concentration makes an influence on Co based system's magnetic properties and glass forming ability. The curves of thermal analysis, obtained using differential scanning calorimetry (DSC), show that the Co (40.2−x) Fe (20.1+x) Ni 6.7 B 22.7 Si 5.3 Nb 5 (x=0–10) have a supercooled liquid region (∆T x ) of about 44 K. The saturation magnetizations (J s ) for as-cast BMG alloys were in the range of 0.62 T−0.81 T. - Highlights: • The effect of Fe concentration on the glass forming ability. • The substitution of an appropriate amount of Fe can enhance the GFA. • The substitution of Fe for Co also improves soft magnetic properties of the BMGs. • The high of J s 0.62−0.81 T with a low H c of 2−289 A/m of the alloys

Effect of Si on Fe-rich intermetallic formation and mechanical properties of heat-treated Al–Cu–Mn–Fe alloys

Science.gov (United States)

Zhao, Yuliang; Zhang, Weiwen; Yang, Chao; Zhang, Datong; Wang, Zhi

2018-04-01

The effect of Si on Fe-rich intermetallics formation and mechanical properties of heat-treated squeeze cast Al-5.0Cu-0.6Mn-0.7Fe alloy was investigated. Our results show that increasing Si content promotes the formation of Al15(FeMn)3(SiCu)2 (${\\alpha}$-Fe), and varying the morphology of T (Al20Cu3Mn2) where the size decreases and the amount increases. The major reason is that Si promotes heterogeneous nucleation of the intermetallics leading to finer precipitates. Si addition significantly enhances ultimate tensile strength and yield strength of the alloys. The strengthening effect is mainly owing to the dispersoid strengthening by increasing volume fraction of T phase and less harmful ${\\alpha}$-Fe with a compact structure, which make the cracks more difficult to initiate and propagation during tensile test. The squeeze cast Al-5.0Cu-0.6Mn-0.7Fe alloy with 1.1% Si shows significantly improved mechanical properties than the alloy without Si addition, which has tensile strength of 386 MPa, yield strength of 280 MPa and elongation of 8.6%.

Effect of Microstructure of Fe-C-V Alloys on Selected Functional Properties

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Kawalec M.

2014-08-01

Full Text Available The cast alloys crystallizing in Fe-C-V system are classified as white cast iron, because all the carbon is bound in vanadium carbides. High vanadium cast iron has a very high abrasion resistance due to hard VC vanadium carbides. However, as opposed to ordinary white cast iron, this material can be treated using conventional machining tools. This article contains the results of the group of Fe-C-V alloys of various microstructure which are been tested metallographic, mechanical using an INSTRON machine and machinability with the method of drilling. The study shows that controlling the proper chemical composition can influence on the type and shape of the crystallized matrix and vanadium carbides. This makes it possible to obtain a high-vanadium cast iron with very high wear resistance while maintaining a good workability.

The microstructure and magnetic properties of melt-spun Fe 76Nd 16B 8 magnetic materials

Science.gov (United States)

Hadjipanayis, G. C.; Dickenson, R. C.; Lawless, K. R.

1986-02-01

The origin of magnetic hardening has been examined in melt-spun Fe 76Nd 16B 8 samples heat-treated at around 700°C. Microstructure studies show the same phases as in sintered magnets consisting of Fe 14Nd 2B, Fe 4NdB 4 and two high-Nd content phases. These phases exist in both equiaxed and faceted crystallites of submicron size. Lorentz microscopy shows domain walls which end at grain boundaries indicating that they are pinned there.

Structure and grindability of cast Ti-5Cr-xFe alloys

International Nuclear Information System (INIS)

Hsu, H.-C.; Pan, C.-H.; Wu, S.-C.; Ho, W.-F.

2009-01-01

The purpose of this study was to investigate the structure, microhardness and grindability of Ti-5Cr and a series of ternary Ti-5Cr-xFe alloys with 0.1, 0.5, 1, 3 and 5 wt.% Fe, respectively. This study evaluated the phase and structure of Ti-5Cr and Ti-5Cr-xFe alloys, using an X-ray diffraction (XRD) for phase analysis and optical microscope for microstructure of the etched alloys. In addition, grindability was evaluated by measuring the amount of metal volume removed after grinding for 1 min at each of the four rotational speeds of the wheel (500, 750, 1000 or 1200 m/min), with the goal of developing a titanium alloy with better machinability than commercially pure titanium (c.p. Ti). The results showed that the structure of Ti-5Cr-xFe alloys is sensitive to the Fe content. With Fe contents higher than 0.5 wt.%, the equi-axed β phase is entirely retained, while ω phase was found in the Ti-5Cr, Ti-5Cr-0.1Fe, Ti-5Cr-0.5Fe and Ti-5Cr-1Fe alloys. The largest quantity of ω phase and highest microhardness were found in Ti-5Cr-0.5Fe and Ti-5Cr-1Fe alloys. The grinding rates of the Ti-5Cr and Ti-5Cr-xFe alloys showed a similar tendency to the microhardness. The Ti-5Cr, Ti-5Cr-0.1Fe, Ti-5Cr-0.5Fe and Ti-5Cr-1Fe alloys exhibited the best grindability, especially at 500, 750 and 1000 m/min. Furthermore, the grindability of the tested metals increased in proportion to grinding speed up to 1000 m/min, with a decrease after 1200 m/min. This study concluded that Fe may be used to harden titanium and improve the grindability

The system study of 1:13 phase formation, the magnetic transition adjustment, and magnetocaloric property in La(Fe,Co){sub 13−x}Si{sub x} alloys

Energy Technology Data Exchange (ETDEWEB)

Chen, Xiang, E-mail: gxucx@163.com [School of Materials Science and Engineering, Sichuan University, Chengdu 610065 (China); Department of Physics and Electronic Informational Engineering, Neijiang Teachers College, Neijiang 641002 (China); Chen, Yungui, E-mail: ygchen60@yahoo.com.cn [School of Materials Science and Engineering, Sichuan University, Chengdu 610065 (China); Tang, Yongbo; Xiao, Dingquan [School of Materials Science and Engineering, Sichuan University, Chengdu 610065 (China)

2014-11-15

The effects of Co on the formation of NaZn{sub 13}-type phase in as-cast and annealed LaFe{sub 16−x}Co{sub x}Si{sub 1.4} and LaFe{sub 11.6}Si{sub 1.4−x}Co{sub x} alloys have been investigated systematically by XRD, SEM, and EDS, respectively. In LaFe{sub 11.6}Si{sub 1.4−x}Co{sub x} alloys, the introduction of Co will hamper the formation of 1:13 and LaFeSi phases, and help the formation of αof (Co, Si) solid solution, so there is almost only α-Fe(Co, Si) solid solution when x reaches 0.7 in as-cast and annealed LaFe{sub 11.6}Si{sub 1.4−x}Co{sub x} alloys. Although the amounts of 1:13 phase increases when x reaches 0.7 in as-cast LaFe{sub 16−x}Co{sub x}Si{sub 1.4} alloys, there is a small amount of α-Fe in LaFe{sub 11.6−x}Co{sub x}Si{sub 1.4} alloys annealed at 1523 K (5 h), which indicates that the annealing time for obtaining a 1:13 single-phase cannot be shortened in our high-temperature and short-time annealing. The studies on the magnetic properties show that the Curie temperature T{sub C} goes up from 207 K to 285 K with increase of Co content from x=0.1 to 0.8. The introduction of Co element weakens the first order magnetic phase transition, which results in the change of magnetic transition type from first to second order at about x=0.3–0.5. At the same time, it has effects on the phase transition temperature interval and magnetic filed interval, and the changing rate of magnetic entropy change dependence on the Co content in LaFe{sub 16−x}Co{sub x}Si{sub 1.4} alloys. The maximum entropy values of LaFe{sub 11.6−x}Co{sub x}Si{sub 1.4} alloys decrease with the increase of Co content, but the relative cooling power does not decrease, the reason of which is that the phase transition temperature interval increases and the first order phase transition character decreases, and the effective refrigeration temperature range becomes big, which is useful to the application of magnetic refrigeration material. - Highlights: • The introduction of Co

Co2FeSi Heusler alloy prepared by arc melting and planar flow casting methods: microstructure and magnetism.

Czech Academy of Sciences Publication Activity Database

Titov, Andrii; Životský, O.; Hendrych, A.; Janičkovič, D.; Buršík, Jiří; Jirásková, Yvonna

2017-01-01

Roč. 131, č. 4 (2017), s. 654-656 ISSN 0587-4246. [CSMAG 2016 - Czech and Slovak Conference on Magnetism /16./. Košice, 13.06.2016-17.06.2016] Institutional support: RVO:68081723 Keywords : Heusler alloy * Surface morphology * Magnetic properties * Arc melting * Planar flow casting Subject RIV: BM - Solid Matter Physics ; Magnetism; BM - Solid Matter Physics ; Magnetism (UFM-A) OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 0.469, year: 2016

Tuning magnetocrystalline anisotropy of α″-Fe{sub 16}N{sub 2} by interstitial impurity doping: A first principles study

Energy Technology Data Exchange (ETDEWEB)

Khan, Imran; Hong, Jisang, E-mail: hongj@pknu.ac.kr

2017-07-01

Highlights: • The electronic structure and magnetic properties of 2s and 2p elements doped α″-Fe{sub 16}N{sub 2} were investigated. • The impurity doping induced local lattice distortions near the impurity site. • The local lattice distortion mainly contributed to enhance the magnetocrystalline anisotropy. • Almost 16% enhancement was achieved in coercive field due to enhancement of the magnetic anisotropy. • The maximum energy product was also enhanced due to impurity doping. - Abstract: The electronic structure and the magnetocrystalline anisotropy of impurity (Li, Be, B, C, and N) doped α″-Fe{sub 16}N{sub 2} were studied by using full potential linearized augmented plane wave method (FLAPW). From the formation energy calculations, it was evident that the 2s and 2p elements except Li could be easily doped into pure α″-Fe{sub 16}N{sub 2}. The impurity doping induced local lattice distortions near the impurity site and the magnetic moment near the impurity atom was substantially suppressed. However, the volume of the cell and the total magnetic moment of the doped systems were weakly suppressed compared to the pure α″-Fe{sub 16}N{sub 2}. Despite this relatively weak suppression in magnetization, the local distortion contributed to enhancing the magnetocrystalline anisotropy. Due to this enhancement in the anisotropy, the coercive field was also enhanced about 12–16% compared with that in pure structure. Along with the enlarged coercive field, the energy product was also increased. These results may suggest that impurity doped α″-Fe{sub 16}N{sub 2} can be used as potential rare earth free permanent magnet.

Microstructure analysis of AISI 304 stainless steel produced by twin-roll thin strip casting process

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

The microstructure of AISI 304 austenite stainless steel fabricated by the thin strip casting process were investigated using optical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD).The microstructures of the casting strips show a duplex structure consisting of delta ferrite and austenite. The volume fraction of the delta ferrite is about 9.74vol% at the center and 6.77vol% at the surface of the casting thin strip, in vermicular and band shapes. On account of rapid cooling and solidification in the continuous casting process, many kinds of inclusions and precipitates have been found. Most of the inclusions and precipitates are spherical complex compounds consisting of oxides, such as, SiO2, MnO, Al2O3,Cr2O3,and FeO or their multiplicity oxides of MnO·Al2O3,2FeO·SiO2, and 2MnO·SiO2. Many defects including dislocations and stacking faults have also formed during the rapid cooling and solidification process, which is helpful to improve the mechanical properties of the casting strips.

High coercivity microcrystalline Nd-rich Nd–Fe–Co–Al–B bulk magnets prepared by direct copper mold casting

Energy Technology Data Exchange (ETDEWEB)

Zhao, L.Z.; Hong, Y. [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Fang, X.G. [Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510640 (China); Qiu, Z.G.; Zhong, X.C. [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Gao, X.S. [Institute for Advanced Materials and Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510640 (China); Liu, Z.W., E-mail: zwliu@scut.edu.cn [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China)

2016-06-15

High coercivity Nd{sub 25}Fe{sub 40}Co{sub 20}Al{sub 15−x}B{sub x} (x=7–15) hard magnets were prepared by a simple process of injection casting. Different from many previous investigations on nanocomposite compositions, the magnets in this work contain hard magnetic Nd{sub 2}(FeCoAl){sub 14}B, Nd-rich, and Nd{sub 1+ε}(FeCo){sub 4}B{sub 4} phases. The magnetic properties, phase evolution, and microstructure of the as-cast and annealed magnets were investigated. As the boron content increased from 7 to 11 at%, the intrinsic coercivity H{sub cj} of the as-cast magnet increased from 816 to 1140 kA/m. The magnets annealed at 750 °C have shown more regular and smaller grains than the as-cast alloys, especially for the x=11 alloy. The high intrinsic coercivities for the annealed alloys with x=8~11 result from the presence of small-sized grains in the microstructure. The highest H{sub cj} of 1427 kA/m was obtained for the heat treated alloy with x=10. This work provides an alternative approach for preparing fully dense Nd-rich bulk hard magnets with relatively good properties. - Highlights: • 2 mm hard magnetic Nd{sub 25}Fe{sub 40}Co{sub 20}Al{sub 15−x}B{sub x} rods were prepared by direct casting. • High coercivity of 1.78 T was achieved in x=11 sample after heat treatment. • Small grains are responsible for the significant increase in H{sub C} after annealing. • Nd{sub 2}Fe{sub 14}B grains with two different sizes lead to two-step demagnetization process.

Microstructure analysis of cofebsinb metallic glasses with a various geometry prepared by planar flow casting and suction casting methods

International Nuclear Information System (INIS)

Hosko, J.; Janotova, J.; Svec, P.; Matko, I.; Janickovic, D.; Svec, P. Sr.

2012-01-01

In this paper we have studied the structure of as-cast Co_4_7Fe_2_0_._9B_2_1_._2Si_4_._6Nb_6_._3 ribbon, bilayer and bulk samples in form of rods up to 5 mm diameter. Amorphous structure of the ribbons and bilayer prepared by PFC was confirmed by XRD characterization. XRD analysis of the bulk sample with 5 mm diameter indicated the presence of crystalline phases. However, XRD analysis of the bulk sample with 4 mm diameter indicated no significant crystalline peaks. From TEM analysis it was found that in-situ BMG composite was obtained in bulk sample. The edge of bulk sample with 4 mm diameter was fully amorphous, however, the center of this sample contains crystalline particles of micron sizes dispersed in the amorphous matrix. Our results suggest that the system Co_4_7Fe_2_0_._9B_2_1_._2Si_4_._6Nb_6_._3 has high GFA because we have prepared various amorphous materials with different shape and thickness using the techniques of suction casting, modified PFC and PFC. The critical diameter of bulk samples with chemical composition Co_4_7Fe_2_0_._9B_2_1_._2Si_4_._6Nb_6_._3 for emergence amorphous phase is 4 mm. (authors)

Improved corrosion resistance of cast carbon steel in sulphur oxides by Alonizing

International Nuclear Information System (INIS)

Holtzer, M.; Dzioba, Z.

1992-01-01

The results of studies on the Alonizing of cast steel and of testing the corrosion resistance of this cast steel in an atmosphere containing 5 to 6% SO 2 + 50% SO 3 at 853 K are described and compared with the results obtained with unalonized cast carbon steel and high-alloy 23Cr-8Ni-2Mo cast steel. The duration of the corrosion tests was 336 hours. The aluminium diffusion layer on cast carbon steel was obtained by holding the specimens in a mixture containing 99% of powered Fe-Al and 1% of NH 4 Cl at 1323 ± 20 K. The holding time was 10 and 20 hours, respectively. The aluminium layer formed on the cast carbon steel was examined by optical microscopy and an X-ray microanalysis. After Alonizing for 10 h the layer had reached a thickness of 950 μm, and contained up to 35% Al. In a mixture of sulphur oxides corrosion rate of the alonized cast carbon steel was by about 600 times lower than of the unalonized cast carbon steel, and by about 50 times lower than that of the 23Cr-8Ni-2Mo cast steel. (orig.) [de

Effect of Heat Treatments on the Microstructure, Hardness and Corrosion Behavior of Nondendritic AlSi9Cu3(Fe Cast Alloy

Directory of Open Access Journals (Sweden)

Nacer ZAZI

2013-09-01

Full Text Available In this paper we studied the influence of heat treatments on properties of AlSi9Cu3(Fe nondendritic cast alloy. Solution heat treatment, six hours at 520 °C, while making the grains more spherical modifies corrosion morphology into intergranular corrosion and corrosion surrounding spherical particles in 3 % NaCl solution. Past solution treatment, quenching at 520 °C after one hour with two weeks of natural aging transform the shape of grains into equiaxes form. Two weeks of natural aging and 30 minutes of aging at 150, 200, 250 °C after solution treatment and quenching give birth to the "Chinese script" form of the Al15(MnFe3Si intermetallic particles. The prolongation of the duration period of aging to one hour at 200 °C is sufficient to transform the morphology of corrosion into located corrosion by pitting, and a longer aging cancels the "Chinese script" form. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.1397

Sputtering and emission intensity of cast irons with different metallurgical structures in a Grimm glow lamp

International Nuclear Information System (INIS)

Fujita, M.; Kashima, J.; Naganuma, K.

1981-01-01

The cathodic sputtering and emission intensities for the white, gray and malleable cast irons in the Grimm glow lamp are discussed. The intensities of the Fe 247.98-nm line for the samples of the three types depend linearly on the electrical power but the slopes of the plots differ. The intensity of the carbon line at 247.86 nm for malleable cast iron is weaker than those for the others. Sputtering is influenced by the form of the graphite, which can lead to distortion of the electrical field. Graphite on malleable cast iron is sputtered not only as atomic carbon but also as moieties containing several carbon atoms. The higher the supplied voltage, the shorter the time for the intensities of the Fe I and C I lines to reach constant values. (Auth.)

Analysis of the Causes of Cracks in a Thick-Walled Bush Made of Die-Cast Aluminum Bronze

Directory of Open Access Journals (Sweden)

Pisarek B.P.

2016-12-01

Full Text Available For the die casting conditions of aluminium bronzes assumed based on the literature data, a thick-walled bush was cast, made of complex aluminium bronze (Cu-Al-Fe-Ni-Cr. After the cast was removed from the mould, cracks were observed inside it. In order to identify the stage in the technological production process at which, potentially, the formation of stresses damaging the continuity of the microstructure created in the cast was possible (hot cracking and/or cold cracking, a computer simulation was performed. The article presents the results of the computer simulation of the process of casting the material into the gravity die as well as solidifying and cooling of the cast in the shape of a thick-walled bush. The simulation was performed with the use of the MAGMA5 program and by application of the CuAl10Ni5,5Fe4,5 alloy from the MAGMA5 program database. The results were compared with the location of the defects identified in the actual cast. As a result of the simulation of the die-casting process of this bush, potential regions were identified where significant principal stresses accumulate, which can cause local hot and cold cracking. Until now, no research has been made of die-cast aluminium bronzes with a Cr addition. Correlating the results of the computer simulation validated by the analysis of the actual cast made it possible to clearly determine the critical regions in the cast exposed to cracking and point to the causes of its occurrence. Proposals of changes in the bush die casting process were elaborated, in order to avoid hot tearing and cold cracking. The article discusses the results of preliminary tests being a prologue to the optimization of the die-casting process parameters of complex aluminium bronze thick-walled bushs.

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

Energy Technology Data Exchange (ETDEWEB)

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

2012-10-30

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

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

Science.gov (United States)

Kim, JaeHwang; Kim, DaeHwan

2018-03-01

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

Method and mold for casting thin metal objects

Science.gov (United States)

Pehrson, Brandon P; Moore, Alan F

2014-04-29

Provided herein are various embodiments of systems for casting thin metal plates and sheets. Typical embodiments include layers of mold cavities that are oriented vertically for casting the metal plates. In some embodiments, the mold cavities include a beveled edge such that the plates that are cast have a beveled edge. In some embodiments, the mold cavities are filled with a molten metal through an open horizontal edge of the cavity. In some embodiments, the mold cavities are filled through one or more vertical feed orifices. Further disclosed are methods for forming a thin cast metal plate or sheet where the thickness of the cast part is in a range from 0.005 inches to 0.2 inches, and the surface area of the cast part is in a range from 16 square inches to 144 square inches.

Effect of Solidification Behavior on Microstructures and Mechanical Properties of Ni-Cr-Fe Superalloy Investment Casting

Science.gov (United States)

Kang, Maodong; Wang, Jun; Gao, Haiyan; Han, Yanfeng; Wang, Guoxiang; He, Shuxian

2017-01-01

The effect of solidification behavior on the microstructures and mechanical properties of Ni-Cr-Fe superalloy investment casting is given. Metallographic and image analysis have been used to quantitatively examine the microstructures’ evolution. For the parts with the thickness of 3 mm and 24 mm, the volume fraction and maximum equivalent radius of the Laves phase increases from 0.3% to 1.2%, from 11.7 μm to 23.4 μm, respectively. Meanwhile, the volume fraction and maximum equivalent radius of carbides increase from 0.3% to 0.5%, from 8.1 μm to 9.9 μm, respectively. In addition, the volume fraction of microporosity increases from 0.3% to 2.7%. As a result, the ultimate tensile strength is reduced from 1125.5 MPa to 820.9 MPa, the elongation from 13.3% to 7.7%, and the quality index from 1294.2 MPa to 954.0 MPa, respectively. A typical brittle fracture is observed on the tensile fracture. As the cooling rate decreases, the microstructures become coarser. PMID:28772611

Influence of Composition on the Environmental Impact of a Cast Aluminum Alloy

Directory of Open Access Journals (Sweden)

Patricia Gómez

2016-05-01

Full Text Available The influence of alloy composition on the environmental impact of the production of six aluminum casting alloys (Al Si12Cu1(Fe, Al Si5Mg, Al Si9Cu3Zn3Fe, Al Si10Mg(Fe, Al Si9Cu3(Fe(Zn and Al Si9 has been analyzed. In order to perform a more precise environmental impact calculation, Life Cycle Assessment (LCA with ReCiPe Endpoint methodology has been used, with the EcoInvent v3 AlMg3 aluminum alloy dataset as a reference. This dataset has been updated with the material composition ranges of the mentioned alloys. The balanced, maximum and minimum environmental impact values have been obtained. In general, the overall impact of the studied aluminum alloys varies from 5.98 × 10−1 pts to 1.09 pts per kg, depending on the alloy composition. In the analysis of maximum and minimum environmental impact, the alloy that has the highest uncertainty is AlSi9Cu3(Fe(Zn, with a range of ±9%. The elements that contribute the most to increase its impact are Copper and Tin. The environmental impact of a specific case, an LED luminaire housing made out of an Al Si12Cu1(Fe cast alloy, has been studied, showing the importance of considering the composition. Significant differences with the standard datasets that are currently available in EcoInvent v3 have been found.

Influence of Composition on the Environmental Impact of a Cast Aluminum Alloy.

Science.gov (United States)

Gómez, Patricia; Elduque, Daniel; Sarasa, Judith; Pina, Carmelo; Javierre, Carlos

2016-05-25

The influence of alloy composition on the environmental impact of the production of six aluminum casting alloys (Al Si12Cu1(Fe), Al Si5Mg, Al Si9Cu3Zn3Fe, Al Si10Mg(Fe), Al Si9Cu3(Fe)(Zn) and Al Si9) has been analyzed. In order to perform a more precise environmental impact calculation, Life Cycle Assessment (LCA) with ReCiPe Endpoint methodology has been used, with the EcoInvent v3 AlMg3 aluminum alloy dataset as a reference. This dataset has been updated with the material composition ranges of the mentioned alloys. The balanced, maximum and minimum environmental impact values have been obtained. In general, the overall impact of the studied aluminum alloys varies from 5.98 × 10 -1 pts to 1.09 pts per kg, depending on the alloy composition. In the analysis of maximum and minimum environmental impact, the alloy that has the highest uncertainty is AlSi9Cu3(Fe)(Zn), with a range of ±9%. The elements that contribute the most to increase its impact are Copper and Tin. The environmental impact of a specific case, an LED luminaire housing made out of an Al Si12Cu1(Fe) cast alloy, has been studied, showing the importance of considering the composition. Significant differences with the standard datasets that are currently available in EcoInvent v3 have been found.

Squeeze casting of aluminum alloy A380: Microstructure and tensile behavior

Directory of Open Access Journals (Sweden)

Li Fang

2015-09-01

Full Text Available A380 alloy with a relatively thick cross-section of 25 mm was squeeze cast using a hydraulic press with an applied pressure of 90 MPa. Microstructure and tensile properties of the squeeze cast A380 were characterized and evaluated in comparison with the die cast counterpart. Results show that the squeeze cast A380 possesses a porosity level much lower than the die cast alloy, which is disclosed by both optical microscopy and the density measurement technique. The results of tensile testing indicate the improved tensile properties, specifically ultimate tensile strength (UTS: 215.9 MPa and elongation (Ef: 5.4%, for the squeeze cast samples over those of the conventional high-pressure die cast part (UTS: 173.7 MPa, Ef: 1.0%. The analysis of tensile behavior shows that the squeeze cast A380 exhibits a high tensile toughness (8.5 MJ·m-3 and resilience (179.3 kJ·m-3 compared with the die cast alloy (toughness: 1.4 MJ·m-3, resilience: 140.6 kJ·m-3, despite that, during the onset of plastic deformation, the strain-hardening rate of the die cast specimen is higher than that of the squeeze cast specimens. The microstructure analyzed by the scanning electron microscopy (SEM shows that both the squeeze and die cast specimens contain the primary α-Al, Al2Cu, Al5FeSi phase and the eutectic Si phase. But, the Al2Cu phase present in the squeeze cast alloy is relatively large in size and quantity. The SEM fractography evidently reveals the ductile fracture features of the squeeze cast A380 alloy.

Microstructural evolution and mechanical properties of a novel FeCrNiBSi advanced high-strength steel: Slow, accelerated and fast casting cooling rates

Energy Technology Data Exchange (ETDEWEB)

Askari-Paykani, Mohsen; Shahverdi, Hamid Reza, E-mail: shahverdi@modares.ac.ir; Miresmaeili, Reza

2016-06-21

In the current work, three different solidification routes and a two-step heat treatment process were applied to a novel FeCrNiBSi alloy system to introduce a new candidate for advanced high-strength steels. The evolution of the microstructure after solidification, heat treatment, and tensile deformation was characterized using optical and electron microscopy techniques, as well as hardness and room temperature uniaxial tensile tests. The effects of the different solidification routes and heat treatment parameters on the deformation and fracture mechanisms of this steel are discussed. Grain refinement, precipitation hardening, and solid solution as a result of the fast casting cooling rate led to an increase in strength at improved ductility. This result can be explained partly by the less severe stress/strain partitioning at the matrix grain/M{sub 2}B interfaces and better interface cohesion. Moreover, the stress/strain partitioning characteristics between the matrix grains and M{sub 2}B led to a higher initial strain hardening rate. The fast casting cooling rate further promoted ductile fracture mechanisms, which is a result of increased cleavage fracture stress. The higher casting cooling rate and two-step heat treatment resulted in a strong increase in formability index, from 8 GPa% to 24 GPa%, at which the mechanical properties occupy the TRIP envelope. Heat treatment of the fast-cooling specimens led to a small reduction in yield and tensile strength and 22% total elongation percentage improvement (from 10% to 32%).

Structure of AlmFe

International Nuclear Information System (INIS)

Skjerpe, P.

1988-01-01

The metastable phase Al m Fe (m=4.9-4.4, bodycentred tetragonal, a=8.84, c=21.6 A) has been examined by transmission electron microscopy and high-resolution electron microscopy (HREM). Crystals, 1-10 μm in size, were extracted from a cast Al-0.25 wt%Fe-0.13wt%Si alloy of commercial purity. By the use of electron diffraction patterns, a possible structure model for Al m Fe was set up, assuming space group I4/mmm. The model was in qualitative agreement with diffraction patterns as well as HREM micrographs, recorded in and . Streaks along hhO in the diffraction patterns were ascribed to faults on (110). (orig.)

The influence of ingot annealing on the corrosion resistance of a PrFeCoBNbP alloy

International Nuclear Information System (INIS)

Oliveira, M.C.L.; Takiishi, H.; Faria, R.N.; Costa, I.

2008-01-01

The influence of the annealing time on the corrosion resistance of a Pr-Fe-Co-B-Nb alloy with the addition of 0.1 wt% P was investigated here using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The cast ingot alloys were annealed at 1100 deg. C for 10, 15 and 20 h. The specimens were immersed for 30 days in naturally aerated 0.02 M Na 2 HPO 4 solution at room temperature, during which period the evolution of the electrochemical behavior was assessed using EIS. The results indicated that the corrosion resistance of the Pr 14 Fe bal Co 16 B 6 Nb 0.1 P 0.25 alloy was related to the annealing time and, hence, to its microstructure. Annealing at 1100 deg. C for 10 h was insufficient to eliminate the Fe-α phase from the alloy microstructure, whereas annealing for 15 and 20 h removed an increasing amount of Fe-α phase, thereby increasing the alloy's corrosion resistance

Phase Transformations in Cast Duplex Stainless Steels

Energy Technology Data Exchange (ETDEWEB)

Kim, Yoon-Jun [Iowa State Univ., Ames, IA (United States)

2004-01-01

Duplex stainless steels (DSS) constitute both ferrite and austenite as a matrix. Such a microstructure confers a high corrosion resistance with favorable mechanical properties. However, intermetallic phases such as σ and χ can also form during casting or high-temperature processing and can degrade the properties of the DSS. This research was initiated to develop time-temperature-transformation (TTT) and continuous-cooling-transformation (CCT) diagrams of two types of cast duplex stainless steels, CD3MN (Fe-22Cr-5Ni-Mo-N) and CD3MWCuN (Fe-25Cr-7Ni-Mo-W-Cu-N), in order to understand the time and temperature ranges for intermetallic phase formation. The alloys were heat treated isothermally or under controlled cooling conditions and then characterized using conventional metallographic methods that included tint etching, and also using electron microscopy (SEM, TEM) and wavelength dispersive spectroscopy (WDS). The kinetics of intermetallic-phase (σ + χ) formation were analyzed using the Johnson-Mehl-Avrami (MA) equation in the case of isothermal transformations and a modified form of this equation in the case of continuous cooling transformations. The rate of intermetallic-phase formation was found to be much faster in CD3MWCuN than CD3MN due mainly to differences in the major alloying contents such as Cr, Ni and Mo. To examine in more detail the effects of these elements of the phase stabilities; a series of eight steel castings was designed with the Cr, Ni and Mo contents systematically varied with respect to the nominal composition of CD3MN. The effects of varying the contents of alloying additions on the formation of intermetallic phases were also studied computationally using the commercial thermodynamic software package, Thermo-Calc. In general, σ was stabilized with increasing Cr addition and χ by increasing Mo addition. However, a delicate balance among Ni and other minor elements such as N and Si also exists. Phase equilibria in DSS can be affected by

Depth, chlorophyll, and total pigment data were collected using bottle casts in a world-wide distribution from 16 March 1997 to 30 January 1998 (NODC Accession 0000292)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Depth, chlorophyll, and total pigment data were collected using bottle casts from TIOGA and other platforms in a world-wide distribution from March 16, 1997 to...

Electrochemical passivation behaviour of nanocrystalline Fe 80 Si ...

Indian Academy of Sciences (India)

Passivation behaviour of nanocrystalline coating (Fe80Si20) obtained by in situ mechanical alloying route is studied and compared with that of the commercial pure iron and cast Fe80Si20 in sodium borate buffer solution at two different pH values (7.7 and 8.4). The coating reveals single passivation at a pH of 7.7 and ...

Comparison of R6 and A16 J estimation methods under combined mechanical and thermal loads with FE results

International Nuclear Information System (INIS)

Nam, Hyun-Suk; Oh, Chang-Young; Kim, Yun-Jae; Jerng, Dong Wook; Ainsworth, Robert A.; Budden, Peter J.; Marie, Stéphane

2015-01-01

This paper compares elastic–plastic values of J calculated using the methods in the UK R6 and the French A16 fitness-for-service procedures with FE results for a vessel with a circumferential surface crack under axial tension and a radial thermal gradient. In the FE analyses, the relative magnitudes and loading sequence of mechanical and thermal loads are systematically varied, together with the material strain hardening exponent. Fully circumferential and semi-elliptical surface crack with two relative crack depths are considered. It is found that the R6 estimates are overall accurate but can be non-conservative at large L_r. The A16 estimates are more conservative than the R6 estimates at small L_r but are conservative even at large L_r. Possible sources of conservatism and non-conservatism in R6 and A16 are discussed. - Highlights: • Accuracy of existing J estimation methods for combined mechanical and thermal loading are compared with FE results. • The methods in the UK R6 and the French A16 procedures are considered. • The R6 estimates are overall accurate but can be non-conservative at large L_r. • The A16 estimates are more conservative than the R6 estimates at small L_r but are conservative even at large L_r. • Possible sources of conservatism and non-conservatism in R6 and A16 are discussed.

Effect of boron addition to the hard magnetic bulk Nd60Fe30Al10 amorphous alloy

International Nuclear Information System (INIS)

Kong, H.Z.; Li, Y.; Ding, J.

2000-01-01

A detailed study of the effect of boron addition to crystallinity, magnetic properties and thermal properties was carried out for alloys Nd 60-x Fe 30 Al 10 B x with x=0, 1, 3 and 5 produced by copper mold chill casting and melt-spinning. The cast rods of alloys Nd 60-x Fe 30 Al 10 B x were largely amorphous. Remanence up to 0.154 T and coercivity up to 355 kA/m were observed, which were higher than those of the bulk amorphous Nd 60 Fe 30 Al 10 rod of the same diameter. A step in hysteresis loop was observed for the hard magnetic cast rod and ribbon melt-spun at a low speed of 5 m/s of the alloys with boron addition. Consistent increase in the amplitude of the step and magnetic field (H) at which the step was observed as the boron content increased. A single magnetic phase with low coercivity was observed for fully amorphous ribbon melt-spun at high speed of 30 m/s. Full crystallization due to heat treatment resulted in transition of hard magnetic amorphous phase of Nd 55 Fe 30 Al 10 B 5 cast rod to paramagnetic crystalline phases. TEM results of the as-cast rods illustrated the existence of numerous minute Nd-crystallites in amorphous matrix

Casting technology for ODS steels - the internal oxidation approach

Science.gov (United States)

Miran, S.; Franke, P.; Möslang, A.; Seifert, H. J.

2017-07-01

The formation of stainless ODS steel by internal oxidation of as-cast steel has been investigated. An alloy (Fe-16Cr-0.2Al-0.05Y, wt.%) was embedded in a (VO/V2O3) powder mixture serving as an oxygen activity buffer and heat treated at 1450 °C for 20 h. After this procedure no oxide scale was present on the surface of the sample but a zone of internal oxidation with a depth of about 2000 μm was formed in its interior. The precipitates within this zone consisted of two types of oxides. Discrete aluminium oxide particles with a size of a few micrometres were formed in outer regions of the specimen. Finer aluminium-yttrium oxides with a size of some hundred nanometres were mainly precipitated in inner regions of the sample. The results can be considered as a promising step towards an alternative production route for ODS steels.

Improving composition of protective coatings for steel casting

International Nuclear Information System (INIS)

Kuz'kina, N.N.; Pegov, V.G.; Bogatenkov, V.F.; Shub, L.G.; Raspopova, N.A.

1983-01-01

A radically new fuel-free slag-forming mixture used as protective coating for steel casting is introduced. The lack of combustible powders precludes explosion and fire Lazard in mixture preparation. Usage of the new mixture in stainless steel casting of Kh18N10T type permitted to improve the ingot surface quality and reduce spoilage from 1.16 to 0.66%

Nodular cast iron and casting monitoring

Directory of Open Access Journals (Sweden)

S. Pietrowski

2008-10-01

Full Text Available In this paper quality monitoring of nodular cast iron and casting made of it is presented. A control system of initial liquid cast iron to spheroidization, after spheroidization and inoculation with using of TDA method was shown. An application of an ultrasonic method to assessment of the graphite form and the metal matrix microstructure of castings was investigated.

Plankton data collected from instrumented tower and net casts in the Greenland Sea from the POLARSTERN from 09 June 1991 to 16 June 1991 (NODC Accession 0000772)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Plankton data were collected using instrumented tower and net casts from the POLARSTERN in the Greenland Sea. Data were collected from 09 June 1991 to 16 June 1991....

Irradiation response of delta ferrite in as-cast and thermally aged cast stainless steel

Energy Technology Data Exchange (ETDEWEB)

Li, Zhangbo; Lo, Wei-Yang [Department of Materials Science and Engineering, Nuclear Engineering Program, University of Florida, Gainesville, FL 32611 (United States); Chen, Yiren [Nuclear Engineering Division, Argonne National Laboratory, Lemont, IL 60439 (United States); Pakarinen, Janne [Belgian Nuclear Research Center (SCK-CEN), Boeretang 200, B-2400 Mol (Belgium); Wu, Yaqiao [Department of Materials Science and Engineering, Boise State University, Boise, ID 83715 (United States); Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States); Allen, Todd [Engineering Physics Department, University of Wisconsin, Madison, WI 53706 (United States); Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Yang, Yong, E-mail: yongyang@ufl.edu [Department of Materials Science and Engineering, Nuclear Engineering Program, University of Florida, Gainesville, FL 32611 (United States)

2015-11-15

To enable the life extension of Light Water Reactors (LWRs) beyond 60 years, it is critical to gain adequate knowledge for making conclusive predictions to assure the integrity of duplex stainless steel reactor components, e.g. primary pressure boundary and reactor vessel internal. Microstructural changes in the ferrite of thermally aged, neutron irradiated only, and neutron irradiated after being thermally aged cast austenitic stainless steels (CASS) were investigated using atom probe tomography. The thermal aging was performed at 400 °C for 10,000 h and the irradiation was conducted in the Halden reactor at ∼315 °C to 0.08 dpa (5.6 × 10{sup 19} n/cm{sup 2}, E > 1 MeV). Low dose neutron irradiation at a dose rate of 5 × 10{sup −9} dpa/s was found to induce spinodal decomposition in the ferrite of as-cast microstructure, and further to enhance the spinodal decomposition in the thermally aged cast alloys. Regarding the G-phase precipitates, the neutron irradiation dramatically increases the precipitate size, and alters the composition of the precipitates with increased, Mn, Ni, Si and Mo and reduced Fe and Cr contents. The results have shown that low dose neutron irradiation can further accelerate the degradation of ferrite in a duplex stainless steel at the LWR relevant condition.

Irradiation response of delta ferrite in as-cast and thermally aged cast stainless steel

International Nuclear Information System (INIS)

Li, Zhangbo; Lo, Wei-Yang; Chen, Yiren; Pakarinen, Janne; Wu, Yaqiao; Allen, Todd; Yang, Yong

2015-01-01

To enable the life extension of Light Water Reactors (LWRs) beyond 60 years, it is critical to gain adequate knowledge for making conclusive predictions to assure the integrity of duplex stainless steel reactor components, e.g. primary pressure boundary and reactor vessel internal. Microstructural changes in the ferrite of thermally aged, neutron irradiated only, and neutron irradiated after being thermally aged cast austenitic stainless steels (CASS) were investigated using atom probe tomography. The thermal aging was performed at 400 °C for 10,000 h and the irradiation was conducted in the Halden reactor at ∼315 °C to 0.08 dpa (5.6 × 10"1"9 n/cm"2, E > 1 MeV). Low dose neutron irradiation at a dose rate of 5 × 10"−"9 dpa/s was found to induce spinodal decomposition in the ferrite of as-cast microstructure, and further to enhance the spinodal decomposition in the thermally aged cast alloys. Regarding the G-phase precipitates, the neutron irradiation dramatically increases the precipitate size, and alters the composition of the precipitates with increased, Mn, Ni, Si and Mo and reduced Fe and Cr contents. The results have shown that low dose neutron irradiation can further accelerate the degradation of ferrite in a duplex stainless steel at the LWR relevant condition.

Evaluation the homogenisation behaviour of Sm-Fe-Nb materials by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Sinan, S. A.; Muryaed, Y.; Alhweg, F. A.

2004-01-01

The microstructure of cast and annealed Sm-Fe-Nb materials were investigated by Moessbauer spectroscopy. The aim of the present work is to study the effect of Nb additions upon the microstructure of Sm 2 Fe 17 material and evaluation the homogenisation behaviour of different Sm-Fe-Nb materials. The niobium free cast material consisting of the Sm 2 Fe 17 phase and significant amounts of the free iron (α -Fe). Therefore, the homogenisation process is necessary to eliminate the free iron and produce a single Sm 2 Fe 17 phase material. This process takes long annealing time, up to seven days. The Sm 9 .5 Fe 8 7.5 Nb 3 alloy contains the lowest amount of α-Fe among, the Sm-Fe-Nb materials. Thus the homogenisation step was carried out with treatment time (12 hours) smaller than the reported annealing time of Nb-free material (Sm 2 Fe 17 ). Therefore, the addition of at 3% Nb reduces the manufacturing cost of the Sm 2 Fe 17 and makes this based material for permanent magnets, more industrially desirable, due to elimination the free iron with lowest treatment time. Also it was found that the existence of the paramagnetic NbFe 2 phase becomes higher after the homogenisation process, which can be explained due to the diffusion of Nb from Sm 2 Fe 17 phase to paramagnetic NbFe 2 phase, during the annealing process. (authors)

SOLUTION TREATMENT EFFECT ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF AUTOMOTIVE CAST ALLOY

Directory of Open Access Journals (Sweden)

Eva Tillová

2012-02-01

Full Text Available The contribution describes influence of the heat treatment (solution treatment at temperature 545°C and 565°C with different holding time 2, 4, 8, 16 and 32 hours; than water quenching at 40°C and natural aging at room temperature during 24 hours on mechanical properties (tensile strength and Brinell hardness and microstructure of the secondary AlSi12Cu1Fe automotive cast alloy. Mechanical properties were measured in line with EN ISO. A combination of different analytical techniques (light microscopy, scanning electron microscopy (SEM were therefore been used for study of microstructure. Solution treatment led to changes in microstructure includes the spheroidization and coarsening of eutectic silicon. The dissolution of precipitates and the precipitation of finer hardening phase further increase the hardness and tensile strength of the alloy. Optimal solution treatment (545°C/4 hours most improves mechanical properties and there mechanical properties are comparable with mechanical properties of primary AlSi12Cu1Fe alloy. Solution treatment at 565 °C caused testing samples distortion, local melting process and is not applicable for this secondary alloy with 12.5 % Si.

