Direct observation of fast-moving twin boundaries in magnetic shape memory alloy Ni-Mn-Ga 5 M martensite

作者：Saren A; Nicholls T; Tellinen J; Ullakko K^*

来源：Scripta Materialia, 2016, 123: 9-12.

DOI：10.1016/j.scriptamat.2016.04.004

• Ferromagnetic shape memory
• Twinning
• Dynamic phenomena
• Ni-Mn-Ga

We report a direct observation of fast Type II twin boundary motion under a pulsed magnetic field excitation in Ni-Mn-Ga 5 M martensite, utilizing high-speed camera technique. Our results demonstrate saturation velocities up to similar to 39 m/s measured along [100] direction for individual boundaries moving at RT, showing an order of magnitude larger values as compared to the earlier studies. Actuation response times of similar to 1 mu s were observed using laser vibrometry technique. The reported results show a minor role of magneto-static forces and emphasize the role of inertia and internal friction in twin boundary dynamics at the measured speeds.

• 出版日期2016-10