Microstructural,crystallographic,and mechanical characteristics in Ni-Mn-Ga alloys directionally solidified under a transverse magnetic field  

作　　者：Xi Li Long Hou Siyuan Yang Ting Zhou Yue Wang Xing Yu Zongbin Li Daoyong Cong Yves Fautrelle Zhongming Ren Yanyan Zhu 

机构地区：[1]Shanghai Key Lab of Advanced High-Temperature Materials and Precision Forming,Shanghai Jiao Tong University,Shanghai 200240,China [2]State Key Laboratory of Advanced Special Steels,Shanghai University,Shanghai 200072,China [3]Key Laboratory for Anisotropy and Texture of Materials,Northeastern University,Shenyang 110819,China [4]Beijing Advanced Innovation Center for Materials Genome Engineering,State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,Beijing 100083,China [5]EPM-Madylam,ENSHMG BP,St Martin d’Heres 38402 CEDEX,France

出　　处：《Journal of Materials Science & Technology》2023年第11期10-21,共12页材料科学技术（英文版）

基　　金：financed by the National Natural Science Foundation of China(Nos.51904183 and 52130204);the Independent Research and Development Project of State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(No.SKLASS 2021-Z07);the Science and Technology Commission of Shanghai Municipality(Nos.19DZ2270200 and 20511107700).

摘　　要：In this study,the effect of transverse magnetic field-assisted directional solidification(MFADS)on the microstructures in Ni-Mn-Ga alloys has been investigated.The results show that the magnetic field is capable of inducing transversal macrosegregation perpendicular to the magnetic field,causing the emergence of martensite clusters in the austenite matrix.Moreover,the magnetic field alleviates the microseg-regation on a dendritic scale and promotes the preferred growth of austenite dendrites.On the basis of the above investigation,several special samples are designed using the MFADS to study the crystallographic evolution and mechanical behavior during thermal/stress-induced martensite transformation.The martensite cluster in the austenite matrix is used to investigate the martensite transformation and growth under cooling-heating cycles.The crystallographic relationship and phase boundary microstructure between martensite and austenite have been characterized.In addition,the microsegregation on a dendritic scale can significantly influence the martensite variant distribution,corresponding to the performance during compressive circles based on the analysis of the deformation gradient tensor.The stress-induced superelasticity is closely dependent on orientation,well explained from the perspective of different resolved shear stress factors and correspondence variant pair formation transformation strain.The crystallographic evolution has been characterized during in-situ stress-induced transformation.The findings not only deepen the understanding of martensite transformation and mechanical behavior under a thermal/stress field in Ni-Mn-Ga alloys but also propose a promising strategy to obtain microstructure-controllable functional alloys by MFADS.

关 键 词：Magnetic field-assisted directional SOLIDIFICATION SEGREGATION Orientation Martensite transformation SUPERELASTICITY 

分 类 号：TG139[一般工业技术—材料科学与工程]