Diffusion Coefficient in the Zinc Coating Shaped on the Surface of Cast Iron and Steel Alloys

Directory of Open Access Journals (Sweden)

Kopyciński D.

2015-06-01

Full Text Available The article presents the method to assess the diffusion coefficient D in the sub-layer of intermetallic phases formed during hot-dip galvanizing “Armco” iron and ductile cast iron EN-GJS-500-7. Hot-dip galvanizing is one of the most popular forms of long-term protection of Fe-C alloys against corrosion. The process for producing a protective layer of sufficient quality is closely related to diffusion of atoms of zinc and iron. The simulation consist in performed a hot-dip galvanizing in laboratory condition above Fe-C alloys, in the Department of Engineering of Cast Alloys and Composites. Galvanizing time ranged from 15 to 300 seconds. Then metallographic specimens were prepared, intermetallic layers were measured and diffusion coefficient (D were calculated. It was found that the diffusion coefficient obtained during hot-dip galvanizing “Armco” iron and zinc is about two orders of magnitude less than the coefficient obtained on ductile cast iron EN-GJS-500-7.

Development of TRIP-Aided Lean Duplex Stainless Steel by Twin-Roll Strip Casting and Its Deformation Mechanism

Science.gov (United States)

Zhao, Yan; Zhang, Weina; Liu, Xin; Liu, Zhenyu; Wang, Guodong

2016-12-01

In the present work, twin-roll strip casting was carried out to fabricate thin strip of a Mn-N alloyed lean duplex stainless steel with the composition of Fe-19Cr-6Mn-0.4N, in which internal pore defects had been effectively avoided as compared to conventional cast ingots. The solidification structure observed by optical microscope indicated that fine Widmannstatten structure and coarse-equiaxed crystals had been formed in the surface and center, respectively, with no columnar crystal structures through the surface to center of the cast strip. By applying hot rolling and cold rolling, thin sheets with the thickness of 0.5 mm were fabricated from the cast strips, and no edge cracks were formed during the rolling processes. With an annealing treatment at 1323 K (1050 °C) for 5 minutes after cold rolling, the volume fractions of ferrite and austenite were measured to be approximately equal, and the distribution of alloying elements in the strip was further homogenized. The cold-rolled and annealed sheet exhibited an excellent combination of strength and ductility, with the ultimate tensile strength and elongation having been measured to be 1000 MPa and 65 pct, respectively. The microstructural evolution during deformation was investigated by XRD, EBSD, and TEM, indicating that ferrite and austenite had different deformation mechanisms. The deformation of ferrite phase was dominated by dislocation slipping, and the deformation of austenite phase was mainly controlled by martensitic transformation in the sequence of γ→ ɛ-martensite→ α'-martensite, leading to the improvement of strength and plasticity by the so-called transformation-induced plasticity (TRIP) effect. By contrast, lean duplex stainless steels of Fe-21Cr-6Mn-0.5N and Fe-23Cr-7Mn-0.6N fabricated by twin-roll strip casting did not show TRIP effects and exhibited lower strength and elongation as compared to Fe-19Cr-6Mn-0.4N.

Glass forming ability and magnetic properties of Co{sub (40.2−x)}Fe{sub (20.1+x)}Ni{sub 6.7}B{sub 22.7}Si{sub 5.3}Nb{sub 5} (x=0–10) bulk metallic glasses produced by suction casting

Energy Technology Data Exchange (ETDEWEB)

Sarlar, Kagan [Physics Department, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey); Physics Department, Kamil Ozdag Faculty of Sciences, Karamanoglu Mehmetbey University, YunusEmre Campus, 70100 Karaman (Turkey); Kucuk, Ilker, E-mail: ikucuk@uludag.edu.tr [Physics Department, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey)

2015-01-15

The effect of Fe concentration on the glass forming ability (GFA) and magnetic properties in Co{sub (40.2−x)}Fe{sub (20.1+x)}Ni{sub 6.7}B{sub 22.7}Si{sub 5.3}Nb{sub 5} (x=0–10) bulk metallic glasses were investigated. By suction casting method, the bulk metallic glasses with diameters up to 2 mm were produced. We try to find out which Fe concentration makes an influence on Co based system's magnetic properties and glass forming ability. The curves of thermal analysis, obtained using differential scanning calorimetry (DSC), show that the Co{sub (40.2−x)}Fe{sub (20.1+x)}Ni{sub 6.7}B{sub 22.7}Si{sub 5.3}Nb{sub 5} (x=0–10) have a supercooled liquid region (∆T{sub x}) of about 44 K. The saturation magnetizations (J{sub s}) for as-cast BMG alloys were in the range of 0.62 T−0.81 T. - Highlights: • The effect of Fe concentration on the glass forming ability. • The substitution of an appropriate amount of Fe can enhance the GFA. • The substitution of Fe for Co also improves soft magnetic properties of the BMGs. • The high of J{sub s} 0.62−0.81 T with a low H{sub c} of 2−289 A/m of the alloys.

Finger printing of medieval investment cast idols by radiography

International Nuclear Information System (INIS)

Venkatraman, B.; Babu Rao, C.; Bhattacharya, D.K.; Raj, Baldev

1993-01-01

Among the various methods, radiography is an important technique that can be used to fingerprint an idol. This is because, these idols are cast structures, and radiography is the most reliable technique for the detection of internal features like casting defects. This paper presents the radiographic methodology adopted and the results of the studies to characterise radiographically three medieval cast idols belonging to different periods 9th, 13th, and 16th century obtained from the government museum Madras. (author). 2 refs., 1 fig., 2 tabs

Effect of Heat Treatment on Commercial AlSi12Cu1(Fe) and AlSi12(b) Aluminum Alloy Die Castings

Science.gov (United States)

Battaglia, E.; Bonollo, F.; Ferro, P.; Fabrizi, A.

2018-03-01

High-pressure die castings (HPDCs) cannot normally be heat-treated at a high temperature because of the presence of inner air/gas- or shrinkage-porosity that may lead to the formation of undesired surface blisters. In this paper, an unconventional heat treatment is proposed. Two secondary Al-Si alloys, AlSi12(b) and AlSi12Cu1(Fe), were stabilization heat-treated at 624 K (350 °C) with soaking times ranging from 1 to 8 hours. Enhancement of both static and dynamic mechanical properties was found to be related to the fragmentation of interconnected eutectic Si particles and the smoothing of coarser crystals. Increased ductility after heat treatment was correlated with a decrease in hardness and Si particle roundness. The formation of Si precipitates within the α-Al matrix was also observed.

Roles of Co element in Fe-based bulk metallic glasses utilizing industrial FeB alloy as raw material

Directory of Open Access Journals (Sweden)

Shouyuan Wang

2017-08-01

Full Text Available A series of Fe-based bulk metallic glasses were fabricated by a conventional copper mold casting method using a kind of Fe-B industrial raw alloy. It is found that Fe-B-Y-Nb bulk metallic glass with 3 at% of Co addition possesses the best glass forming ability, thermal stability, hardness, magnetic property and anti-corrosion property. The hardness test result indicates a synchronically trend with glass-forming ability parameters. The excellent glass-forming ability and a combination of good mechanical and functional properties suggest that the alloys in this work might be good candidates for commercial use.

Enhancement of plasticity of Fe-based bulk metallic glass by Ni substitution for Fe

Energy Technology Data Exchange (ETDEWEB)

Guo, S.F. [State Key Laboratory of Material Processing and Die and Mould Technology, Huazhong University of Science and Technology, 430074 Wuhan (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Li, N.; Zhang, C. [State Key Laboratory of Material Processing and Die and Mould Technology, Huazhong University of Science and Technology, 430074 Wuhan (China); Liu, L., E-mail: sfguo2005@163.co [State Key Laboratory of Material Processing and Die and Mould Technology, Huazhong University of Science and Technology, 430074 Wuhan (China)

2010-08-15

Bulk metallic glasses (BMGs) (Fe{sub 1-x}Ni{sub x}){sub 71}Mo{sub 5}P{sub 12}C{sub 10}B{sub 2} (x = 0, 0.1 and 0.2) with a diameter of 3 mm were synthesized by copper mold casting. The effect of Ni substitution for Fe on the structure, thermal and mechanical properties has been studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and compressive testing. It was found that the substitution of Ni for Fe enhances the glass forming ability, and improves the plasticity of Fe{sub 71}Mo{sub 5}P{sub 12}C{sub 10}B{sub 2} BMG as indicated by the increase in the plastic strain from 3.1% (x = 0) to 5.2% (x = 0.2). The improvement of the plasticity is discussed in term of the reduction of glass transition temperature and the supercooled liquid region due to the substitution of Ni for Fe.

Study of U - Pu - Fe alloys (Masurca critical experiment)

International Nuclear Information System (INIS)

Barthelemy, P.; Boucher, R.

1965-01-01

Three compositions have been studied: 73.5 U - 25 Pu - 1.5 Fe (weight %) 74 U - 25 Pu - 1 Fe 74.5 U - 25 Pu - 0.5 Fe Elaboration and Casting are easy. After two weeks in air 74.5 U - 25 Pu - 0.5 Fe alloys are reduced in powder. As-cast alloys containing 1 and 1,5% Fe are kept undamaged during several months. A rapid oxidisation of the alloys is however observed when the samples undergo the phase transformation (at 595 deg. C and 590 deg. C respectively). Ignition tests in the presence of air show that the oxidisation starts at about 250 deg. C and that the reaction does not spread. Ignition is not observed during heating from 20 to 660 deg. C. The transformation temperature, the melting temperature and the thermal expansion coefficients have been determined by dilatometry. Below the transformation temperature, the principal phases are U-Pu zeta and (U, Pu) 6 Fe. Thermal conductibility, Young modulus, density and heat of fusion have been measured. Compatibility tests show that between U-Pu-Fe and stainless steel a phase of (U, Pu) 6 Fe type is formed. The 74 U - 25 Pu - 1% Fe alloy seems to behave better than 73.5 U - 25 Pu - 1.5% Fe alloy because the (U, Pu) 6 Fe layer is two or three times smaller. Finally, the thermal stability has been studied with the 74 U - 25 Pu - 1% Fe alloy. A dilatometric anomaly (very weak expansion) occurs when the sample is heated above transformation temperature and cooled. But there is no anomaly by thermal cycling from 50 deg. C to 400 deg. C and there is no deterioration of alloys by heat treatments at 100 deg. C, 200 deg. C, 300 deg. C during 5 months under vacuum. (authors) [fr

Permanent Mold Casting of JIS-AC4C Aluminum Alloy Using a Low-Temperature Mold

International Nuclear Information System (INIS)

Yamagata, Hiroshi; Nikawa, Makoto

2011-01-01

Permanent mold casting using mold temperatures below 200 deg. C was conducted to obtain a high-strength, thin-walled casting. Al-7.36 mass% Si -0.18 Cu- 0.27Mg-0.34Fe alloy JIS-AC4C was cast using a bottom pouring cast plan. The product had a rectangular tube shape (70 mm W x 68 mm D x 180 mm H) with wall thicknesses of 1, 3 and 5 mm. The effect of heat insulation at the melt path was compared when using a sand runner insert and when using a steel runner insert as well as a powder mold release agent. Fine microstructures were observed in the casting. The smaller the thickness, the higher the hardness with smaller secondary dendrite arm spacing (SDAS). However, the hardness and the SDAS were unaffected by the mold temperature. It was proposed that the avoidance of the formation of primary α dendrite at the melt path generates a higher strength casting with adequate mold filling.

Identification of intermetallic phases in a eutectic Al-Si casting alloy using electron backscatter diffraction pattern analysis

International Nuclear Information System (INIS)

Kral, M.V.; McIntyre, H.R.; Smillie, M.J.

2004-01-01

Intermetallic phases in sand cast eutectic Al-Si alloys were characterized using a combination of SEM, EDS and EBSD pattern analysis. Chinese script α-phase particles were consistent with cubic Al 19 (Fe,Mn) 5 Si 2 . Plate-shaped β-phase particles were consistent with tetragonal Al 3 (Fe,Mn)Si 2

Casting Technology.

Science.gov (United States)

Wright, Michael D.; And Others

1992-01-01

Three articles discuss (1) casting technology as it relates to industry, with comparisons of shell casting, shell molding, and die casting; (2) evaporative pattern casting for metals; and (3) high technological casting with silicone rubber. (JOW)

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

International Nuclear Information System (INIS)

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

2012-01-01

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

Changes in Structural Characteristics of Hypoeutectic Al-Si Cast Alloy after Age Hardening

Directory of Open Access Journals (Sweden)

Lenka HURTALOVÁ

2012-09-01

Full Text Available The contribution describes influence of the age-hardening consist of solution treatment at 515 °C with holding time 4 hours, water quenching at 40 °C and artificial aging at different temperature 150 °C, 170 °C and 190 °C with different holding time 2, 4, 8, 16 and 32 hours on mechanical properties (tensile strength and Brinell hardness and changes in morphology of eutectic Si, Fe-rich and Cu-rich intermetallic phases in secondary (recycled AlSi9Cu3 cast alloy. A combination of different analytical techniques (light microscopy upon black-white and colour etching, scanning electron microscopy (SEM upon deep etching and energy dispersive X-ray analysis (EDX were therefore been used for the identification of the various phases. Quantitative study of changes in morphology of eutectic Si, Cu-rich and Fe-rich phases was carried out using Image Analyzer software NIS-Elements. Mechanical properties were measured in line with EN ISO. Age-hardening led to changes in microstructure include the spheroidization and coarsening of eutectic silicon, gradual disintegration, shortening and thinning of Fe- rich intermetallic phases, the dissolution of precipitates and the precipitation of finer hardening phase (Al2Cu further increase in the hardness and tensile strength in the alloy.DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2430

Cast iron (CI) based soft magnetic BMG Ci{sub 88.3}Al{sub 2}Ga{sub 1}P{sub 4.35}B{sub 4.35}

Energy Technology Data Exchange (ETDEWEB)

Kane, S N; Lee, H J; Jeong, Y H [Department of Physics, Pohang University of Science and Technology (POSTECH), 790-784 Pohang (Korea, Republic of); Varga, L K, E-mail: varga@szfki.h [RISSPO, Hungarian Academy of Sciences, PO Box 49, 1525 Budapest (Hungary)

2009-01-01

Thermal stability, structure, and magnetic properties of bulk type Ci{sub 88.3}Al{sub 2}Ga{sub 1}P{sub 4.35}B{sub 4.35} alloy in ribbon form have been studied using differential thermal analysis, x-ray diffraction and magnetic measurements. Results reveal that crystallization peak temperature (T{sub x}) and Curie temperature (T{sub c}) of the as-cast alloy are respectively 513 and 370 deg. C. Crystallization of the specimen starts after annealing at 460 deg. C and alpha-Fe is precipitated out. Annealing at temperatures higher than 515 deg. C, produces apart from alpha-Fe, hard magnetic precipitants (Fe{sub 2}B, Fe{sub 3}B), which deteriorate the soft magnetic properties. Lowest coercive field - 9.8 A/m, highest saturation of induction - 1.55 Tesla and best losses - 0.42 W/kg (at 50 Hz and 0.4 kA/m) were obtained for as-cast specimen. Observed good soft magnetic properties of these low cost cast-iron based alloys suggest perspective applications of these soft magnetic alloys as an alternative to the conventional Fe-Si electrical steel and Mn-Zn ferrites.

Study of the central region of the ternary Zr-Nb-Fe diagram

International Nuclear Information System (INIS)

Ramos, Cinthia; Saragovi, Celia; Arias, Delia E.; Granovsky, Marta S.

2003-01-01

The aim of the present work is identifying and characterizing the intermetallic phases and the associated two-phase and three-phase fields of the central region of the Zr-Nb-Fe phase diagram. As cast and 900 C degrees heat treated samples of variable compositions, 10 1 : Fe (Nb x Zr 1-x ) 2 and λ 2 : Zr(Nb x Fe 1-x ) 2 ) were studied. (author)

Solidification and casting

CERN Document Server

Cantor, Brian

2002-01-01

INDUSTRIAL PERSPECTIVEDirect chillcasting of aluminium alloysContinuous casting of aluminium alloysContinuous casting of steelsCastings in the automotive industryCast aluminium-silicon piston alloysMODELLING AND SIMULATIONModelling direct chill castingMold filling simulation of die castingThe ten casting rulesGrain selection in single crystal superalloy castingsDefects in aluminium shape castingPattern formation during solidificationPeritectic solidificationSTRUCTURE AND DEFECTSHetergeneous nucleation in aluminium alloysCo

Development and structural characterization of exchange-spring-like nanomagnets in (Fe,Co)-Pt bulk nanocrystalline alloys

Energy Technology Data Exchange (ETDEWEB)

Crisan, O.; Crisan, A.D.; Mercioniu, I. [National Institute for Materials Physics, P.O. Box MG-7, 077125 Magurele, Bucharest (Romania); Nicula, R. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Advanced Materials Processing, Feuerwerkerstr. 39, CH-3602 Thun (Switzerland); Vasiliu, F., E-mail: fvasiliu@infim.ro [National Institute for Materials Physics, P.O. Box MG-7, 077125 Magurele, Bucharest (Romania)

2016-03-01

FePt-based alloys are currently under scrutiny for their possible use as materials for perpendicular magnetic recording. Another possible application is in the field of permanent magnets without rare-earths, magnets that may operate at higher temperatures than the classic Nd–Fe–B magnets. Within this study, FeCoPt alloys prepared by rapid solidification from the melt are structurally and magnetically characterized. In the as-cast FeCoPt ribbons, a three-phase structure comprising well-ordered CoFePt and CoPt L1{sub 0} phases embedded in a disordered fcc FePt matrix was evidenced by XRD, HREM and SAED. Extended transmission electron microscopy analysis demonstrates the incipient formation of ordered L1{sub 0} phases. X-ray diffraction was used to characterize the phase structure and to obtain the structural parameters of interest for L1{sub 0} ordering. In the as-cast state, the co-existence of hard magnetic CoFePt and CoPt L1{sub 0} tetragonal phases with the soft fcc FePt phase is obtained within a refined microstructure made of alternatively disposed grains (grain sizes from 1 to 7 nm). Following a thermal treatment of 1 h at 670 °C, the soft magnetic fcc matrix phase transforms to tetragonal L1{sub 0} phases (disorder–order transition). The resulting CoPt and CoFePt L1{sub 0} phases have grains of around 5–20 nm in size. In the as-cast state, magnetic measurements show a quite large remanence (0.75 T), close to the value of the parent L1{sub 0} FePt phase. Coercive fields of about 200 kA/m at 5 K were obtained, comparable with those reported for some FePt-based bulk alloys. Upon annealing both remanence and coercivity are increased and values of up to 254 kA/m at 300 K are obtained. The polycrystalline structure of the annealed FeCoPt samples, as well as the formation of multiple c-axis domains in different CoPt and CoFePt regions (which leads to a reduction of the magneto-crystalline anisotropy) may account for the observed coercive fields that are

Chemical data from bottle casts in the Arctic Ocean and other Sea areas by the University of Alaska, from 16 April 1948 to 17 September 2000 (NODC Accession 0000918)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Chemical data were collected using bottle casts from multiple vessels in the Arctic Ocean and other Sea areas from 16 April 1948 to 17 September 2000. Data were...

Bainite obtaining in cast iron with carbides castings

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S. Pietrowski

2010-01-01

Full Text Available In these paper the possibility of upper and lower bainite obtaining in cast iron with carbides castings are presented. Conditions, when in cast iron with carbides castings during continuous free air cooling austenite transformation to upper bainite or its mixture with lower bainte proceeds, have been given. A mechanism of this transformation has been given, Si, Ni, Mn and Mo distribution in the eutectic cell has been tested and hardness of tested castings has been determined.

Comparison of marginal accuracy of castings fabricated by conventional casting technique and accelerated casting technique: an in vitro study.

Science.gov (United States)

Reddy, S Srikanth; Revathi, Kakkirala; Reddy, S Kranthikumar

2013-01-01

Conventional casting technique is time consuming when compared to accelerated casting technique. In this study, marginal accuracy of castings fabricated using accelerated and conventional casting technique was compared. 20 wax patterns were fabricated and the marginal discrepancy between the die and patterns were measured using Optical stereomicroscope. Ten wax patterns were used for Conventional casting and the rest for Accelerated casting. A Nickel-Chromium alloy was used for the casting. The castings were measured for marginal discrepancies and compared. Castings fabricated using Conventional casting technique showed less vertical marginal discrepancy than the castings fabricated by Accelerated casting technique. The values were statistically highly significant. Conventional casting technique produced better marginal accuracy when compared to Accelerated casting. The vertical marginal discrepancy produced by the Accelerated casting technique was well within the maximum clinical tolerance limits. Accelerated casting technique can be used to save lab time to fabricate clinical crowns with acceptable vertical marginal discrepancy.

Effect of impurities on microstructure and structural propertiesof the as-cast and treated Al-Zn alloys

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Douniazed Lamrous

2014-03-01

Full Text Available The microstructure of two Al-Zn alloys (with 10 and 30 wt.%Zn content produced by melting in the high frequency induction furnace were investigated by means of scanning electron microscopy (SEM, energy dispersive X-ray (EDX spectroscopy, X-ray diffraction (XRD analysis and the microhardness tests. The results indicate that the presence of iron impurity causes the formation of eutectic (Al,Zn3Fe in both alloys. The presence of the silicon impurity results in the formation of the phase separation in the Al-10%Zn as-cast alloy. The columnar to equiaxed transition was produced only in the Al-30%Zn as-cast alloy. The Vickers microhardness is higher in the equiaxed zone than in the columnar to equiaxed transition (CET zone. The presence of iron causes intermetallic phase formation (Al, Fe, Si3,6Zn in the Al-30%Zn as-cast alloy enabling an increase in the lattice parameter. After a homogenization treatment, the microstructure of Al-Zn treated alloys consists only of α dendrites and stable eutectic phase.

MICROSTRUCTURAL FEATURES EVALUATION OF AGE-HARDENED A 226 CAST ALLOY BY IMAGE ANALYSIS

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Lenka Kuchariková

2018-01-01

Full Text Available Age-hardening provides one of the most widely used mechanisms for the strengthening of aluminum alloys. The age-hardening involves three steps: solution treatment, quenching and aging. The temperature of solution treatment and aging is very important in order to reach desired properties of castings. The optimum temperature of solution treatment and aging led to formation microstructural features in form which does not lead to decreasing properties, but increasing ones. The major microstructural features in A 226 cast alloys which are responsible for increasing properties are: eutectic Si particles, Cu-rich phases, Fe-rich phases and porosity. The increase of properties depends on morphology, size and volume of microstructural features. In order to assess age-hardening influence on microstructural features in A226 cast alloys were used as possibilities of evaluation by means of image analysis. Quantitative analysis decelerate changes in microstructure includes the spheroidization and coarsening of eutectic silicon, gradual disintegration, shortening and thinning of Fe-rich intermetallic phases, the dissolution of precipitates and the precipitation of finer hardening phase (Al2Cu further increase in the hardness and tensile strength in the alloy. Changes of mechanical properties were measured in line with STN EN ISO.

NWIS Measurements for uranium metal annular castings

International Nuclear Information System (INIS)

Mattingly, J.K.; Valentine, T.E.; Mihalczo, J.T.

1998-01-01

This report describes measurements performed with annular uranium metal castings of different enrichments to investigate the use of 252 Cf-source-driven noise analysis measurements as a means to quantify the amount of special nuclear material (SNM) in the casting. This work in FY 97 was sponsored by the Oak Ridge Y-12 Plant and the DOE Office of Technology Development Programs. Previous measurements and calculational studies have shown that many of the signatures obtained from the source-driven measurement are very sensitive to fissile mass. Measurements were performed to assess the applicability of this method to standard annular uranium metal castings at the Oak Ridge Y-12 plant under verification by the International Atomic Energy Agency (IAEA) using the Nuclear Weapons Identification System (NWIS) processor. Before the measurements with different enrichments, a limited study of source-detector-casting moderator configurations was performed to enhance the correlated information. These configurations consisted of a casting with no reflector and with various thicknesses of polyethylene reflectors up to 10.16 cm in 2.54 cm steps. The polyethylene moderator thickness of 7.62 cm was used for measurements with castings of different enrichments reported here. The sensitivity of the measured parameters to fissile mass was investigated using four castings each with a different enrichment. The high sensitivity of this measurement method to fissile mass and to other material and configurations provides some advantages over existing safeguards methods

Pr2Fe14B/α-Fe nanocomposites for thermal applications

International Nuclear Information System (INIS)

Silva, Suelanny Carvalho da

2012-01-01

In this work, Pr x Fe 94 - x B 6 (x = 6, 8, 10 and 12) nanostructured powders were prepared by a combination of hydrogenation, disproportionation, desorption and recombination (HDDR) process with high energy milling applied to the mixture of an as-cast alloy (Pr 14 Fe 80 B 6 ) and α-Fe. The produced nanoparticles showed magnetic properties comparable to those reported in hyperthermia studies. The optimal time to obtain the magnetic nanoparticles is 5 hours (at 900 rpm). It was verified that longer milling times cause an increase in carbon percentage on the particles. The carbon is derived from oleic acid added as a surfactant in the milling step. The nanocomposites exhibit coercive force ranging from 80 Oe (6.5 kAm -1 ) to 170 Oe (13.5 kAm -1 ) and magnetic moments in the range of 81 129 Am2kg -1 . From the X-ray diffraction analyses, only two phases were found in all samples: α-Fe and the magnetic phase Pr 2 Fe 14 B. Individual nanoparticles with diameter of about 20 nm were verified. The samples studied presented heating when exposed to an alternating magnetic field (f = 222 kHz e H max ∼3.7 kAm -1 ) comparable to reported in literature. Temperature variations (ΔT) of the powders were: 51 K for Pr 6 Fe 88 B 6 , 41 K for Pr 8 Fe 86 B 6 , 38 K for Pr 10 Fe 8 4 B 6 and T = 34 K for Pr 12 Fe 82 B 6 . The specific absorption rates (SARs) of the powders were 201 Wkg -1 for Pr 6 Fe 88 B 6 composition, 158 Wkg -1 on the composition Pr 8 Fe 86 B 6 , and 114 Wkg -1 for Pr 10 Fe 84 B 6 and Pr 12 Fe 82 B 6 compositions. (author)

Formation of microstructure and properties on hot working and heat treatment of high strength modular cast iron

International Nuclear Information System (INIS)

Trajno, A.I.; Yusupov, V.S.; Kugushin, A.A.

1999-01-01

The possibility of plastic deformation of high strength modular cast iron (HSNCI) is under study. The microstructure and mechanical properties of hot worked and heat treated cast iron are investigated for the composition, %: Fe - 2.9 C - 2.4 Si - 0.7 Ni - 0.05 Mg - 0.04 Ce. It is stated that HSNCI can withstand various types of hot working without fracturing. Graphite inclusions lose their modular shape irreversibly during plastic deformation. Subsequent heat treatment affects the metal matrix only. The heating in oxidizing environment is noted to result in cast iron surface decarbonization [ru

Formamidopyrimidines in DNA: mechanisms of formation, repair, and biological effects.

Science.gov (United States)

Dizdaroglu, Miral; Kirkali, Güldal; Jaruga, Pawel

2008-12-15

Oxidatively induced damage to DNA results in a plethora of lesions comprising modified bases and sugars, DNA-protein cross-links, tandem lesions, strand breaks, and clustered lesions. Formamidopyrimidines, 4,6-diamino-5-formamidopyrimidine (FapyAde) and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyGua), are among the major lesions generated in DNA by hydroxyl radical attack, UV radiation, or photosensitization under numerous in vitro and in vivo conditions. They are formed by one-electron reduction of C8-OH-adduct radicals of purines and thus have a common precursor with 8-hydroxypurines generated upon one-electron oxidation. Methodologies using mass spectrometry exist to accurately measure FapyAde and FapyGua in vitro and in vivo. Formamidopyrimidines are repaired by base excision repair. Numerous prokaryotic and eukaryotic DNA glycosylases are highly specific for removal of these lesions from DNA in the first step of this repair pathway, indicating their biological importance. FapyAde and FapyGua are bypassed by DNA polymerases with the insertion of the wrong intact base opposite them, leading to mutagenesis. In mammalian cells, the mutagenicity of FapyGua exceeds that of 8-hydroxyguanine, which is thought to be the most mutagenic of the oxidatively induced lesions in DNA. The background and formation levels of the former in vitro and in vivo equal or exceed those of the latter under various conditions. FapyAde and FapyGua exist in living cells at significant background levels and are abundantly generated upon exposure to oxidative stress. Mice lacking the genes that encode specific DNA glycosylases accumulate these lesions in different organs and, in some cases, exhibit a series of pathological conditions including metabolic syndrome and cancer. Animals exposed to environmental toxins accumulate formamidopyrimidines in their organs. Here, we extensively review the mechanisms of formation, measurement, repair, and biological effects of formamidopyrimidines

Investigation of decomposition of solid solution of Ni-Cr-Fe 77/16/7 over-saturated in carbon during tempering at various temperatures

International Nuclear Information System (INIS)

Duffaut, Francois

1966-01-01

In its first part, this research thesis reports the investigation of the structure of the tempered Ni-Cr-Fe 77/16/7 alloy by using optical and electronic microscopy. The second part addresses the relationship between the structural status of the alloy and its electrochemical behaviour. The third part reports the investigation of the Portevin - Le Chatelier phenomenon in relationship with the decomposition of the solid solution. A last part addresses the investigation of a possible microstructure ordering of the Ni-Cr-Fe 77/16/7 alloy

Multiscale modeling of the influence of Fe content in a Al-Si-Cu alloy on the size distribution of intermetallic phases and micropores

International Nuclear Information System (INIS)

Wang Junsheng; Lee, Peter D.; Li Mei; Allison, John

2010-01-01

A multiscale model was developed to simulate the formation of Fe-rich intermetallics and pores in quaternary Al-Si-Cu-Fe alloys. At the microscale, the multicomponent diffusion equations were solved for multiphase (liquid-solid-gas) materials via a finite difference framework to predict microstructure formation. A fast and robust decentered plate algorithm was developed to simulate the strong anisotropy of the solid/liquid interfacial energy for the Fe-rich intermetallic phase. The growth of porosity was controlled by local pressure drop due to solidification and interactions with surrounding solid phases, in addition to hydrogen diffusion. The microscale model was implemented as a subroutine in a commercial finite element package, producing a coupled multiscale model. This allows the influence of varying casting conditions on the Fe-rich intermetallics, the pores, and their interactions to be predicted. Synchrotron x-ray tomography experiments were performed to validate the model by comparing the three-dimensional morphology and size distribution of Fe-rich intermetallics as a function of Fe content. Large platelike Fe-rich β intermetallics were successfully simulated by the multiscale model and their influence on pore size distribution in shape castings was predicted as a function of casting conditions.

Effect of Ag micro-alloying on the microstructure and properties of Cu-14Fe in situ composite

International Nuclear Information System (INIS)

Liu, K.M.; Lu, D.P.; Zhou, H.T.; Atrens, A.; Zou, J.; Yang, Y.L.; Zeng, S.M.

2010-01-01

This paper studied Ag micro-alloying in the deformation-processed Cu-14Fe in situ composite, by a comparison of Cu-14Fe and Cu-14Fe-0.06Ag. Each alloy was prepared by casting and processed into an in situ composite by hot and cold working. The microstructures were documented using light microscopy and scanning electron microscopy (SEM). The mechanical properties were measured with a tensile-testing machine. The electrical conductivity was measured with a micro-ohmmeter. For both alloys, the as-cast microstructure consisted of a Cu matrix and Fe dendrites; after hot and cold working the microstructure consisted of a Cu matrix containing Fe fibres elongated in the working direction. The as-cast Ag-containing alloy contained finer Fe dendrites. The Ag-containing in situ composite had thinner Fe fibres, higher tensile strength, higher ductility, and higher conductivity. The cold worked Cu-14Fe-0.06Ag in situ composite with cumulative cold deformation strain η = 7.8 (where η = ln(A 0 /A) and A 0 and A are the original and final cross-section areas, respectively), achieved a tensile strength of 930 MPa and a conductivity of 56%IACS (International Annealed Copper Standard; 17.241 nΩ m is defined as 100%IACS). The Ag micro-alloyed in situ composite had a combination of properties comparable to that of a much more expensive alloy containing much more Ag. After 1 h heat treatment at 300 deg. C, the tensile strength was increased to 950 MPa and the conductivity was increased to 56.4%IACS.

Manufacture of tube billets for fuel cans by vacuum centrifugal casting

International Nuclear Information System (INIS)

Zelenskij, V.F.; Neklyudov, I.M.; Chernyj, B.P.

1989-01-01

Vacuum device for induction melting with centrifugal casting in the ingot mold with rotation vertical or horisontal axis is presented. Removing and grinding of nonmetallic inclusions are realized by selection of casting conditions and of chemically active reducer, sound metal with high ductility is obtained. Data on micro- and macrostructure of casted tube billets made of 08Kh18N10T and 06Kh16H15M3B stainless steels, designed for manufacture of fuel cans are presented

DISCOVERY OF Fe Kα X-RAY REVERBERATION AROUND THE BLACK HOLES IN MCG-5-23-16 AND NGC 7314

International Nuclear Information System (INIS)

Zoghbi, A.; Reynolds, C.; Cackett, E. M.; Miniutti, G.; Kara, E.; Fabian, A. C.

2013-01-01

Several X-ray observations have recently revealed the presence of reverberation time delays between spectral components in active galactic nuclei. Most of the observed lags are between the power-law Comptonization component, seen directly, and the soft excess produced by reflection in the vicinity of the black hole. NGC 4151 was the first object to show these lags in the iron K band. Here, we report the discovery of reverberation lags in the Fe K band in two other sources: MCG-5-23-16 and NGC 7314. In both objects, the 6-7 keV band, where the Fe Kα line peaks, lags the bands at lower and higher energies with a time delay of ∼1 ks. These lags are unlikely to be due to the narrow Fe Kα line. They are fully consistent with reverberation of the relativistically broadened iron Kα line. The measured lags, their time scale, and spectral modeling indicate that most of the radiation is emitted at ∼5 and 24 gravitational radii for MCG-5-23-16 and NGC 7314, respectively.

Dalit women in India: at the crossroads of gender, class, and caste

OpenAIRE

Sabharwal, Nidhi Sadana; Sonalkar, Wandana

2015-01-01

As the lowest in the caste hierarchy, Dalits in Indian society have historically suffered caste-based social exclusion from economic, civil, cultural, and political rights. Women from this community suffer from not only discrimination based on their gender but also caste identity and consequent economic deprivation. Dalit women constituted about 16.60 percent of India’s female population in 2011. Dalit women’s problems encompass not only gender and economic deprivation but also discrimination...

Phase Transformation in Cast Superaustenitic Stainless Steels

Energy Technology Data Exchange (ETDEWEB)

Lee Phillips, Nathaniel Steven [Iowa State Univ., Ames, IA (United States)

2006-01-01

Superaustenitic stainless steels constitute a group of Fe-based alloys that are compositionally balanced to have a purely austenitic matrix and exhibit favorable pitting and crevice corrosion resistant properties and mechanical strength. However, intermetallic precipitates such as sigma and Laves can form during casting or exposure to high-temperature processing, which degrade the corrosion and mechanical properties of the material. The goal of this study was to accurately characterize the solid-solid phase transformations seen in cast superaustenitic stainless steels. Heat treatments were performed to understand the time and temperature ranges for intermetallic phase formations in alloys CN3MN and CK3MCuN. Microstructures were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy and wavelength dispersive spectroscopy (EDS, WDS). The equilibrium microstructures, composed primarily of sigma and Laves within purely austenitic matrices, showed slow transformation kinetics. Factors that determine the extent of transformation, including diffusion, nucleation, and growth, are discussed.

Intrinsic evolution of novel (Nd, MM)2Fe14B-system magnetic flakes

Science.gov (United States)

Yu, Xiaoqiang; Zhu, Minggang; Liu, Weiqiang; Li, Yanfeng; Zhang, Jiuxing; Yue, Ming; Li, Wei

2018-01-01

The Nd-substituted (Nd x MM1- x )-Fe-B strip-casting flakes were prepared by induction melting in the vacuum furnace and then subsequently by strip-casting technology. The microstructure and magnetic properties of (Nd x MM1- x )-Fe-B alloys are related to the Nd substitution. 2:14:1 main phases and minor impure phases coexist in the MM-Fe-B flake. For example, La2O3 and CeFe2 impure phases are obviously detected in the x = 0 specimen. As an increase of the Ce concentration is inversely accompanied with the decrease of the Nd content ( x) in (Nd x MM1- x )2Fe14B main phases (0 ≤ x ≤ 1), XRD analysis shows that the overall diffraction peaks of the main phases shift to right domestically because of smaller radius Ce4+. The melting point, spin reorientation phase transition temperature, Curie temperature, magneto-crystalline anisotropy field (at 300 K), and the magnetization ( M 9T) for MM-Fe-B/(Nd0.4MM0.6)-Fe-B/(Nd0.7MM0.3)-Fe-B/Nd-Fe-B strip-casting alloys are 1376.15/1414.15/1439.15/1458.15 K, 74/113/124/135 K, 493.2/538.4/559.7/582.3 K, 48/55.2/64.4/70.1 kOe and 136.5/143.7/151.5/153.7 emu/g, respectively. Due to the varied composition of hard magnetic main phases, M 9T increases gradually with the increase of Nd content ( x). SEM observation and EDX results demonstrate that more Nd and Pr elements aggregate into the 2:14:1 ferromagnetic phase, while less La and Ce elements are prone to the RE-rich region compared with the nominal ratio. As a result, the growth of M 9T becomes extraordinary under maximum external field 9 T, indicating that the (Nd0.7MM0.3)-Fe-B flake may display relatively good magnetic properties and those with higher Nd content have evident effect on magnetization, compositions, and microstructures of hard magnetic main phases. Therefore, practical application of (Nd x MM1- x )-Fe-B-sintered magnets will be very prospective.

Development of thermophysical calculator for stainless steel casting alloys by using CALPHAD approach

Directory of Open Access Journals (Sweden)

In-Sung Cho

2017-11-01

Full Text Available The calculation of thermophysical properties of stainless steel castings and its application to casting simulation is discussed. It is considered that accurate thermophysical properties of the casting alloys are necessary for the valid simulation of the casting processes. Although previous thermophysical calculation software requires a specific knowledge of thermodynamics, the calculation method proposed in the present study does not require any special knowledge of thermodynamics, but only the information of compositions of the alloy. The proposed calculator is based on the CALPHAD approach for modeling of multi-component alloys, especially in stainless steels. The calculator proposed in the present study can calculate thermophysical properties of eight-component systems on an iron base alloy (Fe-C-Si-Cr-Mn-Ni-Cu-Mo, and several Korean standard stainless steel alloys were calculated and discussed. The calculator can evaluate the thermophysical properties of the alloys such as density, heat capacity, enthalpy, latent heat, etc, based on full Gibbs energy for each phase. It is expected the proposed method can help casting experts to devise the casting design and its process easily in the field of not only stainless steels but also other alloy systems such as aluminum, copper, zinc, etc.

Simulation of Stress Distribution in a Thick- Walled Bushing Produced by Die-Casting

Directory of Open Access Journals (Sweden)

Pisarek B.P.

2017-12-01

Full Text Available Metallographic investigations and a computer simulation of stresses in a gravity die-casting bushing were performed. Simulation of the casting process, solidification of the thick-walled bushing and calculations of the stress was performed using MAGMA5.3 software. The size variability of phases κII affecting the formation of phase stresses σf, depending on the location of the metallographic test area, was identified. The distribution of thermal σt and shrinkage stresses σs, depending on the location of the control point SC in the bushing's volume, was estimated. Probably the nature of these stresses will change slightly even after machining. This can cause variations in operating characteristics (friction coefficient, wear. Due to the strong inhomogeneity of the stress distribution in the bushing's casting, it is necessary to perform further tests of the possibility to conduct thermal treatment guaranteeing homogenization of the internal stresses in the casting, as well as to introduce changes in the bushing' s construction and the casting technology. The paper presents the continuation of the results of research aimed at identifying the causes of defects in the thick-walled bushing, die-casting made of CuAl10Fe5Ni5Cr aluminium bronze.

Nanocrystallization in amorphous Fe40Ni40(Si+B)19Mo1-2 ribbons

International Nuclear Information System (INIS)

Saiseng, S.; Winotai, P.; Nilpairuch, S.; Limsuwan, P.; Tang, I.M.

