Study of reorientation of martensite variants under stress in Ti-Ni-Cu by resistivity and by thermoelectric power techniques

Abstract
It is well known that the martensitic phase of shape memory alloys presents a self-accommodation of variants when it is obtained by simple cooling. Theses variants can be reoriented in a new configuration by applying a stress on the material. Macroscopic properties like, electrical and mechanical ones, are very sensitive to this phenomenon. Moreover, it has been proved that thermoelectric power (TEP) is a powerful technique to characterize isotropic properties. In this work, thermoelectric power under stress has been used to study the evolution of the reorientation of variants in a shape memory alloy. The obtained results are compared with those of mechanical and electrical tests.