首页|Microstructure evolution and shape memory behaviors of Ni47Ti44Nb9 alloy subjected to multistep thermomechanical loading with different prestrain levels

Microstructure evolution and shape memory behaviors of Ni47Ti44Nb9 alloy subjected to multistep thermomechanical loading with different prestrain levels

扫码查看
原文链接
  • NETL
  • NSTL
  • 万方数据
Ni47Ti44Nb9 shape memory alloy(SMA)is a promising material in the aerospace field due to its wide transformation hysteresis.The application of shape memory effect depends on multistep thermomechan-ical loading,viz.,low-temperature deformation and subsequent heating to recovery.Low-temperature deformation prestrain plays a pivotal role in shape memory properties tailoring of SMA components.However,microstructure evolution and deformation mechanisms of Ni47Ti44Nb9 SMA subjected to vari-ous prestrain levels are still unclear.To this end,microstructure evolution and shape memory behaviors of Ni47Ti44Nb9 alloy subjected to multistep thermomechanical loading with prestrain levels of 8％-16％at-28 ℃(Ms+30 ℃)were investigated.The results demonstrate that the stress-strain curve of the specimen exhibits four distinct stages at a maximal prestrain of 16％.Whereas stage Ⅱ and stage Ⅲ end at prestrains of～8％and～12％,respectively.In stage Ⅱ,the stress-induced martensitic transformation is accompanied by the dislocation slip of the NiTi matrix and β-Nb inclusions.In stage Ⅲ,in addition to the higher density of dislocations and further growth of stress-induced martensite variants(SIMVs),(00 1)compound twins are introduced as a result of the(0 0 1)deformation twinning in stress-induced martensite.More{2 0-1｝ martensite twins are gradually introduced in stage Ⅳ.Correspondingly,after subsequent unloading and heating,a higher density of {1 1 4｝ austenite twins form in the specimen with a larger prestrain of 16％.With increasing prestrain from 8％to 16％,the recoverable strainεreT upon heating increases first and then decreases.The εreT obtains a maximum of 7.03％at 10％prestrain and de-creases to 6.17％at 16％prestrain.The increase of εreT can be attributed to the formation of new SIMVs,the further growth of existing SIMVs,and the recoverable(0 0 1)compound twins.While the decrease of εreT is mainly associated with the irrecoverable strain by ｛2 0-1｝ martensite twins.The effect of β-Nb inclusions on the evolution of SIMVs is also found herein that deformed β-Nb inclusions can significantly hinder the growth and recoverability of adjacent stress-induced martensite.

Ni47Ti44Nb9 shape memory alloyWide transformation hysteresisThermomechanical loadingMicrostructure evolutionShape memory behaviorsStress-induced martensitic transformationDeformation twinning

Y.H.Zhang、H.Li、Z.W.Yang、X.Liu、Q.F.Gu

展开 >

State Key Laboratory of Solidification Processing,School of Materials Science and Engineering,Northwestern Polytechnical University,Xi'an 710072,China

Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment,Northwestern Polytechnical University,Xi'an 710072,China

National Natural Science Foundation of ChinaNational Science Fund for Excellent Young Scholars

5177544151522509

2024

10.1016/j.jmst.2023.05.076

材料科学技术(英文版)
中国金属学会 中国材料研究学会 中国科学院金属研究所

材料科学技术(英文版)

CSTPCD
影响因子：0.657
ISSN：1005-0302
年,卷(期)：2024.171(4)
  • 48