Heat treatment of hot-isostatic-pressed 60NiTi shape memory alloy:Microstructure,phase transformation and mechanical properties  

作　　者：Yinghao Zhou Xiyu Yao Wenfei Lu Dandan Liang Xiaodi Liu Ming Yan Jun Shen 

机构地区：[1]College of Mechatronics and Control Engineering,Shenzhen University,Shenzhen 518060,China [2]Department of Materials Science and Engineering,Shenzhen Key Laboratory for Additive Manufacturing of High-performance Materials,Southern University of Science and Technology,Shenzhen 518055,China

出　　处：《Journal of Materials Science & Technology》2022年第12期124-135,共12页材料科学技术（英文版）

摘　　要：60NiTi alloy is considered to be a promising material for specialized bearing and gear applications due to its high hardness,strength,and low modulus.However,fabricating 60NiTi through conventional processing methods is challenging due to the brittleness and poor workability.In this study,60NiTi with high relative density was successfully fabricated directly from pre-alloyed powder through hot isostatic pressing.The effects of solution and aging treatments on microstructure and mechanical properties were systematically studied by advanced characterization techniques.The hot-isostatic-pressed 60NiTi showed low average hardness and elastic strain due to the formation of a soft Ni_(3)Ti phase and B2 NiTi matrix.Solution treatment above 1000℃dissolved the Ni_(3)Ti phase and promoted the formation of nanoscale Ni_(4)Ti_(3)precipitates,which significantly improved the hardness,strength,and elastic strain of 60NiTi.The formation of the Ni_(4)Ti_(3) phase can be mainly attributed to the driving forces induced by the chemical supersaturation and mechanical stress concentration.Finally,the phase transformation mechanisms during heat treatment and compression test were discussed.

关 键 词：Ni-rich 60NiTi Hot isostatic pressing Heat treatment Phase transformation Mechanical properties 

分 类 号：TG156.9[金属学及工艺—热处理] TG139.6[金属学及工艺—金属学]