Crystal structure and thermal stability of
martensite in Cu-25Al-3Mn alloy
martensite in Cu-25Al-3Mn alloy
(1. Department of Materials Science and Engineering,
Central South University, Changsha 410083, China;
2. School of Materials Science and Engineering,
Hefei University of Technology, Hefei 230009, China)
Central South University, Changsha 410083, China;
2. School of Materials Science and Engineering,
Hefei University of Technology, Hefei 230009, China)
Abstract: The martensite structure in Cu-25Al-3Mn alloy and its thermal cycling a nd aging behavior are studied. It is convinced that the M2H martensite can be obtained by water-quenched, and the atoms distribution on the basal plane of the martensite is: (corner)—Al; (center of the plane)—Cu; (middle o f b-side)—22/25Cu+3/25Mn. The lattice parameters are determined to be a=0.4459nm, b=0.5279nm, c=0.4241nm, β=88.64°. The triangle and other complicated configurations consisting of the variant group in the martensite are discovered. It is showed that the tested alloy has a high thermal stability when aging at average temperature in the parent phase, and the thermoelastic martensite amount is up to 90% after aging for 96h at 400℃. The thermal cycling has a little influence on the transformation temperature (Ms). When the number of thermal cycles is up to 1000, the increasing of Ms is only 8℃.
Key words: shape memory alloy; Cu-Al-Mn alloy; thermal stability; thermal cycling