Researchers at Texas A&M University, College Station, have examined stress-induced martensitic phase transformations in magnetic shape memory alloys via in-situ nanoindentation techniques. They discovered two distinctive types of martensitic phase transformation: A reversible gradual L21-to-10M/14M phase transformion at low stress, and an irreversible abrupt transition from residual L21-to-L10 martensite at higher stress. This study provides new perspectives on understanding stress-induced phase transformations in MSMAs.
During their in-situ nanoindentation experiments on Ni54Fe19Ga27 in a transmission electron microscope, the team discovered two distinctive types of martensitic phase transformation: A reversible gradual L21-to-10M/14M phase transformation at low stress, and an irreversible abrupt transition from residual L21-to-L10 martensite at higher stress. This study provides new perspectives on understanding stress induced phase transformations in MSMAs.
The research was led by Dr. Xinghang Zhang in the Department of Mechanical Engineering. A paper titled “Two Types of Martensitic Phase Transformations in Magnetic Shape Memory Alloys by in-situ Nanoindentation Studies” was published in the March 31 issue (2014) of Advanced Materials. The first author of the paper is Mr. Yue Liu, a Ph.D. candidate in Dr. Zhang’s research group.
The co-authors of this paper include Dr. Ibrahim Karaman in the Department of Materials Science and Engineering and Dr. Haiyan Wang in the Department of Electrical Engineering at Texas A&M University. This research in Zhang’s group is supported by the National Science Foundation (NSF), the Civil, Mechanical and Manufacturing Innovation (CMMI) Division, under grant no. 1129065.
