Microstructure evolution and mechanical behavior of Ni-rich Ni-Mn-Ga alloys under compressive and tensile stresses  

作　　者：Yue Wang Siyuan Yang Ting Zhou Long Hou Lansong Ba Yves Fautrelle Zhongming Ren Yanyan Zhu Zongbin Li Xi Li 

机构地区：[1]State Key Laboratory of Advanced Special Steels,Shanghai University,Shanghai 200072,China [2]Shanghai Key Lab of Advanced High-temperature Materials and Precision Forming,Shanghai Jiao Tong University,Shanghai 200240,China [3]EPM-Madylam,ENSHMG BP 38402St Martin d’Heres Cedex,France [4]School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China [5]Key Laboratory for Anisotropy and Texture of Materials,Northeastern University,Shenyang 110819,China

出　　处：《Journal of Materials Science & Technology》2022年第2期113-122,共10页材料科学技术（英文版）

基　　金：supported partly by the National Natural Science Foundation of China(Nos.51904183,51690164 and 51805321);Shanghai Science and Technology Committee Grant(19XD1401600 and 19010500300);Project funded by China Postdoctoral Science Foundation(2018M640375,2019T120330)。

摘　　要：The microstructure evolution and mechanical behavior in directionally solidified Ni-rich Ni-Mn-Ga alloys with nominal compositions of Ni_(58)Mn_(25)Ga_(17) and Ni_(60)Mn_(25)Ga_(15) under compressive and tensile stresses have been investigated.The composition distribution shows the element Ni segregates in gamma phase,while elements Mn and Ga segregate in martensite phase.Furthermore,the microstructure orientation examined by electron backscatter diffraction(EBSD)indicates that beta phase has a preferred growth orientation of(001)_(A) in Ni_(58)Mn_(25)Ga_(17) alloys,while gamma phase has a preferred growth orientation of(001)_(γ) in Ni_(60)Mn_(25)Ga_(15) alloys.The fracture morphology suggests that the existence of ductile y phase can reduce the crack propagation and promote fracture strain,particularly in the Ni_(60)Mn_(25)Ga_(15) alloys.Finally,Schmid factor and deformation gradient tensor were calculated to well explain the crystallographic evolution during the detwinning under compressive and tensile stresses.The present findings not only elucidate the mechanism ofγphase on the mechanical behavior of Ni-rich Ni-Mn-Ga alloys,but also shed light on the composition design of high temperature Ni-Mn-Ga shape memory alloys.

关 键 词：NI-MN-GA Gamma phase TENSILE COMPRESSIVE EBSD 

分 类 号：TG139.6[一般工业技术—材料科学与工程]