2004-01-01

Cut Fe 40 Ni 40 (Si+B) 19 Mo 1-2 ribbons were annealed for 2 h at various temperatures between 350 deg. C and 600 deg. C. XRD and Mossbauer effect spectroscopy (ME) measurements were then performed on all of the ribbons. The magnetic properties of several ribbons were measured using a vibrating sample magnetometer (VSM). A differential thermal analysis scan (over the range 20-800 deg. C) of the as-cast ribbon showed two phase transitions; the first at 454 deg. C and the second at 525 deg. C. Both the XRD and ME spectra of the as cast, the 350 deg. C and 400 deg. C annealed ribbons showed that they were amorphous. The ME spectra of the 450 deg. C, 475 deg. C and 500 deg. C annealed ribbons showed that these ribbons contained α-Fe, α-Fe(Si) and t-Fe 2 B nanocrystallites. For the ribbons annealed above 550 deg. C, crystallites of t-Fe 2 B, t-Fe 3 B, t-Fe 5 SiB 2 and FCC-FeNi appeared, with the α-Fe and α-Fe(Si) crystallites disappearing. The sextets of all of the Fe compounds appeared in the ME spectra of the 525 deg. C annealed ribbon. The VSM measurements supported the picture of a two-stage phase transitions; amorphous phase→a nanocrystalline phase (Fe-containing nanocrystallites in an amorphous matrix) at 454 deg. C and then a second transition, the nanocrystalline phase→a disordered alloy containing Fe-B and Fe-Ni crystallites at 525 deg. C

Comparison of Heavy-Duty Scuffing Behavior between Chromium-Based Ceramic Composite and Nickel-Chromium-Molybdenum-Coated Ring Sliding against Cast Iron Liner under Starvation

Directory of Open Access Journals (Sweden)

Yan Shen

2017-10-01

Full Text Available A running-in and starved lubrication experiment is designed to investigate the heavy-duty scuffing behavior of piston ring coatings against cast iron (Fe cylinder liner using the piston ring reciprocating liner test rig. The scuffing resistance of the piston ring with the chromium-based ceramic composite coating (CKS, and that with the thermally sprayed nickel-chromium-molybdenum coating (NCM is compared at different nominal pressures (40~100 MPa and temperatures (180~250 °C. With the failure time as a criterion, the rank order is as follows: NCM/Fe > CKS/Fe. Before the scoring occurs at the interface of the piston ring and cylinder liner (PRCL, the cast iron liner enters into a “polish wear” stage, and iron-based adhesive materials begin to form on the piston ring surface. With the macroscopic adhesion formation, the plastic shearing cycle causes surface damages mainly due to abrasive effects for the CKS/Fe pairs and adhesive effects for the NCM/Fe pairs.

The influence of surface layer nitriding on phase composition and tribological properties of cast steel

International Nuclear Information System (INIS)

Brzozka, K; Gorka, B; Gawronski, M; Budzynowski, T W

2010-01-01

The effect of two-stage low-temperature nitriding on atomic structure and mechanical properties of selected cast steels is investigated. Conversion electron Moessbauer spectroscopy has been used to investigate nitrides formation. In order to study tribological characteristics, tests of friction and reflecting electron microscopy measurements have been performed. It has been found that thin nitrides layer (composed mainly of γ'-Fe 4 N) arises in the course of the nitriding procedure in most of investigated cast steels, what considerably affects their microstructure and tribological properties.

Development of Fe-B Based Bulk Metallic Glasses: Morphology of Residual Phases in Fe50Ni16Mo6B18Zr10 Glass

Directory of Open Access Journals (Sweden)

Tiburce A. Aboki

2013-04-01

Full Text Available Iron-boron based bulk metallic glasses (BMG development has been initiated using Fe40Ni38Mo4B18 as precursor. Addition of zirconium up to 10 atomic % along with the reduction of Ni proportion improves the glass forming ability (GFA, which is optimum when Ni is suppressed in the alloy. However melting instability occurred during the materials fabrication resulting in the formation of residual crystalline phases closely related to the amorphous phase. Microstructure study shows an evolution from amorphous structure to peculiar acicular structure, particularly for Fe50Ni16Mo6B18Zr10, suggesting the amorphous structure as interconnected atomic sheets like “atomic mille feuilles” whose growth affects the alloys’ GFA.

The cavitation erosion of ultrasonic sonotrode during large-scale metallic casting: Experiment and simulation.

Science.gov (United States)

Tian, Yang; Liu, Zhilin; Li, Xiaoqian; Zhang, Lihua; Li, Ruiqing; Jiang, Ripeng; Dong, Fang

2018-05-01

Ultrasonic sonotrodes play an essential role in transmitting power ultrasound into the large-scale metallic casting. However, cavitation erosion considerably impairs the in-service performance of ultrasonic sonotrodes, leading to marginal microstructural refinement. In this work, the cavitation erosion behaviour of ultrasonic sonotrodes in large-scale castings was explored using the industry-level experiments of Al alloy cylindrical ingots (i.e. 630 mm in diameter and 6000 mm in length). When introducing power ultrasound, severe cavitation erosion was found to reproducibly occur at some specific positions on ultrasonic sonotrodes. However, there is no cavitation erosion present on the ultrasonic sonotrodes that were not driven by electric generator. Vibratory examination showed cavitation erosion depended on the vibration state of ultrasonic sonotrodes. Moreover, a finite element (FE) model was developed to simulate the evolution and distribution of acoustic pressure in 3-D solidification volume. FE simulation results confirmed that significant dynamic interaction between sonotrodes and melts only happened at some specific positions corresponding to severe cavitation erosion. This work will allow for developing more advanced ultrasonic sonotrodes with better cavitation erosion-resistance, in particular for large-scale castings, from the perspectives of ultrasonic physics and mechanical design. Copyright © 2018 Elsevier B.V. All rights reserved.

New high strength technologically ecological and expedient economically advantageous alloys on Fe-C base

International Nuclear Information System (INIS)

Kolev, B.V.

2003-01-01

The paper presents framework a part of by now obtained results of the authors studies in the period 1967(68) - 2002 about possibilities for obtaining new high-strength and wear resistant cast alloys on, Fe-C base (complex alloyed steels and cast irons of different systems with different structure, reflected in over 125 articles, 15 inventions (patents) and other scientific studies. The paper includes summarized results and discussion. Key words: new austenite steels and cast irons, mechanical characteristics, wear resistance. (Original)

FeNbB bulk metallic glass with high boron content

Energy Technology Data Exchange (ETDEWEB)

Stoica, M.; Das, Jayanta; Eckert, Juergen [IFW Dresden, Institute for Complex Materials, P.O. Box 270016, D-01171 Dresden (Germany); Hajlaoui, Khalil; Yavari, Alain Reza [LTPCM-CNRS, I.N.P. Grenoble, 1130 Rue de la Piscine, BP 75, F-38402 University Campus (France)

2007-07-01

Fe-based alloys able to form magnetic bulk metallic glasses (BMGs) are of the type transition metal - metalloid and often contain 5 or more elements. Usually, the metalloid content is around 20 atomic %. Very recently, the Fe{sub 66}Nb{sub 4}B{sub 30} alloy was found to be able to form BMG by copper mold casting technique, despite its high metalloid content. Several composition with boron contents around 30 at. % or even higher were calculated since 1993 as possible compositions of the remaining amorphous matrix after the first stage of nanocrystallization of Finemet-type Fe{sub 77}Si{sub 14}B{sub 9} glassy ribbons with 0.5 to 1 atomic % Cu and a few percent Nb addition. Melt-spun ribbons of all calculated compositions were found to be glassy. The composition of the ternary Fe-based BMG investigated in the present study resulted as an optimization of all possibilities. The alloy is ferromagnetic with glass transition temperature T{sub g}=845 K, crystallisation temperature T{sub x}=876 K, liquidus temperature T{sub liq}=1451 K and mechanical strength of 4 GPa. The coercivity of as-cast samples is very low, around 1.5 A/m. The present contribution aims at discussing the thermal stability, mechanical and magnetic properties of the Fe{sub 66}Nb{sub 4}B{sub 30} BMG.

A study for preparation of Ti-Fe coating by high temperature sintering method

International Nuclear Information System (INIS)

Hu Yonghai

1995-03-01

A new technology for preparation of Ti-Fe alloy coating on the steel substrate was investigated by high temperature sintering method. The pulp of titanium hydride powder was coated on the cleaned steel substrate, then heated in vacuum for desorption of hydrogen and sintered at high temperature in argon atmosphere for forming Ti-Fe alloy coating. The electron probe analysis shows a strong coherent diffusion layer formed between the elements of titanium and iron. X-ray diffraction analysis indicates that the coating consists of α-Ti, TiFe and TiFe 2 three phases. The wear resistance of the coating is twice as large as that of grey cast iron and the hardness determined can reach 7300∼7800 N/mm 2 . The coating is almost porous free. The corrosion potential increases with the time and the corrosion resistance is near to that of pure titanium. The working life of ridge-type diaphragm valve coated by Ti-Fe alloy for carbonization tower of alkali factories is five times higher than that of valve made of grey cast iron. Therefore, this new technology can be widely used in metallurgical, chemical and nuclear industries. (9 figs., 10 tabs.)

The characteristics of precipitates in 18% Cr/30% Ni cast steel with additions of Nb and Ti

International Nuclear Information System (INIS)

Piekarski, B.

1995-01-01

The microstructure of austenitic cast steel with approx. 0.3%C, 4.37%Si, 0.69%Mn, 17.8%Cr, 29.3%Ni, 1.47%Nb and 1.07%Ti have been examined after ageing at 900 C for 300 h. There was found five precipitates: M 23 C 6 , MnS, Ni 3 Fe, (Ti,Nb)C and an intermetallic Ni-Nb-S phase. Ni, Nb, Si-rich precipitate could have been formed in as cast condition. (author)

Fibreglass Total Contact Casting, Removable Cast Walkers, and Irremovable Cast Walkers to Treat Diabetic Neuropathic Foot Ulcers: A Health Technology Assessment

Science.gov (United States)

Costa, Vania; Tu, Hong Anh; Wells, David; Weir, Mark; Holubowich, Corinne; Walter, Melissa

2017-01-01

Background Diabetic neuropathic foot ulcers are a risk factor for lower leg amputation. Many experts recommend offloading with fibreglass total contact casting, removable cast walkers, and irremovable cast walkers as a way to treat these ulcers. Methods We completed a health technology assessment, which included an evaluation of clinical benefits and harms, value for money, and patient preferences for offloading devices. We performed a systematic literature search on August 17, 2016, to identify randomized controlled trials that compared fibreglass total contact casting, removable cast walkers, and irremovable cast walkers with other treatments (offloading or non-offloading) in patients with diabetic neuropathic foot ulcers. We developed a decision-analytic model to assess the cost-effectiveness of fibreglass total contact casting, removable cast walkers, and irremovable cast walkers, and we conducted a 5-year budget impact analysis. Finally, we interviewed people with diabetes who had lived experience with foot ulcers, asking them about the different offloading devices and the factors that influenced their treatment choices. Results We identified 13 randomized controlled trials. The evidence suggests that total contact casting, removable cast walkers, and irremovable cast walkers are beneficial in the treatment of neuropathic, noninfected foot ulcers in patients with diabetes but without severe peripheral arterial disease. Compared to removable cast walkers, ulcer healing was improved with total contact casting (moderate quality evidence; risk difference 0.17 [95% confidence interval 0.00–0.33]) and irremovable cast walkers (low quality evidence; risk difference 0.21 [95% confidence interval 0.01–0.40]). We found no difference in ulcer healing between total contact casting and irremovable cast walkers (low quality evidence; risk difference 0.02 [95% confidence interval −0.11–0.14]). The economic analysis showed that total contact casting and irremovable

NWIS casting measurements taken during demonstrations to Russian visitors

International Nuclear Information System (INIS)

Mullens, J.A.; Valentine, T.E.; Mihalczo, J.T.

1998-01-01

This report describes a set of NWIS measurements made during demonstrations to Russian visitors on August 28, 1997. These measurements will be given to the Russian visitors from Arzamus-16 as part of their NWIS training (part of a DOE laboratory-to-laboratory exchange program). These measurements are made on standard highly enriched Uranium annular castings (as used for storage). Associated NWIS calibration runs were made in air (no casting, just the NWIS Californium source and detectors)

Effects of grain refinement on cast structure and tensile properties of superalloy K4169 at high pouring temperature

Directory of Open Access Journals (Sweden)

Zi-qi Jie

2016-03-01

Full Text Available In order to improve the filling ability of large complex thin wall castings, the pouring temperature should be increased, but this will result in the grain coarsening. To overcome this problem, two kinds of grain refiners of Co-Fe-Nb and Cr-Fe-Nb ternary alloys, which contain high stability compound particles, were prepared. The effects of the refiners on the as-cast structures and tensile properties of the K4169 superalloy with different casting conditions were studied by analyzing specimens 110 mm long and 20 mm in diameter. Results showed that the mixture addition of the two refiners in the melt of K4169 can reduce the columnar grain region and decrease the equiaxed grain size greatly. After refinement, the amount of Laves phase decreases and its morphology changes from island to blocky structure. The carbides in the fine grain samples are fine and dispersive. Meanwhile, the porosity in specimens is decreased due to grain refinement. As a result, the yield strength, ultimate strength and the elongation of the specimens are increased. The grain refinement mechanisms are also discussed.

DISCOVERY OF Fe K{alpha} X-RAY REVERBERATION AROUND THE BLACK HOLES IN MCG-5-23-16 AND NGC 7314

Energy Technology Data Exchange (ETDEWEB)

Zoghbi, A.; Reynolds, C. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Cackett, E. M. [Department of Physics and Astronomy, Wayne State University, 666 W. Hancock St, Detroit, MI 48201 (United States); Miniutti, G. [Centro de Astrobiologia (CSIC-INTA), Dep. de Astrosica, P.O. Box 78, E-28691 Villanueva de la Canada, Madrid (Spain); Kara, E.; Fabian, A. C., E-mail: azoghbi@astro.umd.edu [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom)

2013-04-20

Several X-ray observations have recently revealed the presence of reverberation time delays between spectral components in active galactic nuclei. Most of the observed lags are between the power-law Comptonization component, seen directly, and the soft excess produced by reflection in the vicinity of the black hole. NGC 4151 was the first object to show these lags in the iron K band. Here, we report the discovery of reverberation lags in the Fe K band in two other sources: MCG-5-23-16 and NGC 7314. In both objects, the 6-7 keV band, where the Fe K{alpha} line peaks, lags the bands at lower and higher energies with a time delay of {approx}1 ks. These lags are unlikely to be due to the narrow Fe K{alpha} line. They are fully consistent with reverberation of the relativistically broadened iron K{alpha} line. The measured lags, their time scale, and spectral modeling indicate that most of the radiation is emitted at {approx}5 and 24 gravitational radii for MCG-5-23-16 and NGC 7314, respectively.

Three-dimensional rigid multiphase networks providing high-temperature strength to cast AlSi10Cu5Ni1-2 piston alloys

International Nuclear Information System (INIS)

Asghar, Z.; Requena, G.; Boller, E.

2011-01-01

The three-dimensional (3-D) architecture of rigid multiphase networks present in AlSi10Cu5Ni1 and AlSi10Cu5Ni2 piston alloys in as-cast condition and after 4 h spheroidization treatment is characterized by synchrotron tomography in terms of the volume fraction of rigid phases, interconnectivity, contiguity and morphology. The architecture of both alloys consists of α-Al matrix and a rigid long-range 3-D network of Al 7 Cu 4 Ni, Al 4 Cu 2 Mg 8 Si 7 , Al 2 Cu, Al 15 Si 2 (FeMn) 3 and AlSiFeNiCu aluminides and Si. The investigated architectural parameters of both alloys studied are correlated with room-temperature and high-temperature (300 deg. C) strengths as a function of solution treatment time. The AlSi10Cu5Ni1 and AlSi10Cu5Ni2 alloys behave like metal matrix composites with 16 and 20 vol.% reinforcement, respectively. Both alloys have similar strengths in the as-cast condition, but the AlSi10Cu5Ni2 is able to retain ∼15% higher high temperature strength than the AlSi10Cu5Ni1 alloy after more than 4 h of spheroidization treatment. This is due to the preservation of the 3-D interconnectivity and the morphology of the rigid network, which is governed by the higher degree of contiguity between aluminides and Si.

Control of cast iron and casts manufacturing by Inmold method

Directory of Open Access Journals (Sweden)

S. Pietrowski

2009-07-01

Full Text Available In this paper the usability of cast iron spheroidizing process in mould control by ATD method as well as by ultrasonic method were presented. Structure of instrumentation needed for control form performance of cast iron spheroidizing by Inmold method was illustrated. Author, pointed out that amount of magnesium master alloy should obtain 0,8 ÷ 1,0% of mass in form at all. Such quantity of preliminary alloy assure of obtain of nodular graphite in cast iron. In consequence of this, is reduce the cast iron liquidus temperature and decrease of recalescence temperature of graphite-eutectic crystallization in compare with initial cast iron. Control of casts can be carried out by ultrasonic method. In plain cast iron, ferritic-pearlitic microstructure is obtaining. Additives of 1,5% Cu ensure pearlitic structure.

The casting of western sculpture during the XIXth century: sand casting versus lost wax casting

NARCIS (Netherlands)

Beentjes, T.P.C.

2014-01-01

This paper will discuss research into bronze casting techniques as practiced during the XIXth and early XXth century. Both natural sand casting (fonte au sable naturel) and lost wax casting (fonte à la cire perdue) were employed during this period and sometimes rivalled for commissions. Before the

Oxidation behavior of a Ni-Fe support in SOFC anode atmosphere

DEFF Research Database (Denmark)

Xu, Na; Chen, Ming; Han, Minfang

2018-01-01

In this work, we investigated the long-term oxidation behavior of a Ni-Fe (1:1 weight ratio) support for solid oxide fuel cell (SOFC) applications. Ni-Fe supports were obtained through tape casting, high temperature sintering and pre-reducing in 97% H2/N2 (9/91)-3% H2O at 750 and 1000 °C, respect...... annealed in the two atmospheres maintained sufficiently high conductivity. The results from the current work demonstrate that the porous Ni-Fe support can be well employed in SOFCs, especially metal-supported SOFCs....

Optimization of the composition and structure of heat-resistant casting aluminium alloys with additions of cerium, iron, nickel and zirconium

International Nuclear Information System (INIS)

Belov, N.A.; Lavrishchev, Yu.V.

2000-01-01

A study is made of the effect of composition and structure on mechanical properties of cast alloys of the Al-Ce-Ni-Fe-Zr system in which binary and ternary eutectics with participation of low alloyed aluminium solid solution and Al 4 Ce, Al 3 Ni and Al 9 FeNi phases are crystallized. It is found that microhardness of eutectics is heavily dependent on the volume fraction of aluminides and their dispersivity. It was shown that essential hardening of aluminium matrix can be achieved at the cost of zirconium additive in quantity of 0.6 % when using two-stage manufacturing operation. Experimental compositions of Al-10 % Ce-5% Ni-0.6 % Zr and Al-1.5 % Fe-1.5 % Ni-0.6 % Zr on the basis of ternary and binary eutectics respectively as billets essentially exceed industrial heat-resistant cast aluminium alloys AK12MMgN and AM5 as to a set of room and high-temperature mechanical properties and hot brittleness index [ru

Temperature profile and water depth collected from XIANG YANG HONG 05 in the South China Sea using BT and XBT casts from 16 November 1986 to 03 December 1986 (NODC Accession 8700009)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth were collected using BT and XBT casts from the XIANG YANG HONG 05 in the South China Sea. Data were collected from 16 November...

Temperature profiles from XBT casts from the DELTA SUD as part of the Marine Resources Monitoring, Assessment and Prediction (MARMAP) project from 1975-02-09 to 1975-03-16 (NODC Accession 7500643)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profiles were collected from XBT casts from the DELTA SUD from 09 February 1975 to 16 March 1975. Data were collected by the Delta Steamship Co. as part...

Creep of cast Fe-36Al-2Ti alloy

Czech Academy of Sciences Publication Activity Database

Dobeš, Ferdinand; Kratochvíl, P.; Milička, Karel

2006-01-01

Roč. 14, 10-11 (2006), s. 1199-1203 ISSN 0966-9795. [EUROMAT 2005. Praha, 05.09.2005-08.09.2005] R&D Projects: GA ČR(CZ) GA106/05/0409 Institutional research plan: CEZ:AV0Z20410507 Keywords : iron aluminides, based on FeAl * creep * mechanical testing Subject RIV: JG - Metallurgy Impact factor: 1.943, year: 2006

Crystal structure and magnetic properties of a nitrogenated melt-spun Sm[sub 2]Fe[sub 17] compound

Energy Technology Data Exchange (ETDEWEB)

Yang, Choong-Jin [Electromagnetic Materials Laboratory, Research Institute of Industrial Science and Technology, P.O. Box 135, 790-330 Pohang (Korea, Republic of); Lee, Woo-Young [Electromagnetic Materials Laboratory, Research Institute of Industrial Science and Technology, P.O. Box 135, 790-330 Pohang (Korea, Republic of); Choi, Seung-Duck [Electromagnetic Materials Laboratory, Research Institute of Industrial Science and Technology, P.O. Box 135, 790-330 Pohang (Korea, Republic of)

1994-05-15

Sm[sub 2]Fe[sub 17]N[sub 2.9] compound powders were prepared from parent alloys of Sm[sub 2]Fe[sub 17] which were made by both arc melting and rapid solidification processes. The cast Sm[sub 2]Fe[sub 17] contained mixed phases of SmFe[sub 3] and [alpha]-Fe, and correspondingly formed less Sm[sub 2]Fe[sub 17]N[sub x] with a rather large amount of residual [alpha]-Fe after nitrogenation. The melt-spun Sm[sub 2]Fe[sub 17] compound, however, was single phase and exhibited a negligible amount of residual [alpha]+Fe after nitrogenation. The residual amount of free iron was found to increase as a function of milling time and to impede the development of promising permanent magnetic properties. The melt-spun Sm[sub 2]Fe[sub 17]N[sub x] compound powders exhibited a coercivity value [sub i]H[sub c] of 5 kOe, which is double that of the as-cast Sm[sub 2]Fe[sub 17]N[sub x] powders and a high remanence B[sub r]=60 e.m.u. g[sup -1]. The average magnetic moment of Fe atoms in the crystal is estimated to be 2.29 [mu][sub B] and the Fe atom in the 6c site exhibits the highest magnetic moment of 2.65 [mu][sub B]. The expansion in the c axial direction of the nitrogenated crystal was found to be mainly due to extension of Sm(6c)-Fe(c) and Fe(18f)-Fe(18f) distances. ((orig.))

Fe2O3/MWCNTs nanocomposite decorated glassy carbon electrode ...

Indian Academy of Sciences (India)

2018-03-23

Mar 23, 2018 ... (GCE) was prepared by drop casting Fe2O3/MWCNTs onto the surface of GCE. Scanning .... three times with ethanol and distilled water, and then dried in the oven at 60 .... and could undergo the following conversion: 2H.

Y-chromosomal insights into the genetic impact of the caste system in India.

Science.gov (United States)

Zerjal, Tatiana; Pandya, Arpita; Thangaraj, Kumarasamy; Ling, Edmund Y S; Kearley, Jennifer; Bertoneri, Stefania; Paracchini, Silvia; Singh, Lalji; Tyler-Smith, Chris

2007-03-01

The caste system has persisted in Indian Hindu society for around 3,500 years. Like the Y chromosome, caste is defined at birth, and males cannot change their caste. In order to investigate the genetic consequences of this system, we have analysed male-lineage variation in a sample of 227 Indian men of known caste, 141 from the Jaunpur district of Uttar Pradesh and 86 from the rest of India. We typed 131 Y-chromosomal binary markers and 16 microsatellites. We find striking evidence for male substructure: in particular, Brahmins and Kshatriyas (but not other castes) from Jaunpur each show low diversity and the predominance of a single distinct cluster of haplotypes. These findings confirm the genetic isolation and drift within the Jaunpur upper castes, which are likely to result from founder effects and social factors. In the other castes, there may be either larger effective population sizes, or less strict isolation, or both.

Martensite shear phase reversion-induced nanograined/ultrafine-grained Fe-16Cr-10Ni alloy: The effect of interstitial alloying elements and degree of austenite stability on phase reversion

Energy Technology Data Exchange (ETDEWEB)

Misra, R.D.K., E-mail: dmisra@louisiana.edu [Center for Structural and Functional Materials, University of Louisiana at Lafayette, Madison Hall Room 217, P.O. Box 44130, Lafayette, LA 70504-1430 (United States); Zhang, Z.; Venkatasurya, P.K.C. [Center for Structural and Functional Materials, University of Louisiana at Lafayette, Madison Hall Room 217, P.O. Box 44130, Lafayette, LA 70504-1430 (United States); Somani, M.C.; Karjalainen, L.P. [Department of Mechanical Engineering, University of Oulu, P.O. Box 4200, Oulu 90014 (Finland)

2010-11-15

Research highlights: {yields} Development of a novel process involving phase-reversion annealing process. {yields} Austensite stability strongly influences development of nanograined structure. {yields} Interstitial elements influence microstructural evolution during annealing. - Abstract: We describe here an electron microscopy study of microstructural evolution associated with martensitic shear phase reversion-induced nanograined/ultrafine-grained (NG/UFG) structure in an experimental Fe-16Cr-10Ni alloy with very low interstitial content. The primary objective is to understand and obtain fundamental insights on the influence of degree of austenite stability (Fe-16Cr-10Ni, 301LN, and 301 have different austenite stability index) and interstitial elements (carbon and nitrogen) in terms of phase reversion process, microstructural evolution during reversion annealing, and temperature-time annealing sequence. A relative comparison of Fe-16Cr-10Ni alloy with 301LN and 301 austenitic stainless steels indicated that phase reversion in Fe-16Cr-10Ni occurred by shear mechanism, which is similar to that observed for 301, but is different from the diffusional mechanism in 301LN steel. While the phase reversion in the experimental Fe-16Cr-10Ni alloy and 301 austenitic stainless steel occurred by shear mechanism, there were fundamental differences between these two alloys. The reversed strain-free austenite grains in Fe-16Cr-10Ni alloy were characterized by nearly same crystallographic orientation, where as in 301 steel there was evidence of break-up of martensite laths during reversion annealing resulting in several regions of misoriented austenite grains in 301 steel. Furthermore, a higher phase reversion annealing temperature range (800-900 deg. C) was required to obtain a fully NG/UFG structure of grain size 200-600 nm. The difference in the phase reversion and the temperature-time sequence in the three stages is explained in terms of Gibbs free energy change that

Selective transport of Fe(III) using ionic imprinted polymer (IIP) membrane particle

Science.gov (United States)

Djunaidi, Muhammad Cholid; Jumina, Siswanta, Dwi; Ulbricht, Mathias

2015-12-01

The membrane particles was prepared from polyvinyl alcohol (PVA) and polymer IIP with weight ratios of 1: 2 and 1: 1 using different adsorbent templates and casting thickness. The permeability of membrane towards Fe(III) and also mecanism of transport were studied. The selectivity of the membrane for Fe(III) was studied by performing adsorption experiments also with Cr(III) separately. In this study, the preparation of Ionic Imprinted Polymer (IIP) membrane particles for selective transport of Fe (III) had been done using polyeugenol as functional polymer. Polyeugenol was then imprinted with Fe (III) and then crosslinked with PEGDE under alkaline condition to produce polyeugenol-Fe-PEGDE polymer aggregates. The agrregates was then crushed and sieved using mesh size of 80 and the powder was then used to prepare the membrane particles by mixing it with PVA (Mr 125,000) solution in 1-Methyl-2-pyrrolidone (NMP) solvent. The membrane was obtained after casting at a speed of 25 m/s and soaking in NaOH solution overnight. The membrane sheet was then cut and Fe(III) was removed by acid to produce IIP membrane particles. Analysis of the membrane and its constituent was done by XRD, SEM and size selectivity test. Experimental results showed the transport of Fe(III) was faster with the decrease of membrane thickness, while the higher concentration of template ion correlates with higher Fe(III) being transported. However, the transport of Fe(III) was slower for higher concentration of PVA in the membrane. IImparticles works through retarded permeation mechanism, where Fe(III) was bind to the active side of IIP. The active side of IIP membrane was dominated by the -OH groups. The selectivity of all IIP membranes was confirmed as they were all unable to transport Cr (III), while NIP (Non-imprinted Polymer) membrane was able transport Cr (III).

Microstructure and mechanical properties of lost foam cast 356 alloys

Directory of Open Access Journals (Sweden)

Qi-gui Wang

2015-05-01

Full Text Available Microstructure and mechanical properties of lost foam cast aluminum alloys have been investigated in both primary A356 (0.13% Fe and secondary 356 (0.47%. As expected, secondary 356 shows much higher content of Fe-rich intermetallic phases, and in particular the porosity in comparison with primary A356. The average area percent and size (length of Fe-rich intermetallics change from about 0.5% and 6 祄 in A356 to 2% and 25 祄 in 356 alloy. The average area percent and maximum size of porosity also increase from about 0.4% and 420 祄 to 1.4% and 600 祄, respectively. As a result, tensile ductility decreases about 60% and ultimate tensile strength declines about 8%. Lower fatigue strength was also experienced in the secondary 356 alloy. Low cycle fatigue (LCF strength decreased from 187 MPa in A356 to 159 MPa in 356 and high cycle fatigue (HCF strength also declined slightly from 68 MPa to 64 MPa.

The microwave magnetic performance of Sm3+ doped BaCo2Fe16O27

International Nuclear Information System (INIS)

Wang Lixi; Song Jie; Zhang Qitu; Huang Xiaogu; Xu Naicen

2009-01-01

W-type barium hexaferrites doped with Sm 3+ , Ba 1-x Sm x Co 2 Fe 16 O 27 (x = 0.0, 0.05, 0.1, 0.15, 0.2) were prepared by the conventional solid-state reaction. The structure and electromagnetic properties of the calcined samples were studied using powder X-ray diffraction (XRD) and network analyzer (Agilent 8722ET). All the XRD patterns showed the single phase of the magnetoplumbite barium ferrite without other intermediate phase when x ≤ 0.15. The microwave electromagnetic properties of the samples have been studied at the frequency range from 2 GHz to 18 GHz. It was shown that ε' and ε'' increased slightly, and the maximum of ε'' shifted to low frequency position with Sm 3+ ions doping. The μ'' and μ' values were improved significantly when x = 0.15, and the peak value of μ'' was about 1.6 at 7 GHz and 1.75 at 18 GHz position, respectively, exhibiting excellent microwave magnetic performance. Furthermore, the reasons have also been discussed using electromagnetic theory. Ba 0.85 Sm 0.15 Co 2 Fe 16 O 27 powders (85% by weight) were mixed with epoxy resin to form compound coating materials with different thicknesses, the reflection loss values of which were also measured. It is shown that the reflection loss value increases with the increase of the coating thickness under our experimental range. The maximum of reflection loss reached about -23 dB and it was below -10 dB at the frequency range from 8 GHz to 18 GHz, when the thickness was 1.8 mm.

Marginal Accuracy of Castings Fabricated with Ringless Casting Investment System and Metal Ring Casting Investment System: A Comparative Study.

Science.gov (United States)

Kalavathi, M; Sachin, Bhuvana; Prasanna, B G; Shreeharsha, T V; Praveen, B; Ragher, Mallikarjuna

2016-02-01

The thermal expansion of the investment can be restricted by the metal casting ring because the thermal expansion of the ring is less than that of the investment. The ringless casting procedure is in use in clinical dentistry, though there is little scientific data to support its use in fixed partial dentures. In this study, marginal discrepancy of castings produced with the ringless casting technique and the conventional technique using the metal rings were compared. A total of 30 wax patterns were fabricated directly on a metal die. Optical stereomicroscope was used to measure the marginal discrepancy between the metal die and wax patterns. A total of 15 castings were invested using Bellavest T phosphate-bonded investment with the ringless technique and 15 were invested with the same investment with a metal ring; 30 castings were produced using a nickel-chromium ceramo-metal alloy. The internal surface of the castings was not modified and seated with finger pressure. The vertical marginal discrepancy was measured using an optical stereomicroscope at a magnification of 100x. The data obtained were statistically analyzed using students t-test (paired t-test and unpaired t-test). The castings of the ringless technique provided less vertical marginal discrepancy (240.56 ± 45.81 μ) than the castings produced with the conventional metal ring technique (281.98± 53.05 μ). The difference was statistically significant. The ringless casting technique had produced better marginal accuracy compared with conventional casting technique. Ringless casting system can be used routinely for clinical purpose.

Electronic configuration of nFe/3Cr/nFe (n=1-6) trilayers in FM state

International Nuclear Information System (INIS)

Botana, J.; Pereiro, M.; Baldomir, D.; Arias, J.E.; Warda, K.; Wojtczak, L.

2007-01-01

Ab initio calculations have been performed on several ultrathin Fe/Cr/Fe trilayer systems in ferromagnetic configuration, with a fixed width of the spacer chromium slab of three atomic monolayers, and both iron slabs symmetrically varying in a range from 1 to 6 atomic monolayers. We have calculated the charge distribution of these trilayers and calculated and plotted the density of states of every one of them. We have identified Friedel-like oscillations of the charge distribution from the Mulliken population analysis in the Fe slabs

Experimental research of slab cast over precast joists with prestressed reinforcement

Directory of Open Access Journals (Sweden)

Koyankin Aleksandr Aleksandrovich

2016-03-01

Full Text Available At the present time reinforced concrete is the main construction material in civil and industrial construction. Cast-in-place and precast construction is gradually becoming a more widespread type of house-building, but still there is a lack of data, including experimental data, which allows evaluating the stress and strain state of a construction of a slab cast over precast joists. Experimental research of stress and strain state of slab cast over precast joists with prestressed reinforcement was carried out. An experimental model of a fragment of a hybrid precast/cast-in-place building was produced and tested (reduction scale 1:6. The experimental investigations of slab cast over precast joists with prestressed reinforcement proved that the construction solution of the framework offered in the previous works of the authors possess good stiffness, crack-resistance and bearing capacity. It well fits for constructing the slabs of long spans in residential and public buildings.

Travelling Through Caste

OpenAIRE

Kumar, Raj

2016-01-01

With its peculiar caste system, India is considered the most stratified of all known societies in human history. This system is ‘peculiar’ as it divides human beings into higher and lower castes and this division is backed by certain religious sanctions based on the sociological concepts of ‘purity’ and ‘pollution’. While the higher caste is associated with ‘purity’, the lower caste is associated with ‘pollution’. The people of the lower castes are not allowed to undertake religious journeys ...

Effect of Grain Size Reduction by Sodium Molybdate on Mechanical Properties of Al-0.7Fe Alloy

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M. Alizadeh

2015-12-01

Full Text Available Sodium molybdate (Na2MoO4 as a grain refiner was used to refine the microstructure of Al-0.7Fe alloy. Al-Fe samples with the addition of 0.1, 0.2, 0.3, 0.4 and 0.5 wt.% sodium molybdate were fabricated by casting in sand molds at 750 ͦC. The microstructures of the as-cast samples were investigated by scanning electron microscopy (SEM and the present phases were revealed by X-ray diffraction (XRD. The effect of sodium molybdate on the microstructure was examined by measuring the average grain sizes of the alloys, determining the widths of intermetallic compounds and carrying out hardness and tensile tests. The results showed that the addition of sodium molybdate modified the microstructure of Al-Fe alloy by reducing the average grain sizes. Also, it was found that the optimum amount of sodium molybdate to add to Al-0.7Fe alloy melt was 0.3 wt.% in this study.

Tensile ductility of an AlCoCrFeNi multi-phase high-entropy alloy through hot isostatic pressing (HIP) and homogenization

Energy Technology Data Exchange (ETDEWEB)

Tang, Zhi, E-mail: Zhi.Tang@alcoa.com [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996 (United States); Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA 24061 (United States); Senkov, Oleg N. [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, OH 45433 (United States); Parish, Chad M. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Zhang, Chuan; Zhang, Fan [CompuTherm LLC, 437 S. Yellowstone Dr., Suite 217, Madison, WI 53719 (United States); Santodonato, Louis J. [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996 (United States); Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Wang, Gongyao [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996 (United States); Zhao, Guangfeng; Yang, Fuqian [Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States); Liaw, Peter K., E-mail: pliaw@utk.edu [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996 (United States)

2015-10-28

The microstructure and phase composition of an AlCoCrFeNi high-entropy alloy (HEA) were studied in as-cast (AlCoCrFeNi-AC, AC represents as-cast) and homogenized (AlCoCrFeNi-HP, HP signifies hot isostatic pressed and homogenized) conditions. The AlCoCrFeNi-AC ally has a dendritric structure in the consisting primarily of a nano-lamellar mixture of A2 (disordered body-centered-cubic (BCC)) and B2 (ordered BCC) phases, formed by an eutectic reaction. The homogenization heat treatment, consisting of hot isostatic pressed for 1 h at 1100 °C, 207 MPa and annealing at 1150 °C for 50 h, resulted in an increase in the volume fraction of the A1 phase and formation of a Sigma (σ) phase. Tensile properties in as-cast and homogenized conditions are reported at 700 °C. The ultimate tensile strength was virtually unaffected by heat treatment, and was 396±4 MPa at 700 °C. However, homogenization produced a noticeable increase in ductility. The AlCoCrFeNi-AC alloy showed a tensile elongation of only 1.0%, while after the heat-treatment, the elongation of AlCoCrFeNi-HP was 11.7%. Thermodynamic modeling of non-equilibrium and equilibrium phase diagrams for the AlCoCrFeNi HEA gave good agreement with the experimental observations of the phase contents in the AlCoCrFeNi-AC and AlCoCrFeNi-HP. The reasons for the improvement of ductility after the heat treatment and the crack initiation subjected to tensile loading were discussed.

On the structural and magnetic properties of amorphous Fe84-xWxB16 alloys in dependence of W content

International Nuclear Information System (INIS)

Novakova, A.A.; Sidorova, G.V.; Katsnelson, A.A.; Szasz, A.; Kojnok, J.

1990-01-01

A series of rapidly solidificated amorphous Fe 84-x W x B 16 (x=0-5) alloys have been studied. A strictly linear decrease of H eff versus concentration of W has been observed by Moessbauer spectroscopy. (orig.)

Caste and power

DEFF Research Database (Denmark)

Roy, Dayabati

2011-01-01

This paper explores the institution of caste and its operation in a micro-level village setting of West Bengal, an Indian state, where state politics at grass roots level is vibrant with functioning local self-government and entrenched political parties. This ethnographic study reveals that caste...... relations and caste identities have overarching dimensions in the day-to-day politics of the study villages. Though caste almost ceases to operate in relation to strict religious strictures, under economic compulsion the division of labour largely coincides with caste division. In the cultural......–ideological field, the concept of caste-hierarchy seems to continue as an influencing factor, even in the operation of leftist politics....

Integrated System of Thermal/Dimensional Analysis for Quality Control of Metallic Melt and Ductile Iron Casting Solidification

Science.gov (United States)

Stan, Stelian; Chisamera, Mihai; Riposan, Iulian; Neacsu, Loredana; Cojocaru, Ana Maria; Stan, Iuliana

2018-03-01

The main objective of the present work is to introduce a specific experimental instrument and technique for simultaneously evaluating cooling curves and expansion or contraction of cast metals during solidification. Contraction/expansion analysis illustrates the solidification parameters progression, according to the molten cast iron characteristics, which are dependent on the melting procedure and applied metallurgical treatments, mold media rigidity and thermal behavior [heat transfer parameters]. The first part of the paper summarizes the performance of this two-mold device. Its function is illustrated by representative shrinkage tendency results in ductile cast iron as affected by mold rigidity (green sand and furan resin sand molds) and inoculant type (FeSi-based alloys), published in part previously. The second part of the paper illustrates an application of this equipment adapted for commercial foundry use. It conducts thermal analysis and volume change measurements in a single ceramic cup so that mold media as well as solidification conditions are constants, with cast iron quality as the variable. Experiments compared gray and ductile cast iron solidification patterns. Gray iron castings are characterized by higher undercooling at the beginning and at the end of solidification and lower graphitic expansion. Typically, ductile cast iron exhibits higher graphitic, initial expansion, conducive for shrinkage formation in soft molds.

Thermal stability, thermal expansion and grain-growth in exchange-coupled Fe-Pt-Ag-B bulk nanocomposite magnets

International Nuclear Information System (INIS)

Nicula, R.; Crisan, O.; Crisan, A.D.; Mercioniu, I.; Stir, M.; Vasiliu, F.

2015-01-01

Highlights: • Formation of the L10 FePt hard-magnetic phase (>90%) directly in the as-cast state. • Specific alternating hard/soft nanostructure is stable to 600 °C without grain growth. • Anisotropic and non-linear thermal expansion effects. • The FePtAgB alloy behaves like a single magnetic phase (full exchange coupling). - Abstract: Rare-earth free (RE-free) exchange coupling nanocomposite magnets are intensively studied nowadays due to their potential use in applications demanding stable high-temperature operation and corrosion resistance. In this respect, the FePt alloy system is one of the most actively addressed potential permanent magnet solutions. In FePt alloys, promising magnetic features arise from the co-existence of hard magnetic L1 0 FePt and soft magnetic L1 2 Fe 3 Pt phases emerged from the same metastable precursor. The present work deals with an in-situ temperature-resolved synchrotron radiation study of the thermal stability, thermal expansion and microstructure evolution in exchange-coupled FePtAgB alloys. The as-cast microstructural state as well as the optimized magnetic behavior are given as reference and correlated to the observed microstructural evolution with temperature. The melt-spun Fe 48 Pt 28 Ag 6 B 18 alloy ribbons were examined in situ by synchrotron X-ray powder diffraction from ambient temperature up to 600 °C. The FePt-Fe 3 Pt exchange-coupled microstructure achieved by rapid solidification is not significantly altered during the high temperature exposure. The thermal expansion of the FePt L1 0 unit cell has been found to be strongly anisotropic, being essentially an in-plane expansion which may be seen as an anisotropic invar effect. For the FePt L1 0 phase, a significant deviation from linear thermal expansion is observed at the Curie temperature T C = 477 °C. This non-linear behavior above T C is tentatively linked to a diffusion/segregation mechanism of Ag. The promising hard magnetic properties as well as the

Technological Aspects of Low-Alloyed Cast Steel Massive Casting Manufacturing

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Szajnara J.

2013-12-01

Full Text Available In the paper authors have undertaken the attempt of explaining the causes of cracks net occurrence on a massive 3-ton cast steel casting with complex geometry. Material used for casting manufacturing was the low-alloyed cast steel with increased wear resistance modified with vanadium and titanium. The studies included the primary and secondary crystallization analysis with use of TDA and the qualitative and quantitative analysis of non-metallic inclusions.

