Effect of Ni doping on mechanical properties and phase transformation in Co-V-Ga high-temperature shape memory alloys  

作　　者：Siyuan Yang Ting Zhou Long Hou Xiangyu Li Jizhou Ci Shiwei Lu Jiantao Wang Zhipeng Long Xing Yu Yves Fautrelle Zongbin Li Zhongming Ren Xi Li 

机构地区：[1]State Key Laboratory of Advanced Special Steels,Shanghai University,Shanghai 200072,China [2]EPM-Madylam,ENSHMG BP 38402St Martin d’Heres Cedex,France [3]Key Laboratory for Anisotropy and Texture of Materials,Northeastern University,Shenyang 110819,China [4]Shanghai Key Lab of Advanced High-temperature Materials and Precision Forming,Shanghai Jiao Tong University,Shanghai 200240,China

出　　处：《Journal of Materials Science & Technology》2024年第26期244-252,共9页材料科学技术(英文版)

基　　金：supported by the National Key R&D Program of China(Nos.2023YFB3506701 and 2022YFB3706801);the National Natural Science Foundation of China(Nos.52174365,52004155,and 52130204).

摘　　要：In the present work,the effects of Ni doping on the microstructure and mechanical properties of Co-V-Ga high-temperature shape memory alloy have been studied.It has been found thatγphase occurs in the form of precipitation or even dendrite microstructure when Ni content continuously increases in the alloy.The composition distribution showed the elements Co and Ni segregated in theγphase,while elements V and Ga concentrated in the martensite phase.Moreover,the phase transition temperature increased by Ni-doping in Co-V-Ga alloys due to the increase in e/a of the alloy.However,the abundant presence ofγphase hindered the shear phase transformation and created a large number of grain boundaries to reduce Ms temperature when Ni content continuously increased.In addition,electron backscattered diffraction(EBSD)results verified that the presence ofγphase could hinder the expansion of cracks,and improve the strength and plasticity of the alloy.Furthermore,it could be found the shape memory effect could maintain a relatively high recovery rate when Ni content was within a certain extent.However,the shape memory effect of the alloy significantly decreased in the presence ofγphase with dendrite microstructure.The current research results not only clarify the influence of Ni doping on the microstructure and mechanical behavior of Co-V-Ga alloys,but also provide guidance for element doping to prepare high-temperature shape memory alloys(HTSMAs)with excellent performance.

关 键 词：Co-V-Ga alloys High temperature shape memory alloys DOPING Mechanical properties 

分 类 号：TG1[金属学及工艺—金属学]