The modulus and damping of martensitic Ni49Mn26Ga25 (wt%) cantilevers that deformed by twin motion when bent were investigated at room temperature. The modulus increased logarithmically as a function of aging time while the damping decreased commensurably. Both changes signal a gradual reduction of the twin boundary mobility. The logarithmic time dependence indicated a wide distribution of relaxation times. This distribution resulted from the volume dependence of the adaptation kinetics of nano-sized short range ordered clusters to the martensitic symmetry.

Twin Stabilization in a Ferromagnetic Shape Memory Alloy. L.Dai, M.Wuttig, E.Pagounis: Scripta Materialia, 2006, 55[9], 807-10