Effect of ageing time 200 °C on microstructure behaviour of Al-Zn-Cu-Mg cast alloys

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Pratiwi Diah Kusuma

2017-01-01

Full Text Available Al-Zn-Cu-Mg is heat treatable alloy that can be used in many hightech applications, such as aerospace and military. The main objective of this study is to investigate the influence of ageing process in microstrucure behaviour of Al-9Zn-5Cu-4Mg cast alloy by performing SEM analysis and its correlation with hardness tests of as-cast Al-9Zn-5Cu-4Mg alloy and heat treated Al-9Zn-5Cu-4Mg cast alloy. The results show the deployment of precipitation spread over the dendrite and also the presence of second phases Mg3Zn3Al2 , Cu2FeAl7 , CuAl2, and CuMgAl2 in as-cast Al-9Zn-5Cu-4Mg alloy. The presence of all these second phases are affecting to the toughness of aluminium alloy and the presence of MgZn2 leads the impairment of hardness value of heat-treated Al-9Zn-5Cu-5Mg cast alloy.

Reducing the Incidence of Cast-related Skin Complications in Children Treated With Cast Immobilization.

Science.gov (United States)

Difazio, Rachel L; Harris, Marie; Feldman, Lanna; Mahan, Susan T

2017-12-01

Cast immobilization remains the mainstay of pediatric orthopaedic care, yet little is known about the incidence of cast-related skin complications in children treated with cast immobilization. The purposes of this quality improvement project were to: (1) establish a baseline rate of cast-related skin complications in children treated with cast immobilization, (2) identify trends in children who experienced cast-related skin complications, (3) design an intervention aimed at decreasing the rate of cast-related skin complications, and (4) determine the effectiveness of the intervention. A prospective interrupted time-series design was used to determine the incidence of cast-related skin complications overtime and compare the rates of skin complications before and after an intervention designed to decrease the incidence of cast-related heel complications. All consecutive patients who were treated with cast immobilization from September 2012 to September 2014 were included. A cast-related skin complications data collection tool was used to capture all cast-related skin complications. A high rate of heel events was noted in our preliminary analysis and an intervention was designed to decrease the rate of cast-related skin complications, including the addition of padding during casting and respective provider education. The estimated cast-related skin events rate for all patients was 8.9 per 1000 casts applied. The rate for the total preintervention sample was 13.6 per 1000 casts which decreased to 6.6 in the postintervention sample. When examining the heel-only group, the rate was 17.1 per 1000 lower extremity casts applied in the preintervention group and 6.8 in the postintervention group. Incorporating padding to the heel of lower extremity cast was an effective intervention in decreasing the incidence of cast-related skin complications in patients treated with cast immobilization. Level II.

Temperature profile and other data collected using CTD casts in the North/South Pacific Ocean from NOAA Ship MALCOLM BALDRIGE and other platform from 16 February 1991 to 98 December 1991 (NODC Accession 9200156)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and other data were collected using CTD casts from NOAA Ship MALCOLM BALDRIGE and NOAA Ship DISCOVERER in the North/South Pacific Ocean from 16...

Magnetic studies of melt spun NdFeAl-C alloys

International Nuclear Information System (INIS)

Rodriguez Torres, C.E.; Cabrera, A.F.; Sanchez, F.H.; Billoni, O.V.; Urreta, S.E.; Fabietti, L.M.

2004-01-01

Alloys with compositions Nd 60-x C x Fe 30 Al 10 (x=0, 1, 5 and 10) were processed by melt spinning at a tangential speed of 5 m/s. The as-cast ribbons were characterized by X-ray diffraction, Moessbauer Effect spectroscopy and their room temperature hysteresis loops. The substitution of Nd by C is found to affect the phase selection, from mainly DHCP-Nd for x=0 to DHCP-Nd /FCC-Nd for the other ones. Moessbauer spectra of all the as-cast samples indicate that Fe is present in crystalline magnetic phases as well as in a paramagnetic one. The major crystalline phase was identified as a μ-type (or A1) metastable phase, which is reported to have a large anisotropy field and a relatively high saturation polarization. Interstitial C stabilizes the μ-type phase and improves its average hyperfine field. The magnetic measurements display an increase of coercivity and remanence with the C concentration

Vacuum die casting of silicon sheet for photovoltaic applications. First quarterly report, March 16-June 30, 1979

Energy Technology Data Exchange (ETDEWEB)

None

1979-01-01

The obtective of this program is to develop a vacuum die-casting process for producing silicon sheet suitable for photovoltaic cells and to develop production techniques for optimization of polycrystallie silicon solar cell output. Efforts will examine process methods which are directed toward minimum cost processing of silicon into a quality suitable for producing solar cells with a terrestrial efficiency greater than 12% and having the potential to be scaled for large quantity production. In the vacuum die casting technique, silicon is melted under vacuum, and an evacuated die with a thin rectangular cavity is inserted into the melt. Liquid silicon is then injected into the die using a positive pressure of an inert gas. The major portion of the die casting work will be performed at Stanford Research Institute International under subcontract. The initial approach will follow parallel tracks: (1) obtain mechanical design parameters by using boron nitride, which has been shown to be non-wetting to silicon; (2) optimize silicon nitride material composition and coatings by sessile drop experiments; (3) test effectiveness of fluoride salt interfacial media with a graphite mold; and (4) test effect of surface finish using both boron nitride and graphite. Having established the material and mechanical boundary conditions, a finalized version of the prototype assembly will be constructed and the casting varibles determined. Polycrystalline silicon solar cells, with and without impurities, will be fabricated, characterized, and optimized at ARCCO Solar. The major activities will focus on the use of Wacker SILCO, HEM and in-house materials until vacuum die cast wafers are available. A baseline process with vacuum metallized contacts will be established and a reference mass production process with screen-printed metallization and high-throughput diffusions will also be obtained.

Microstructure and mechanical properties of a new type of austempered boron alloyed high silicon cast steel

Directory of Open Access Journals (Sweden)

Chen Xiang

2013-05-01

Full Text Available In the present paper, a new type of austempered boron alloyed high silicon cast steel has been developed, and its microstructures and mechanical properties at different temperatures were investigated. The experimental results indicate that the boron alloyed high silicon cast steel comprises a dendritic matrix and interdendritic eutectic borides in as-cast condition. The dendritic matrix is made up of pearlite, ferrite, and the interdendritic eutectic boride is with a chemical formula of M2B (M represents Fe, Cr, Mn or Mo which is much like that of carbide in high chromium white cast iron. Pure ausferrite structure that consists of bainitic ferrite and retained austenite can be obtained in the matrix by austempering treatment to the cast steel. No carbides precipitate in the ausferrite structure and the morphology of borides remains almost unchanged after austempering treatments. Secondary boride particles precipitate during the course of austenitizing. The hardness and tensile strength of the austempered cast steel decrease with the increase of the austempering temperature, from 250 篊 to 400 篊. The impact toughness is 4-11 J昪m-2 at room temperature and the impact fracture fractogragh indicates that the fracture is caused by the brittle fracture of the borides.

Microstructure, SDAS and Mechanical Properties of A356 alloy Castings Made in Sand and Granulated Blast Furnace Slag Moulds

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Jinugu B. R.

2017-03-01

Full Text Available Investigations were carried out to ensure the granulated blast furnace (GBF slag as an alternative mould material in foundry industry by assessing the cast products structure property correlations. Sodium silicate-CO2 process was adopted for preparing the moulds. Three types of moulds were made with slag, silica sand individually and combination of these two with 10% sodium silicate and 20 seconds CO2 gassing time. A356 alloy castings were performed on these newly developed slag moulds. The cast products were investigated for its metallography and mechanical properties. Results reveal that cast products with good surface finish and without any defects were produced. Faster heat transfers in slag moulds enabled the cast products with fine and refined grain structured; and also, lower Secondary Dendrite Arm Spacing (SDAS values were observed than sand mould. Slag mould casting shows improved mechanical properties like hardness, compression, tensile and impact strength compared to sand mould castings. Two types of tensile fracture modes, namely cleavage pattern with flat surfaces representing Al−Si eutectic zone and the areas of broken Fe-rich intermetallic compounds which appear as flower-like morphology was observed in sand mould castings. In contrast, GBF slag mould castings exhibit majority in dimple fracture morphology with traces of cleavage fracture. Charpy impact fractured surfaces of sand mould castings shows both transgranular and intergranular fracture modes. Only intergranular fracture mode was noticed in both GBF slag and mixed mould castings.

Water physics and chemistry data from moored current meter and bottle casts in the Gulf of Mexico as part of the Brine Disposal project, 1980-11-20 to 1981-03-16 (NODC Accession 8100530)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Water physics and chemistry data were collected using moored current meter and bottle casts in the Gulf of Mexico from November 20, 1980 to March 16, 1981. Data were...

Laboratory scale fabrication of Nd-Fe-B sintered magnets; Fabricacao de imas sinterizados de Nd-Fe-B em escala piloto

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, Daniel; Beneduce Neto, Flavio; Landgraf, Fernando Jose Gomes; Neiva, Augusto Camara; Romero, Sergio; Missell, Frank Patrick

1993-12-31

Results are presented on magnetic properties of Nd-Fe-B sauntered magnets produced from 1 kg of alloy caste in vacuum induction furnace. The fabrication viability of these magnets, with properties similar to the commercial magnets, and the influence of particle size in the energy product, through the effect on the H{sub k} field, is confirmed 12 refs., 7 figs., 1 tab.

Moessbauer-spectroscopic study of structure and magnetism of the exchange-coupled layer systems Fe/FeSn{sub 2}, and Fe/FeSi/Si and the ion-implanted diluted magnetic semiconductor SiC(Fe); Moessbauerspektroskopische Untersuchung von Struktur und Magnetismus der austauschgekoppelten Schichtsysteme Fe/FeSn{sub 2} und Fe/FeSi/Si und des ionenimplantierten verduennten magnetischen Halbleiters SiC(Fe)

Energy Technology Data Exchange (ETDEWEB)

Stromberg, Frank

2009-07-07

''lower'' FeSi layers the interdiffusion of Fe is inhibited. For thicker FeSi layers (t{sub FeSi} {approx} 20 A) the formation of the metastable defective c-FeSi phase was detected. For the first time an oscillating antiferromagnetic exchange coupling between the Fe layers with a period of {approx} 6 Aas a function of the FeSi thickness. In the third part of this work we attempted to produce a diluted magnetic semiconductor by ion implantation of {sup 57}Fe into SiC(0001) wafer. For doses {>=} 2 x 10{sup 16} ions cm{sup -2} and after thermal annealing superparamagnetic Fe{sub 3}Si nanoclusters were found with CEMS, XRD and TEM (Transmission Electron Microscopy), which were epitaxially embedded in the SiC matrix. Besides Fe{sub 3}Si no other phases were observed. For the lowest doses of 1 x 10{sup 16} ions cm{sup -2} the CEM spectra at 4.2 K gave evidence of ferromagnetism and the absence of nanoparticles. The upper limit under which there are no segregations of secondary phases was therefore limited to 1-3 at.% Fe. (orig.)

Temperature profiles from XBT casts from the SANTA CRUZ and other platforms as part of the Marine Resources Monitoring, Assessment and Prediction (MARMAP) project from 1975-08-16 to 1975-10-23 (NODC Accession 7501041)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profiles were collected from XBT casts from the SANTA CRUZ and other platforms from 16 August 1975 to 23 October 1975. Data were collected by Grace...

Wear Resistance of TiC Reinforced Cast Steel Matrix Composite

Directory of Open Access Journals (Sweden)

Sobula S.

2017-03-01

Full Text Available Wear resistance of TiC-cast steel metal matrix composite has been investigated. Composites were obtained with SHSB method known as SHS synthesis during casting. It has been shown the differences in wear between composite and base cast steel. The Miller slurry machine test were used to determine wear loss of the specimens. The slurry was composed of SiC and water. The worn surface of specimens after test, were studied by SEM. Experimental observation has shown that surface of composite zone is not homogenous and consist the matrix lakes. Microscopic observations revealed the long grooves with SiC particles indented in the base alloy area, and spalling pits in the composite area. Due to the presence of TiC carbides on composite layer, specimens with TiC reinforced cast steel exhibited higher abrasion resistance. The wear of TiC reinforced cast steel mechanism was initially by wearing of soft matrix and in second stage by polishing and spalling of TiC. Summary weight loss after 16hr test was 0,14÷0,23 g for composite specimens and 0,90 g for base steel.

Effect of cast steel production metallurgy on the emergence of casting defects

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L. Čamek

2016-10-01

Full Text Available The paper documents metallurgical possibilities of high alloy cast steel production in open induction medium frequency furnaces and an electric arc furnace in a gravity die casting foundry. The observation was focused on the emergence of gas defects in steel castings. The content of gases achieved during the metallurgical processes was evaluated for every unit of the production equipment and the casting ladle before casting into disposable sand moulds. The sand mould area was considered to be constant. The aim was to evaluate the current metallurgical possibilities of affecting the content of gases in high alloy cast steel in the current technical conditions of the foundry.

SPRAY CASTING

OpenAIRE

SALAMCI, Elmas

2010-01-01

ABSTRACT This paper is designed to provide a basic review of spray casting. A brief overview of the historical development of spray  casting and the description of plant and equipment have been given. Following metallurgical characteristics of spray formed alloys, process parameters and solidification mechanism of spray deposition have been discussed in detail. Finally, microstructure and mechanical properties of the selected spray cast Al-Zn-Mg-Cu alloys have been presented and comp...

Multidisciplinary approach to improve the quality of below-knee plaster casting.

Science.gov (United States)

Williams, John Teudar; Kedrzycki, Marta; Shenava, Yathish

2018-01-01

In our trauma unit, we noted a high rate of incorrectly applied below-knee casts for ankle fractures, in some cases requiring reapplication. This caused significant discomfort and inconvenience for patients and additional burden on plaster-room services. Our aim was to improve the quality of plaster casts and reduce the proportion that needed to be reapplied. Our criteria for plaster cast quality were based on the British Orthopaedic Association Casting Standards (2015) and included neutral (plantargrade) ankle position, adequacy of fracture reduction and rate of cast reapplication. Baseline data collection was performed over a 2-month period by two independent reviewers. After distributing findings and presenting to relevant departments, practical casting sessions with orthopaedic technicians were arranged for the multidisciplinary team responsible for casting. This was later supplemented by new casting guidelines in clinical areas and available online. Postintervention data collection was performed over two separate cycles to assess the effect and permanence of intervention. Data from the preintervention period (n=29) showed median ankle position was 32° plantarflexion (PF), with nine (31%) inadequate reductions and six (20%) backslabs reapplied. Following Plan-Do-Study-Act (PDSA) 1, ankle position was significantly improved (median 25° PF), there were fewer inadequate reductions (12%; 2/17) and a lower rate of reapplication (0%; 0/17). After PDSA 2 (n=16), median ankle position was 21° PF, there was one (6%) inadequate reduction and two (12%) reapplications of casts. Following implementation of plaster training sessions for accident and emergency and junior orthopaedic staff, in addition to publishing guidance and new protocol, there has been a sustained improvement in the quality of below-knee backslabs and fewer cast reapplications. These findings justify continuation and expansion of the current programme to include other commonly applied plaster casts.

Preparation and characterization of Fe-based bulk metallic glasses in plate form

International Nuclear Information System (INIS)

Lavorato, G.C.; Fiore, G.; Castellero, A.; Baricco, M.; Moya, J.A.

2012-01-01

Amorphous alloys with composition (at%) Fe 48 Cr 15 Mo 14 C 15 B 6 Gd 2 (alloy A) and Fe 48 Cr 15 Mo 14 C 15 B 6 Y 2 (alloy B) were prepared either using pure elements (A and B1) and a commercial AISI430 steel as a base material (B2). When prepared from pure elements both alloys (A and B1) could be cast in plate form with a fixed thickness of 2 mm and variable lengths between 10 and 20 mm by means of copper-mold injection in air atmosphere. In the case of alloy B2, prepared using commercial grade raw materials, rods of 2 mm diameter were obtained. X-ray diffraction and scanning electron microscopy observations confirmed that an amorphous structure was obtained in all the as-cast samples. A minor fraction of crystalline phases (oxides and carbides) was detected on the as-cast surface. Differential scanning calorimetry measurements showed a glass transition temperature at 856 K for alloy A and 841 K for alloy B1, and an onset crystallization temperature of 887 K for alloy A and 885 K for alloy B1. In the case of alloy B2 a slightly different crystallization sequence was observed. Values of hardness (∼13 GPa) and the Young modulus (∼180 GPa) were measured by nanoindentation for both the alloys. The effects of adverse casting conditions (such as air atmosphere, non-conventional injection copper mold casting and partial replacement of pure elements with commercial grade raw materials) on the glass formation and properties of the alloy are discussed.

Preparation and characterization of Fe-based bulk metallic glasses in plate form

Energy Technology Data Exchange (ETDEWEB)

Lavorato, G.C. [INTECIN (FIUBA-CONICET), Paseo Colon 850, Capital Federal (Argentina); Dipartimento di Chimica IFM and NIS, Universita di Torino, Torino (Italy); Fiore, G.; Castellero, A.; Baricco, M. [Dipartimento di Chimica IFM and NIS, Universita di Torino, Torino (Italy); Moya, J.A., E-mail: jmoya.fi.uba@gmail.com [IESIING, Facultad de Ingenieria e Informatica, UCASAL, Salta (Argentina); CONICET (Argentina)

2012-08-15

Amorphous alloys with composition (at%) Fe{sub 48}Cr{sub 15}Mo{sub 14}C{sub 15}B{sub 6}Gd{sub 2} (alloy A) and Fe{sub 48}Cr{sub 15}Mo{sub 14}C{sub 15}B{sub 6}Y{sub 2} (alloy B) were prepared either using pure elements (A and B1) and a commercial AISI430 steel as a base material (B2). When prepared from pure elements both alloys (A and B1) could be cast in plate form with a fixed thickness of 2 mm and variable lengths between 10 and 20 mm by means of copper-mold injection in air atmosphere. In the case of alloy B2, prepared using commercial grade raw materials, rods of 2 mm diameter were obtained. X-ray diffraction and scanning electron microscopy observations confirmed that an amorphous structure was obtained in all the as-cast samples. A minor fraction of crystalline phases (oxides and carbides) was detected on the as-cast surface. Differential scanning calorimetry measurements showed a glass transition temperature at 856 K for alloy A and 841 K for alloy B1, and an onset crystallization temperature of 887 K for alloy A and 885 K for alloy B1. In the case of alloy B2 a slightly different crystallization sequence was observed. Values of hardness ({approx}13 GPa) and the Young modulus ({approx}180 GPa) were measured by nanoindentation for both the alloys. The effects of adverse casting conditions (such as air atmosphere, non-conventional injection copper mold casting and partial replacement of pure elements with commercial grade raw materials) on the glass formation and properties of the alloy are discussed.

TECHNOLOGICAL PARAMETERS OF SLUGS CASTING OF GREY CAST IRON BY FROSTING

Directory of Open Access Journals (Sweden)

E. I. Marukovich

2009-01-01

Full Text Available The relation of geometrical parametres of casting with technological ones is shown. The monogram for definition of basic technological parametres of obtaining of castings by the method of continuously-cyclic iterative casting by freezing-up is presented.

Colour Metallography of Cast Iron - Chapter 3: Spheroidal Graphite Cast Iron (Ⅳ

Directory of Open Access Journals (Sweden)

Zhou Jiyang

2010-11-01

Full Text Available Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application and combine cast iron technology with some hi-techs (for example, computer technology. Nevertheless, cast iron is a multi-element and multi-phase alloy and has complex and variety of structures and still has great development potential in structure and property. For further studying and developing cast iron, theoretical research work is important promise, and the study on solidification process and control mechanism of graphite morphology is fundamental for improving property of cast iron and developing new type of cast iron. Metallography of cast iron normally includes two sections: liquid phase transformation and solid phase transformation. The book, Colour Metallography of Cast Iron, uses colour metallography technique to study solidification structures of cast irons: graphite, carbides, austenite and eutectics; and focuses on solidification processes. With progress of modern solidification theory, the control of material solidification process becomes important measure for improving traditional materials and developing new materials. Solidification structure not only influences mechanical and physical properties of cast iron, but also affects its internal quality. The book uses a large amount of colour photos to describe the formation of solidification structures and their relations. Crystallization phenomena, which cannot be displayed with traditional metallography, are presented and more phase transformation information is obtained from these colour

Colour Metallography of Cast Iron - Chapter 3: Spheroidal Graphite Cast Iron (Ⅰ

Directory of Open Access Journals (Sweden)

Zhou Jiyang

2010-02-01

Full Text Available Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application and combine cast iron technology with some hi-techs (for example, computer technology. Nevertheless, cast iron is a multi-element and multi-phase alloy and has complex and variety of structures and still has great development potential in structure and property. For further studying and developing cast iron, theoretical research work is important promise, and the study on solidification process and control mechanism of graphite morphology is fundamental for improving property of cast iron and developing new type of cast iron. Metallography of cast iron normally includes two sections: liquid phase transformation and solid phase transformation. The book, Colour Metallography of Cast Iron, uses colour metallography technique to study solidification structures of cast irons: graphite, carbides, austenite and eutectics; and focuses on solidification processes. With progress of modern solidification theory, the control of material solidification process becomes important measure for improving traditional materials and developing new materials. Solidification structure not only influences mechanical and physical properties of cast iron, but also affects its internal quality. The book uses a large amount of colour photos to describe the formation of solidification structures and their relations. Crystallization phenomena, which cannot be displayed with traditional metallography, are presented and more phase transformation information is obtained from these colour

Colour Metallography of Cast Iron - Chapter 4: Vermicular Graphite Cast Iron (Ⅱ

Directory of Open Access Journals (Sweden)

Zhou Jiyang

2011-05-01

Full Text Available Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application and combine cast iron technology with some hi-techs (for example, computer technology. Nevertheless, cast iron is a multi-element and multi-phase alloy and has complex and variety of structures and still has great development potential in structure and property. For further studying and developing cast iron, theoretical research work is important promise, and the study on solidification process and control mechanism of graphite morphology is fundamental for improving property of cast iron and developing new type of cast iron. Metallography of cast iron normally includes two sections: liquid phase transformation and solid phase transformation. The book, Colour Metallography of Cast Iron, uses colour metallography technique to study solidification structures of cast irons: graphite, carbides, austenite and eutectics; and focuses on solidification processes. With progress of modern solidification theory, the control of material solidification process becomes important measure for improving traditional materials and developing new materials. Solidification structure not only influences mechanical and physical properties of cast iron, but also affects its internal quality. The book uses a large amount of colour photos to describe the formation of solidification structures and their relations. Crystallization phenomena, which cannot be displayed with traditional metallography, are presented and more phase transformation information is obtained from these colour

Mössbauer and Kerr microscopy investigation of crystallization in FeCoB ribbons

Energy Technology Data Exchange (ETDEWEB)

Reddy, V. Raghavendra, E-mail: varimalla@yahoo.com, E-mail: vrreddy@csr.res.in; Hussain, Zaineb; Babu, Hari [UGC DAE Consortium for Scientific Research, University Campus, Kandhwa Road, Indore-452001 India (India); Shrivastava, Namrata [School of Physics, DAVV, Khandwa Road, Indore – 452001 India (India); Gupta, Ajay [Amity Centre for Spintronic Materials, Amity University, Noida 201303.India (India)

2016-05-23

The present work reports the crystallization study of amorphous FeCoB ribbons using x-ray diffraction, {sup 57}Fe Mössbauer spectroscopy in transmission mode and magneto-optical Kerr (MOKE) microscopy. Annealing at 673 K is found to result in crystallization. From the Mossbauer measurements it is observed that the Fe magnetic moments are in the plane of sample for as-cast ribbon; α-FeCo, (Fe{sub 0.5}Co{sub 0.5}){sub 2}B and Fe{sub 2}B phases are formed after crystallization. MOKE microscopy revealed that wide 180° domain walls & narrow fingerprint domains are observed before crystallization and fine domains are observed after crystallization. The results are explained in terms of the presence of internal stresses and their annealing with thermal heat treatment.

A study of magnetoplumbite-type (M-type) cobalt-titanium-substituted barium ferrite, BaCoxTixFe12-2xO19 (x = 1-6)

International Nuclear Information System (INIS)

Teh, G.B.; Saravanan, N.; Jefferson, D.A.

2007-01-01

Cobalt(II)-titanium(IV)-substituted barium ferrite forming the chemical formula of BaCo x Ti x Fe 12-2x O 19 (x = 1-6) have been investigated using X-ray diffraction spectroscopy (XRD), Superconducting Quantum Interference Device (SQUID) and high-resolution transmission electron microscopy (HRTEM). The specimen of magnetoplumbite (M-type) Co-Ti-substituted BaFe 12 O 19 were synthesised via sol-gel method using ethylene glycol as precursor. Significant increase in line broadening of the XRD patterns were observed indicating the decrease of particle sizes due to the Co(II)-Ti(IV) substitution. BaCo 3 Ti 3 Fe 6 O 19 showed the highest coercivity but moderate saturation and remnant magnetisations. HRTEM imaging showed that Co(II)-Ti(IV) substitution in the system of BaCo x Ti x Fe 12-2x O 19 (x = 1-6) produced no drastic change in the structure of the M-type ferrites. Most of the M-types crystals examined by HRTEM displayed a long axis perpendicular to the c-axis of the M-type structure. Disordered crystals showing the intergrowth between Co-Ti-substituted barium ferrite and the spinel-structured iron oxide were detected

Microstructural development in a rapidly solidified Al-Fe-V-Si alloy

International Nuclear Information System (INIS)

Park, W.J.; Baek, E.R.; Lee, Sunghak; Kim, N.J.

1991-01-01

TEM is used to investigate microstructural development in a rapidly solidified Al-Fe-V-Si alloy. The as-cast microstructure of a rapidly solidified Al-Fe-V-Si alloy was found to vary depending on casting conditions and also through the thickness of ribbon. For completely Zone A ribbon, intercellular phase consists of a microquasi-crystalline phase, while for the Zone A and Zone B mixed ribbon, it consists of a silicide phase. In either case, formation of globular particles of a cluster microquasi-crystalline phase is observed near the air side of the ribbon. Annealing study shows significant differences in the final microstructure depending on the initial status of the ribbon. Completely Zone A ribbon, whose microstructure is composed of a microquasi-crystalline phase, results in a very coarse microstructure after annealing as compared to the Zone A and Zone B mixed ribbon. This result has important implications for the development of high-performance elevated-temperature Al alloys. 12 refs

FeNbB bulk metallic glass: the influence of fluxing technique

Energy Technology Data Exchange (ETDEWEB)

Stoica, Mihai; Eckert, Juergen [IFW Dresden, Institute for Complex Materials, P.O. Box 270116, D-01171 Dresden (Germany); Kumar, Santosh [IFW Dresden, Institute for Complex Materials, P.O. Box 270116, D-01171 Dresden (Germany); Materials Science Centre, Indian Institute of Technology, Kharagpur 721302 (India); Roth, Stefan [IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden (Germany); Ram, Shanker [Materials Science Centre, Indian Institute of Technology, Kharagpur 721302 (India); Yavari, Alain Reza [LTPCM-CNRS, Institut National Politechnique de Grenoble, 1130 Rue de la Piscine, BP 75, Saint Martin d' Heres Campus 38402 (France)

2008-07-01

Recently, a new Fe-based BMG containing only 3 elements and a very high boron (Fe{sub 66}Nb{sub 4}B{sub 30}) content was synthesized. The preparation of this BMG was done by employing the copper mould casting method and using the fluxing technique. This new BMG is ferromagnetic, with a Curie temperature around 550 K and a saturation magnetization of 105 emu/g. Differential scanning calorimetry (DSC) investigations revealed a reduced glass transition temperature of 0.58 and an extension of the supercooled liquid region of about 31 K, values which indicate a relatively good thermal stability. Fluxed and not-fluxed master alloys were used to cast samples. The present work aims to discuss, for both kinds of samples, the kinetics of the phase formation using the Kissinger analysis and Johnson-Mehl-Avrami plots, correlated with the results obtained from X-ray diffraction (XRD) of samples with different metastable structures. Additionally, the magnetic behaviour of different phase(s) is discussed.

The deformation of wax patterns and castings in investment casting technology

Directory of Open Access Journals (Sweden)

A. Herman

2012-01-01

Full Text Available The dimensional accuracy of the final casting of Inconel alloy 738 LC is affected by many aspects. One of them is the choice of method and time of cooling wax model for precision investment casting. The main objective was to study the initial deformation of the complex shape of the casting of the rotor blades. Various approaches have been tested for cooling wax pattern. When wax models are cooling on the air, without clamping in jig for cooling, deviations from the ideal shape of the casting are very noticeable (up to 8 mm and most are in extreme positions of the model. When blade is cooled in fixing jig in water environment, the resulting deviations compared with cooling in air are significantly larger, sometimes up to 10 mm. This itself does not mean that the final shape of the casting is dimensionally more accurate with usage of wax models, which have deviations from the ideal position smaller. Another deformation occurs when shell mould is produced around wax pattern and furthermore deformations emerge while casting of blade is cooling. This paper demonstrates first steps in describing complex process of deformations of Inconel alloy blades produced with investment casting technology by comparing results from thermal imagery, simulations in foundry simulation software ProCAST 2010 and measurements from CNC scanning system Carl Zeiss MC 850. Conclusions are so far not groundbreaking, but it seems deformations of wax pattern and deformations of castings do in some cases cancel each other by having opposite directions. Describing entirely whole process of deformations will help increase precision of blade castings so that models at the beginning and blades in the end are the same.

Laboratory scale fabrication of Nd-Fe-B sintered magnets

International Nuclear Information System (INIS)

Rodrigues, Daniel; Beneduce Neto, Flavio; Landgraf, Fernando Jose Gomes; Neiva, Augusto Camara; Romero, Sergio; Missell, Frank Patrick

1992-01-01

Results are presented on magnetic properties of Nd-Fe-B sauntered magnets produced from 1 kg of alloy caste in vacuum induction furnace. The fabrication viability of these magnets, with properties similar to the commercial magnets, and the influence of particle size in the energy product, through the effect on the H k field, is confirmed

Influence of additives on the microstructure and tensile properties of near-eutectic Al-10.8%Si cast alloy

International Nuclear Information System (INIS)

Mohamed, A.M.A.; Samuel, A.M.; Samuel, F.H.; Doty, H.W.

2009-01-01

The continuing quest for aluminum castings with enhanced mechanical properties for applications in the automotive industries has intensified the interest in aluminum-silicon alloys. In Al-Si alloys, the properties are influenced by the shape and distribution of the eutectic silicon particles in the matrix, as also by the iron intermetallics and copper phases that occur upon solidification. The detailed microstructure and tensile properties of as-cast and heat-treated new experimental alloy belonging to cast Al-Si near-eutectic alloys have been investigated as a function of Fe, Mn, Cu, and Mg content. Microstructural examination was carried out using optical microscopy, image analysis, and electron probe microanalysis (EPMA), wavelength dispersive spectroscopic (WDS) analysis facilities. Tensile properties upon artificial aging in the temperature range of 155-240 o C for 5 h were also investigated. The results show that the volume fraction of Fe-intermetallics increases as the iron or manganese contents increase. Compact polygonal or star-like particles form when the sludge factor is greater than 2.1. The Al 2 Cu phase was observed to dissolve almost completely during solution heat treatment of all the alloys studied, especially those containing high levels of Mg and Fe, while Al 5 Cu 2 Mg 8 Si 6 , sludge, and α-Fe phases were found to persist after solution heat treatment. The β-Al 5 (Fe,Mn)Si phase dissolved partially in Sr-modified alloys, and its dissolution became more pronounced after solution heat treatment. At 0.5% Mn, the β-Fe phase forms when the Fe content is above 0.75%, causing the tensile properties to decrease drastically. The same results are obtained when the levels of both Fe and Mn are increased beyond 0.75%, because of sludge formation. On the other hand, the tensile properties of the Cu-containing alloys are affected slightly at high levels of Mg as a result of the formation of Al 5 Cu 2 Mg 8 Si 6 which decreases the amount of free Mg

Creep and residual mechanical properties of cast superalloys and oxide dispersion strengthened alloys

Science.gov (United States)

Whittenberger, J. D.

1981-01-01

Tensile, stress-rupture, creep, and residual tensile properties after creep testing were determined for two typical cast superalloys and four advanced oxide dispersion strengthened (ODS) alloys. The superalloys examined included the nickel-base alloy B-1900 and the cobalt-base alloy MAR-M509. The nickel-base ODS MA-757 (Ni-16CR-4Al-0.6Y2O3 and the iron-base ODS alloy MA-956 (Fe-20Cr-5Al-0.8Y2O3) were extensively studied, while limited testing was conducted on the ODS nickel-base alloys STCA (Ni-16Cr-4.5Al-2Y2O3) with a without Ta and YD-NiCrAl (Ni-16Cr-5Al-2Y2O3). Elevated temperature testing was conducted from 114 to 1477 K except for STCA and YD-NiCrAl alloys, which were only tested at 1366 K. The residual tensile properties of B-1900 and MAR-M509 are not reduced by prior creep testing (strains at least up to 1 percent), while the room temperature tensile properties of ODS nickel-base alloys can be reduced by small amounts of prior creep strain (less than 0.5 percent). The iron-base ODS alloy MA-956 does not appear to be susceptible to creep degradation at least up to strains of about 0.25 percent. However, MA-956 exhibits unusual creep behavior which apparently involves crack nucleation and growth.

Microstructure And Mechanical Properties Of An Al-Zn-Mg-Cu Alloy Produced By Gravity Casting Process

Directory of Open Access Journals (Sweden)

Saikawa S.

2015-06-01

Full Text Available High-strength aluminum alloy are widely used for structural components in aerospace, transportation and racing car applications. The objective of this study is to enhance the strength of the Al-Zn-Mg-Cu alloy used for gravity casting process. All alloys cast into stepped-form sand mold (Sand-mold Casting; SC and Y-block shaped metal mold(Permanent mold Casting; PC C and then two –step aged at 398-423 K after solution treated at 743 K for 36 ks. The tensile strength and total elongation of the two-step aged SC alloys were 353-387 MPa and about 0.4% respectively. This low tensile properties of the SC alloys might be caused by remaining of undissolved crystallized phase such as Al2CuM, MgZn2 and Al-Fe-Cu system compounds. However, good tensile properties were obtained from PC alloys, tensile strength and 0.2% proof stress and elongation were 503-537 MPa, 474-519 MPa and 1.3-3.3%.

Evolution of the microstructure and magnetic properties of as-cast and melt spun Fe2NiAl alloy during aging

International Nuclear Information System (INIS)

Menushenkov, V.P.; Gorshenkov, M.V.; Shchetinin, I.V.; Savchenko, A.G.; Savchenko, E.S.; Zhukov, D.G.

2015-01-01

Fe 2 NiAl-based alloy with the nominal composition Fe 51.1 Ni 23.5 Al 23.7 Si 1.7 was prepared by casting and melt-spinning. Comparison of the phase composition, microstructure and magnetic properties of water-quenched bulk samples and melt spun ribbons after isothermal aging in the 500–900 °C range were carried out. TEM investigations of the decomposition of the solid solution into β- and β 2 phases during cooling or quenching and subsequent aging have revealed different types of decomposition products. The optimal periodic modulated structure with coercive force H c ~700 Oe was observed after cooling of as-cast alloy at a critical rate. In this structure the paramagnetic β 2 phase forms a continuous network that isolates elongated single domain ferromagnetic β particles. The water-quenched bulk samples and melt spun ribbons were characterized by zone structure with zones about 10 nm and 4 nm in size. The isothermal aging of quenched samples resulted in the formation of modulated microstructure dissimilar to those of the optimal state. The coarsening of ferromagnetic β particles as well as deterioration of the magnetic insulation of β particles occur in bulk samples after aging at T ag >700 °C that decreases H c ≤350 Oe. The dependence δ M (H) was measured and negative values of δ M (H) in the H=0–2000 Oe range indicate that magnetostatic interactions between the β particles are dominant. The melt spun ribbons were characterized by the presence of antiphase domain boundaries (APD) and discontinuous precipitation (DP) products at grain boundaries (GB). The cellular areas at GBs consisting of alternating lamellas of β′- and β 2 ′ type phases were formed after aging the ribbons at T ag >500 °C. At T ag >700 °C the modulated structure formed inside grains and the wide intergranular double-layer of β and β 2 phases develops by the coalescence of the primary DP products that decrease H c ≤250 Oe. MFM image of the magnetic structure

Structure of Oxide Nanoparticles in Fe-16Cr MA/ODS Ferritic Steel

Energy Technology Data Exchange (ETDEWEB)

Hsiung, L; Fluss, M; Kimura, A

2010-04-06

Oxide nanoparticles in Fe-16Cr ODS ferritic steel fabricated by mechanical alloying (MA) method have been examined using high-resolution transmission electron microscopy (HRTEM) techniques. A partial crystallization of oxide nanoparticles was frequently observed in as-fabricated ODS steel. The crystal structure of crystalline oxide particles is identified to be mainly Y{sub 4}Al{sub 2}O{sub 9} (YAM) with a monoclinic structure. Large nanoparticles with a diameter larger than 20 nm tend to be incoherent and have a nearly spherical shape, whereas small nanoparticles with a diameter smaller than 10 nm tend to be coherent or semi-coherent and have faceted boundaries. The oxide nanoparticles become fully crystallized after prolonged annealing at 900 C. These results lead us to propose a three-stage formation mechanism of oxide nanoparticles in MA/ODS steels.

Study of microstructure and correlative magnetic property in bulk Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} permanent magnet

Energy Technology Data Exchange (ETDEWEB)

Man, H.; Xu, H. [Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China); Liu, H.W. [The Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); Tan, X.H., E-mail: tanxiaohua123@163.com [Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China); Peng, J.C.; Bai, Q. [Laboratory for Microstructures, Shanghai University, Shanghai 200444 (China)

2012-11-01

Highlights: Black-Right-Pointing-Pointer A fully dense bulk Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} permanent magnet was obtained by the simple process of copper mold casting and subsequent annealed at 943 K. Black-Right-Pointing-Pointer The relationship between microstructures and correlative magnetic property of Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} alloy was investigated. Black-Right-Pointing-Pointer The high value of intrinsic coercivity of 1191 kA/m was obtained due to the existence of hard magnetic Nd{sub 2}Fe{sub 14}B phase. - Abstract: The correlation between microstructure and magnetic property of a bulk Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} alloy are investigated. The microstructure of the as-cast Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} alloy shows a small amount of NbFeB phase with a grain size of 500 nm embedded in an amorphous matrix. The as-cast sample shows soft magnetic behavior at room temperature, after a heat treatment the hard magnetic properties are observed. A fully dense bulk Fe{sub 61}Nd{sub 10}B{sub 25}Nb{sub 4} permanent magnet is obtained with an intrinsic coercivity ({sub i}H{sub c}) of 1191 kA/m and a maximum energy product ((BH){sub max}) of 31.7 kJ/m{sup 3} after annealing at 943 K for 20 min. The corresponding microstructure consists of Nd{sub 2}Fe{sub 14}B, NdFe{sub 4}B{sub 4} and NbFeB phases. The existence of the hard magnetic Nd{sub 2}Fe{sub 14}B phase is the reason resulting in a high value of {sub i}H{sub c}. On the other hand, the influences of NdFe{sub 4}B{sub 4} and NbFeB phases in the annealed specimen on the magnetic properties are also discussed.

Development of weldable, corrosion-resistant iron-aluminide (FeAl) alloys

Energy Technology Data Exchange (ETDEWEB)

Maziasz, P.J.; Goodwin, G.M.; Wang, X.L.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

1997-04-01

A boron-microalloyed FeAl alloy (Fe-36Al-0.2Mo-0.05Zr-0.13C, at.%, with 100-400 appm B) with improved weldability and mechanical properties was developed in FY 1994. A new scale-up and industry technology development phase for this work began in FY 1995, pursuing two parallel paths. One path was developing monolithic FeAl component and application technology, and the other was developing coating/cladding technology for alloy steels, stainless steels and other Fe-Cr-Ni alloys. In FY 1995, it was found that cast FeAl alloys had good strength at 700-750{degrees}C, and some (2.5%) ductility in air at room-temperature. Hot-extruded FeAl with refined grain size was found to have ductility and to also have good impact-toughness at room-temperature. Further, it was discovered that powder-metallurgy (P/M) FeAl, consolidated by direct hot-extrusion at 950-1000{degrees}C to have an ultra fine-grained microstructure, had the highest ductility, strength and impact-toughness ever seen in such intermetallic alloys.

Au nanoparticles grafted on Fe{sub 3}O{sub 4} as effective SERS substrates for label-free detection of the 16 EPA priority polycyclic aromatic hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Du, Jingjing; Xu, Jianwei; Sun, Zhenli; Jing, Chuanyong, E-mail: cyjing@rcees.ac.cn

2016-04-07

Several methods and materials have been explored for the sensitive and practicable detection of polycyclic aromatic hydrocarbons (PAHs). However, it is still a challenge to develop simple and cost-effective sensing techniques for PAHs. Herein we report the synthesis and construction of Fe{sub 3}O{sub 4}@Au SERS substrate. This magnetic substrate was composed by Fe{sub 3}O{sub 4} microspheres and Au NPs. The size, morphology, and surface composition of Fe{sub 3}O{sub 4}@Au were characterized by multiple complimentary techniques including scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray powder diffraction. The spatial distributions of electro-magnetic field enhancement around Fe{sub 3}O{sub 4}@Au was calculated using finite difference time domain (FDTD) simulations. As a result of its remarkable sensitivity, the Fe{sub 3}O{sub 4}@Au-based SERS assay has been applied to detect the 16 EPA priority PAHs. The LODs achieved by our method (100–5 nM, 16.6–1.01 μg L{sup −1}) make it promising for the rapid screening of highly contaminated cases. As a proof-of-concept study, the substrate was applied in SERS sensing of PAHs in river matrix. The 16 PAHs could be differentiated based upon their characteristic SERS peaks. Most importantly, the detection was successfully conducted using a portable Raman spectrometer, which could be used for on-site monitoring of PAHs. - Highlights: • SERS detection of the 16 EPA priority PAHs was conducted. • The satellite-core structure lead to high SERS enhancement by confined hotspots. • The approach does not require expensive instrumentation or large sample volumes. • The effective protocol is useful for the identification of hydrophobic molecules.

