Microstructure and high-temperature shape-memory effect in Ni54Mn25Ga21 alloy

• Published in: Transactions of Nonferrous Metals Society of China Vol. 16; no. 3; pp. 502 - 506
• Main Author: 马云庆 蒋庆保 李岩 徐惠彬 王翠萍 刘兴军
• Format: Journal Article
• Language: English
• Published: Department of Materials Science and Engineering, Xiamen University, Xiamen 361005, China%Department of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China 01.06.2006
• Subjects: Ni2MnGa; Ni54Mn25Ga21; 显微结构; 马氏体转变; 高温形状记忆效应; microstructure; martensitic transformation; high-temperature shape-memory effect; Ni2MnGa Heusler alloy
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(06)60087-3

Ni54Mn25Ga21 alloy was prepared to investigate the microstructure, martensitic transformation and high-temperature shape-memory effect. Ni54Mn25Ga21 alloy exhibits single phase of non-modulated martensite with tetragonal structure at room temperature. Its martensitic start temperature Ms, martensitic finish temperature Mf on cooling, and austenitic start temperature As, austenitic finish temperature Af on heating are 260.2, 237.8, 262.5 and 287.8 ℃, respectively. The compressive strength and strain of Ni54Mn25Ga21 single crystal were measured to be 845 MPa and 20.5%, respectively, with compressive axis along the growth direction of the rods. An excellent shape-memory strain of 6.1%, which is the best performance among high-temperature shape-memory alloys up to the present, is obtained when prestrained to 8%.