Deformation mechanism of Cu-Al-Ni shape memory alloys fabricated via laser powder b e d fusion:Tension-compression asymmetry  

作　　者：Yankun Zhang Lianyong Xu Lei Zhao Danyang Lin Minqian Liu Wei Chen Yongdian Han 

机构地区：[1]School of Materials Science and Engineering,Tianjin University,Tianjin 300350,China [2]Tianjin Key Laboratory of Advanced Joining Technology,Tianjin 300350,China [3]State Key Laboratory of Engines,Tianjin University,Tianjin 300350,China [4]State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin 150001,China

出　　处：《Journal of Materials Science & Technology》2023年第36期14-26,共13页材料科学技术（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.52275365).

摘　　要：Introducing the unique advantage of additive manufacturing technology into copper-based shape memory alloys(SMAs)to fabricate high-performance alloys has garnered great attention in recent years,but the intrinsic relationships between microstructure and mechanical properties need to be further clarified.In this paper,the microstructural evolution of ternary CuAlNi SMAs fabricated by laser powder bed fusion(LPBF)under the tensile-compressive loading was investigated to determine the underlying mechanism of tension-compression asymmetry,that is,excellent compressive but poor tensile properties.Multiscale characterization of the different deformation stages revealed the numerous activated deformation mech-anism on the 18R martensite matrix.A twin-related transformation dominated the main plastic defor-mation process due to lower stacking faults energy and high-density pre-existing planer defects in the CuAlNi SMAs.Deformation twinning nucleated at prior austenite boundaries and developed into parallel and network structures inside the parent grain of different sizes.In addition,the preferred orientation in different stages,the stress-inducedγphase transformation,and the interaction between dislocations and stacking faults are discussed.These results not only provide significant insights to understand the detwinning and deformation twinning process of SMAs but also establish the essential framework of mi-crostructure and mechanical properties of Cu-based SMAs fabricated by LPBF.

关 键 词：Shape memory alloys Cu-based Laser powder bed fusion Microstructural evolution Deformation mechanism 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG665[金属学及工艺—金属材料]