Current meter data from moored current meter casts in the Northeast Pacific Ocean as part of the Ocean Prediction Through Observation Modeling and Analysis (OPTOMA) project, 1984-09-26 to 1985-07-16 (NODC Accession 9600075)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Current meter data were collected using moored current meter casts in the Northeast Pacific Ocean from September 26, 1984 to July 16, 1985. Data were submitted by...

Direct Cast U-6Nb – 2017 Progress on Cylindrical Castings

Energy Technology Data Exchange (ETDEWEB)

Aikin, Jr., Robert M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-10-04

This report describes work to further develop a sound technical basis and best practices for mold design and process parameters for the Direct Casting of U-6wt%Nb components. One major challenge to the production of U-6Nb components is the propensity for niobium segregation during casting and solidification. This is especially true for cylindrical castings where the vertical side walls allow flotation of Nb resulting in severe inverse macrosegregation. In this work, a small (120 mm diameter by 180 mm tall) and large cylinder (250 mm diameter by 310 mm tall) are examined with a focus on reducing, or eliminating, niobium segregation. It is demonstrated that counter gravity casting (top-to-bottom solidification) can be used to minimize segregation in the small cylinder. Attempts to counter gravity cast the large cylinder were unsuccessful, in large part due to size limitations of the current furnace. A path forward for casting of the large cylinders is discussed.

Preparing Magnetocaloric LaFeSi Uniform Microstructures by Spark Plasma Sintering

DEFF Research Database (Denmark)

Vicente, N.; Ocanã, J.; Neves Bez, Henrique

2014-01-01

Spark Plasma Sintering (SPS) of LaFeSi alloy powders was conducted to prepare magnetocaloric La-Fe-Si-based uniform microstructures. Two electrically insulating discs made of alumina were interposed between the punches and powder sample inhibiting the flow of electric current across the powder...... from hydrogenated and decrypted casting ingot. The characterizations of sintered samples were performed by Scanning Electron Microscopy (SEM), Archimedes principle, Vicker’s hardness and microhardness. The uniformity of the microstructure was evaluated by checking the evidence of position on the Vicker...

Anodization of cast aluminium alloys produced by different casting methods

Directory of Open Access Journals (Sweden)

K. Labisz

2008-08-01

Full Text Available In this paper the usability of two casting methods, of sand and high pressure cast for the anodization of AlSi12 and AlSi9Cu3 aluminium cast alloys was investigated. With defined anodization parameters like electrolyte composition and temperature, current type and value a anodic alumina surface layer was produced. The quality, size and properties of the anodic layer was investigated after the anodization of the chosen aluminium cast alloys. The Alumina layer was observed used light microscope, also the mechanical properties were measured as well the abrasive wear test was made with using ABR-8251 equipment. The researches included analyze of the influence of chemical composition, geometry and roughness of anodic layer obtained on aluminum casts. Conducted investigations shows the areas of later researches, especially in the direction of the possible, next optimization anodization process of aluminum casting alloys, for example in the range of raising resistance on corrosion to achieve a suitable anodic surface layer on elements for increasing applications in the aggressive environment for example as materials on working building constructions, elements in electronics and construction parts in air and automotive industry.

Liquid metal extraction of Nd from NdFeB magnet scrap

Energy Technology Data Exchange (ETDEWEB)

Xu, Yanchen [Iowa State Univ., Ames, IA (United States)

1999-12-10

This research involves using molten magnesium (Mg) to remove neodymium (Nd) from NdFeB magnet scrap by diffusion. The results show that liquid metal extraction of Nd may be a viable and inexpensive method for recovering the expensive rare earth element Nd for use in Mg castings.

Review of Grain Refinement of Cast Metals Through Inoculation: Theories and Developments

Science.gov (United States)

Liu, Zhilin

2017-10-01

The inoculation method of grain refinement is widely used in research and industry. Because of its commercial and engineering importance, extensive research on the mechanisms/theories of grain refinement and development of effective grain refiners for diverse cast metals/alloys has been conducted. In 1999, Easton and St. John reviewed the mechanisms of grain refinement of cast Al alloys. Since then, grain refinement in alloys of Al, Mg, Fe, Ti, Cu, and Zn has evolved a lot. However, there is still no full consensus on the mechanisms/theories of grain refinement. Moreover, some new grain refiners developed based on the theories do not ensure efficient grain refinement. Thus, the factors that contribute to grain refinement are still not fully understood. Clarification of the prerequisite issues that occur in grain refinement is required using recent theories. This review covers multiple metals/alloys and developments in grain refinement from the last twenty years. The characteristics of effective grain refiners are considered from four perspectives: effective particle/matrix wetting configuration, sufficiently powerful segregating elements, preferential crystallographic matching, and geometrical features of effective nucleants. Then, recent mechanisms/theories on the grain refinement of cast metals/alloys are reviewed, including the peritectic-related, hypernucleation, inert nucleant, and constitutional supercooling-driven theories. Further, developments of deterministic and probabilistic modeling and nucleation crystallography in the grain refinement of cast metals are reviewed. Finally, the latest progress in the grain refinement of cast Zn and its alloys is described, and future work on grain refinement is summarized.

Cast iron - a predictable material

Directory of Open Access Journals (Sweden)

Jorg C. Sturm

2011-02-01

Full Text Available High strength compacted graphite iron (CGI or alloyed cast iron components are substituting previously used non-ferrous castings in automotive power train applications. The mechanical engineering industry has recognized the value in substituting forged or welded structures with stiff and light-weight cast iron castings. New products such as wind turbines have opened new markets for an entire suite of highly reliable ductile iron cast components. During the last 20 years, casting process simulation has developed from predicting hot spots and solidification to an integral assessment tool for foundries for the entire manufacturing route of castings. The support of the feeding related layout of the casting is still one of the most important duties for casting process simulation. Depending on the alloy poured, different feeding behaviors and self-feeding capabilities need to be considered to provide a defect free casting. Therefore, it is not enough to base the prediction of shrinkage defects solely on hot spots derived from temperature fields. To be able to quantitatively predict these defects, solidification simulation had to be combined with density and mass transport calculations, in order to evaluate the impact of the solidification morphology on the feeding behavior as well as to consider alloy dependent feeding ranges. For cast iron foundries, the use of casting process simulation has become an important instrument to predict the robustness and reliability of their processes, especially since the influence of alloying elements, melting practice and metallurgy need to be considered to quantify the special shrinkage and solidification behavior of cast iron. This allows the prediction of local structures, phases and ultimately the local mechanical properties of cast irons, to asses casting quality in the foundry but also to make use of this quantitative information during design of the casting. Casting quality issues related to thermally driven

Serial casting for neuromuscular flatfoot and vertical talus in an adolescent with hereditary spastic paraplegia.

Science.gov (United States)

Sweet, Laurene A; OʼNeill, Lindsey M; Dobbs, Matthew B

2014-01-01

The purpose of this report is to explore assessment and serial casting intervention for painful rigid flatfoot deformities with vertical talus in an adolescent girl with hereditary spastic paraplegia who was nonambulatory. The participant's right foot underwent 2 phases of casting with correction first toward hindfoot inversion and then dorsiflexion. Because of a vertical talus, her left foot required an intermediate casting toward plantar flexion, inversion, and forefoot adduction prior to casting toward dorsiflexion. The patient improved despite the underlying progressive neuromuscular disorder. Pain ameliorated and she returned to supported standing and transfers. Spasticity decreased bilaterally and the flexibility of her foot deformities improved to allow orthotic fabrication in subtalar neutral. Results were maintained at 12 and 16 months. Individualized multiphase serial casting requires further investigation with patients such as those with hereditary spastic paraplegia.

Dimensional control of die castings

Science.gov (United States)

Karve, Aniruddha Ajit

The demand for net shape die castings, which require little or no machining, is steadily increasing. Stringent customer requirements are forcing die casters to deliver high quality castings in increasingly short lead times. Dimensional conformance to customer specifications is an inherent part of die casting quality. The dimensional attributes of a die casting are essentially dependent upon many factors--the quality of the die and the degree of control over the process variables being the two major sources of dimensional error in die castings. This study focused on investigating the nature and the causes of dimensional error in die castings. The two major components of dimensional error i.e., dimensional variability and die allowance were studied. The major effort of this study was to qualitatively and quantitatively study the effects of casting geometry and process variables on die casting dimensional variability and die allowance. This was accomplished by detailed dimensional data collection at production die casting sites. Robust feature characterization schemes were developed to describe complex casting geometry in quantitative terms. Empirical modeling was utilized to quantify the effects of the casting variables on dimensional variability and die allowance for die casting features. A number of casting geometry and process variables were found to affect dimensional variability in die castings. The dimensional variability was evaluated by comparisons with current published dimensional tolerance standards. The casting geometry was found to play a significant role in influencing the die allowance of the features measured. The predictive models developed for dimensional variability and die allowance were evaluated to test their effectiveness. Finally, the relative impact of all the components of dimensional error in die castings was put into perspective, and general guidelines for effective dimensional control in the die casting plant were laid out. The results of

The Tendencies of Piece Casting from Modified Irons

Directory of Open Access Journals (Sweden)

Cinca Ionel Lupinca

2010-10-01

Full Text Available In this paper we have presented the metalographic studies made on the grey cast irons treated with complex modifying substances, type FeSiMgRE (Mg alloy and their influence on the compactness degree of graphite separations. For research and experiments, a melt of grey iron was produced in an induction furnace of a capacity of 5to, starting with a metallic charge made from 100% synthetic pig iron. We realized eight practical charge made modification, by using different combinations of modifying substance and in different concentrations. The addition of carbon to the melt was performed using electrode graphite powder in the metallic charge.

Temperature profiles from XBT casts from the G.B. KELEZ and other platforms as part of the Marine Resources Monitoring, Assessment and Prediction (MARMAP) project from 1980-05-16 to 1980-05-18 (NODC Accession 8000385)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profiles were collected from XBT casts from the G.B. KELEZ and other platforms from 16 May 1980 to 18 May 1980. Data were collected by the National...

Bacteriology data from moored buoy casts and other instruments in the Delaware Bay and North Atlantic Ocean during the Ocean Continental Shelf (OCS-Mid Atlantic Ocean) project, 1976-11-05 to 1977-08-16 (NODC Accession 7800207)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Bacteriology data were collected using moored buoy casts and other instruments in the Delaware Bay and North Atlantic Ocean from November 5, 1976 to August 16, 1977....

Removal of C and SiC from Si and FeSi during ladle refining and solidification

Energy Technology Data Exchange (ETDEWEB)

Klevan, Ole Svein

1997-12-31

The utilization of solar energy by means of solar cells requires the Si to be very pure. The purity of Si is important for other applications as well. This thesis mainly studies the total removal of carbon from silicon and ferrosilicon. The decarburization includes removal of SiC particles by stirring and during casting in addition to reduction of dissolved carbon by gas purging. It was found that for three commercial qualities of FeSi75, Refined, Gransil, and Standard lumpy, the refined quality is lowest in carbon, followed by Gransil and Standard. A decarburization model was developed that shows the carbon removal by oxidation of dissolved carbon to be a slow process at atmospheric pressure. Gas stirring experiments have shown that silicon carbide particles are removed by transfer to the ladle wall. The casting method of ferrosilicon has a strong influence on the final total carbon content in the commercial alloy. Shipped refined FeSi contains about 100 ppm total carbon, while the molten alloy contains roughly 200 ppm. The total carbon out of the FeSi-furnace is about 1000 ppm. It is suggested that low values of carbon could be obtained on an industrial scale by injection of silica combined with the use of vacuum. Also, the casting system could be designed to give low carbon in part of the product. 122 refs., 50 figs., 24 tabs.

Draft ASME code case on ductile cast iron for transport packaging

International Nuclear Information System (INIS)

Saegusa, T.; Arai, T.; Hirose, M.; Kobayashi, T.; Tezuka, Y.; Urabe, N.; Hueggenberg, R.

2004-01-01

The current Rules for Construction of ''Containment Systems for Storage and Transport Packagings of Spent Nuclear Fuel and High Level Radioactive Material and Waste'' of Division 3 in Section III of ASME Code (2001 Edition) does not include ductile cast iron in its list of materials permitted for use. The Rules specify required fracture toughness values of ferritic steel material for nominal wall thickness 5/8 to 12 inches (16 to 305 mm). New rule for ductile cast iron for transport packaging of which wall thickness is greater than 12 inches (305mm) is required

Simulation of distortion and residual stress in high pressure die casting – modelling and experiments

International Nuclear Information System (INIS)

Hofer, P; Kaschnitz, E; Schumacher, P

2012-01-01

Two individual high-pressure die-casting geometries were developed in order to study the influence of process parameters and different alloys on the distortion behaviour of castings. These geometries were a stress lattice and a V-shaped sample tending to form residual stress due to different wall thickness respectively by a deliberate massive gating system. In the experimental castings the influence of the most important process parameters such as die temperature and die opening time and the cooling regime was examined. The time evolution of process temperatures was measured using thermal imaging. The heat transfer coefficients were adapted to the observed temperature distributions. Castings were produced from the two alloys AlSi12 and AlSi10MnMg. The distortion of the castings was measured by means of a tactile measuring device. For the alloy AlSi10MnMg thermo-physical and thermo-mechanical data were obtained using differential scanning calorimetry, laser flash technique, dilatometry and tensile testing at elevated temperatures. These data were used for modelling the material behaviour of the AlSi10MnMg alloy in the numerical model while for the alloy AlSi12(Fe) literature data were used. Process and stress simulation were conducted using the commercial FEM software ANSYS Workbench. A survey on the results of the comparison between simulation and experiment is given for both alloys.

The Effect of Ultrasonic Melt Treatment on the Microstructure and Mechanical Properties of Al-7Si-0.35Mg Casting Alloys

International Nuclear Information System (INIS)

Kim, Soo-Bae; Cho, Young-Hee; Lee, Jung-Moo; Jung, Jae-Gil; Lim, Su Gun

2017-01-01

The effect of ultrasonic melt treatment (UST) on the microstructure and mechanical properties of Al-7Si-0.35Mg (A356) casting alloys was investigated. The particular aim of this study was to analyze the mechanism involved in the strengthening of the A356 alloys when fabricated by UST. The UST had little effect on the sizes of the α-Al grain and eutectic Si at a melt temperature of 750 ℃, and the yield strength of the A356 alloy was increased by UST by approximately 16%. After T6 heat treatment, however, both alloys prepared with and without UST had similar levels of yield strength. These results are possibly associated with a change in the type and the volume fraction of intermetallics due to UST. UST greatly reduced the volume fractions of the intermetallics which were formed upon solidification, resulting in alloys with predominantly β-Al_5FeSi instead of π-Al_8FeMg_3Si_6. However, T6 heat treatment, especially a solid solution treatment at 530 ℃ for 8 hours, led to the dissolving of intermetallics such as Mg_2Si and π -Al_8FeMg_3Si_6 and as a result their volume fractions were further reduced to similar levels in both alloys with and without UST.

The Effect of Ultrasonic Melt Treatment on the Microstructure and Mechanical Properties of Al-7Si-0.35Mg Casting Alloys

Energy Technology Data Exchange (ETDEWEB)

Kim, Soo-Bae; Cho, Young-Hee; Lee, Jung-Moo; Jung, Jae-Gil [Korea Institute of Materials Science, Changwon (Korea, Republic of); Lim, Su Gun [Gyeongsang National University, Jinju (Korea, Republic of)

2017-04-15

The effect of ultrasonic melt treatment (UST) on the microstructure and mechanical properties of Al-7Si-0.35Mg (A356) casting alloys was investigated. The particular aim of this study was to analyze the mechanism involved in the strengthening of the A356 alloys when fabricated by UST. The UST had little effect on the sizes of the α-Al grain and eutectic Si at a melt temperature of 750 ℃, and the yield strength of the A356 alloy was increased by UST by approximately 16%. After T6 heat treatment, however, both alloys prepared with and without UST had similar levels of yield strength. These results are possibly associated with a change in the type and the volume fraction of intermetallics due to UST. UST greatly reduced the volume fractions of the intermetallics which were formed upon solidification, resulting in alloys with predominantly β-Al{sub 5}FeSi instead of π-Al{sub 8}FeMg{sub 3}Si{sub 6}. However, T6 heat treatment, especially a solid solution treatment at 530 ℃ for 8 hours, led to the dissolving of intermetallics such as Mg{sub 2}Si and π -Al{sub 8}FeMg{sub 3}Si{sub 6} and as a result their volume fractions were further reduced to similar levels in both alloys with and without UST.

Does the casting mode influence microstructure, fracture and properties of different metal ceramic alloys?

Science.gov (United States)

Bauer, José Roberto de Oliveira; Grande, Rosa Helena Miranda; Rodrigues-Filho, Leonardo Eloy; Pinto, Marcelo Mendes; Loguercio, Alessandro Dourado

2012-01-01

The aim of the present study was to evaluate the tensile strength, elongation, microhardness, microstructure and fracture pattern of various metal ceramic alloys cast under different casting conditions. Two Ni-Cr alloys, Co-Cr and Pd-Ag were used. The casting conditions were as follows: electromagnetic induction under argon atmosphere, vacuum, using blowtorch without atmosphere control. For each condition, 16 specimens, each measuring 25 mm long and 2.5 mm in diameter, were obtained. Ultimate tensile strength (UTS) and elongation (EL) tests were performed using a Kratos machine. Vickers Microhardness (VM), fracture mode and microstructure were analyzed by SEM. UTS, EL and VM data were statistically analyzed using ANOVA. For UTS, alloy composition had a direct influence on casting condition of alloys (Wiron 99 and Remanium CD), with higher values shown when cast with Flame/Air (p casting condition" influenced the EL and VM results, generally presenting opposite results, i.e., alloy with high elongation value had lower hardness (Wiron 99), and casting condition with the lowest EL values had the highest VM values (blowtorch). Both factors had significant influence on the properties evaluated, and prosthetic laboratories should select the appropriate casting method for each alloy composition to obtain the desired property.

Nanocrystalline NdFeB magnet prepared by mechanically activated disproportionation and desorption-recombination in-situ sintering

International Nuclear Information System (INIS)

Xiaoya, Liu; Yuping, Li; Lianxi, Hu

2013-01-01

The process of mechanically activated disproportionation and desorption-recombination in-situ sintering was proposed to synthesize highly densified nanocrystalline NdFeB magnet, and its validity was demonstrated by experimental investigation with the use of a Nd 16 Fe 76 B 8 (atomic ratio) alloy. Firstly, the as-cast alloy was disproportionated by mechanical milling in hydrogen, with the starting micron-sized Nd 2 Fe 14 B phase decomposed into an intimate mixture of nano-structured NdH 2.7 , Fe 2 B and α-Fe phases. The as-disproportionated alloy powders were compacted by cold pressing and then subjected to desorption-recombination in-situ sintering. The microstructure of both the as-disproportionated and the subsequently sintered samples was characterized by X-ray diffraction and electron transmission microscopy, respectively. The magnetic properties of the sintered samples were measured by using vibrating sample magnetometer. The results showed that, by vacuum sintering, not only was the powder compact consolidated, but also the as-disproportionated microstucture transformed into nanocrystalline Nd 2 Fe 14 B phase via the well-known desorption-recombination reaction, thus giving rise to nanocrystalline NdFeB magnet. In the present study, the optimal sintering parameters were found to be 780 °C×30 min. In this case, the coercivity, the remanence, and maximum energy product of the magnet sample achieved 0.8 T, 635.3 kA/m, and 106.3 kJ/m 3 , respectively. - Highlights: ► Nano-structured disproportionated NdFeB alloy powders by mechanical milling in hydrogen. ► Highly densified green magnet compact by cold pressing of as-disproportionated NdFeB alloy powders. ► Nanocrystalline NdFeB magnets by desorption-recombination in-situ sintering under vacuum. ► Magnetic properties significantly improved by relative density enhancement and nanocrystallization of Nd 2 Fe 14 B phase. ► The effects of sintering parameters on magnetic properties and the underlying

Magnetocaloric effect in the La0.8Ce0.2Fe11.4-xCoxSi1.6 compounds

International Nuclear Information System (INIS)

Wang, G.F.; Song, L.; Li, F.A.; Ou, Z.Q.; Tegus, O.; Brueck, E.; Buschow, K.H.J.

2009-01-01

The effects of substitution of Co for Fe on the magnetic and magnetocaloric properties of La 0.8 Ce 0.2 Fe 11.4-x Co x Si 1.6 (0, 0.2, 0.4, 0.6, 0.8 and 1.0) compounds have been investigated. X-ray diffraction shows that all compounds crystallize in the NaZn 13 -type structure. Magnetic measurements show that the Curie temperature (T C ) can be tuned between 184 and 294 K by changing the Co content from 0 to 1. A field-induced methamagnetic transition occurs in samples with x=0, 0.2 and 0.4. The magnetic entropy changes of the compounds have been determined from the isothermal magnetization measurements by using the Maxwell relation.

Phase composition of iron-rich R-Fe-Si (R=Dy, Ho, Er) alloys

International Nuclear Information System (INIS)

Ivanova, G.V.; Makarova, G.M.; Shcherbakova, E.V.; Belozerov, E.V.

2005-01-01

Phase composition is studied in iron-rich alloys of R-Fe-Si (R=Dy, Ho, Er). In the as-cast state R 2 (Fe, Si) 17 of type Th 2 Ni 17 and R(Fe, Si) 12 compounds are observed; in the alloys of rated composition of R(Fe 0.85 Si 0.15 ) 8.5 (R=Dy, Er) a compound R 2 (Fe, Si) 17 of Th 2 Zn 17 -type is revealed as well. The annealing at 1273 K results in formation of Dy 3 (Fe, Si) 29 and also the compounds with the presumed composition of Dy 4 (Fe, Si) 41 and Ho 4 (Fe, Si) 41 . As this takes place the alloys contain a transition structure as well that represents a set of small-sized areas with various type short-range order in mutual displacement of Fe-Fe(Si) dumpbell chains. The process of phase formation at 1273 K is faced with difficulties. Even the annealing for 1000 h does not result in the state of equilibrium [ru

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.

Advanced Experimental Analysis of Controls on Microbial Fe(III) Oxide Reduction - Final Report - 09/16/1996 - 03/16/2001; FINAL

International Nuclear Information System (INIS)

Roden, Eric E.

2001-01-01

Considering the broad influence that microbial Fe(III) oxide reduction can have on subsurface metal/organic contaminant biogeochemistry, understanding the mechanisms that control this process is critical for predicting the behavior and fate of these contaminants in anaerobic subsurface environments. Knowledge of the factors that influence the rates of growth and activity of Fe(III) oxide-reducing bacteria is critical for predicting (i.e., modeling) the long-term influence of these organisms on the fate of contaminants in the subsurface, and for effectively utilizing Fe(III) oxide reduction and associated geochemical affects for the purpose of subsurface metal/organic contamination bioremediation. This research project will refine existing models for microbiological and geochemical controls on Fe(III) oxide reduction, using laboratory reactor systems that mimic, to varying degrees, the physical and chemical conditions of the subsurface. Novel experimental methods for studying the kinetics of microbial Fe(III) oxide reduction and measuring growth rates of Fe(III) oxide-reducing bacteria will be developed. These new methodologies will be directly applicable to studies on subsurface contaminant transformations directly coupled to or influenced by microbial Fe(III) oxide reduction

Phase-inversion tape-casting preparation and significant performance enhancement of Ce0.9Gd0.1O1.95- La0.6Sr0.4Co0.2Fe0.8O3-δ dual-phase asymmetric membrane for oxygen separation

DEFF Research Database (Denmark)

Huang, Hua; Cheng, Shiyang; Gao, Jianfeng

2014-01-01

The dual-phase Ce0.9Gd0.1O1.95–La0.6Sr0.4Co0.2Fe0.8O3−δ asymmetric membrane was prepared via a phase-inversion tape-casting method. The membrane consisted of a thicker porous support layer and a thinner dense layer. When the dense side of the membrane was coated with a La0.6Sr0.4CoO3−δ catalytic...

Investigation of Ti-Fe-Co bulk alloys with high strength and enhanced ductility

International Nuclear Information System (INIS)

Louzguine-Luzgin, Dmitri V.; Louzguina-Luzgina, Larissa V.; Kato, Hidemi; Inoue, Akihisa

2005-01-01

High-strength Ti-Fe-Co alloys were produced in the shape of arc-melted ingots with the dimensions of about 20-25mm in diameter and 7-10mm in height. The structure of the Ti-Fe-Co alloys (at Fe/Co ratio >1) studied by X-ray diffractometry and scanning electron microscopy consisted of an ordered Pm3-bar m Ti(FeCo) compound and a disordered body-centered cubic Im3-bar m β-Ti solid solution. The optimization of the Ti-Fe-Co alloy composition is performed from the viewpoint of both high strength and ductility. The strongest Ti-Fe-Co alloys have a hypereutectic structure and exhibit a high strength of about 2000MPa and a plastic deformation of 15%. The high strength and ductility values can be achieved without using the injection mould casting or rapid solidification procedure. The deformation behavior and the fractography of Ti-Fe-Co alloys are studied in detail

Groundwater monitoring in the area of open cast Belchatow

International Nuclear Information System (INIS)

Zimnicki, R.; Soltyk, W.; Derda, M.; Chmielewski, A.G.; Owczarczyk, A.

2006-01-01

Groundwater analyses in the area of the open cast lignite mine Belchatow and Szczercow have been continued since 2000. The field work contains analyses of macro- and microion concentrations as well as measurements of tritium, 222 Rn and mean radioactivity ( 40 K). Complementary to these analyses, isotope ratios of δ 34 S/ 32 S and δ 18 O/ 16 O in SO 4 2- ion and δD in water have been investigated. In 2005 samples of water from boreholes and drains in the area of Szczercow open cast were taken and analyzed. It was found that the groundwater was not polluted, its quality and purity being in agreement with the approved groundwater purity standards

Screening of cannabis-related problems among youth: the CPQ-A-S and CAST questionnaires

Directory of Open Access Journals (Sweden)

Fernandez-Artamendi Sergio

2012-04-01

Full Text Available Abstract Background Cannabis use among young people is a significant problem, making particularly necessary validated screening instruments that permit secondary prevention. The purpose of this study was to analyze and compare the psychometric properties of the CAST and CPQ-A-S questionnaires, two screening instruments specifically addressing the youth population. Methods Information was obtained on sociodemographics, frequency of substance use, psychopathological symptoms and cannabis-use problems, and the CPQ-A-S and CAST were applied, as well as an infrequency scale for discarding responses made randomly. The sample was made up of 144 young people aged 16 to 20 that had used cannabis in the last month, of which 71.5% were boys. Mean age of the sample was 17.38 years (SD = 1.16. Results The results show that from the psychometric point of view both the CAST and the CPQ-A-S are good screening instruments. Conclusions The CAST is shorter and presents slightly better internal consistency than the CPQ-A-S. Both instruments show high sensitivity and specificity in the detection of young people dependent on cannabis according to the DSM IV-TR criteria. The CPQ-A-S appears to show greater capacity for detecting psychopathological distress associated with use. Both questionnaires yield significant odds ratios as predictors of frequent cannabis use and of the DSM IV-TR abuse and dependence criteria. In general, the CPQ-A-S emerges as a better predictor than the CAST.

Systematic review of spica casting for the treatment of paediatric diaphyseal femur fractures.

Science.gov (United States)

Tisherman, R T; Hoellwarth, J S; Mendelson, S A

2018-04-01

Paediatric femur fractures are commonly encountered and often successfully managed with spica casting. Despite spica casting's long history there is little formal guidance for optimal outcomes and no consolidation of existing literature. The purpose of this study is to review the available literature regarding the use of spica casting for the management of paediatric diaphyseal femur fractures. The PubMed database was queried for all research articles including the phrase "spica". A total of 788 abstracts were reviewed for relevance to the current study. Data was extracted from all available research studies which specified tolerance for fracture angulation or shortening in the cast. Additionally, all articles describing alternative materials, methods for spica application, and complications of spica casting were reviewed. In all, 106 articles were found relevant to the management of diaphyseal femur fractures in the paediatric population. The aggregated, accepted fracture shortening decreased from 16 mm to 18 mm before age ten years to 12 mm to 14 mm after puberty. Aggregated, accepted angulation decreased from 14° to 16° varus/valgus and 18° to 22° pro/recurvatum before age two years, to 6° to 8° and 10° to 12° by puberty, respectively. The overall reported complication rate was 19.6%, with the most common complication being skin compromise in 8.2% of patients, followed by unacceptable angulation at the fracture site in 4.2% of patients and excessive limb shortening in 1.9% of patients. This article reviews the available spica casting literature and compiles the available data. Spica casting offers a safe, effective means for definitive management of paediatric diaphyseal femur fractures. Future research identifying the rate and pattern of remodelling as it relates to angulation and shortening at various patient ages, particularly beyond the aforementioned norms, would be valuable to identify true biological tolerances versus accepted expert opinion

The Effects of Fe-Particles on the Tensile Properties of Al-Si-Cu Alloys

Directory of Open Access Journals (Sweden)

Anton Bjurenstedt

2016-12-01

Full Text Available The effect of Fe-rich particles has been a topic for discussion in the aluminum casting industry because of the negative impact they exert on the mechanical properties. However, there are still contradictions on the effects of various morphologies of Fe-particles. In this study, microstructural characterization of tensile tested samples has been performed to reveal how unmodified and modified Fe-rich particles impact on the tensile behavior. Analysis of additions of Fe modifiers such as Mn and Cr, showed higher amounts of primary Fe-rich particles (sludge with increased porosity and, as result, degraded tensile properties. From the fracture analysis of tensile tested hot isostatic pressed (HIPed samples it could be concluded that the mechanical properties were mainly governed by the Fe-rich particles, which were fracturing through cleavage, not by the porosity.

Accuracy of single-abutment digital cast obtained using intraoral and cast scanners.

Science.gov (United States)

Lee, Jae-Jun; Jeong, Ii-Do; Park, Jin-Young; Jeon, Jin-Hun; Kim, Ji-Hwan; Kim, Woong-Chul

2017-02-01

Scanners are frequently used in the fabrication of dental prostheses. However, the accuracy of these scanners is variable, and little information is available. The purpose of this in vitro study was to compare the accuracy of cast scanners with that of intraoral scanners by using different image impression techniques. A poly(methyl methacrylate) master model was fabricated to replicate a maxillary first molar single-abutment tooth model. The master model was scanned with an accurate engineering scanner to obtain a true value (n=1) and with 2 intraoral scanners (CEREC Bluecam and CEREC Omnicam; n=6 each). The cast scanner scanned the master model and duplicated the dental stone cast from the master model (n=6). The trueness and precision of the data were measured using a 3-dimensional analysis program. The Kruskal-Wallis test was used to compare the different sets of scanning data, followed by a post hoc Mann-Whitney U test with a significance level modified by Bonferroni correction (α/6=.0083). The type 1 error level (α) was set at .05. The trueness value (root mean square: mean ±standard deviation) was 17.5 ±1.8 μm for the Bluecam, 13.8 ±1.4 μm for the Omnicam, 17.4 ±1.7 μm for cast scanner 1, and 12.3 ±0.1 μm for cast scanner 2. The differences between the Bluecam and the cast scanner 1 and between the Omnicam and the cast scanner 2 were not statistically significant (P>.0083), but a statistically significant difference was found between all the other pairs (POmnicam, 9.2 ±1.2 μm for cast scanner 1, and 6.9 ±2.6 μm for cast scanner 2. The differences between Bluecam and Omnicam and between Omnicam and cast scanner 1 were not statistically significant (P>.0083), but there was a statistically significant difference between all the other pairs (POmnicam in video image impression had better trueness than a cast scanner but with a similar level of precision. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by

Microstructure Formation and Fracturing Characteristics of Grey Cast Iron Repaired Using Laser

Science.gov (United States)

Liu, Dan; Shi, Yongjun

2014-01-01

The repairing technology based on laser rapid fusion is becoming an important tool for fixing grey cast iron equipment efficiently. A laser repairing protocol was developed using Fe-based alloy powders as material. The microstructure and fracturing feature of the repaired zone (RZ) were analyzed. The results showed that regionally organized RZ with good density and reliable metallurgical bond can be achieved by laser repairing. At the bottom of RZ, dendrites existed in similar direction and extended to the secondary RZ, making the grains grow extensively with inheritance with isometric grains closer to the surface substrate. The strength of the grey cast iron base material was maintained by laser repairing. The base material and RZ were combined with robust strength and fracture resistance. The prevention and deflection of cracking process were analyzed using a cracking process model and showed that the overall crack toughness of the materials increased. PMID:25032230

Data and analyses of phase relations in the Ce-Fe-Sb ternary system.

Science.gov (United States)

Zhu, Daiman; Xu, Chengliang; Li, Changrong; Guo, Cuiping; Zheng, Raowen; Du, Zhenmin; Li, Junqin

2018-02-01

These data and analyses support the research article "Experimental study on phase relations in the Ce-Fe-Sb ternary system" Zhu et al. (2017) [1]. The data and analyses presented here include the experimental results of XRD, SEM and EPMA for the determination of the whole liquidus projection and the isothermal section at 823 K in the Ce-Fe-Sb system. All the results enable the understanding of the constituent phases and the solidification processes of the as-cast alloys as well as the phase relations and the equilibrium regions at 823 K in the Ce-Fe-Sb ternary system over the entire composition.

Clean Metal Casting

Energy Technology Data Exchange (ETDEWEB)

Makhlouf M. Makhlouf; Diran Apelian

2002-02-05

The objective of this project is to develop a technology for clean metal processing that is capable of consistently providing a metal cleanliness level that is fit for a given application. The program has five tasks: Development of melt cleanliness assessment technology, development of melt contamination avoidance technology, development of high temperature phase separation technology, establishment of a correlation between the level of melt cleanliness and as cast mechanical properties, and transfer of technology to the industrial sector. Within the context of the first task, WPI has developed a standardized Reduced Pressure Test that has been endorsed by AFS as a recommended practice. In addition, within the context of task1, WPI has developed a melt cleanliness sensor based on the principles of electromagnetic separation. An industrial partner is commercializing the sensor. Within the context of the second task, WPI has developed environmentally friendly fluxes that do not contain fluorine. Within the context of the third task, WPI modeled the process of rotary degassing and verified the model predictions with experimental data. This model may be used to optimize the performance of industrial rotary degassers. Within the context of the fourth task, WPI has correlated the level of melt cleanliness at various foundries, including a sand casting foundry, a permanent mold casting foundry, and a die casting foundry, to the casting process and the resultant mechanical properties. This is useful in tailoring the melt cleansing operations at foundries to the particular casting process and the desired properties of cast components.

Structural and superconducting properties of as-cast Nb3Al

International Nuclear Information System (INIS)

Mondal, Puspen; Manekar, Meghmalhar; Roy, S.B.; Kumar, Ravi; Ganguli, Tapas

2007-01-01

We present the results of x-ray diffraction and magnetization measurements on the as-cast compound Nb 3 Al. X-ray diffraction shows the presence of the Al 5 Nb 3 Al phase along with a bcc Nb-Al solid solution. The average grain size of Nb 3 Al estimated from the line broadening is about 35 nm. Magnetization measurements show a superconducting transition temperature of about 16.8 K which is amongst the highest known T c for the as-cast sample. In the superconducting state, the sample shows interesting thermo-magnetic history effects in the temperature and field variation of magnetization. (author)

Accuracy of Gypsum Casts after Different Impression Techniques and Double Pouring.

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Stephania Caroline Rodolfo Silva

Full Text Available This study evaluated the accuracy of gypsum casts after different impression techniques and double pouring. Ten patients were selected and for each one it was obtained 5 partial putty/wash impressions with vinyl polysiloxane (VPS material from teeth #13 to #16 with partial metal stock trays. The following techniques were performed: (1 one-step; two-step relief with: (2 PVC film; (3 slow-speed tungsten carbide bur and scalpel blade, (4 small movements of the tray and (5 without relief-negative control. The impressions were disinfected with 0.5% sodium hypochlorite for 10 minutes and stored during 110 and 230 minutes for the first and second pouring, respectively, with type IV gypsum. Three intra-oral lateral photographs of each patient were taken using a tripod and a customized radiographic positioner. The images were imported into ImageJ software and the total area of the buccal surface from teeth #13 to #16 was measured. A 4.0% coefficient of variance was criterion for using these measurements as Baseline values. The casts were photographed and analyzed using the same standardization for the clinical images. The area (mm2 obtained from the difference between the measurements of each gypsum cast and the Baseline value of the respective patient were calculated and analyzed by repeated-measures two way-ANOVA and Mauchly's Sphericity test (α = 0.05. No significant effect was observed for Impression technique (P = 0.23, Second pouring (P = 0.99 and their interaction (P = 0.25. The impression techniques and double pouring did not influence the accuracy of the gypsum casts.

Hydrogen-producing microflora and Fe-Fe hydrogenase diversities in seaweed bed associated with marine hot springs of Kalianda, Indonesia.

Science.gov (United States)

Xu, Shou-Ying; He, Pei-Qing; Dewi, Seswita-Zilda; Zhang, Xue-Lei; Ekowati, Chasanah; Liu, Tong-Jun; Huang, Xiao-Hang

2013-05-01

Microbial fermentation is a promising technology for hydrogen (H(2)) production. H(2) producers in marine geothermal environments are thermophilic and halotolerant. However, no one has surveyed an environment specifically for thermophilic bacteria that produce H(2) through Fe-Fe hydrogenases (H(2)ase). Using heterotrophic medium, several microflora from a seaweed bed associated with marine hot springs were enriched and analyzed for H(2) production. A H(2)-producing microflora was obtained from Sargassum sp., 16S rRNA genes and Fe-Fe H(2)ase diversities of this enrichment were also analyzed. Based on 16S rRNA genes analysis, 10 phylotypes were found in the H(2)-producing microflora showing 90.0-99.5 % identities to known species, and belonged to Clostridia, Gammaproteobacteria, and Bacillales. Clostridia were the most abundant group, and three Clostridia phylotypes were most related to known H(2) producers such as Anaerovorax odorimutans (94.0 % identity), Clostridium papyrosolvens (98.4 % identity), and Clostridium tepidiprofundi (93.1 % identity). For Fe-Fe H(2)ases, seven phylotypes were obtained, showing 63-97 % identities to known Fe-Fe H(2)ases, and fell into four distinct clusters. Phylotypes HW55-3 and HM55-1 belonged to thermophilic and salt-tolerant H(2)-producing Clostridia, Halothermothrix orenii-like Fe-Fe H(2)ases (80 % identity), and cellulolytic H(2)-producing Clostridia, C. papyrosolvens-like Fe-Fe H(2)ases (97 % identity), respectively. The results of both 16S rRNA genes and Fe-Fe H(2)ases surveys suggested that the thermophilic and halotolerant H(2)-producing microflora in seaweed bed of hot spring area represented previously unknown H(2) producers, and have potential application for H(2) production.

Influence of M=Al, Ga and Si on microstructure and HDDR-processing of Sm2(Fe,M)17 and magnetic properties of their nitrides and carbides

International Nuclear Information System (INIS)

Kubis, M.; Gutfleisch, O.; Gebel, B.; Mueller, K.-H.; Schultz, L.

1999-01-01

Microstructural investigations by means of scanning electron microscopy and X-ray diffraction showed that the formation of high amounts of α-Fe in as-cast Sm 2 (Fe,M) 17 alloys can be suppressed by using the substitutions M=Al or Si together with excess Sm. Ga, on the other hand, does not induce this beneficial effect. The hydrogen absorption and desorption behaviour was investigated by temperature-pressure-analysis and hydrogen differential thermal analysis. Decreasing amounts of hydrogen were absorbed in Sm 2 (Fe,M) 17 for increasing contents of all substitutions M=Ga, Al and Si due to their stabilising effect on the 2:17 phase with regard to its disproportionation. Compared with the homogenised alloys, the as-cast materials show a weaker interstitial hydrogen absorption and a stronger disproportionation reaction at lower temperatures due to the higher content of Sm-rich phases in the as-cast alloys. A second cycle of the hydrogenation-disproportionation-desorption-recombination (HDDR) process leads to a faster disproportionation reaction at lower temperatures due to the grain refinement during the first cycle. Magnetic properties of as-cast and homogenised materials were investigated after HDDR treatment and nitrogenation or carburisation of pre-milled powders. Nitrogenated and carburised samples showed coercivities up to 3.0 T and 2.3 T, respectively. There were only slight differences of the magnetic properties of materials prepared from homogenised and from as-cast samples. (orig.)

The impact of caste on the growth of male Sikhs in Punjab, India.

Science.gov (United States)

Singh, L P; Harrison, G A

1997-01-01

This study is based on a cross-sectional sample of 442 Sikh boys and young male adults who were born in and around the town of Phagwara, in the state of Punjab, India, and stayed there all their lives. The sample comprised Sikh boys at three crucial phases of growth, at 5-6, 10-11 and 15-16 years, and young adults around 18 years of age. The sample comprised three distinct caste groups, viz. Jats, Ramgarhias and Ravidassias, belonging respectively to upper, middle and lower socioeconomic strata of the Sikh community. Differences in stature and body weight are particularly marked around early adolescence, and there is some indication of caste differences reappearing in young adults. In the case of body mass index, however, the differences seem most marked in late adolescence. There is no clear directional pattern to the way skinfolds change, but inter-caste differences become more marked with age. There is a suggestion of continuing growth beyond 16 years of age, and indications that the well-off groups grow more, as compared to the poor groups, during this period. Comparisons of young adults with older groups of the same caste indicate an increase in body weight with age, but smaller stature in the older groups. There is thus evidence for a secular stature increase among present-day Punjabi Sikhs.

Size effect on L10 ordering and magnetic properties of chemically synthesized FePt and FePtAu nanoparticles

Science.gov (United States)

Jia, Zhiyong; Kang, Shishou; Shi, Shifan; Nikles, David E.; Harrell, J. W.

