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Strain rate response of a Zr-based composite fabricated by Bridgman solidification

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International Journal of Minerals,Metallurgy and Materials 2010年第2期17卷 214-219页

作者： Jun-wei Qiao Yong Zhang ji-heng li Guo-liang Chen State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

Zr58.5Ti14.3Nb5.2Cu6.1Ni4.9Be11.0 bulk metallic glass matrix composites,containingβ-Zr dendrites,were fabricated by Bridgman solidification at the withdrawal velocity of 1.0 mm/s through a temperature gradient of～45 K/*** to the increasing compressive strain rates,the monotonic increasing and decreasing were obtained for the maximum strength and the fracture strain,*** results show that high strain rate may induce the insufficient time for the interaction between shear bands and the crystalline phase,and early fracture occurs as a *** fractographs are consistent with the mechanical properties,and the failure mode of the present Zr-based composites is in agreement with the frame of the ellipse criterion.

关键词： bulk metallic glass composites Bridgman solidification mechanical properties

Influence of yttrium on the structure and magnetostriction of Fe_(83)Ga_(17) alloy

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International Journal of Minerals,Metallurgy and Materials 2012年第9期19卷 849-855页

作者： Xi-ming Xiao Xue-xu Gao ji-heng li jian-xin Xie State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Polycrystalline Fe83Ga17 alloy rods with various amounts of yttrium were prepared by high vacuum induction melting. It is found that yttrium addition has a significant effect on the structure and magnetostriction of Fes3Ga17 alloy. The small addition of yttrium alters the solidification character and the grain shape of Fe83Ga17 alloy, and as a result, columnar grains with the 〈100〉 preferential direction are pro- duced. Yttrium addition improves the magnetostrictive performance of the as-cast Fes3Ga17 alloy. The magnetostriction values of the as-cast alloy with 0.32at% and 0.64at% yttrium addition go up to 119×10^-6 and 137×10^-6 under 15 MPa compressive stress, respectively. The energy dispersive spectroscopy （EDS） result shows that almost all of the yttrium atoms exist in the Y2Fe17-xGax phase. A small amount of this kind of secondary phase cannot obviously increase the saturate magnetic field.

关键词： gallium alloys iron alloys yttrium magnetostfiction supercooling polycrystallirte materials

Enhancement of ductility and improvement of abnormal Goss grain growth of magnetostrictive Fe–Ga rolled alloys

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International Journal of Minerals,Metallurgy and Materials 2018年第4期25卷 444-452页

作者： ji-heng li Chao Yuan Xing Mu Xiao-qian Bao Xue-xu Gao State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing

The influences of initial microstructures on the mechanical properties and the recrystallization texture of magnetostrictive 0.1 at% Nb C-doped Fe83 Ga17 alloys were investigated. The directionally solidified columnar-grained structure substantially enhanced the tensile elongation at intermediate temperatures by suppressing fracture along the transverse boundaries. Compared with tensile elongations of 1.0% at 300℃ and 12.0% at 500℃ of the hot-forged equiaxed-grained alloys, the columnar-grained alloys exhibited substantially increased tensile elongations of 21.6% at 300℃ and 46.6% at 500℃. In the slabs for rolling, the introduction of 〈001〉-oriented columnar grains also promotes the secondary recrystallization of Goss grains in the finally annealed sheets, resulting in an improvement of the saturation magnetostriction. For the columnar-grained specimens, the inhomogeneous microstructure and disadvantage in number and size of Goss grains are improved in the primarily annealed sheets, which is beneficial to the abnormal growth of Goss grains during the final annealing process.

