Effect of Grain Boundary on Pseudo-elastic Deformation of Cu-Zn-Si Bicrystal of Shape Memory Alloy

Abstract

Two sorts of Cu-Zn-Si pseudo-elastic bicrystals of shape memory alloy were tested in tension to know the effects of the grain boundary. The remaining martensites were observed in the vicinity of the grain boundary, and the propriety of analyses through use of m/m。 and Nᵢj values and of the compatibility of the plastic strain were studied. The variant of martensite occurring primarily in each grain during deformation, can be predicted with use of them value (shear factor of the variant) in general. The analyses through use of m/mᵢ and Nᵢj values and the equations of the plastic strain compatibility are sufficiently useful to know the variant of martensite nucleated additionally in the vicinity of the grain boundary. However, the possibility of activation of slip must be considered in this case. The reversible strain of the isoaxial bicrystal is larger than that of the non-isoaxial bicrystal. However, the relation between the reversible strain and the misorientation of bicrystal is not yet sufficiently known.