2005-05-01

There is growing evidence that FePt nanoparticles become increasingly difficult to chemically order as the size approaches a few nanometers. We have studied the chemical ordering of FePt and FePtAu nanoparticle arrays as a function of particle size. Monodisperse Fe49Pt51 and Fe48Pt44Au8 nanoparticles with a size about 6nm were synthesized by the simultaneous decomposition of iron pentacarbonyl and reduction of platinum acetylacetonate and gold (III) acetate in a mixture of phenyl ether and hexadecylamine (HDA), with 1-adamantanecarboxylic acid and HDA as stabilizers. The nanoparticles were dispersed in toluene, films of the particles were cast onto silicon wafers from the dispersion, and the films were annealed in a tube furnace with flowing Ar +5%H2. The magnetic anisotropy and switching volumes were determined from time- and temperature-dependent coercivity measurements. By comparing with 3-nm FePt and FePtAu nanoparticles of comparable composition, the phase transformation is easier for the larger particles. Under the same annealing conditions, the larger particles have higher anisotropy and order parameter. Additive Au is very effective in enhancing the chemical ordering in both small and large particles, with x-ray diffraction superlattice peaks appearing after annealing at 350°C. Dynamic remnant coercivity measurements and magnetic switching volumes suggest particle aggregation at the higher annealing temperatures in both small and large particles.

Caste System

OpenAIRE

Hoff, Karla

2016-01-01

In standard economics, individuals are rational actors and economic forces undermine institutions that impose large inefficiencies. The persistence of the caste system is evidence of the need for psychologically more realistic models of decision-making in economics. The caste system divides South Asian society into hereditary groups whose lowest ranks are represented as innately polluted. ...

Magnetic and anomalous magnetic viscosity in the bulk amorphous ferromagnet Pr58Fe24Al18 and partially amorphous ferromagnet Pr60Fe24Al16

International Nuclear Information System (INIS)

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

2009-01-01

A number of ferromagnetic Pr-Fe-Al alloys have been prepared by argon arc melting and quenching into a copper mould. The alloy of composition Pr 58 Fe 24 Al 18 is identified as being amorphous (bulk metallic glass or bulk amorphous ferromagnet), and a range of magnetic measurements have been performed to explore differences and similarities between it and a partially amorphous alloy, containing a significant crystalline fraction, Pr 60 Fe 24 Al 16 . For both alloys, measurements of the irreversible susceptibility, and magnetic viscosity on the major hysteresis loop are reported. From the magnetic viscosity data, the fluctuation field is determined. The behaviour of the anomalous magnetic viscosity (non-monotonic behaviour of the magnetic viscosity, where the magnetisation as a function of time is seen to increase, reach a peak, and then decrease), on the recoil curve that leads to the dc demagnetised state is investigated. Both alloys display non-monotonic behaviour. After dc demagnetisation, spontaneous remagnetisation is observed in both alloys, and some comments are made on the thermal remagnetisation behaviour of the amorphous alloy. The anomalous magnetic viscosity is interpreted in the context of the Preisach model, as it predicts a simple functional relationship between the time taken to reach a peak and the applied magnetic field. The experimental data for both alloys is in good agreement with this prediction.

SLIP CASTING METHOD

Science.gov (United States)

Allison, A.G.

1959-09-01

S>A process is described for preparing a magnesium oxide slip casting slurry which when used in conjunction with standard casting techniques results in a very strong "green" slip casting and a fired piece of very close dimensional tolerance. The process involves aging an aqueous magnestum oxide slurry, having a basic pH value, until it attains a specified critical viscosity at which time a deflocculating agent is added without upsetting the basic pH value.

Ageing and life prediction of cast duplex stainless steel components

International Nuclear Information System (INIS)

Chung, H.M.

1992-01-01

Cast duplex stainless steels, used extensively in nuclear, chemical and petroleum industries because of higher strength, better weldability, higher resistance to stress corrosion cracking, and soundness of casting, are susceptible to thermal aging embrittlement during service at temperatures as low as ∼250 o C. Recent advances in understanding the aging mechanisms, kinetics, and mechanical properties are presented, with emphasis on application of the material in safety-significant components in a nuclear reactor. Aging embrittlement is primarily due to spinodal decomposition of ferrite involving segregation of Fe, Cr, and Ni, and precipitation of M 23 C 6 on ferrite-austenite boundaries or in ferrite. Aging kinetics are strongly influenced by synergistic effects of other metallurgical reactions that occur in parallel with the spinodal decomposition, i.e. clustering of Ni, Mo, and Si and G-phase precipitation in ferrite. A number of methods are outlined for estimating end-of-life aging, depending on several factors such as degree of permissible conservatism, availability of component archive material, and methods of estimating and verifying the activation energy of aging. (Author)

Heat treatment giving a stable high temperature micro-structure in cast austenitic stainless steel

Science.gov (United States)

Anton, Donald L.; Lemkey, Franklin D.

1988-01-01

A novel micro-structure developed in a cast austenitic stainless steel alloy and a heat treatment thereof are disclosed. The alloy is based on a multicomponent Fe-Cr-Mn-Mo-Si-Nb-C system consisting of an austenitic iron solid solution (.gamma.) matrix reinforced by finely dispersed carbide phases and a heat treatment to produce the micro-structure. The heat treatment includes a prebraze heat treatment followed by a three stage braze cycle heat treatment.

Gating Systems for Sizeable Castings from Al Alloys Cast into Ceramic Moulds

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I. Stachovec

2012-04-01

Full Text Available In contrast to casting to conventional non-reusable “sand” moulds, for which calculating technique for an optimum design of the gating system is comparatively well-developed, a trial-and-error method is applied mostly for casting to ceramic shell moulds made by the investment casting technology. A technologist selects from gating systems of several types (that are standardized by the foundry mostly on the basis of experience. However, this approach is not sustainable with ever growing demands on quality of castings and also the economy of their fabrication as well as with new types of complex sizeable castings introduced to the production gradually (by new customers from the aircraft industry above all any more. The simulation software may be used as a possible tool for making the process of optimising gating systems more effective.

Semisolid casting with ultrasonically melt-treated billets of Al-7mass%Si alloys

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Yoshiki Tsunekawa

2012-02-01

Full Text Available The demand for high performance cast aluminum alloy components is often disturbed by increasing impurity elements, such as iron accumulated from recycled scraps. It is strongly required that coarse plate-like iron compound of モ-Al5FeSi turns into harmless form without the need for applying refining additives or expensive virgin ingots. The microstructural modification of Al-7mass%Si alloy billets with different iron contents was examined by applying ultrasonic vibration during the solidification. Ultrasonically melt-treated billets were thixocast right after induction heating up to the semisolid temperature of 583 ìC, the microstructure and tensile properties were evaluated in the thixocast components. Globular primary メ-Al is required to fill up a thin cavity in thixocasting, so that the microstructural modification by ultrasonic melt-treatment was firstly confirmed in the billets. With ultrasonic melt-treatment in the temperature range of 630 ìC to 605 ìC, the primary メ-Al transforms itself from dendrite into fine globular in morphology. The coarse plate-like モ-Al5FeSi compound becomes markedly finer compared with those in non-treated billets. Semisolid soaking up to 583 ìC, does not appreciably affect the size of モ-Al5FeSi compounds; however, it affects the solid primary メ-Al morphology to be more globular, which is convenient for thixocasting. After thixocasting with preheated billets, eutectic silicon plates are extremely refined due to the rapid solidification arising from low casting temperature. The tensile strength of thixocast samples with different iron contents does not change much even at 2mass% of iron, when thixocast with ultrasonically melt-treated billets. However, thixocast Al-7mass%Si-2mass%Fe alloy with non-treated billets exhibits an inferior strength of 80 MPa, compared with 180 MPa with ultrasonically melt-treated billets. The elongation is also improved by about a factor of two in thixocastings with

Influences of biomass heat and biochemical energy storages on the land surface fluxes and radiative temperature

Science.gov (United States)

Gu, Lianhong; Meyers, Tilden; Pallardy, Stephen G.; Hanson, Paul J.; Yang, Bai; Heuer, Mark; Hosman, Kevin P.; Liu, Qing; Riggs, Jeffery S.; Sluss, Dan; Wullschleger, Stan D.

2007-01-01

The interest of this study was to develop an initial assessment on the potential importance of biomass heat and biochemical energy storages for land-atmosphere interactions, an issue that has been largely neglected so far. We conducted flux tower observations and model simulations at a temperate deciduous forest site in central Missouri in the summer of 2004. The model used was the comprehensive terrestrial ecosystem Fluxes and Pools Integrated Simulator (FAPIS). We first examined FAPIS performance by testing its predictions with and without the representation of biomass energy storages against measurements of surface energy and CO2 fluxes. We then evaluated the magnitudes and temporal patterns of the biomass energy storages calculated by FAPIS. Finally, the effects of biomass energy storages on land-atmosphere exchanges of sensible and latent heat fluxes and variations of land surface radiative temperature were investigated by contrasting FAPIS simulations with and without these storage terms. We found that with the representation of the two biomass energy storage terms, FAPIS predictions agreed with flux tower measurements fairly well; without the representation, however, FAPIS performance deteriorated for all predicted surface energy flux terms although the effect on the predicted CO2 flux was minimal. In addition, we found that the biomass heat storage and biochemical energy storage had clear diurnal patterns with typical ranges from -50 to 50 and -3 to 20 W m-2, respectively; these typical ranges were exceeded substantially when there were sudden changes in atmospheric conditions. Furthermore, FAPIS simulations without the energy storages produced larger sensible and latent heat fluxes during the day but smaller fluxes (more negative values) at night as compared with simulations with the energy storages. Similarly, without-storage simulations had higher surface radiative temperature during the day but lower radiative temperature at night, indicating that the

Multiscale modeling for the prediction of casting defects in investment cast aluminum alloys

International Nuclear Information System (INIS)

Hamilton, R.W.; See, D.; Butler, S.; Lee, P.D.

2003-01-01

Macroscopic modeling of heat transfer and fluid flow is now routinely used for the prediction of macroscopic defects in castings, while microscopic models are used to investigate the effects of alloy changes on typical microstructures. By combining these two levels of modeling it is possible to simulate the casting process over a wider range of spatial and temporal scales. This paper presents a multiscale model where micromodels for dendrite arm spacing and microporosity are incorporated into a macromodel of heat transfer and in order to predict the as cast microstructure and prevalence of microscopic defects, specifically porosity. The approach is applied to aluminum alloy (L169) investment castings. The models are compared with results obtained by optical image analysis of prepared slices, and X-ray tomography of volume samples from the experiments. Multiscale modeling is shown to provide the designer with a useful tool to improve the properties of the final casting by testing how altering the casting process affects the final microstructure including porosity

Microstructure and magnetism of Co2FeAl Heusler alloy prepared by arc and induction melting compared with planar flow casting

Science.gov (United States)

Titov, A.; Jiraskova, Y.; Zivotsky, O.; Bursik, J.; Janickovic, D.

2018-04-01

This paper is devoted to investigations of the structural and magnetic properties of the Co2FeAl Heusler alloy produced by three technologies. The alloys prepared by arc and induction melting have resulted in coarse-grained samples in contrast to the fine-grained ribbon-type sample prepared by planar flow casting. Scanning electron microscopy completed by energy dispersive X-ray spectroscopy, X-ray diffraction, Mössbauer spectroscopy, and magnetic methods sensitive to both bulk and surface were applied. The chemical composition was slightly different from the nominal only for the ribbon sample. From the viewpoint of magnetic properties, the bulk coercivity and remnant magnetization have followed the structure influenced by the technology used. Saturation magnetization was practically the same for samples prepared by arc and induction melting, whereas the magnetization of ribbon is slightly lower due to a higher Al content at the expense of iron and cobalt. The surface magnetic properties were markedly influenced by anisotropy, grain size, and surface roughness of the samples. The surface roughness and brittleness of the ribbon-type sample did not make domain structure observation possible. The other two samples could be well polished and their highly smooth surface has enabled domain structure visualization by both magneto-optical Kerr microscopy and magnetic force microscopy.

Optimization of excess Bi doping to enhance ferroic orders of spin casted BiFeO3 thin film

International Nuclear Information System (INIS)

Gupta, Surbhi; Gupta, Vinay; Tomar, Monika; James, A. R.; Pal, Madhuparna; Guo, Ruyan; Bhalla, Amar

2014-01-01

Multiferroic Bismuth Ferrite (BiFeO 3 ) thin films with varying excess bismuth (Bi) concentration were grown by chemical solution deposition technique. Room temperature multiferroic properties (ferromagnetism, ferroelectricity, and piezoelectricity) of the deposited BiFeO 3 thin films have been studied. High resolution X-ray diffraction and Raman spectroscopy studies reveal that the dominant phases formed in the prepared samples change continuously from a mixture of BiFeO 3 and Fe 2 O 3 to pure BiFeO 3 phase and, subsequently, to a mixture of BiFeO 3 and Bi 2 O 3 with increase in the concentration of excess Bi from 0% to 15%. BiFeO 3 thin films having low content (0% and 2%) of excess Bi showed the traces of ferromagnetic phase (γ-Fe 2 O 3 ). Deterioration in ferroic properties of BiFeO 3 thin films is also observed when prepared with higher content (15%) of excess Bi. Single-phased BiFeO 3 thin film prepared with 5% excess Bi concentration exhibited the soft ferromagnetic hysteresis loops and ferroelectric characteristics with remnant polarization 4.2 μC/cm 2 and saturation magnetization 11.66 emu/g. The switching of fine spontaneous domains with applied dc bias has been observed using piezoresponse force microscopy in BiFeO 3 thin films having 5% excess Bi. The results are important to identify optimum excess Bi concentration needed for the formation of single phase BiFeO 3 thin films exhibiting the improved multiferroic properties.

[The surface roughness analysis of the titanium casting founding by a new titanium casting investment material].

Science.gov (United States)

Liang, Qin-ye; Wu, Xia-yi; Lin, Xue-feng

2012-04-01

To investigate the surface roughness property of the titanium castings cast in a new investment for titanium casting. Six wax patterns (20 mm × 20 mm × 0.5 mm) were invested using two investments: three in a new titanium investment material and three in the control material (Rematitan Plus). Six titanium specimens were obtained by conventional casting. After casting, surface roughness of the specimens were evaluated with a surface profilometer. The surface roughness of the specimens cast in new titanium investment material was (1.72 ± 0.08) µm, which was much smaller than that from Rematitan Plus [(1.91 ± 0.15) µm, P cast using these two investment materials are both smooth enough to fulfill the demand of the titanium precision-casting for prosthodontic clinical use.

Equilibrium phase of high-entropy FeCoNiCrCu0.5 alloy at elevated temperature

International Nuclear Information System (INIS)

Lin, C.-M.; Tsai, H.-L.

2010-01-01

The phase transformations of FeCoNiCrCu 0.5 alloy with the as-cast structure and heat-treated structures were studied. The as-cast alloy specimens were first heated at 1050 o C with a holding time of 1 h. Serial heat-treatment processes at 350 o C, 500 o C, 650 o C, 800 o C, 950 o C, 1100 o C, 1250 o C and 1350 o C with a holding time of 24 h were then carried out to understand the phase evolution and the relationship between the microstructure and the hardness of the specimens. The microstructures were investigated and chemical analyses performed by optical microscopy (OM), scanning elector microscopy (SEM), X-ray diffractometer (XRD) and transmission elector microscopy (TEM). The results show that FCC peaks were observed from the X-ray diffraction of the as-cast specimens and a precipitate phase was present in the specimens that had been heated to 950 o C. The hardness of the FeCoNiCrCu 0.5 alloy remained unchanged in the specimens that underwent various heat treatments that were applied in this study.

Modeling Fe II Emission and Revised Fe II (UV) Empirical Templates for the Seyfert 1 Galaxy I Zw 1

Science.gov (United States)

Bruhweiler, F.; Verner, E.

2008-03-01

We use the narrow-lined broad-line region (BLR) of the Seyfert 1 galaxy, I Zw 1, as a laboratory for modeling the ultraviolet (UV) Fe II 2100-3050 Å emission complex. We calculate a grid of Fe II emission spectra representative of BLR clouds and compare them with the observed I Zw 1 spectrum. Our predicted spectrum for log [nH/(cm -3) ] = 11.0, log [ΦH/(cm -2 s-1) ] = 20.5, and ξ/(1 km s-1) = 20, using Cloudy and an 830 level model atom for Fe II with energies up to 14.06 eV, gives a better fit to the UV Fe II emission than models with fewer levels. Our analysis indicates (1) the observed UV Fe II emission must be corrected for an underlying Fe II pseudocontinuum; (2) Fe II emission peaks can be misidentified as that of other ions in active galactic nuclei (AGNs) with narrow-lined BLRs possibly affecting deduced physical parameters; (3) the shape of 4200-4700 Å Fe II emission in I Zw 1 and other AGNs is a relative indicator of narrow-line region (NLR) and BLR Fe II emission; (4) predicted ratios of Lyα, C III], and Fe II emission relative to Mg II λ2800 agree with extinction corrected observed I Zw 1 fluxes, except for C IV λ1549 (5) the sensitivity of Fe II emission strength to microturbulence ξ casts doubt on existing relative Fe/Mg abundances derived from Fe II (UV)/Mg II flux ratios. Our calculated Fe II emission spectra, suitable for BLRs in AGNs, are available at http://iacs.cua.edu/people/verner/FeII. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 05-26555.

Examination and Elimination of Defects in Cone Casting Made of Ductile Cast Iron

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Guzik E.

2013-12-01

Full Text Available In the scope of existing cooperation with the Foundry of Cast Iron ZM “WSK Rzeszów” Ltd. there was carried out research work of microstructure and mechanical properties in the walls of a cone casting made of ductile cast iron. The particular attention was being put to the search of the potential brittle phases which have deleterious effect on ductility and dynamic properties of highly strained use of the casting prone to the potential risk of cracks during the highly strained use.

Colour Metallography of Cast Iron

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Zhou Jiyang

2009-05-01

Full Text Available Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application and combine cast iron technology with some hi-techs (for example, computer technology. Nevertheless, cast iron is a multi-element and multi-phase alloy and has complex and variety of structures and still has great development potential in structure and property. For further studying and developing cast iron, theoretical research work is important promise, and the study on solidification process and control mechanism of graphite morphology is fundamental for improving property of cast iron and developing new type of cast iron.Metallography of cast iron normally includes two sections: liquid phase transformation and solid phase transformation. The book, Colour Metallography of Cast Iron , uses colour metallography technique to study solidification structures of cast irons: graphite, carbides, austenite and eutectics; and focuses on solidification processes. With progress of modern solidification theory, the control of material solidification process becomes important measure for improving traditionalmaterials and developing new materials. Solidification structure not only influences mechanical and physical properties of cast iron, but also affects its internal quality. The book uses a large amount of colour photos to describe the formation of solidification structures and their relations. Crystallization phenomena, which cannot be displayed with traditional metallography, are presented and more phase transformation information is obtained from these colour

Effect of cooling rate on the microstructure and properties of FeCrVC

International Nuclear Information System (INIS)

Bleckmann, M.; Gleinig, J.; Hufenbach, J.; Wendrock, H.; Giebeler, L.; Zeisig, J.; Diekmann, U.; Eckert, J.; Kühn, U.

2015-01-01

Highlights: • Effect of cooling rate on microstructure and microhardness of newly developed steel. • Intensive study of DSC measurements was done including different cooling rates. • Examinations by XRD, EDS and EBSD as well as microhardness on the DSC samples. • Matrix phase changes with cooling rates from ferrit to martensite. • Thermodynamic calculations of solidification process shows good agreement. - Abstract: In this work a systematic investigation of the influence of the cooling rate on the microstructure and properties of a newly developed Fe92.7Cr4.2V2.1C1 (FeCrVC) tool steel is presented. By applying a tailored casting process and sufficiently high cooling rates excellent mechanical properties are obtained for the presented alloy already in the as-cast state. Since no subsequent heat treatment is required, the cooling parameters applied during the casting process play a key role with respect to the evolving microstructure and resulting properties. In the present publication the effect of the cooling rate on the microstructure and properties of as-solidified FeCrVC was investigated. By using differential scanning calorimetry (DSC), several samples were heated up and cooled with continuous rates of 3–50 K/min. The received DSC data was used to investigate the alloy’s solidification and phase transformation behavior. Subsequently, these samples were studied regarding their properties and microstructure by different analysis methods (EDX/WDX, EBSD, XRD). With increasing cooling rates the liquidus and solidus temperature are lowered, whereas the solidification interval is enlarged. A higher cooling rate is accompanied by a lower solidification time which results in a refinement of the dendritic microstructure. Furthermore, with rising cooling rates the microhardness increased. This provides the opportunity to make predictions from the applied cooling parameters upon the hardness and vice versa and enables one to draw first conclusions on the

Modeling and Optimization of Direct Chill Casting to Reduce Ingot Cracking

Energy Technology Data Exchange (ETDEWEB)

Das, S.K.; Ningileri, S.; Long, Z.; Saito, K.; Khraisheh, M.; Hassan, M.H.; Kuwana, K.; Han, Q.; Viswanathan, S.; Sabau, A.S.; Clark, J.; Hyrn, J. (ANL)

2006-08-15

Approximately 68% of the aluminum produced in the United States is first cast into ingots prior to further processing into sheet, plate, extrusions, or foil. The direct chill (DC) semi-continuous casting process has been the mainstay of the aluminum industry for the production of ingots due largely to its robust nature and relative simplicity. Though the basic process of DC casting is in principle straightforward, the interaction of process parameters with heat extraction, microstructural evolution, and development of solidification stresses is too complex to analyze by intuition or practical experience. One issue in DC casting is the formation of stress cracks [1-15]. In particular, the move toward larger ingot cross-sections, the use of higher casting speeds, and an ever-increasing array of mold technologies have increased industry efficiencies but have made it more difficult to predict the occurrence of stress crack defects. The Aluminum Industry Technology Roadmap [16] has recognized the challenges inherent in the DC casting process and the control of stress cracks and selected the development of 'fundamental information on solidification of alloys to predict microstructure, surface properties, and stresses and strains' as a high-priority research need, and the 'lack of understanding of mechanisms of cracking as a function of alloy' and 'insufficient understanding of the aluminum solidification process', which is 'difficult to model', as technology barriers in aluminum casting processes. The goal of this Aluminum Industry of the Future (IOF) project was to assist the aluminum industry in reducing the incidence of stress cracks from the current level of 5% to 2%. Decreasing stress crack incidence is important for improving product quality and consistency as well as for saving resources and energy, since considerable amounts of cast metal could be saved by eliminating ingot cracking, by reducing the scalping thickness of

Casting characteristics of Al-Mg alloy 535 cast in permanent moulds

International Nuclear Information System (INIS)

Fasoyinu, F.A.; Thomson, J.; Cousineau, D.; Castles, T.; Sahoo, M.

2002-01-01

Aluminum alloy 535 could be used for automotive and marine applications because of its good corrosion resistance against mild alkaline and salt spray exposure. The majority of components from this alloy are usually produced by sand casting because it is prone to hot shortness and has poor fluidity when poured in permanent moulds. In an attempt to improve its castability in permanent moulds, casting characteristics such as casting fluidity and hot tear resistance have been studied. In addition, the effectiveness of titanium, boron, scandium, zirconium and a combination of selected elements from this group as grain refiners were evaluated. It s shown that alloy 535 exhibits good casting fluidity when poured with adequate metal superheat and that there is significant improvement in hot tear resistance following grain refinement. (author)

Effect of Nickel Equivalent on Austenite Transition Ratio in Ni-Mn-Cu Cast Iron

Directory of Open Access Journals (Sweden)

Janus A.

2013-06-01

Full Text Available Determined was quantitative effect of nickel equivalent value on austenite decomposition degree during cooling-down castings of Ni-Mn- Cu cast iron. Chemical composition of the alloy was 1.8 to 5.0 % C, 1.3 to 3.0 % Si, 3.1 to 7.7 % Ni, 0.4 to 6.3 % Mn, 0.1 to 4.9 % Cu, 0.14 to 0.16 % P and 0.03 to 0.04 % S. Analysed were castings with representative wall thickness 10, 15 and 20 mm. Scope of the examination comprised chemical analysis (including WDS, microscopic observations (optical and scanning microscopy, image analyser, as well as Brinell hardness and HV microhardness measurements of structural components.

Evolution of Primary Fe-Rich Compounds in Secondary Al-Si-Cu Alloys

Science.gov (United States)

Fabrizi, Alberto; Capuzzi, Stefano; Timelli, Giulio

Although iron is usually added in die cast Al-Si foundry alloys to prevent die soldering, primary Fe-rich particles are generally considered as "hardspot" inclusions which compromise the mechanical properties of the alloy, namely ductility and toughness. As there is no economical methods to remove the Fe excess in secondary Al-Si alloys at this time, the control of solidification process and chemical composition of the alloy is a common industrial practice to overcome the negative effects connected with the presence of Fe-rich particles. In this work, the size and morphology as well as the nucleation density of primary Fe-rich particles have been studied as function of cooling rate and alloy chemical composition for secondary Al-Si-Cu alloys. The solidification experiments were carried out using differential scanning calorimetry whereas morphology investigations were conducted using optical and scanning electron microscopy. Mcrosegregations and chemical composition of primary Fe-rich particles were examined by energy dispersive spectroscopy.

Shielding of electromagnetic fields by metallic glasses with Fe and Co matrix

International Nuclear Information System (INIS)

Nowosielski, R.; Griner, S.

1997-01-01

The influence of chemical composition and magnetic and electric properties for shielding of electromagnetic fields with frequency 10-1000 kHz, by metallic glasses has been analysed. For investigation were selected two groups of metallic glasses with matrix of Fe and Co. Particularly, in there were selected metallic glasses as follows; Fe 78 Si 9 B 13 , Co 68 Fe 4 Mo 1.5 Si 13.5 B 13 , Co 69 Mo 2 Fe 4 Si 14 B 11 , Co 70.5 Fe 2.5 Mn 4 Mo 1 Si 9 B 15 . The experiments were realised for casting metallic glasses by the CMBS method in the form of strips with width 10 mm. Obtained results of shielding indicate clear for very good shielding effectiveness of one layer shields both electric and magnetic components of electromagnetic fields, although shielding of magnetic component is smaller than electric. (author). 17 refs, 5 figs, 9 tabs

Influence of M=Al, Ga and Si on microstructure and HDDR-processing of Sm{sub 2}(Fe,M){sub 17} and magnetic properties of their nitrides and carbides

Energy Technology Data Exchange (ETDEWEB)

Kubis, M.; Gutfleisch, O.; Gebel, B.; Mueller, K.-H.; Schultz, L. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany). Inst. fuer Metallische Werkstoffe; Harris, I.R. [School of Metallurgy and Materials, University of Birmingham, Birmingham, B15 2TT (United Kingdom)

1999-02-01

Microstructural investigations by means of scanning electron microscopy and X-ray diffraction showed that the formation of high amounts of {alpha}-Fe in as-cast Sm{sub 2}(Fe,M){sub 17} alloys can be suppressed by using the substitutions M=Al or Si together with excess Sm. Ga, on the other hand, does not induce this beneficial effect. The hydrogen absorption and desorption behaviour was investigated by temperature-pressure-analysis and hydrogen differential thermal analysis. Decreasing amounts of hydrogen were absorbed in Sm{sub 2}(Fe,M){sub 17} for increasing contents of all substitutions M=Ga, Al and Si due to their stabilising effect on the 2:17 phase with regard to its disproportionation. Compared with the homogenised alloys, the as-cast materials show a weaker interstitial hydrogen absorption and a stronger disproportionation reaction at lower temperatures due to the higher content of Sm-rich phases in the as-cast alloys. A second cycle of the hydrogenation-disproportionation-desorption-recombination (HDDR) process leads to a faster disproportionation reaction at lower temperatures due to the grain refinement during the first cycle. Magnetic properties of as-cast and homogenised materials were investigated after HDDR treatment and nitrogenation or carburisation of pre-milled powders. Nitrogenated and carburised samples showed coercivities up to 3.0 T and 2.3 T, respectively. There were only slight differences of the magnetic properties of materials prepared from homogenised and from as-cast samples. (orig.) 21 refs.

Applying RP-FDM Technology to Produce Prototype Castings Using the Investment Casting Method

Directory of Open Access Journals (Sweden)

M. Macků

2012-09-01

Full Text Available The research focused on the production of prototype castings, which is mapped out starting from the drawing documentation up to theproduction of the casting itself. The FDM method was applied for the production of the 3D pattern. Its main objective was to find out whatdimensional changes happened during individual production stages, starting from the 3D pattern printing through a silicon mouldproduction, wax patterns casting, making shells, melting out wax from shells and drying, up to the production of the final casting itself.Five measurements of determined dimensions were made during the production, which were processed and evaluated mathematically.A determination of shrinkage and a proposal of measures to maintain the dimensional stability of the final casting so as to meetrequirements specified by a customer were the results.

Determination of localized Fe2+/Fe3+ ratios in inks of historic documents by means of μ-XANES

International Nuclear Information System (INIS)

Proost, K.; Janssens, K.; Wagner, B.; Bulska, E.; Schreiner, M.

2004-01-01

An important part of the European cultural heritage is composed of hand-written documents. Many of these documents were drawn up with iron-gall ink. This type of ink present a serious conservation problem, as it slowly oxidizes ('burns') the paper it is written on, thereby gradually disintegrating the historic document. Acid hydrolysis of the cellulose and/or the oxidation of organic compounds promoted by radical intermediates that are formed due to the presence of Fe 2+ ions are considered to be the cause of the disintegration. μ-XANES measurements were performed with a lateral resolution of 30-50 μm in order to determine the local Fe 2+ /Fe 3+ ratio in 19th C. documents from the Austrian National Archives and fragments of 16th C documents from the Polish National Library. In the 19th C documents, no significant amount of Fe 2+ was detected. On the other hand, in the 16th C fragments, significant amounts of Fe 2+ and appreciable differences in distribution of Fe 2+ and Fe 3+ within individual letters/ink stains were observed

Casting of microstructured shark skin surfaces and possible applications on aluminum casting parts

Directory of Open Access Journals (Sweden)

Todor Ivanov

2011-02-01

Full Text Available Within the project Functional Surfaces via Micro- and Nanoscaled Structures?which is part of the Cluster of Excellence 揑ntegrative Production Technology?established and financed by the German Research Foundation (DFG, an investment casting process to produce 3-dimensional functional surfaces down to a structural size of 1 μm on near-net-shape-casting parts has been developed. The common way to realize functional microstructures on metallic surfaces is to use laser ablation, electro discharge machining or micro milling. The handicap of these processes is their limited productivity. The approach of this project to raise the efficiency is to use the investment casting process to replicate microstructured surfaces by moulding from a laser-microstructured grand master pattern. The main research objective deals with the investigation of the single process steps of the investment casting process with regard to the moulding accuracy. Actual results concerning making of the wax pattern, suitability of ceramic mould and core materials for casting of an AlSi7Mg0.3 alloy as well as the knock-out behavior of the shells are presented. By using of the example of an intake manifold of a gasoline race car engine, a technical shark skin surface has been realized to reduce the drag of the intake air. The intake manifold consists of an air-restrictor with a defined inner diameter which is microstructured with technical shark skin riblets. For this reason the inner diameter cannot be drilled after casting and demands a very high accuracy of the casting part. A technology for the fabrication and demoulding of accurate microstructured castings are shown. Shrinkage factors of different moulding steps of the macroscopic casting part as well as the microscopic riblet structure have been examined as well.

Effect of Nb aggregates on Zr2Fe

International Nuclear Information System (INIS)

Ramos, Cinthia P.

2001-01-01

The binary Zr-Fe phase diagram revision, performed by Arias et al., accepted the intermetallic Zr 2 Fe crystalline structure as tetragonal and determined that the presence of a third element like oxygen, nitrogen or carbon, stabilizes a cubic phase. Nevitt et al. studying Ti, Zr and Hf alloys with transition metals as second or third element and ternary systems with oxygen as third element, systematized the occurrence of phases with a cubic Ti 2 Ni type crystalline structure. From previous studies in the Zr-Nb-Fe system, it is an agreed fact that Nb presence in the Zr 2 Fe intermetallic stabilizes a cubic Ti 2 Ni type phase. The purpose of the present work is to determine the stability range of the Zr 2 Fe intermetallic with Nb contents, the existence range of the ternary cubic Ti 2 Ni type phase (designated Λ) and the corresponding two-phase region. We analyze as cast and heat treated (800 C degrees) Zr-Nb-Fe alloys with 35 atomic % Fe and Nb contents between 0.5 and 15 atomic %. The determination and characterization of the phases is made by optical and scanning electron microscopy, X-ray diffraction microprobe analysis and Moessbauer Spectroscopy. Joining these techniques together it is found, among many other things, that the Zr 2 Fe phase would accept up to around 0.5 atomic % Nb in solution and that the two-phase region Zr 2 Fe+Λ would be stable in the (0.5 - 3.5) Nb atomic % range. It is proposed as well a 800 C degrees section of the ternary (Zr-Nb-Fe) in the studied region. (author) [es

Aluminium Foam and Magnesium Compound Casting Produced by High-Pressure Die Casting

Directory of Open Access Journals (Sweden)

Iban Vicario

2016-01-01

Full Text Available Nowadays, fuel consumption and carbon dioxide emissions are two of the main focal points in vehicle design, promoting the reduction in the weight of vehicles by using lighter materials. The aim of the work is to evaluate the influence of different aluminium foams and injection parameters in order to obtain compound castings with a compromise between the obtained properties and weight by high-pressure die cast (HPDC using aluminium foams as cores into a magnesium cast part. To evaluate the influence of the different aluminium foams and injection parameters on the final casting products quality, the type and density of the aluminium foam, metal temperature, plunger speed, and multiplication pressure have been varied within a range of suitable values. The obtained compound HPDC castings have been studied by performing visual and RX inspections, obtaining sound composite castings with aluminium foam cores. The presence of an external continuous layer on the foam surface and the correct placement of the foam to support injection conditions permit obtaining good quality parts. A HPDC processed magnesium-aluminium foam composite has been developed for a bicycle application obtaining a suitable combination of mechanical properties and, especially, a reduced weight in the demonstration part.

Evolution of the microstructure and magnetic properties of as-cast and melt spun Fe{sub 2}NiAl alloy during aging

Energy Technology Data Exchange (ETDEWEB)

Menushenkov, V.P., E-mail: menushenkov@gmail.com; Gorshenkov, M.V.; Shchetinin, I.V.; Savchenko, A.G.; Savchenko, E.S.; Zhukov, D.G.

2015-09-15

Fe{sub 2}NiAl-based alloy with the nominal composition Fe{sub 51.1}Ni{sub 23.5}Al{sub 23.7}Si{sub 1.7} was prepared by casting and melt-spinning. Comparison of the phase composition, microstructure and magnetic properties of water-quenched bulk samples and melt spun ribbons after isothermal aging in the 500–900 °C range were carried out. TEM investigations of the decomposition of the solid solution into β- and β{sub 2} phases during cooling or quenching and subsequent aging have revealed different types of decomposition products. The optimal periodic modulated structure with coercive force H{sub c}~700 Oe was observed after cooling of as-cast alloy at a critical rate. In this structure the paramagnetic β{sub 2} phase forms a continuous network that isolates elongated single domain ferromagnetic β particles. The water-quenched bulk samples and melt spun ribbons were characterized by zone structure with zones about 10 nm and 4 nm in size. The isothermal aging of quenched samples resulted in the formation of modulated microstructure dissimilar to those of the optimal state. The coarsening of ferromagnetic β particles as well as deterioration of the magnetic insulation of β particles occur in bulk samples after aging at T{sub ag}>700 °C that decreases H{sub c}≤350 Oe. The dependence δ{sub M}(H) was measured and negative values of δ{sub M}(H) in the H=0–2000 Oe range indicate that magnetostatic interactions between the β particles are dominant. The melt spun ribbons were characterized by the presence of antiphase domain boundaries (APD) and discontinuous precipitation (DP) products at grain boundaries (GB). The cellular areas at GBs consisting of alternating lamellas of β′- and β{sub 2}′ type phases were formed after aging the ribbons at T{sub ag}>500 °C. At T{sub ag}>700 °C the modulated structure formed inside grains and the wide intergranular double-layer of β and β{sub 2} phases develops by the coalescence of the primary DP products that

Constituent phase diagrams of the Al-Cu-Fe-Mg-Ni-Si system and their application to the analysis of aluminium piston alloys

Energy Technology Data Exchange (ETDEWEB)

Belov, N.A. [Moscow Institute of Steel and Alloys, Leninsky prosp. 4, Moscow 119049 (Russian Federation); Eskin, D.G. [Netherlands Institute for Metals Research, Rotterdamseweg 137, 2628AL Delft (Netherlands)]. E-mail: deskin@nimr.nl; Avxentieva, N.N. [Moscow Institute of Steel and Alloys, Leninsky prosp. 4, Moscow 119049 (Russian Federation)

2005-10-15

The evaluation of phase equilibria in quinary systems that constitute the commercially important Al-Cu-Fe-Mg-Ni-Si alloying system is performed in the compositional range of casting alloys by means of metallography, electron probe microanalysis, X-ray diffractometry, differential scanning calorimetry, and by the analysis of phase equilibria in the constituent systems of lesser dimensionality. Suggested phase equilibria are illustrated by bi-, mono- and invariant solidification reactions, polythermal diagrams of solidification, distributions of phase fields in the solid state, and isothermal and polythermal sections. Phase composition of as-cast alloys is analyzed in terms of non-equilibrium solidification. It is shown that the increase in copper concentration in piston Al-Si alloys results in the decrease in the equilibrium solidus from 540 to 505 deg C. Under non-equilibrium solidification conditions, piston alloys finish solidification at {approx}505 deg C. Iron is bound in the quaternary Al{sub 8}FeMg{sub 3}Si{sub 6} phase in low-iron alloys and in the ternary Al{sub 9}FeNi and Al{sub 5}FeSi phases in high-iron alloys.

Determination of the 54Fe(n, 2n)53gFe and 54Fe(n, 2n)53mFe cross sections averaged over a 235U fission neutron spectrum

International Nuclear Information System (INIS)

Ribeiro Guevara, S.; Arribere, M.; Kestelman, A.J.

2002-01-01

The reaction cross sections averaged over a 235 U fission neutron spectrum have been measured for the 54 Fe(n, 2n) 53g Fe and 54 Fe(n, 2n) 53m Fe threshold reactions. The values found are, respectively: (1.14 ± 0.13) μb, and (0.52 ± 0.16) μb. The measured cross sections are referred to the (111± 3) mb standard cross section of the 58 Ni(n, p) 58m+g Co reaction. The (81.7 ± 2.2) mb standard cross section value for the 54 Fe(n, p) 54 Mn reaction, was also used as a monitor to check the results obtained with the Ni standard, leading to an excellent agreement. (author)

Applying RP-FDM Technology to Produce Prototype Castings Using the Investment Casting Method

Directory of Open Access Journals (Sweden)

Macků M.

2012-09-01

Full Text Available The research focused on the production of prototype castings, which is mapped out starting from the drawing documentation up to the production of the casting itself. The FDM method was applied for the production of the 3D pattern. Its main objective was to find out what dimensional changes happened during individual production stages, starting from the 3D pattern printing through a silicon mould production, wax patterns casting, making shells, melting out wax from shells and drying, up to the production of the final casting itself. Five measurements of determined dimensions were made during the production, which were processed and evaluated mathematically. A determination of shrinkage and a proposal of measures to maintain the dimensional stability of the final casting so as to meet requirements specified by a customer were the results.

Casting AISI 316 steel by gel cast

International Nuclear Information System (INIS)

Ozols, A; Thern, G; Rozenberg, S; Barreiro, M; Marajofsky, A

2004-01-01

The feasibility of producing AISI 316 steel components from their powders and avoiding their compaction is analyzed. A casting technique is tested that is similar to gel casting, used for ceramic materials. In the initial stage, the process consists of the formulation of a concentrated barbotine of powdered metal in a solution of water soluble organic monomers, which is cast in a mold and polymerized in situ to form a raw piece in the shape of the cavity. The process can be performed under controlled conditions using barbotines with a high monomer content from the acrylimide family. Then, the molded piece is slowly heated until the polymer is eliminated, and it is sintered at temperatures of 1160 o C to 1300 o C under a dry hydrogen atmosphere, until the desired densities are attained. The density and micro structure of the materials obtained are compared with those for the materials compacted and synthesized by the conventional processes. The preliminary results show the feasibility of the process for the production of certain kinds of structural components (CW)

Addition of iron for the removal of the {beta}-AlFeSi intermetallic by refining of {alpha}-AlFeSi phase in an Al-7.5Si-3.6Cu alloy

Energy Technology Data Exchange (ETDEWEB)

Belmares-Perales, S. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon (Mexico); Zaldivar-Cadena, A.A., E-mail: azaldiva70@hotmail.com [Facultad de Ingenieria Civil, Departamento de Ecomateriales y Energia, Instituto de Ingenieria Civil, Av. Fidel Velasquez and Av. Universidad S/N, Cd. Universitaria, San Nicolas de los Garza, N.L. 66450 (Mexico)

2010-10-25

Addition of iron into the molten metal for the removal of the {beta}-AlFeSi intermetallic by refining of {alpha}-AlFeSi phase has been studied. Solidification conditions and composition determine the final microstructure and mechanical properties of a casting piece. It is known that increasing the iron content will produce an increasing of the {alpha}-AlFeSi and {beta}-AlFeSi phases. This phenomenon was confirmed with calculations made by Thermo-Calc{sup TM} software and validated with experimental results, however, the technique of iron addition in this study plays an important role on the solidification kinetics of these iron phases because the refining of {alpha}-AlFeSi and removal of {beta}-AlFeSi phases can be improved. Final results showed an improvement in mechanical properties by removal and refining of {beta}-AlFeSi and {alpha}-AlFeSi phases, respectively. This study shows a new method of removal of {beta}-AlFeSi that could be adopted in the aluminum smelting industry in aluminum alloys with a low cooling rate with a secondary dendritic spacing of about 37 {mu}m.

