Simultaneous enhancement of mechanical and shape memory properties by heat-treatment homogenization of Ti_(2)Ni precipitates in TiNi shape memory alloy fabricated by selective laser melting

作     者：H.Z.Lu L.H.Liu C.Yang X.Luo C.H.Song Z.Wang J.Wang Y.D.Su Y.F.Ding L.C.Zhang Y.Y.Li H.Z.Lu;L.H.Liu;C.Yang;X.Luo;C.H.Song;Z.Wang;J.Wang;Y.D.Su;Y.F.Ding;L.C.Zhang;Y.Y.Li

作者机构：National Engineering Research Center of Near-net-shape Forming for Metallic MaterialsSouth China University of TechnologyGuangzhou 510640China Musculoskeletal Oncology DepartmentSun Yat-Sen University Cancer CenterGuangzhouGuangdong ProvinceChina Shenyang Aircraft Design and Research InstituteShenyang 110035China Guangdong Huayi Plumbing Fittings Industry Co.Ltd.Kaiping 529321China School of EngineeringEdith Cowan University270 Joondalup DriveJoondalupPerthWA 6027Australia 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2022年第101卷第6期

页      面：205-216页

核心收录：

学科分类：08[工学] 0817[工学-化学工程与技术] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0802[工学-机械工程] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：supported financially by the Key-Area Research and Development Program of Guangdong Province (No. 2020B090923001) the National Natural Science Foundation of China (No. U19A2085) the Key Basic and Applied Research Program of Guangdong Province (No. 2019B030302010) the financial support from the China Postdoctoral Science Foundation (No. 2019M662908) Guangdong Basic and Applied Basic Research Foundation (No.2019A1515110215) the Fundamental Research Funds for the Central Universities (No.2020ZYGXZR030)。 

主　　题：Shape memory alloy Selective laser melting Heat treatment Mechanical properties Shape memory properties 

摘      要：The excellent shape memory and mechanical properties of Ti Ni shape memory alloys(SMAs) fabricated using selective laser melting(SLM) are highly desirable for a wide range of critical applications. In this study, we examined the simultaneous enhancement of mechanical and shape memory properties using heat-treatment homogenization of Ti_(2)Ni precipitates in a Ti_(50.6)Ni_(49.4)SMA fabricated using SLM. Specifically, because of the complete solution treatment, nanoscale spherical Ti_(2)Ni precipitates were homogeneously dispersed throughout the grain interior. Interestingly, the resultant SMA exhibited an ultrahigh tensile strength of 880 ± 13 MPa, a large elongation of 22.4 ± 0.4%, and an excellent shape memory effect, with a recovery rate of 98% and ultrahigh recoverable strain of 5.32% after ten loading–unloading cycles. These simultaneously enhanced properties are considerably superior than those of most previously reported Ti Ni SMAs fabricated using additive manufacturing. Fundamentally, the enhancement in tensile strength is ascribed to precipitation strengthening and work hardening, and the large plasticity is mainly attributed to the homogeneous nanoscale globular Ti_(2)Ni precipitates, which effectively impeded the rapid propagation of microcracks. Furthermore, the enhanced shape memory properties are derived from the suppression of dislocation movement and formation of retained stabilized martensite by the presence of high-density dislocations, nanoscale Ti_(2)Ni precipitates, and abundant interfaces. The obtained results provide insight into the enhancement of the two types of properties in Ti Ni SMAs and will accelerate the wider application of SMAs.