关键词： magnetostriction iron-gallium alloys columnar grain ductility abnormal grain growth

Influence of Al on the magnetostriction of Fe-Ga polycrystal alloys under compressive stress

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International Journal of Minerals,Metallurgy and Materials 2014年第1期21卷 52-57页

作者： Long-long liao Mei-ling Fang jie Zhu ji-heng li jian Wang State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing

Fe80Ga20-xAlx （x = 0, 6, 9, 14） ingots were prepared from high purity elements using a vacuum induction system. X-ray diffraction patterns show that the alloys are A2 disordered structures. The influence of the partial substitution of Ga in Fe-Ga alloys with A1 on their magnetostrictive properties was investigated, and the effects of different heat treatment conditions on the magnetostriction and microstructure of the alloy rods were also examined. The saturation magnetostriction value of FesoGa2o can reach to 240 x 10-6 under a compressive stress of 20 MPa. The Fe80GallA19 alloy has many good properties, such as low hysteresis, high linearity of the magnetostriction curve, and low saturated magnetic field, which make it a potential candidate for magnetostrictive actuator and transducer applications. It is found that subgrains have little influence on the magnetostriction of Fe-Ga alloys.

关键词： iron-gallium alloys polycrystals aluminum magnetostriction compressive stress

Single Goss grain growth by isothermal annealing in rolled Fe–Al–Ga–Nb C sheets

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Rare Metals 2023年第10期42卷 3537-3544页

作者： Yang-Yang liu ji-heng li Xiao-Long li Xing Mu Xiao-Qian Bao Xue-Xu Gao State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing100083China

The(Fe_(82)Al_(13.5)Ga_(4.5))_(99.9)(NbC)_(0.1) sheets with strong Goss texture and large magnetostriction were prepared by rolling and isothermal annealing *** Goss grain growth was observed in sheets undergoing isothermal annealing at 1050 ℃ for 1 h using Ar as protecting *** annealing time increasing to 8 h at1050℃,a largest magnetostriction of 154×10^(-6) is obtained in sheet and a large λ_(//)(the maximum magnetostriction with magnetic field parallel to rolling direction)of 160×10^(-6) along the rolling direction is also *** fact that a λ_(//) of 160×10^(-6) along RD can be achieved with only 4.5 at% Ga in the Fe-18 at%(Al,Ga) sheet is of practical *** with previous studies in Fe-Al and Fe-Ga sheets,this paper provides a more efficient approach to prepare strong Goss textured *** this way,a slow continuous heating process,sulfur-induced surface energy control and high-temperature annealing above 1200 ℃ are no more *** shows a good prospect for industrial production of high-performance magnetostrictive alloy sheets.

关键词： Fe–Al–Ga sheet Isothermal annealing Goss texture Magnetostriction

Microstructure and magnetostrictive performance of NbC-doped <100>oriented Fe-Ga alloys

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International Journal of Minerals,Metallurgy and Materials 2015年第1期22卷 52-58页

作者： Chao Yuan ji-heng li Wen-lan Zhang Xiao-qian Bao Xue-xu Gao State Key Laboratory of Advanced Metals and Materials University of Science and Technology Beijing

The〈100〉oriented Fe83Ga17 alloy rods with various NbC contents less than 1at%were prepared by the directional solidification method at a growth rate of 720 mm·h^-1. Low NbC-content was found to affect the oriented grain growth and slightly improve the〈100〉ori-entation. Flat grain boundaries in the alloys with low NbC contents less than 0.2at%became greatly curved at higher NbC contents, and a large amount of Nb-rich precipitates were observed in the alloys with high NbC contents. Small amounts of NbC, less than 0.2at%, resulted in an increase in magnetostrictive strain due to the improvement of the〈100〉orientation, and a high magnetostrictive strain value of 335 ×10^-6 under a pre-stress of 15 MPa was obtained in the 0.1at%NbC-doped alloys. The magnetostrictive performance obviously decreased with the NbC addition higher than 0.5at%, and the strain sensitivity under no pre-stress was lower than that in the binary Fe？Ga alloy.