Addition of iron for the removal of the β-AlFeSi intermetallic by refining of α-AlFeSi phase in an Al-7.5Si-3.6Cu alloy

International Nuclear Information System (INIS)

Belmares-Perales, S.; Zaldivar-Cadena, A.A.

2010-01-01

Addition of iron into the molten metal for the removal of the β-AlFeSi intermetallic by refining of α-AlFeSi phase has been studied. Solidification conditions and composition determine the final microstructure and mechanical properties of a casting piece. It is known that increasing the iron content will produce an increasing of the α-AlFeSi and β-AlFeSi phases. This phenomenon was confirmed with calculations made by Thermo-Calc TM software and validated with experimental results, however, the technique of iron addition in this study plays an important role on the solidification kinetics of these iron phases because the refining of α-AlFeSi and removal of β-AlFeSi phases can be improved. Final results showed an improvement in mechanical properties by removal and refining of β-AlFeSi and α-AlFeSi phases, respectively. This study shows a new method of removal of β-AlFeSi that could be adopted in the aluminum smelting industry in aluminum alloys with a low cooling rate with a secondary dendritic spacing of about 37 μm.

Symptomatic stent cast.

LENUS (Irish Health Repository)

Keohane, John

2012-02-03

Biliary stent occlusion is a major complication of endoscopic stent insertion and results in repeat procedures. Various theories as to the etiology have been proposed, the most frequently studied is the attachment of gram negative bacteria within the stent. Several studies have shown prolongation of stent patency with antibiotic prophylaxis. We report the case of stent occlusion from a cast of a previously inserted straight biliary stent; a "stent cast" in an 86-year-old woman with obstructive jaundice. This was retrieved with the lithotrypter and she made an uneventful recovery. This is the first reported case of a biliary stent cast.

A Soft Casting Technique for Managing Pediatric Hand and Foot Burns.

Science.gov (United States)

Choi, Young Mee; Nederveld, Cindy; Campbell, Kristen; Moulton, Steven

2018-04-04

Hand and foot burns in children are difficult to dress. The authors have developed a soft casting technique to manage burns to these areas. The aim of this study is to report the outcomes using weekly dressing changes with a soft casting technique to manage pediatric hand and foot burns in the outpatient setting. A retrospective chart review was performed on children with burns to the hands or feet, who underwent dressing changes with a soft casting technique at the Children's Hospital Colorado Burn Center. Soft casting was performed by placing antibiotic ointment-impregnated nonadherent gauze over the burn wound(s), wrapping the extremity using rolled gauze, applying soft cast pad, plaster, soft cast tape, and an elastic bandage. This was changed weekly. Two hundred ninety-eight children with hand burns had a mean age of 16.8 ± 2 months. Two hundred forty-eight children had partial thickness burn injuries (83%), 50 had full thickness burn injuries (17%), and the mean total body surface area (TBSA) was 1 ± 2.4%. The mean time to heal was 10.1 ± 1.7 days for all subjects. Sixty-six children with foot burns were identified with a mean age of 24 ± 2.6 months. Forty-six children had partial thickness injuries (70%), 20 had full thickness burn injuries (30%), and the mean TBSA was 2.3 ± 2.9%. The mean time to heal was 14.1 ± 2.2 days for all subjects. Weekly dressing changes using a soft casting technique are effective for the outpatient management of pediatric hand and foot burns. This method avoids costly inpatient hospital care, reduces the number of painful dressing changes, and allows children to heal in their own environment.

Current meter data from moored current meter casts in the TOGA Area - Pacific (30 N to 30 S) as part of the Equatorial Pacific Ocean Climate Studies (EPOCS) project from 1984-04-16 to 1985-10-01 (NODC Accession 8700147)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Current meter data were collected using moored current meter casts in the TOGA Area - Pacific (30 N to 30 S) from April 16, 1984 to October 1, 1985. Data were...

Fracture Mechanisms in Steel Castings

Directory of Open Access Journals (Sweden)

Stradomski Z.

2013-09-01

Full Text Available The investigations were inspired with the problem of cracking of steel castings during the production process. A single mechanism of decohesion - the intergranular one - occurs in the case of hot cracking, while a variety of structural factors is decisive for hot cracking initiation, depending on chemical composition of the cast steel. The low-carbon and low-alloyed steel castings crack due to the presence of the type II sulphides, the cause of cracking of the high-carbon tool cast steels is the net of secondary cementite and/or ledeburite precipitated along the boundaries of solidified grains. Also the brittle phosphor and carbide eutectics precipitated in the final stage solidification are responsible for cracking of castings made of Hadfield steel. The examination of mechanical properties at 1050°C revealed low or very low strength of high-carbon cast steels.

Nanocrystalline NdFeB magnet prepared by mechanically activated disproportionation and desorption-recombination in-situ sintering

Energy Technology Data Exchange (ETDEWEB)

Xiaoya, Liu; Yuping, Li [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Lianxi, Hu, E-mail: hulx@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2013-03-15

The process of mechanically activated disproportionation and desorption-recombination in-situ sintering was proposed to synthesize highly densified nanocrystalline NdFeB magnet, and its validity was demonstrated by experimental investigation with the use of a Nd{sub 16}Fe{sub 76}B{sub 8} (atomic ratio) alloy. Firstly, the as-cast alloy was disproportionated by mechanical milling in hydrogen, with the starting micron-sized Nd{sub 2}Fe{sub 14}B phase decomposed into an intimate mixture of nano-structured NdH{sub 2.7}, Fe{sub 2}B and {alpha}-Fe phases. The as-disproportionated alloy powders were compacted by cold pressing and then subjected to desorption-recombination in-situ sintering. The microstructure of both the as-disproportionated and the subsequently sintered samples was characterized by X-ray diffraction and electron transmission microscopy, respectively. The magnetic properties of the sintered samples were measured by using vibrating sample magnetometer. The results showed that, by vacuum sintering, not only was the powder compact consolidated, but also the as-disproportionated microstucture transformed into nanocrystalline Nd{sub 2}Fe{sub 14}B phase via the well-known desorption-recombination reaction, thus giving rise to nanocrystalline NdFeB magnet. In the present study, the optimal sintering parameters were found to be 780 Degree-Sign C Multiplication-Sign 30 min. In this case, the coercivity, the remanence, and maximum energy product of the magnet sample achieved 0.8 T, 635.3 kA/m, and 106.3 kJ/m{sup 3}, respectively. - Highlights: Black-Right-Pointing-Pointer Nano-structured disproportionated NdFeB alloy powders by mechanical milling in hydrogen. Black-Right-Pointing-Pointer Highly densified green magnet compact by cold pressing of as-disproportionated NdFeB alloy powders. Black-Right-Pointing-Pointer Nanocrystalline NdFeB magnets by desorption-recombination in-situ sintering under vacuum. Black-Right-Pointing-Pointer Magnetic properties significantly

Neutron irradiation effects in Fe and Fe-Cr at 300 °C

International Nuclear Information System (INIS)

Chen, Wei-Ying; Miao, Yinbin; Gan, Jian; Okuniewski, Maria A.; Maloy, Stuart A.; Stubbins, James F.

2016-01-01

Fe and Fe-Cr (Cr = 10–16 at.%) specimens were neutron-irradiated at 300 °C to 0.01, 0.1 and 1 dpa. The TEM observations indicated that the Cr significantly reduced the mobility of dislocation loops and suppressed vacancy clustering, leading to distinct damage microstructures between Fe and Fe-Cr. Irradiation-induced dislocation loops in Fe were heterogeneously observed in the vicinity of grown-in dislocations, whereas the loop distribution observed in Fe-Cr is much more uniform. Voids were observed in the irradiated Fe samples, but not in irradiated Fe-Cr samples. Increasing Cr content in Fe-Cr results in a higher density, and a smaller size of irradiation-induced dislocation loops. Orowan mechanism was used to correlate the observed microstructure and hardening, which showed that the hardening in Fe-Cr can be attributed to the formation of dislocation loops and α′ precipitates. -- Graphical abstract: Addition of Cr in Fe suppressed the mobility of mobile 1/2<111> dislocation loops and increased the proportion of immobile <100> dislocation loops, leading to a transition of loop distribution from highly heterogeneous to uniform. Display Omitted

MICROSTRUCTURE AND TENSILE PROPERTIES OF Fe3Al-BASED ALLOYS WITH VC AND TiC ADDITIONS

Institute of Scientific and Technical Information of China (English)

W.L.Xu; Y.S.Sun; S.S.Ding

2001-01-01

Microstructure and tensile properties of Fe3Al-based alloys with additions of TiC andVC particles have been investigated.Results show that the formation of TiC particlesresults in the refinement of the macrostructure of as-cast ingots.Although the additionof VC particles does not cause significant change of the as-cast microstructure,themicrostructure of the alloy after hot-working and recrystallization has been found tobe refined.The formation of both VC and TiC particles results in the increase of yieldstrength,especially at high temperature of 600℃.

Modelling the Cast Component Weight in Hot Chamber Die Casting using Combined Taguchi and Buckingham's π Approach

Science.gov (United States)

Singh, Rupinder

2018-02-01

Hot chamber (HC) die casting process is one of the most widely used commercial processes for the casting of low temperature metals and alloys. This process gives near-net shape product with high dimensional accuracy. However in actual field environment the best settings of input parameters is often conflicting as the shape and size of the casting changes and one have to trade off among various output parameters like hardness, dimensional accuracy, casting defects, microstructure etc. So for online inspection of the cast components properties (without affecting the production line) the weight measurement has been established as one of the cost effective method (as the difference in weight of sound and unsound casting reflects the possible casting defects) in field environment. In the present work at first stage the effect of three input process parameters (namely: pressure at 2nd phase in HC die casting; metal pouring temperature and die opening time) has been studied for optimizing the cast component weight `W' as output parameter in form of macro model based upon Taguchi L9 OA. After this Buckingham's π approach has been applied on Taguchi based macro model for the development of micro model. This study highlights the Taguchi-Buckingham based combined approach as a case study (for conversion of macro model into micro model) by identification of optimum levels of input parameters (based on Taguchi approach) and development of mathematical model (based on Buckingham's π approach). Finally developed mathematical model can be used for predicting W in HC die casting process with more flexibility. The results of study highlights second degree polynomial equation for predicting cast component weight in HC die casting and suggest that pressure at 2nd stage is one of the most contributing factors for controlling the casting defect/weight of casting.

Raman-spectroscopic (Fe/Fe+Mg, CO2) and Structural studies of Mg-Fe cordierites

International Nuclear Information System (INIS)

Haefeker, U.

2013-01-01

In the course of this dissertation synthetic hexagonal and orthorhombic Mg-Fe-cordierites have been investigated with Raman-spectroscopy and XRD methods. Cordierite´s Mg- and Fe-end-members as well as their Mg-Fe solid solutions with the chemical formula (Mg, Fe 2+ ) 2 Al 4 Si 5 O 18 *nH 2 O have been synthesized. Raman-data of synthetic hydrous Mg- and Fe-cordierites have been obtained in the wavenumber-region 100-1250 cm-1 and the experimental data were then compared with the results of quantum-mechanical calculations. 86 theoretical bands could be related to specific vibrational modes of the tetrahedral and octahedral sites of the cordierite structure. Maximum and mean deviation between experimentally-derived bands and calculated modes were ±7 cm -1 for Mg-cordierite and ±19 cm -1 for Fe-cordierite. Spectra comparison revealed a trend of peak downshifting as a consequence of Fe-incorporation. The calculations now allow more accurate interpretation of the Raman spectra with respect to structural changes of cordierite, resulting from Al-Si ordering and Mg-Fe exchange. Atomic motions in cordierite have been compared with those of the structurally similar mineral beryl. Investigations of 16 H 2 O-bearing synthetic well-ordered Mg-Fe-cordierites (XFe =0-1) with micro-Raman spectroscopy revealed a linear correlation between the Fe/Mg ratio and the position of certain Raman peaks. The peaks (wave-number Mg-/Fe-cordierite) at 122/111, 262/257, 430/418, 579/571, 974/967, and 1012/1007 cm -1 were selected for a detailed deconvolution analysis . The shifts of these peaks were then plotted vs. XFe and regression of the data lead to the formulation of a set of linear equations. In addition, the effect of different H 2 O contents and the degree of Al-Si ordering on the Fe/Mg determination were also investigated. Testing the calibration against data from six well-characterized natural cordierite samples yielded excellent agreement. Existing calibration diagrams for CO 2

Mechanism and application of a newly developed pressure casting process: horizontal squeeze casting

Directory of Open Access Journals (Sweden)

Li Peijie

2014-07-01

Full Text Available Compared to traditional high-pressure die casting (HPDC, horizontal squeeze casting (HSC is a more promising way to fabricate high-integrity castings, owing to a reduced number of gas and shrinkage porosities produced in the casting. In this paper, the differences between HSC and HPDC are assessed, through which it is shown that the cavity filling velocity and the size of the gating system to be the most notable differences. Equipment development and related applications are also reviewed. Furthermore, numerical simulation is used to analyze the three fundamental characteristics of HSC: slow cavity filling, squeeze feeding and slow sleeve filling. From this, a selection principle is given based on the three related critical casting parameters: cavity filling velocity, gate size and sleeve filling velocity. Finally, two specific applications of HSC are introduced, and the future direction of HSC development is discussed.

Study of the influence of the temperature in the magnetic properties and in microstructure in the permanent magnets Pr-Fe-B-Nb-Co based obtained by hydrogen

International Nuclear Information System (INIS)

Silva, Suelanny Carvalho da

2007-01-01

Fine magnetic powders were produced using the hydrogenation disproportionation desorption and recombination (HDDR) process. The first stage in this work involved an investigation of the effect of the Co content and range of desorption/ recombination temperatures between 800 and 900 deg C with the purpose of optimizing the HDDR treatment for Pr 14 Fe 80 B 6 and Pr 14 Fe bal Co x B 6 Nb 0,1 (x= 0, 4, 8, 10, 12, 16) alloys. The cast alloys were annealed at 1100 deg C for 20 hours for homogenization. The processing temperature (desorption/ recombination) affected the microstructure and magnetic properties of the bonded magnets. The alloy with low cobalt content (4 at.%) required the highest reaction temperature (880 deg C) to yield anisotropic bonded magnets. The optimum temperature for alloys with 8 at.% Co and 10 at.% Co were 840 deg C and 820 deg C, respectively. Alloys with high cobalt content (12 at.% and 16 at.%) were processed at 840 deg C. The optimum desorption temperature for achieving high anisotropy for Pr 14 Fe 80 B 6 and Pr 14 Fe 79,9 B 6 Nb 0,1 was 820 deg C. The best remanence (862 mT) was achieved with the Pr 14 Fe 67,9 B 6 Co 12 Nb 0,1 magnet, processed at 840 deg C. Each alloy required an optimum reaction temperature and exhibited a particular microstructure according to the composition. The second stage of the work involved the characterization, for each temperature, of the Pr 14 Fe 80 B 6 HDDR powder processed using X-ray diffraction analysis. The samples of the HDDR material were studied by synchrotron radiation powder diffraction using the Rietveld method for cell refinement, phase quantification and crystallite sizes determination. Scanning electron microscopy has also been employed to reveal the morphology of the HDDR powder. (author)

NUMERICAL MODELING OF HARDENING OF UNINTERRUPTEDLY-CASTED BRONZE CASTING

Directory of Open Access Journals (Sweden)

E. I. Marukovich

2009-01-01

Full Text Available The three-dimensional numerical model for calculation of thermal fields during solidification of continuously casted bronze casting is developed. Coefficients of heat transfer on borders of calculation areas on the basis of the solution of inverse heat transfer conduction problem are determined. The analysis of thermal fields, depending on loop variables of drawing and the sizes of not cooled zone of crystallizer is curried out.

Thromboprophylaxis after Knee Arthroscopy and Lower-Leg Casting.

Science.gov (United States)

van Adrichem, Raymond A; Nemeth, Banne; Algra, Ale; le Cessie, Saskia; Rosendaal, Frits R; Schipper, Inger B; Nelissen, Rob G H H; Cannegieter, Suzanne C

2017-02-09

The use of thromboprophylaxis to prevent clinically apparent venous thromboembolism after knee arthroscopy or casting of the lower leg is disputed. We compared the incidence of symptomatic venous thromboembolism after these procedures between patients who received anticoagulant therapy and those who received no anticoagulant therapy. We conducted two parallel, pragmatic, multicenter, randomized, controlled, open-label trials with blinded outcome evaluation: the POT-KAST trial, which included patients undergoing knee arthroscopy, and the POT-CAST trial, which included patients treated with casting of the lower leg. Patients were assigned to receive either a prophylactic dose of low-molecular-weight heparin (for the 8 days after arthroscopy in the POT-KAST trial or during the full period of immobilization due to casting in the POT-CAST trial) or no anticoagulant therapy. The primary outcomes were the cumulative incidences of symptomatic venous thromboembolism and major bleeding within 3 months after the procedure. In the POT-KAST trial, 1543 patients underwent randomization, of whom 1451 were included in the intention-to-treat population. Venous thromboembolism occurred in 5 of the 731 patients (0.7%) in the treatment group and in 3 of the 720 patients (0.4%) in the control group (relative risk, 1.6; 95% confidence interval [CI], 0.4 to 6.8; absolute difference in risk, 0.3 percentage points; 95% CI, -0.6 to 1.2). Major bleeding occurred in 1 patient (0.1%) in the treatment group and in 1 (0.1%) in the control group (absolute difference in risk, 0 percentage points; 95% CI, -0.6 to 0.7). In the POT-CAST trial, 1519 patients underwent randomization, of whom 1435 were included in the intention-to-treat population. Venous thromboembolism occurred in 10 of the 719 patients (1.4%) in the treatment group and in 13 of the 716 patients (1.8%) in the control group (relative risk, 0.8; 95% CI, 0.3 to 1.7; absolute difference in risk, -0.4 percentage points; 95% CI, -1.8 to 1

Crystallization study of amorphous system Fe84-xWxB16 (x = 3;5)

International Nuclear Information System (INIS)

Novakova, A.A.; Sidorova, G.V.; Kiseleva, T.Yu.; Szasz, A.

1992-01-01

A complex study of the crystallization process of the amorphous system was carried out by Moessbauer spectroscopy, X-ray diffraction and DTA. Alloy samples crystallized at 600deg C contain the following phases: α-Fe, Fe 3 B and solid solution (Fe, W) 3 B. (orig.)

Study of high-coercivity sintered NdFeB magnets

International Nuclear Information System (INIS)

Bai, G.; Gao, R.W.; Sun, Y.; Han, G.B.; Wang, B.

2007-01-01

Magnetic powders for sintered NdFeB magnets have been prepared by using an advanced processing method including strip casting, hydrogen decrepitation, jet milling and rubber isotropic press. The effects of Dy, Ga and Co addition on the microstructure and magnetic properties of sintered magnets have been investigated. By adopting a suitable component ratio and adjusting proper technological parameters, we have prepared high-coercivity sintered NdFeB magnets with hard magnetic properties of j H c =25.6 kOe, B r =13.2 kG and (BH) max =39.9 MGOe. The temperature coefficient of coercivity of the magnets (between 20 and 150 deg. C) is -0.53% deg. C. The magnetic properties at high temperature satisfy the needs of permanent magnet motors

The X-ray Telescope of the CAST Experiment

CERN Document Server

Kotthaus, Rainer; Friedrich, P.; Kang, D.; Hartmann, R.; Kuster, M.; Lutz, G.; Strüder, L.

2005-01-01

The CERN Axion Solar Telescope (CAST) searches for solar axions employing a 9 Tesla superconducting dipole magnet equipped with 3 independent detection systems for X-rays from axion-photon conversions inside the 10 m long magnetic field. Results of the first 6 months of data taking in 2003 imply a 95 % CL upper limit on the axion-photon coupling constant of 1.16x10(-10) GeV(-1) for axion masses < 0.02 eV. The most sensitive detector of CAST is a X-ray telescope consisting of a Wolter I type mirror system and a fully depleted pn-CCD as focal plane detector. Exploiting the full potential of background suppression by focussing X-rays emerging from the magnet bore, the axion sensitivity obtained with telescope data taken in 2004, for the first time in a controlled laboratory experiment, will supersede axion constraints derived from stellar energy loss arguments.

Effect of Si on the glass-forming ability, thermal stability and magnetic properties of Fe-Co-Zr-Mo-W-B alloys

Energy Technology Data Exchange (ETDEWEB)

Wang, W.-M. [Institute for Metallic Materials, IFW Dresden, P.O. 270016, Dresden D-01171 (Germany); Key Lab of Liquid Structure and Heredity of Materials, Shandong University, Jinan 250061 (China); Gebert, A. [Institute for Metallic Materials, IFW Dresden, P.O. 270016, Dresden D-01171 (Germany)], E-mail: a.gebert@ifw-dresden.de; Roth, S.; Kuehn, U.; Schultz, L. [Institute for Metallic Materials, IFW Dresden, P.O. 270016, Dresden D-01171 (Germany)

2008-07-14

This paper presents investigations on the effect of Si on the glass-forming ability, thermal stability and magnetic properties of the Fe-Co-Zr-Mo-W-B samples (group I: Fe{sub 60}Co{sub 8}Zr{sub 10}Mo{sub 5}W{sub 2}B{sub 15-x}Si{sub x}, 1 {<=} x {<=} 4; group II: Fe{sub 60}Co{sub 8}Zr{sub 10-x}Mo{sub 5}W{sub 2}B{sub 15}Si{sub x}, 0 {<=} x {<=} 4; group III: Fe{sub 60}Co{sub 8}Zr{sub 8}Mo{sub 5}W{sub 2}B{sub 17-x}Si{sub x}, 0 {<=} x {<=} 2) prepared by melt spinning, injection casting, and centrifugal casting methods. It is found that the glass-forming ability (GFA) of the alloys in group I is more deteriorated than that in group II, and that the alloys in group III can be cast into the rods of 1-3 mm diameter without crystalline reflections in their XRD patterns. For the amorphous ribbons and rods, a non-monotonic change of the nearest neighbour distance r{sub 1} with increasing Si content c{sub Si} was detected, which is parallel to that of the glass transition and crystallization temperatures T{sub g} and T{sub x}, but opposite to that of the magnetization at room temperature M{sub RT} and the Curie temperature T{sub c}. This correlation can be interpreted by a structure model presuming that iron atoms appear simultaneously in two types of local structures in the amorphous samples.

Study of U - Pu - Fe alloys (Masurca critical experiment); Etudes d'alliages U-Pu-Fe (experience critique MASURCA)

Energy Technology Data Exchange (ETDEWEB)

Barthelemy, P; Boucher, R [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1965-07-01

Three compositions have been studied: 73.5 U - 25 Pu - 1.5 Fe (weight %) 74 U - 25 Pu - 1 Fe 74.5 U - 25 Pu - 0.5 Fe Elaboration and Casting are easy. After two weeks in air 74.5 U - 25 Pu - 0.5 Fe alloys are reduced in powder. As-cast alloys containing 1 and 1,5% Fe are kept undamaged during several months. A rapid oxidisation of the alloys is however observed when the samples undergo the phase transformation (at 595 deg. C and 590 deg. C respectively). Ignition tests in the presence of air show that the oxidisation starts at about 250 deg. C and that the reaction does not spread. Ignition is not observed during heating from 20 to 660 deg. C. The transformation temperature, the melting temperature and the thermal expansion coefficients have been determined by dilatometry. Below the transformation temperature, the principal phases are U-Pu zeta and (U, Pu){sub 6}Fe. Thermal conductibility, Young modulus, density and heat of fusion have been measured. Compatibility tests show that between U-Pu-Fe and stainless steel a phase of (U, Pu){sub 6}Fe type is formed. The 74 U - 25 Pu - 1% Fe alloy seems to behave better than 73.5 U - 25 Pu - 1.5% Fe alloy because the (U, Pu){sub 6}Fe layer is two or three times smaller. Finally, the thermal stability has been studied with the 74 U - 25 Pu - 1% Fe alloy. A dilatometric anomaly (very weak expansion) occurs when the sample is heated above transformation temperature and cooled. But there is no anomaly by thermal cycling from 50 deg. C to 400 deg. C and there is no deterioration of alloys by heat treatments at 100 deg. C, 200 deg. C, 300 deg. C during 5 months under vacuum. (authors) [French] Trois compositions ont ete etudiees: 73,5 U - 25 Pu - 1,5 Fe (% ponderaux) 74 U - 25 Pu - 1 Fe 74,5 U - 25 Pu - 0,5 Fe Les elaborations et mises en forme sont-faciles. Les alliages a 0,5% de fer tombent en poudre apres 15 jours d'exposition a l'air. Les alliages a 1 et 1,5% de fer, bruts de coulee, se conservent plusieurs mois. Cependant

Casting thermal simulation

International Nuclear Information System (INIS)

Shamsuddin bin Sulaiman

1994-01-01

The whole of this study is concerned with process simulation in casting processes. This study describes the application of the finite element method as an aid to simulating the thermal design of a high pressure die casting die by analysing the cooling transients in the casting cycle. Two types of investigation were carried out to model the linear and non-linear cooling behavior with consideration of a thermal interface effect. The simulated cooling for different stages were presented in temperature contour form. These illustrate the successful application of the Finite Element Method to model the process and they illustrate the significance of the thermal interface at low pressure

Characterization of microstructure, texture and magnetic properties in twin-roll casting high silicon non-oriented electrical steel

Energy Technology Data Exchange (ETDEWEB)

Li, Hao-Ze; Liu, Hai-Tao, E-mail: liuht@ral.neu.edu.cn; Liu, Zhen-Yu, E-mail: zyliu@mail.neu.edu.cn; Lu, Hui-Hu; Song, Hong-Yu; Wang, Guo-Dong

2014-02-15

An Fe-6.5 wt.% Si-0.3 wt.% Al as-cast sheet was produced by twin-roll strip casting process, then treated with hot rolling, warm rolling and annealing. A detailed study of the microstructure and texture evolution at different processing stages was carried out by optical microscopy, X-ray diffraction and electron backscattered diffraction analysis. The initial as-cast strip showed strong columnar grains and pronounced < 001 >//ND texture. The hot rolled and warm rolled sheets were characterized by large amounts of shear bands distributed through the thickness together with strong < 110 >//RD texture and weak < 111 >//ND texture. After annealing, detrimental < 111 >//ND texture almost disappeared while beneficial (001)<210 >, (001)<010 >, (115)<5 − 10 1 > and (410) < 001 > recrystallization textures were formed, thus the magnetic induction of the annealed sheet was significantly improved. The recrystallization texture in the present study could be explained by preferred nucleation and grain growth mechanism. - Highlights: • A high silicon as-cast strip with columnar structure was produced. • A thin warm rolled sheet without large edge cracks was obtained. • Microstructure and texture evolution at each stage were investigated. • Beneficial (001)<210 >, (001)<010 >, (410)<001 > recrystallization textures were formed. • The magnetic induction of annealed sheet was significantly improved.

Clean Metal Casting; FINAL

International Nuclear Information System (INIS)

Makhlouf M. Makhlouf; Diran Apelian

2002-01-01

The objective of this project is to develop a technology for clean metal processing that is capable of consistently providing a metal cleanliness level that is fit for a given application. The program has five tasks: Development of melt cleanliness assessment technology, development of melt contamination avoidance technology, development of high temperature phase separation technology, establishment of a correlation between the level of melt cleanliness and as cast mechanical properties, and transfer of technology to the industrial sector. Within the context of the first task, WPI has developed a standardized Reduced Pressure Test that has been endorsed by AFS as a recommended practice. In addition, within the context of task1, WPI has developed a melt cleanliness sensor based on the principles of electromagnetic separation. An industrial partner is commercializing the sensor. Within the context of the second task, WPI has developed environmentally friendly fluxes that do not contain fluorine. Within the context of the third task, WPI modeled the process of rotary degassing and verified the model predictions with experimental data. This model may be used to optimize the performance of industrial rotary degassers. Within the context of the fourth task, WPI has correlated the level of melt cleanliness at various foundries, including a sand casting foundry, a permanent mold casting foundry, and a die casting foundry, to the casting process and the resultant mechanical properties. This is useful in tailoring the melt cleansing operations at foundries to the particular casting process and the desired properties of cast components

Mutagenesis and repair of DNA

International Nuclear Information System (INIS)

Janion, C.; Grzesiuk, E.; Fabisiewicz, A.; Tudek, B.; Ciesla, J.; Graziewicz, M.; Wojcik, A.; Speina, E.

1998-01-01

Full text. The discovery that the mfd gene codes for a transcription-coupling repair factor (TRCF) prompted us to re-investigate the MFD (mutation frequency decline) phenomenon in E.coli K-12 strain when mutations were induced by ultraviolet light, halogen light or MMS-treatment. These studies revealed that: (i) the process of MFD involves the proofreading activity of DNA pol III and the mismatch repair system, as well as, TRCF and the UvrABC-excinuclease (ii) a semi-rich plate test may be replaced by a rich liquid medium, (iii) the T-T pyrimidine dimers are the lesions excised with the highest activity, and (iv) overproduction of UmuD(D'C) proteins leads to a great increase in mutant frequency in irradiated and MMS-treated cells. The role of mismatch repair (MR) in MMS-induced mutagenesis is obscured by the fact that the spectra of mutational specificity are different in bacteria proficient and deficient in MR. It has been found that transposons Tn10 (and Tn5) when inserted into chromosomal DNA of E. coli influence the phenotype lowering the survival and frequency of mutations induced by UV or halogen light irradiation. This is connected with a deficiency of UmuD(D') and UmuC proteins. Transformation of bacteria with plasmids bearing the umuD(D')C genes, suppresses the effects of the transposon insertion, a phenomenon which has not been described before. Single-stranded DNA of M13mp18 phage was oxidized in vitro by a hydroxyl radical generating system including hypoxanthine/xanthine oxidase/Fe3+/EDTA, and it was found that Fapy-Ade, Fapy-Gua, 8-oxyAde and thymine glycol were the main products formed. Replication of the oxidized template by T7 phage DNA polymerase, Klenow fragment of polymerase I, or polymerase beta from bovine thymus has revealed that oxidized pyrimidines are stronger blockers than oxidized purines for T7 phage and Klenow fragment polymerases and the blocking potency depends on the neighboring bases and on the type of polymerase. Studies of

Effect of alloying elements on solidification of primary austenite in Ni-Mn-Cu cast iron

Directory of Open Access Journals (Sweden)

A. Janus

2011-04-01

Full Text Available Within the research, determined were direction and intensity of alloying elements influence on solidification way (directional orvolumetric of primary austenite dendrites in hypoeutectic austenitic cast iron Ni-Mn-Cu. 50 cast shafts dia. 20 mm were analysed.Chemical composition of the alloy was as follows: 1.7 to 3.3 % C, 1.4 to 3.1 % Si, 2.8 to 9.9 % Ni, 0.4 to 7.7 % Mn, 0 to 4.6 % Cu, 0.14 to0.16 % P and 0.03 to 0.04 % S. The discriminant analysis revealed that carbon influences solidification of primary austenite dendrites most intensively. It clearly increases the tendency to volumetric solidification. Influence of the other elements is much weaker. This means that the solidification way of primary austenite dendrites in hypoeutectic austenitic cast iron Ni-Mn-Cu does not differ from that in an unalloyed cast iron.

14 CFR 23.621 - Casting factors.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Casting factors. 23.621 Section 23.621... Casting factors. (a) General. The factors, tests, and inspections specified in paragraphs (b) through (d... structural castings except castings that are pressure tested as parts of hydraulic or other fluid systems and...

Hair casts

OpenAIRE

Sweta S Parmar; Kirti S Parmar; Bela J Shah

2014-01-01

Hair casts or pseudonits are circumferential concretions, which cover the hair shaft in such a way that, it could be easily removed. They are thin, cylindrical, and elongated in length. We present an unusual case of an 8-year-old girl presenting with hair casts. Occurrence of these is unusual, and they may have varied associations. This patient was suffering from developmental delay. It is commonly misdiagnosed as and very important to differentiate from pediculosis capitis.

Optimization of excess Bi doping to enhance ferroic orders of spin casted BiFeO{sub 3} thin film

Energy Technology Data Exchange (ETDEWEB)

Gupta, Surbhi; Gupta, Vinay, E-mail: drguptavinay@gmail.com [Department of Physics and Astrophysics, University of Delhi, Delhi (India); Tomar, Monika [Department of Physics, Miranda Housea, University of Delhi, Delhi (India); James, A. R. [Defence Metallurgical Research Laboratory, Hyderabad (India); Pal, Madhuparna; Guo, Ruyan; Bhalla, Amar [Department of Electrical and Computer Engineering, College of Engineering, University of Texas at SanAntonio, San Antonio 78249 (United States)

2014-06-21

Multiferroic Bismuth Ferrite (BiFeO{sub 3}) thin films with varying excess bismuth (Bi) concentration were grown by chemical solution deposition technique. Room temperature multiferroic properties (ferromagnetism, ferroelectricity, and piezoelectricity) of the deposited BiFeO{sub 3} thin films have been studied. High resolution X-ray diffraction and Raman spectroscopy studies reveal that the dominant phases formed in the prepared samples change continuously from a mixture of BiFeO{sub 3} and Fe{sub 2}O{sub 3} to pure BiFeO{sub 3} phase and, subsequently, to a mixture of BiFeO{sub 3} and Bi{sub 2}O{sub 3} with increase in the concentration of excess Bi from 0% to 15%. BiFeO{sub 3} thin films having low content (0% and 2%) of excess Bi showed the traces of ferromagnetic phase (γ-Fe{sub 2}O{sub 3}). Deterioration in ferroic properties of BiFeO{sub 3} thin films is also observed when prepared with higher content (15%) of excess Bi. Single-phased BiFeO{sub 3} thin film prepared with 5% excess Bi concentration exhibited the soft ferromagnetic hysteresis loops and ferroelectric characteristics with remnant polarization 4.2 μC/cm{sup 2} and saturation magnetization 11.66 emu/g. The switching of fine spontaneous domains with applied dc bias has been observed using piezoresponse force microscopy in BiFeO{sub 3} thin films having 5% excess Bi. The results are important to identify optimum excess Bi concentration needed for the formation of single phase BiFeO{sub 3} thin films exhibiting the improved multiferroic properties.

HFIR Fuel Casting Support

Energy Technology Data Exchange (ETDEWEB)

Imhoff, Seth D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gibbs, Paul Jacob [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Solis, Eunice Martinez [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-09-28

Process exploration for fuel production for the High Flux Isotope Reactor (HFIR) using cast LEU-10wt.%Mo as an initial processing step has just begun. This project represents the first trials concerned with casting design and quality. The studies carried out over the course of this year and information contained in this report address the initial mold development to be used as a starting point for future operations. In broad terms, the final billet design is that of a solid rolling blank with an irregular octagonal cross section. The work covered here is a comprehensive view of the initial attempts to produce a sound casting. This report covers the efforts to simulate, predict, cast, inspect, and revise the initial mold design.

Characterization of Low-Symmetry Structures from Phase Equilibrium of Fe-Al System—Microstructures and Mechanical Properties

Directory of Open Access Journals (Sweden)

Piotr Matysik

2015-03-01

Full Text Available Fe-Al intermetallic alloys with aluminum content over 60 at% are in the area of the phase equilibrium diagram that is considerably less investigated in comparison to the high-symmetry Fe3Al and FeAl phases. Ambiguous crystallographic information and incoherent data referring to the phase equilibrium diagrams placed in a high-aluminum range have caused confusions and misinformation. Nowadays unequivocal material properties description of FeAl2, Fe2Al5 and FeAl3 intermetallic alloys is still incomplete. In this paper, the influence of aluminum content and processing parameters on phase composition is presented. The occurrence of low-symmetry FeAl2, Fe2Al5 and FeAl3 structures determined by chemical composition and phase transformations was defined by scanning electron microscopy (SEM and energy-dispersive X-ray spectroscopy (EDS examinations. These results served to verify diffraction investigations (XRD and to explain the mechanical properties of cast materials such as: hardness, Young’s modulus and fracture toughness evaluated using the nano-indentation technique.

Sixty Years of Casting Research

Science.gov (United States)

Campbell, John

2015-11-01

The 60 years of solidification research since the publication of Chalmer's constitutional undercooling in 1953 has been a dramatic advance of understanding which has and continues to be an inspiration. In contrast, 60 years of casting research has seen mixed fortunes. One of its success stories relates to improvements in inoculation of gray irons, and another to the discovery of spheroidal graphite iron, although both of these can be classified as metallurgical rather than casting advances. It is suggested that true casting advances have dated from the author's lab in 1992 when a critical surface turbulence condition was defined for the first time. These last 20 years have seen the surface entrainment issues of castings developed to a sufficient sophistication to revolutionize the performance of light alloy and steel foundries. However, there is still a long way to go, with large sections of the steel and Ni-base casting industries still in denial that casting defects are important or even exist. The result has been that special ingots are still cast poorly, and shaped casting operations have suffered massive losses. For secondary melted and cast materials, electro-slag remelting has the potential to be much superior to expensive vacuum arc remelting, which has cost our aerospace and defense industries dearly over the years. This failure to address and upgrade our processing of liquid metals is a serious concern, since the principle entrainment defect, the bifilm, is seen as the principle initiator of cracks in metals; in general, bifilms are the Griffith cracks that initiate failures by cracking. A new generation of crack resistant metals and engineering structures can now be envisaged.

The analysis of composite properties reinforced with particles from palm oil industry waste produced by casting methods

Science.gov (United States)

Tugiman; Ariani, F.; Taher, F.; Hasibuan, M. S.; Suprianto

2017-12-01

Palm oil processing industries are very attractive because they offer plenty products with high economic value. The CPO factory processes not only produces crude palm oil but also generates fly ash (FA) particles waste in its final process. The purpose of this investigation to analyze and increase the benefits of particles as reinforcement materials for fabricating aluminum matrix composites (AMC’s) by different casting route. Stirring, centrifugal and squeeze casting method was conducted in this study. Further, the chemical composition of FA particles, densities and mechanical properties have been analyzed. The characteristics of composite material were investigated using an Optical microscope, scanning electron microscope (SEM), hardness (Brinell), impact strength (Charpy). The pin on disc method was used to measure the wear rate. The results show that SiO2, Fe2O3, and Al2O3 are the main compounds of fly ash particles. These particles enhanced the hardness and reduce wear resistance of aluminum matrix composites. The squeeze method gives better results than stir and centrifugal casting.

Engineering design of centrifugal casting machine

Science.gov (United States)

Kusnowo, Roni; Gunara, Sophiadi

2017-06-01

Centrifugal casting is a metal casting process in which metal liquid is poured into a rotating mold at a specific temperature. Given round will generate a centrifugal force that will affect the outcome of the casting. Casting method is suitable in the manufacture of the casting cylinder to obtain better results. This research was performed to design a prototype machine by using the concept of centrifugal casting. The design method was a step-by-step systematic approach in the process of thinking to achieve the desired goal of realizing the idea and build bridges between idea and the product. Design process was commenced by the conceptual design phase and followed by the embodiment design stage and detailed design stage. With an engineering design process based on the method developed by G. E. Dieter, draft prototype of centrifugal casting machine with dimension of 550×450×400 mm, ¼ HP motor power, pulley and belt mechanism, diameter of 120-150mm, simultaneously with the characteristics of simple casting product, easy manufacture and maintenance, and relatively inexpensive, was generated.

MFM of nanocrystalline NdFeB: a study of the effect of processing route on the micromagnetic structure

Science.gov (United States)

Al-Khafaji, M. A.; Marashi, S. P. H.; Rainforth, W. M.; Gibbs, M. R. J.; Davies, H. A.; Bishop, J. E. L.; Heydon, G.

1998-12-01

The magnetic domain structure of near stoichiometric (Nd 11.8Fe 82.3B 5.9) nanocrystalline alloy ribbon has been examined using magnetic force microscopy (MFM) as a function of processing conditions. Amorphous structured ribbons of Nd 2Fe 14B with an average thickness of 25 μm were produced by chill block melt-spinning. Subsequently, samples were heat treated at 600°C for 4 min to produce a nanocrystalline structure consisting of Nd 2Fe 14B grains of average size ˜35 nm. These were compared to ribbons of the same composition, but melt spun directly to the nanocrystalline state, also with an average grain size of ˜35 nm. MFM imaging was undertaken using CoCr, NiFe and Fe/SiO 2 coated pyramidal Si tips. The as-cast amorphous ribbons exhibited weak magnetic contrast with a correlation length of 130±20 nm, but with a small elongation in one direction, as shown by Fourier transforms of the MFM images. Nanocrystalline samples produced by devitrification exhibited longer correlation lengths of 1000±50 nm and with a stronger angular component to the Fourier transform. The application of a 5 T field to the nanophase sample in a direction normal to the sample plane resulted in a reduction of the correlation length to 600±50 nm and a reduction in the directionality of the magnetic contrast. However, the application of a 5 T field in the plane of the ribbon resulted in an elongation of the contrast in a direction parallel to the applied field, irrespective of the in-plane field direction. In contrast, ribbon melt spun directly to a nanocrystalline structure exhibited a uniform Fourier transform both in the as-cast and remanent states. The length scale of dominant magnetic structure was 350±30 nm for the as-cast and 620±30 nm for the remanent state. Within the dominant magnetic structure, a finer structure was apparent, of a scale comparable to the grain size.

Clean Cast Steel Technology, Phase IV

Energy Technology Data Exchange (ETDEWEB)

Charles E. Bates

2003-02-24

The objective of the Clean Cast Steel Technology Program was to improve casting product quality by removing or minimizing oxide defects and to allow the production of higher integrity castings for high speed machining lines. Previous research has concentrated on macro-inclusions that break, chip, or crack machine tool cutters and drills and cause immediate shutdown of the machining lines. The overall goal of the project is to reduce the amount of surface macro-inclusions and improve the machinability of steel castings. Macro-inclusions and improve the machinability of steel castings. Macro-inclusions have been identified by industrial sponsors as a major barrier to improving the quality and marketability of steel castings.

