Microstructural evolution and superelastic properties of ultrafine-graine d NiTi-base d shape memory alloy via sintering of amorphous ribbon precursor  

作　　者：W.S.Cai H.Z.Lu H.Z.Li Z.Liu H.B.Ke W.H.Wang C.Yang 

机构地区：[1]National Engineering Research Center of Near-net-shape Forming for Metallic Materials,Guangdong Provincial Key Laboratory for Processing and Forming of Advanced Metallic Materials,South China University of Technology,Guangzhou 510640,China [2]Songshan Lake Materials Laboratory,Dongguan 523808,China [3]Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Journal of Materials Science & Technology》2023年第7期80-92,共13页材料科学技术（英文版）

基　　金：This work was financially supported by the Key Basic and Applied Research Program of Guangdong Province(No.2019B030302010);the National Natural Science Foundation of China(No.U19A2085);the Key-Area Research and Develop-ment Program of Guangdong Province(No.2020B090923001);Special thanks to Sinoma Institute of Materials Research(Guang Zhou)Co.,Ltd.(SIMR)for its support in TEM testing.

摘　　要：NiTi-based shape memory alloys(SMAs)are considered as cutting-edge intelligent functional materials.However,it remains a great challenge to obtain ultrafine-grained(UFGed)bulk materials with mm-scale size as well as outstanding superelastic properties.Here,UFGed bulk Ti_(35)Zr_(15)Ni_(35)Cu_(15)NiTi-based SMA is successfully prepared via spark plasma sintering of amorphous ribbon precursor at different sintering temperatures,and microstructural evolution and superelastic properties are symmetrically investigated.It is found that its grain size ranges from UFG to micro-grain with increased sintering temperature regard-less of the predominant B2 matrix in all bulk samples.Interestingly,the orientation relationships between B2 matrix and nano-scale fcc(Ti,Zr)_(2)Ni precipitate evolve from coherent to incoherent.Consequently,the UFGed samples exhibit perfect superelasticity with the high recoverable strain of∼5.8%,the stable recov-ery rate above 99%,and the great critical stress inducing martensitic transformation higher than 1 GPa,far superior to the corresponding ones of suction-cast micro-grained TiZrNiCu SMAs.Fundamentally,the perfect superelasticity is attributed to the good resistance to dislocation slip or grain boundary slip by residual nano-scale amorphous phase or secondary phase of coherent and semi-coherent fcc(Ti,Zr)_(2)Ni precipitate.In addition,the gentle superelastic plateau is associated to the favorable transfer stress and the strong ability to accommodate dislocation movement,which is generated by the coherent interface between nano-scale fcc(Ti,Zr)_(2)Ni and UFGed B2 matrix.These results suggest that spark plasma sintering of amorphous alloy precursor is a feasible route to obtaining excellent superelasticity in NiTi-based SMAs.

关 键 词：Shape memory alloy Amorphous alloy Microstructure SUPERELASTICITY 

分 类 号：TB333[一般工业技术—材料科学与工程] TG139.6[金属学及工艺—合金]