EFFECTS OF AGING ON PSEUDOELASTIC BEHAVIOR IN CU-15.0AT-PERCENT-SN ALLOY SINGLE-CRYSTALS

The effect of aging on pseudoelasticity in a shape memory alloy was st udied using single crystals of a CuSn alloy, in which the martensitic transformation behaviour is fairly susceptible to an aging treatment. The aging effect on the nucleation of martensite was investigated in t he specimens aged in the parent phase. The effect on the growth of mar tensite was studied by strain aging during tensile testing, and also b y the analysis of strain rate dependence of pseudoelasticity. The form er effect is attributed to the embryo exhaustion due to the diffusion of Sn atoms, originally proposed by Kennon. On the other hand the latt er is explained from the pinning of a martensite/parent interface by t he diffusion of Sn atoms.