Surface dosimetry for breast radiotherapy in the presence of immobilization cast material

International Nuclear Information System (INIS)

Kelly, Andrew; Hardcastle, Nicholas; Metcalfe, Peter; Cutajar, Dean; Quinn, Alexandra; Cardoso, Michael; Rosenfeld, Anatoly; Foo, Kerwyn; Barlin, Sheree

2011-01-01

Curative breast radiotherapy typically leaves patients with varying degrees of cosmetic damage. One problem interfering with cosmetically acceptable breast radiotherapy is the external contour for large pendulous breasts which often results in high doses to skin folds. Thermoplastic casts are often employed to secure the breasts to maintain setup reproducibility and limit the presence of skin folds. This paper aims to determine changes in surface dose that can be attributed to the use of thermoplastic immobilization casts. Skin dose for a clinical hybrid conformal/IMRT breast plan was measured using radiochromic film and MOSFET detectors at a range of water equivalent depths representative of the different skin layers. The radiochromic film was used as an integrating dosimeter, while the MOSFETs were used for real-time dosimetry to isolate the contribution of skin dose from individual IMRT segments. Strips of film were placed at various locations on the breast and the MOSFETs were used to measure skin dose at 16 positions spaced along the film strips for comparison of data. The results showed an increase in skin dose in the presence of the immobilization cast of up to 45.7% and 62.3% of the skin dose without the immobilization cast present as measured with Gafchromic EBT film and MOSFETs, respectively. The increase in skin dose due to the immobilization cast varied with the angle of beam incidence and was greatest when the beam was normally incident on the phantom. The increase in surface dose with the immobilization cast was greater under entrance dose conditions compared to exit dose conditions.

Surface dosimetry for breast radiotherapy in the presence of immobilization cast material

Science.gov (United States)

Kelly, Andrew; Hardcastle, Nicholas; Metcalfe, Peter; Cutajar, Dean; Quinn, Alexandra; Foo, Kerwyn; Cardoso, Michael; Barlin, Sheree; Rosenfeld, Anatoly

2011-02-01

Curative breast radiotherapy typically leaves patients with varying degrees of cosmetic damage. One problem interfering with cosmetically acceptable breast radiotherapy is the external contour for large pendulous breasts which often results in high doses to skin folds. Thermoplastic casts are often employed to secure the breasts to maintain setup reproducibility and limit the presence of skin folds. This paper aims to determine changes in surface dose that can be attributed to the use of thermoplastic immobilization casts. Skin dose for a clinical hybrid conformal/IMRT breast plan was measured using radiochromic film and MOSFET detectors at a range of water equivalent depths representative of the different skin layers. The radiochromic film was used as an integrating dosimeter, while the MOSFETs were used for real-time dosimetry to isolate the contribution of skin dose from individual IMRT segments. Strips of film were placed at various locations on the breast and the MOSFETs were used to measure skin dose at 16 positions spaced along the film strips for comparison of data. The results showed an increase in skin dose in the presence of the immobilization cast of up to 45.7% and 62.3% of the skin dose without the immobilization cast present as measured with Gafchromic EBT film and MOSFETs, respectively. The increase in skin dose due to the immobilization cast varied with the angle of beam incidence and was greatest when the beam was normally incident on the phantom. The increase in surface dose with the immobilization cast was greater under entrance dose conditions compared to exit dose conditions.

Trends in the Production of Castings in the World and in Poland in the XXI Century

Directory of Open Access Journals (Sweden)

Soiński M.S.

2016-06-01

Full Text Available The paper presents data concerning the total production of castings over the 2000-2014 period, both on a global scale, and in Poland. The basic types of casting alloys were taken into account. Changes in the production volume and structure over the period of the analysed 15 years were pointed out with respect to countries leading in foundry production. The topmost position in the world foundry industry is held by China for several years (with almost 45% share in the foundry market, the second place is taken by India (with almost 9% share. A distinct reduction in the shares of the once significant producers of castings, such as USA, Japan, Germany, Russia, Italy, or France, was observed over the 2000-2014 period. Poland had a share of 1.16% in 2000, and of 1.02% in 2014. Comparing the detailed data concerning the years 2000 and 2014, one can see that the fractions of castings made of ductile iron, cast steel, aluminium alloys, or magnesium alloys increase on a global scale, while such alloys as grey cast iron or malleable are in decline.

Cast thermally stable high temperature nickel-base alloys and casting made therefrom

International Nuclear Information System (INIS)

Acuncius, D.A.; Herchenroeder, R.B.; Kirchner, R.W.; Silence, W.L.

1977-01-01

A cast thermally stable high temperature nickel-base alloy characterized by superior oxidation resistance, sustainable hot strength and retention of ductility on aging is provided by maintaining the alloy chemistry within the composition molybdenum 13.7% to 15.5%; chromium 14.7% to 16.5%; carbon up to 0.1%, lanthanum in an effective amount to provide oxidation resistance up to 0.08%; boron up to 0.015%; manganese 0.3% to 1.0%; silicon 0.2% to 0.8%; cobalt up to 2.0%; iron up to 3.0%; tungsten up to 1.0%; copper up to 0.4%; phosphorous up to 0.02%; sulfur up to 0.015%; aluminum 0.1% to 0.5% and the balance nickel while maintaining the Nv number less than 2.31

Microstructure and mechanical properties of Al/Fe-aluminide in-situ composite prepared by reactive stir casting route

International Nuclear Information System (INIS)

Chatterjee, Subhranshu; Sinha, Arijit; Das, Debdulal; Ghosh, Sumit; Basumallick, Amitava

2013-01-01

Iron aluminide particulate reinforced aluminium composites were prepared by a simple liquid metal stir casting route. The particulate intermetallic reinforcements were formed by in-situ reaction between molten aluminium and a rotating mild steel stirrer at 800 °C. X-ray diffraction studies were carried out to identify the types of iron aluminide particulates present in the as cast composite. Compositional variations of the composite samples were estimated with the aid of energy dispersive spectroscopy. The microstructural features of the composite were studied with respect to different heat treatment schedules and deformation conditions. Microhardness and nanoindentation measurements were also carried out to assess the micromechanical behaviour e.g., hardness and elastic modulus in micrometric length scale of the composite samples. Tensile tests and fractographic analysis were performed to estimate the mechanical properties and determine the mode of failure of the samples. The microstructure and mechanical properties of the composite samples were correlated and discussed

Studies of structural and magnetic properties of glass-coated nanocrystalline Fe79Hf7B12Si2 microwires

International Nuclear Information System (INIS)

Garcia, C.; Zhukov, A.; Gonzalez, J.; Zhukova, V.; Varga, R.; Val, J.J. del; Larin, V.; Blanco, J.M.

2006-01-01

In the present work we deal with the fabrication of thin of Fe 79 Hf 7 B 12 Si 2 (low Si content) glass-coated microwire with a nanocrystalline structure and structural and coercivity characterization of such samples which can be considered as a new family of these nanocrystalline materials. Pieces of 10 cm of this microwire were annealed (300-600 deg. C during 1 h). The structural characteristics of the as-cast and annealed samples were determined, at room temperature, by X-ray diffraction (XRD) technique. XRD measurements allow to obtain the evolution of the grain size (15-35 nm) and relative volume fraction (5-60%) of the nanograins as a function of he annealing temperature in the annealed samples. Coercive field (H c ) of the as-cast and annealed samples has been evaluated from the hysteresis loop of the samples obtained by a conventional induction method at 100 Hz. Thermal dependence H c is quite similar to that reported in other nanocrystalline Fe-based alloys. It slightly decreases from the as-cast state (relaxation process) showing small maximum at around 700 K (pre-nucleation of nanograins) decreasing significantly between 773-873 K (exchange coupling of the nanograins)

Magnetic and thermal behaviour of the amorphous ferromagnet Fe79B16Si5

International Nuclear Information System (INIS)

Shaisha, E.E.; Bahgat, A.A.

1985-01-01

Spin waves in the amorphous ferromagnet Fe 79 B 16 Si 5 are studied by Moessbauer effect spectroscopy. The magnetic hyperfine field (MHF) is measured at the Fe sites of such a ferromagnet, which exhibits a temperature dependence of the form, H(T)/H(0) = (1 - BT/sup 3/2/ - CT/sup 5/2/), indicative of spin wave excitations in amorphous ferromagnets. The T/sup 3/2/ behaviour and the distribution of the exchange interactions are studied in detail as a function of the MHF. The spin wave excitations constant B/sub 3/2/ = BT/sub C//sup 3/2/ = 0.3 +- 0.05 and C/sub 5/2/ = CT/sub C//sup 5/2/ = 0.3 +- 0.05,Are obtained by fitting the experimental data, and where T/sub C/ = 670 K. The results sh=ow that the contribution of C/sub 5/2/ is extremely effective above 124 K, while the ratio C/sub 5/2//C/sub 3/2/ = 1.0 indicates that the present magnetic interaction is of long range order character. On the other hand, fluctuations of the exchange interaction constant are found to decrease with increasing temperature. Some information regarding the directions of the magnetic moments are obtained during the study of the magnetic anisotropy course. The values of the Einstein and Debye temperatures as measured from the thermal shift results are theta/sub E/ = 250 K and theta/sub D/ = 350 K,And from the Moessbauer factor measurements theta/sub E/ = 165 K and theta/sub D/ = 285 K. (autho=r)

Mechanical behaviour of Nd-Fe-B alloys in the semi-solid state

International Nuclear Information System (INIS)

Oliveira, I.L.; Sinka, V.; Ferrante, M.

1996-01-01

Two alloys with composition Nd 17.6 Fe 75.3 B1.2 Cu 5.9 and Nd 15.9 Fe 77.7 B 5 Cu 1.4 were vacuum induction melted and cast into cylindrical ingots. Samples with 12.3 and 13 mm diameter were deformed with different rates and deformation ratios. One alloy was deformed at 800 deg C between two parallel disks under constant load. Results show that these alloys behave as no-Newtonian fluids. This fact gives a better understanding of both magnetic and crystallographic texture development. Also, changes were detected in the behaviour of semisolid in the course of deformation. (author)

Water physical and chemical data from current meter and bottle casts from the H.J.W. FAY and other platforms as part of the Ocean Continental Shelf - Mid Atlantic (OCS - Mid Atlantic) project, 1977-05-16 to 1977-09-15 (NODC Accession 7800386)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Water physical and chemical data were collected using current meter and bottle casts from the H.J.W. FAY and other platforms from May 16, 1977 to September 15, 1977....

Relationship between casting modulus and grain size in cast A356 aluminium alloys

International Nuclear Information System (INIS)

Niklas, A; Abaunza, U; Fernández-Calvo, A I; Lacaze, J

2012-01-01

Microstructure of Al-Si alloy castings depends most generally on melt preparation and on the cooling rate imposed by the thermal modulus of the component. In the case of Al-Si alloys, emphasis is put during melt preparation on refinement of pro-eutectic (Al) grains and on modification of the Al-Si eutectic. Thermal analysis has been used since long to check melt preparation before casting, i.e. by analysis of the cooling curve during solidification of a sample cast in an instrumented cup. The conclusions drawn from such analysis are however valid for the particular cooling conditions of the cups. It thus appeared of interest to investigate how these conclusions could extrapolate to predict microstructure in complicated cast parts showing local changes in the solidification conditions. For that purpose, thermal analysis cups and instrumented sand and die castings with different thermal moduli and thus cooling rates have been made, and the whole set of cooling curves thus recorded has been analysed. A statistical analysis of the characteristic features of the cooling curves related to grain refinement in sand and die castings allowed determining the most significant parameters and expressing the cube of grain size as a polynomial of these parameters. After introduction of a further parameter quantifying melt refining an excellent correlation, with a R 2 factor of 0.99 was obtained.

Comparison of residual stresses in sand- and chill casting of ductile cast iron wind turbine main shafts

International Nuclear Information System (INIS)

Sonne, M R; Hattel, J H; Frandsen, J O

2015-01-01

In this work, simulations of pouring, solidification and cooling, and residual stress evolution of sand and chill cast wind turbine main shafts is performed. The models are made in the commercial software MAGMAsoft. As expected, the cooling rate of the sand casting is shown to be much lower than for the chill casting, resulting in a very course microstructure. From the simulations the nodule count is found to be 17 nodules per mm 2 and 159 nodules per mm 2 for the sand and chill casting, respectively, in the critical region of the main bearing seat. This is verified from nodule counts performed on the real cast main shafts. Residual stress evaluations show an overall increase of the maximum principal stress field for the chill casting, which is expected. However, the stresses are found to be in compression on the surface of the chill cast main shaft, which is unforeseen. (paper)

Comparison of residual stresses in sand- and chill casting of ductile cast iron wind turbine main shafts

DEFF Research Database (Denmark)

Sonne, Mads Rostgaard; Frandsen, J. O.; Hattel, Jesper Henri

2015-01-01

In this work, simulations of pouring, solidification and cooling, and residual stress evolution of sand and chill cast wind turbine main shafts is performed. The models are made in the commercial software MAGMAsoft. As expected, the cooling rate of the sand casting is shown to be much lower than...... for the chill casting, resulting in a very course microstructure.From the simulations the nodule count is found to be 17 nodules per mm2 and 159 nodules permm2 for the sand and chill casting, respectively, in the critical region of the main bearing seat.This is verified from nodule counts performed on the real...... cast main shafts. Residual stressevaluations show an overall increase of the maximum principal stress field for the chill casting,which is expected. However, the stresses are found to be in compression on the surface of thechill cast main shaft, which is unforeseen....

Microstructural effects of phosphorus on pressure die cast Al-12Si components

Directory of Open Access Journals (Sweden)

Suárez-Peña, B.

2007-10-01

Full Text Available The refinement of cuboidal silicon in eutectic Al-Si alloys by phosphorus additions used to manufacture pressure die cast components was studied. The results show that the addition of phosphorus in the form of AlFeP mother alloy before process degassing, leads to the best refinement of the size of the Si-cuboids phase, among several phosphorus additions analysed in the present research.

Se ha estudiado el afino del silicio cuboidal en aleaciones eutécticas Al-Si por acción del fósforo, en piezas obtenidas mediante la técnica de fundición a presión. Tras la adición de fósforo en pruebas industriales, en las que dicho elemento se incorpora al baño con diversas composiciones, los mejores resultados se obtienen con la adición de la aleación madre AlFeP, previa al desgasificado industrial.

Optimizing the Gating System for Steel Castings

Directory of Open Access Journals (Sweden)

Jan Jezierski

2018-04-01

Full Text Available The article presents the attempt to optimize a gating system to produce cast steel castings. It is based on John Campbell’s theory and presents the original results of computer modelling of typical and optimized gating systems for cast steel castings. The current state-of-the-art in cast steel casting foundry was compared with several proposals of optimization. The aim was to find a compromise between the best, theoretically proven gating system version, and a version that would be affordable in industrial conditions. The results show that it is possible to achieve a uniform and slow pouring process even for heavy castings to preserve their internal quality.

Wear resistance of cast iron

Directory of Open Access Journals (Sweden)

S. Pietrowski

2008-10-01

Full Text Available In this paper investigations of abrasive and adhesive wear resistance of different cast iron grades have been presented. Examinations showed, that the most advantageous pair of materials is the cast iron – the hardened steel with low-tempered martensite. It was found, that martensitic nodular cast iron with carbides is the most resistant material.

National Metal Casting Research Institute final report. Volume 2, Die casting research

Energy Technology Data Exchange (ETDEWEB)

Jensen, D. [University of Northern Iowa, Cedar Falls, IA (United States). Dept. of Industrial Technology] [comp.

1994-06-01

Four subprojects were completed: development and evaluation of die coatings, accelerated die life characterization of die materials, evaluation of fluid flow and solidification modeling programs, selection and characterization of Al-based die casting alloys, and influence of die materials and coatings on die casting quality.

Study of the influence of the temperature in the magnetic properties and in microstructure in the permanent magnets Pr-Fe-B-Nb-Co based obtained by hydrogen; Estudo da influencia da temperatura nas propriedades magneticas e na microestrutura nos imas permanentes a base de Pr-Fe-B-Nb-Co obtidos com hidrogenio

Energy Technology Data Exchange (ETDEWEB)

Silva, Suelanny Carvalho da

2007-07-01

Fine magnetic powders were produced using the hydrogenation disproportionation desorption and recombination (HDDR) process. The first stage in this work involved an investigation of the effect of the Co content and range of desorption/ recombination temperatures between 800 and 900 deg C with the purpose of optimizing the HDDR treatment for Pr{sub 14}Fe{sub 80}B{sub 6} and Pr{sub 14}Fe{sub bal}Co{sub x}B{sub 6}Nb{sub 0,1} (x= 0, 4, 8, 10, 12, 16) alloys. The cast alloys were annealed at 1100 deg C for 20 hours for homogenization. The processing temperature (desorption/ recombination) affected the microstructure and magnetic properties of the bonded magnets. The alloy with low cobalt content (4 at.%) required the highest reaction temperature (880 deg C) to yield anisotropic bonded magnets. The optimum temperature for alloys with 8 at.% Co and 10 at.% Co were 840 deg C and 820 deg C, respectively. Alloys with high cobalt content (12 at.% and 16 at.%) were processed at 840 deg C. The optimum desorption temperature for achieving high anisotropy for Pr{sub 14}Fe{sub 80}B{sub 6} and Pr{sub 14}Fe{sub 79,9}B{sub 6}Nb{sub 0,1} was 820 deg C. The best remanence (862 mT) was achieved with the Pr{sub 14}Fe{sub 67,9}B{sub 6}Co{sub 12}Nb{sub 0,1} magnet, processed at 840 deg C. Each alloy required an optimum reaction temperature and exhibited a particular microstructure according to the composition. The second stage of the work involved the characterization, for each temperature, of the Pr{sub 14}Fe{sub 80}B{sub 6} HDDR powder processed using X-ray diffraction analysis. The samples of the HDDR material were studied by synchrotron radiation powder diffraction using the Rietveld method for cell refinement, phase quantification and crystallite sizes determination. Scanning electron microscopy has also been employed to reveal the morphology of the HDDR powder. (author)

DEVELOPMENT OF A CAST STONE FORMULATION FOR HANFORD TANK WASTES

International Nuclear Information System (INIS)

COOKE; ATTERIDGE; AVILA

2005-01-01

The U.S. Department of Energy (DOE) Hanford Site, the location of plutonium production for the US. nuclear weapons program, is the focal point of a broad range of waste remediation efforts. This presentation will describe a test program to develop a ''cast stoney'' formulation for the stabilization of certain Hanford tank wastes (Lockrem 2005). The program consisted of (1) a short series of tests with nonradioactive simulant to select preferred dry reagent formulations (DRF) and determine allowable liquid addition levels, (2) waste form performance testing on cast stone made from the DRF formulations using low-activity waste (LAW) simulant, (3) waste form performance testing on cast stone made from the preferred DRF using LAW, (4) waste form validation testing on a selected nominal cast stone formulation using the preferred DRF and LAW simulant, and (5) technetium ''getter'' testing with cast stone made with LAW simulant and with LAW. In addition, nitrate leaching observations were drawn from nitrate leachability data obtained in the course of waste form performance testing. The nitrate leachability index results are presented along with data on other performance criteria The results of this study led to the selection of a specific DRF. The key attributes of the DRF/waste loading combination considered were presence of ''bleed'' (or free) water, volume change on curing, compressive strength, maximum curing temperature, toxicity characteristic leaching testing, ANSYANS-16.1 (Measurement of the Leachability of Solidified Low-Level Radioactive Wastes by a Short-Term Test Procedure) leachability, and hydraulic conductivity. Important considerations included that the monoliths could be produced using readily available, low-cost reagents. The key results from each of these testing and evaluation activity categories will be summarized

Materials for Advanced Ultrasupercritical Steam Turbines Task 4: Cast Superalloy Development

Energy Technology Data Exchange (ETDEWEB)

Thangirala, Mani

2015-09-30

validated with solidification simulation analysis and the casting met NDT inspection and acceptance criteria. Heat treated and sectioned to extract trepan samples at different locations comparing with cast on coupons test data. Material properties requisite for design, such as tensile, creep/rupture, LCF, Fracture Toughness, Charpy V-notch chemical analysis testing were carried out. The test results will be presented in the final report. The typical Haynes 282 large size Steam Turbine production casting from Order to Delivery foundry schedule with the activity break up is shown in Figures 107 and 108. • From Purchase Order placement to Casting pouring ~ 26 weeks. 1. Sales and commercial review 3 2. Engineering Drawings/models review 4 3. Pattern and core box manufacturing 6 4. Casting process engineering review 4 5. FEM and solidification simulation analysis 4 6. Gating & Feeder Attachments, Ceramic tiling 2 7. Molding and coremaking production scheduling 6 8. Melting planning and schedule 3 9. Pouring, cooling and shake out 2 • From Pouring to casting Delivery ~ 29 weeks 10. Shot blast and riser cutting, gates removal 3 11. Homogenizing , solutionizing HT furnace prep 4 12. Grinding, Fettling 2 13. Aging HT Cycle, cooling 2 14. VT and LPT NDT inspections 2 15. Radiographic inspection 4 16. Mechanical testing, Chemical analysis test certs 4 17. Casting weld repair upgrades and Aging PWHT 4 18. NDT after weld repairs and casting upgrades 3 19. Casting Final Inspection and test certifications 3 20. Package and delivery 2 Hence the Total Lead time from P.O to Casting delivery is approximately 55 weeks. The Task 4.2 and Task 4.3 activities and reporting completed.

[Cohort study of the incidence of heel pressure sores in patients with leg casts at the Rizzoli Orthopedic Hospital and of the associated risk factors].

Science.gov (United States)

Forni, Cristiana; Zoli, Marina; Loro, Loretta; Tremosini, Morena; Mini, Sandra; Pirini, Valter; Turrini, Roberta; Durante, Stefano; Nicolini, Annamaria; Riccioni, Francesca; Girolami, Roberto

2009-01-01

Pressure sores, especially at the heel, are a side effect of the cast. To assess the incidence of late skin complications (heel pressure sores) of a cast and determine risk factors. All consecutive patients treated with a leg cast over a 16 months observation time were recruited. Risk factors were identified by the nurse that placed the cast and skin lesions classified with the NPUAP scale when the cast was removed. In the 216 enrolled patients 17.6% (38) developed a pressure sore: 16/124 in orthopedic wards; 22/92 in oncology wards. The multivariate analysis identified the following risk factors: administration of cytotoxic drugs (p = 0.033; OR = 2.61; having a cancer did not increase the risk); skin redness before cast application (p = 0.001; OR = 4.44) and having reported symptoms after the application (p = 0.000; OR = 7.86). Pressure sores were mainly stage 1 and only 6/216 (2.4%) > or = stage II. The type of plaster cast, the material, the number of days it was worn and having had a surgery are not significant risk factors. Pressure sores related to leg plaster casts are a frequent complication in at risk sub-groups. The acknowledgement and identification of specific risk factors may allow to identify and evaluate preventive interventions to improve the care of these patients.

The evaluation of working casts prepared from digital impressions.

Science.gov (United States)

Hwang, Y C; Park, Y S; Kim, H K; Hong, Y S; Ahn, J S; Ryu, J J

2013-01-01

The aim of this study is to evaluate the reproducibility of working casts of a digital impression system by comparing them with the original, virtual, and rapid prototyping casts. A total of 54 cast sets in clinically stable occlusion were used. They were scanned by an iTero intraoral scanner and converted into STL format virtual casts. Rapid prototyping casts and polyurethane casts were fabricated from the iTero milling system based on the virtual casts. Several horizontal and vertical measurements were performed from the four types of casts, that is, original stone casts, virtual casts, rapid prototyping casts, and polyurethane casts of iTero. Measurement error, intraclass correlation coefficient (ICC), and differences among the casts were calculated and compared. Casts from iTero milling machines exhibited greater dimensional differences and lower ICC values than did other casts. In addition, many of the measurements of the iTero working casts showed statistically significant differences in comparison to the three other types of casts. In contrast, there were no statistically significant differences between the virtual and original casts. Virtual casts made by the iTero intraoral scanner exhibited excellent reproducibility. However, the casts from the iTero milling machine showed greater dimensional differences and lower reproducibility compared to other types of casts.

Improved polycrystalline Ni{sub 54}Mn{sub 16}Fe{sub 9}Ga{sub 21} high-temperature shape memory alloy by γ phase distributing along grain boundaries

Energy Technology Data Exchange (ETDEWEB)

Yang, Shuiyuan; Zhang, Fan; Zhang, Kaixin; Huang, Yangyang; Wang, Cuiping; Liu, Xingjun [Xiamen Univ. (China). Fujian Key Laboratory of Materials Genome

2016-09-15

In this study, the shape recovery and mechanical properties of Ni{sub 54}Mn{sub 16}Fe{sub 9}Ga{sub 21} high-temperature shape memory alloy are improved simultaneously. This results from the low, about 4.4%, volume fraction of γ phase being almost completely distributed along grain boundaries. The recovery strain gradually increases with the increase in residual strain with a shape recovery rate of above 68%, up to a maximum value of 5.3%. The compressive fracture strain of Ni{sub 54}Mn{sub 16}Fe{sub 9}Ga{sub 21} alloy is about 35%. The results further reveal that when applying a high compression deformation two types of cracks form and propagate either within martensite grains (type I) or along the boundaries between martensite phase and γ phase (type II) in the present two-phase alloy.

Temperature and microstructure characteristics of silumin casting AlSi9 made with investment casting method

Directory of Open Access Journals (Sweden)

S. Pietrowski

2011-07-01

Full Text Available This work presents the research result of the temperature distribution and the microstructure in certain parts of the field-glass body frame casting made from silumin AlSi9 using the investment casting method in the ceramic mould. It was proved that the highest temperature of the silumin appears in the sprue in which the silumin is in the liquid-solid state, though the process of silumin crystallization in the casting is finished. It was stated that in certain elements of the casting the side opposite to the runner crystallizes and cools fastest. The differences in the rate of crystalline growth and cooling of certain casting elements cause differ- ent microstructure in them which can also influence the mechanic properties.It is necessary to state that the temperature of the initial heating of the ceramic mold equal to 60oC guarantees obtaining of the castings without defects and of little porosity. Incomplete modification of the silumin with strontium causes silica precipitation to appear close to the spherical ones.

Photophysical Studies of Spin Cast Polymer Films

Science.gov (United States)

1988-07-13

Polymeric Materials contained research presentations on fundamental radiation chemistry and physics as well as on technological applications of polymer ...on Polymeric Materials," X~os Hoos. ueensland. Australia., August 16-19, 1987 ,7 COSAII CODES I&. SUBJECT TEAMS (Conuo an itwre it r~,*Ctzy Mid od@0ty...by biOck mumblrJ _ILO GR UP SU8 -GaOUP 9. AaSTkRAC7T (COn1nue an r*"wne it noatamey and iwaf by bWok nuffltr) Snim casting is a commonly used technique

Development of NdFeB magnet through hydrogen decrepitation

International Nuclear Information System (INIS)

Akhtar, S.; Farooque, M.; Haider, A.; Ahmad, Z.

2009-01-01

Neodymium based magnets are the powerful permanent magnet of today. This paper will discuss iron based rare earth magnets. NdFeB sintered magnet material has been developed. The magnets are produced by powder metallurgy route involving hydrogen decrepitation technique for making fine powder. After melting and casting, the NdFeB alloy is subject to hydrogen atmosphere. Hydrogen slowly absorbs into the solid alloy and makes it brittle, which upon milling becomes fine powder. Hydrogen is then removed by placing the powder at temperature around 800 deg. C under vacuum. Then the powders are pressed under isostatic conditions and sintered at temperature range of 1020-1050 deg. C. Post sintering is done at 800 deg. C and 580 deg. C followed by quenching. Energy product in the range of 8 MGOe is achieved. (author)

Study of high-coercivity sintered NdFeB magnets

Energy Technology Data Exchange (ETDEWEB)

Bai, G. [School of Physics and Microelectronics, Shandong University, Jinan, 250100 (China); Department of Mathematics and Physics, Xi' an Institute of Technology, Xi' an, 710032 (China); Gao, R.W. [School of Physics and Microelectronics, Shandong University, Jinan, 250100 (China)]. E-mail: gaorwbox@sdu.edu.cn; Sun, Y. [School of Physics and Microelectronics, Shandong University, Jinan, 250100 (China); Han, G.B. [School of Physics and Microelectronics, Shandong University, Jinan, 250100 (China); Wang, B. [School of Physics and Microelectronics, Shandong University, Jinan, 250100 (China); Baotou Rare Earth Research Institute, Batou 014030 (China)

2007-01-15

Magnetic powders for sintered NdFeB magnets have been prepared by using an advanced processing method including strip casting, hydrogen decrepitation, jet milling and rubber isotropic press. The effects of Dy, Ga and Co addition on the microstructure and magnetic properties of sintered magnets have been investigated. By adopting a suitable component ratio and adjusting proper technological parameters, we have prepared high-coercivity sintered NdFeB magnets with hard magnetic properties of {sub j} H {sub c}=25.6 kOe, B {sub r}=13.2 kG and (BH){sub max}=39.9 MGOe. The temperature coefficient of coercivity of the magnets (between 20 and 150 deg. C) is -0.53% deg. C. The magnetic properties at high temperature satisfy the needs of permanent magnet motors.

Segregation in cast products

Indian Academy of Sciences (India)

Unknown

The agreement with experimental data is mostly qualitative. The paper also ... For example, a high degree of positive segregation in the central region .... solute in a cast product, important ones being: size of casting, rate of solidification, mode.

Characterization of Low-Symmetry Structures from Phase Equilibrium of Fe-Al System-Microstructures and Mechanical Properties.

Science.gov (United States)

Matysik, Piotr; Jóźwiak, Stanisław; Czujko, Tomasz

2015-03-04

Fe-Al intermetallic alloys with aluminum content over 60 at% are in the area of the phase equilibrium diagram that is considerably less investigated in comparison to the high-symmetry Fe₃Al and FeAl phases. Ambiguous crystallographic information and incoherent data referring to the phase equilibrium diagrams placed in a high-aluminum range have caused confusions and misinformation. Nowadays unequivocal material properties description of FeAl₂, Fe₂Al₅ and FeAl₃ intermetallic alloys is still incomplete. In this paper, the influence of aluminum content and processing parameters on phase composition is presented. The occurrence of low-symmetry FeAl₂, Fe₂Al₅ and FeAl₃ structures determined by chemical composition and phase transformations was defined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) examinations. These results served to verify diffraction investigations (XRD) and to explain the mechanical properties of cast materials such as: hardness, Young's modulus and fracture toughness evaluated using the nano-indentation technique.

Metal-loaded SBA-16-like silica – Correlation between basicity and affinity towards hydrogen

International Nuclear Information System (INIS)

Ouargli-Saker, R.; Bouazizi, N.; Boukoussa, B.; Barrimo, Diana; Paola-Nunes-Beltrao, Ana; Azzouz, A.

2017-01-01

Highlights: • Metal dispersion in longitudinal channels confers adsorption properties to SBA-16. • Both Fe"0-NPs and Cu"0-NPs seem to be responsible of this effect. • Effect of the repetitive adsorption-desorption cycles on CO_2 and water sorption. • Hydrogen storage on the functionalized materials. - Abstract: Nanoparticles of Cu"o (CuNPs) and Fe"o (FeNPs) were dispersed in SBA-16-like silica, resulting metal-loaded materials (Cu-SBA-16 and Fe-SBA-16) with improved affinity towards hydrogen. Electron microscopy and X-ray diffraction showed that MNP dispersion occurs mainly inside SBA-16 channels. MNP incorporation was found to confer affinity to the silica surface, since higher CO_2 retention capacity (CRC) was registered Cu/SBA-16 and Fe/SBA-16. This was accompanied by a significant improvement of the affinity towards hydrogen, as supported by hydrogen adsorption tests. This was explained in terms of strong hydrogen interaction with MNP and lattice oxygen atoms. The results reported herein open new prospects for SBA-16 as potential adsorbents for hydrogen storage.

Metal-loaded SBA-16-like silica – Correlation between basicity and affinity towards hydrogen

Energy Technology Data Exchange (ETDEWEB)

Ouargli-Saker, R. [Department of Materials Engineering, University of Science and Technology, El M’naouer, BP 1505, Oran (Algeria); Nanoqam, Department of Chemistry, University of Quebec at Montreal, H3C3P8 (Canada); Bouazizi, N. [Nanoqam, Department of Chemistry, University of Quebec at Montreal, H3C3P8 (Canada); Unité de recherche, Electrochimie, Matériaux et Environnement, Faculté des Sciences de Gabès, Université de Gabès, Cité Erriadh, 6072 Gabès (Tunisia); Boukoussa, B. [Department of Materials Engineering, University of Science and Technology, El M’naouer, BP 1505, Oran (Algeria); Lqamb, Laboratório de Química Analítica Ambiental, Faculdade de Química, Pontifícia Universidade Católica do Rio Grande do Sul (Brazil); Barrimo, Diana [Nanoqam, Department of Chemistry, University of Quebec at Montreal, H3C3P8 (Canada); Paola-Nunes-Beltrao, Ana [Nanoqam, Department of Chemistry, University of Quebec at Montreal, H3C3P8 (Canada); Laboratory of Materials Chemistry L.C.M, University of Oran1 Ahmed Ben Bella, BP 1524, El-Mnaouer, 31000 Oran (Algeria); Azzouz, A., E-mail: azzouz.a@uqam.ca [Nanoqam, Department of Chemistry, University of Quebec at Montreal, H3C3P8 (Canada)

2017-07-31

Highlights: • Metal dispersion in longitudinal channels confers adsorption properties to SBA-16. • Both Fe{sup 0}-NPs and Cu{sup 0}-NPs seem to be responsible of this effect. • Effect of the repetitive adsorption-desorption cycles on CO{sub 2} and water sorption. • Hydrogen storage on the functionalized materials. - Abstract: Nanoparticles of Cu{sup o} (CuNPs) and Fe{sup o} (FeNPs) were dispersed in SBA-16-like silica, resulting metal-loaded materials (Cu-SBA-16 and Fe-SBA-16) with improved affinity towards hydrogen. Electron microscopy and X-ray diffraction showed that MNP dispersion occurs mainly inside SBA-16 channels. MNP incorporation was found to confer affinity to the silica surface, since higher CO{sub 2} retention capacity (CRC) was registered Cu/SBA-16 and Fe/SBA-16. This was accompanied by a significant improvement of the affinity towards hydrogen, as supported by hydrogen adsorption tests. This was explained in terms of strong hydrogen interaction with MNP and lattice oxygen atoms. The results reported herein open new prospects for SBA-16 as potential adsorbents for hydrogen storage.

Genetic structure of Rajaka caste and affinities with other caste populations of Andhra Pradesh, India.

Science.gov (United States)

Parvatheesam, C; Babu, B V; Babu, M C

1997-01-01

The present study gives an account of the genetic structure in terms of distribution of a few genetic markers, viz., A1A2B0, Rh(D), G6PD deficiency and haemoglobin among the Rajaka caste population of Andhra Pradesh, India. The genetic relationships of the Rajaka caste with other Andhra caste populations were investigated in terms of genetic distance, i.e., Sq B (mn) of Balakrishnan and Sanghvi. Relatively lesser distance was established between the Rajaka and two Panchama castes. Also, the pattern of genetic distance corroborates the hierarchical order of the Hindu varna system.

White cast iron with a nano-eutectic microstructure and high tensile strength and considerable ductility prepared by an aluminothermic reaction casting

International Nuclear Information System (INIS)

La, Peiqing; Wei, Fuan; Hu, Sulei; Li, Cuiling; Wei, Yupeng

2013-01-01

A white cast iron with nano-eutectic microstructure was prepared by an aluminothermic reaction casting. Microstructures of the cast iron were investigated by optical microscope (OM), electron probe micro-analyzer (EPMA), scanning electron microscope (SEM) and X-ray diffraction (XRD). Mechanical properties of the cast iron were tested. The results showed that the cast iron consisted of pearlite and cementite phases. Lamellar spacing of the pearlite phase was in a range of 110–275 nm and much smaller than that of the Ni-Hard 2 cast iron. Hardness of the cast iron was 552 Hv, tensile strength was 383 MPa, total elongation was 3% and compressive strength was 2224 MPa. Tensile strength and hardness of the cast iron was same to Ni-Hard 2 cast iron, besides the ductility was much better than that of the Ni-Hard 2 cast iron which is much expensive than the cast iron.

Modelling of flow phenomena during DC casting

NARCIS (Netherlands)

Zuidema, J.

2005-01-01

Modelling of Flow Phenomena during DC Casting Jan Zuidema The production of aluminium ingots, by semi-continuous casting, is a complex process. DC Casting stands for direct chill casting. During this process liquid aluminium transforms to solid aluminium while cooling down. This is not an

CHARACTERIZATION OF PHASES IN SECONDARY AlZn10Si8Mg CAST ALLOY

Directory of Open Access Journals (Sweden)

Eva Tillová

2011-04-01

Full Text Available Using recycled aluminium cast alloys is profitable in many aspects. Requiring only 5 % of the energy to produce secondary metal as compared to primary metal and generates only 5 % of the green house gas emissions, the recycling of aluminium is therefore beneficial of both environmental and economical point of view. Secondary AlZn10Si8Mg (UNIFONT® - 90 cast alloy are used for engine and vehicle constructions, hydraulic unit and mouldmaking without heat treatment. Properties include good castability, very good mechanical strength and elongation, light weight, good wear resistance, low thermal expansion and very good machining. Improved mechanical properties are strongly dependent upon the morphologies, type and distribution of the secondary phases, which are in turn a function of alloy composition and cooling rate. The presence of additional elements as Mg, Mn, Fe, or Cu allows many complex intermetallic phases to form, which make characterisation non-trivial. These include, for example, Mg2Si, Al2CuMg and AlFeMn phases, all of which may have some solubility for additional elements. Phase’s identification in aluminium alloys is often non-trivial due to the fact that some of the phases have either similar crystal structures or only subtle changes in their chemistries. A combination different analytical techniques (light microscopy upon black-white and colour etching, scanning electron microscopy (SEM upon deep etching, energy dispersive X-ray analysis (EDX and HV 0.01 microhardness measurement were therefore been used for the identification of the various phase.

Mechanical properties of as-cast microalloyed steels produced via investment casting

International Nuclear Information System (INIS)

Najafi, H.; Rassizadehghani, J.; Norouzi, S.

2011-01-01

Tensile and room temperature Charpy V-notch impact tests were used to evaluate the variations in the as-cast mechanical properties of a low-carbon steel produced via shell mould investment casting and containing combinations of vanadium, niobium and titanium. Tensile results indicate that the yield strength and ultimate tensile strength (UTS) have increased up to respectively 615 MPa and 770 MPa due to the fine-scale microalloy precipitates in the microalloyed samples. Room temperature impact test results show that while addition of vanadium individually has not changed the impact energy, Nb has decreased it considerably. However, examination of fracture surfaces reveals that all microalloyed samples have failed by transgranular cleavage. Based on the transmission electron microscope (TEM) studies, it seems that carbonitrides being greater than 50 nm in size and formed along prior austenite grain boundaries before γ transformation are responsible for the observed reduction in impact energies and brittle fracture. In comparison to sand mould casting, the yield and UTS obtained from investment casting are superior. Furthermore, although the impact energies of Nb-containing alloys are approximately the same as those obtained from sand moulds, the impact energy of the alloy containing only vanadium has improved considerably.

Heat treatment of the EN AC-AlSi9Cu3(Fe alloy

Directory of Open Access Journals (Sweden)

J. Pezda

2010-04-01

Full Text Available Silumins are widely used in automotive, aviation and shipbuilding industries; as having specific gravity nearly three times lower than specific gravity of cast iron the silumins can be characterized by high mechanical properties. Additionally, they feature good casting properties, good machinability and good thermal conductivity. i.e. properties as required for machinery components operating in high temperatures and at considerable loads. Mechanical properties of the silumins can be upgraded, implementing suitably selected heat treatment. In the paper is presented an effect of modification and heat treatment processes on mechanical properties of the EN AC-AlSi9Cu3(Fe alloy. Investigated alloy has undergone typical processes of modification and refining, and next heat treatment. Temperature range of the heat treatment operations was determined on base of curves from the ATD method. Obtained results concern registered melting and solidification curves from the ATD method and strength tests. On base of the performed tests one has determined range of the heat treatment parameters which would assure obtainment of the best possible mechanical properties of the EN AC-AlSi9Cu3(Fe alloy.

Effect of the oxidation rate and Fe(II) state on microbial nitrate-dependent Fe(III) mineral formation

Science.gov (United States)

Senko, John M.; Dewers , Thomas A.; Krumholz, Lee R.

2005-01-01

A nitrate-dependent Fe(II)-oxidizing bacterium was isolated and used to evaluate whether Fe(II) chemical form or oxidation rate had an effect on the mineralogy of biogenic Fe(III) (hydr)oxides resulting from nitrate-dependent Fe(II) oxidation. The isolate (designated FW33AN) had 99% 16S rRNA sequence similarity to Klebsiella oxytoca. FW33AN produced Fe(III) (hydr)oxides by oxidation of soluble Fe(II) [Fe(II)sol] or FeS under nitrate-reducing conditions. Based on X-ray diffraction (XRD) analysis, Fe(III) (hydr)oxide produced by oxidation of FeS was shown to be amorphous, while oxidation of Fe(II)sol yielded goethite. The rate of Fe(II) oxidation was then manipulated by incubating various cell concentrations of FW33AN with Fe(II)sol and nitrate. Characterization of products revealed that as Fe(II) oxidation rates slowed, a stronger goethite signal was observed by XRD and a larger proportion of Fe(III) was in the crystalline fraction. Since the mineralogy of Fe(III) (hydr)oxides may control the extent of subsequent Fe(III) reduction, the variables we identify here may have an effect on the biogeochemical cycling of Fe in anoxic ecosystems.