关键词： iron gallium alloys magnetostriction texture niobium carbide directional solidification

Inhibition force of precipitates for promoting abnormal grain growth in magnetostrictive Fe83Ga17-(B,NbC) alloy sheets

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Rare Metals 2017年第11期36卷 886-893页

作者： ji-heng li Wen-Lan Zhang Chao Yuan Xiao-Qian Bao Xue-Xu Gao State Key Laboratory of Advanced Metals and Materials University of Science and Technology Beijing 100083 China

Inhibition force of precipitate particles for pro- moting abnormal grain growth in magnetostrictive Feg3Ga17-（B,NbC） alloy sheets was investigated in this study. After a continuous heating and a high-temperature annealing, the Fe83Gat7 ＋ 0.5 at% B alloy sheets do not occur significant abnormal grain growth. Correspondingly, textures of { 111 }〈112〉 and { 100}〈00l〉 in addition to the Goss texture are obtained in the final annealed alloy sheets. By contrast, after the same annealing processes, the size of {110} textured grains is very large in the final annealed Fe83Gaj7 ＋ 0.5 at% NbC alloy sheets due to the abnormal grain growth, which results in a sharp Goss texture. BN precipitates were introduced into Fes3Ga17 ＋ 0.2 at% B alloy sheets by nitriding annealing at 800℃ for 2 min under NH3 atmosphere. The abnormal grain growth of Goss grains is achieved in 0.2 at% B-doped Fe83Ga17 alloy sheets after a high-temperature annealing, which is attributed to the enhanced inhibition force by introducing BN precipitates. During the recrystallization annealing process, Fe2B precipitates is easy to coarsen and decom- pose at high temperature due to the low thermal stability, resulting in a decrease or even disappearance of the inhi- bition force. For NbC and BN precipitates, the thermal stability and hardness of particles are both better than those of Fe2B precipitates, leading to strong inhibition force. Because of the preferred Goss texture, the magnetostriction of 2.05 × 10-4 and 1.81 × 10 4 is obtained in the sec- ondary recrystallized Fe83Gal7 ＋ 0.5 at% NbC and Fes3Gaw ＋ 0.2 at% B alloy sheets, respectively.

关键词： Fe-Ga alloy Magnetostriction Grain growth Inhibition force Precipitates

Secondary recrystallization of Goss texture in magnetostrictive Fe–Ga-based sheets

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Rare Metals 2020年第11期39卷 1288-1294页

作者： Chao Yuan Xue-Xu Gao ji-heng li Xiao-Qian Bao State Key Laboratory of Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

To avoid the unfavorable effect of precipitates on magnetic properties,low addition of 0.16 wt%NbC was employed in Fe_(82.5)Ga_(17.5)alloy,and 0.27 mm sheets were successfully prepared by a rolling *** Goss texture was obtained in Fe-Ga sheets by two-stage annealing *** sulfur annealing in quartz ampoules was made to produce the preferred growth of Goss texture,with a 51%increase in the observed saturation magnetostriction,from 87×10^(-6)in the Ar-annealed sheets to 132×10^(-6)in the S-annealed ***,large amounts of S-rich and Nb-rich precipitates were formed in the S-annealed ***-temperature annealing of the S-annealed sheets at 1,200℃under a flow hydrogenargon atmosphere could effectively eliminate the precipitates and promote the selective growth of(110)grains due to the low surface *** grains(~2 cm)of secondary recrystallization were achieved in the final annealed sheets,with the maximum average saturation magnetostriction of 180×10^(-6).

关键词： Fe–Ga alloy Goss texture Magnetostriction Secondary recrystallization

Magnetostriction and magnetization of <110> oriented Tb0.27Dy0.73Fe1.95 alloys with different compressive prestresses

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Rare Metals 2020年第2期39卷 176-180页

作者： Xing Mu Hai-Jun Tang Xue-Xu Gao Xiao-Qian Bao ji-heng li State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing100083China China Academy of Civil Aviation Science and Technology Beijing100028China

oriented Tb0.27Dy0.73Fe1.95 alloys were studied under different applied compressive *** saturation magnetostriction by 500×10-6 is obtained for the sample under 5 MPa than that under no applied *** understand the effect of prestress on the magnetostrictive coefficient,differential magnetostrictive coefficient,relative permeability and coercive force were studied in *** results show that the maximum differential magnetostrictive coefficient is about 37 x 10-9 m·A-1,about two times that without *** addition,the saturation magnetostriction coefficient increases gradually with the stress increasing,while the maximum differential magnetostrictive coefficient *** saturation inductions under different stresses are similar to a value of about 1.1 *** relative permeability decreases with stress increasing.

关键词： Tb-Dy-Fe Compressive prestress Magnetostriction