Heat conduction during phase transformation in shape memory alloy

Abstract
Heat conduction phenomena in a shape memory alloy which undergoes a martensitic transformation between a low temperature phase of martensite and a high temperature phase is analysed. This analysis takes into account the phase transformation latent heat in the heat equation in addition to the classical heat conduction. Since this problem is similar to solid-liquid phase change problems, the so called "enthalpy method" used in the transient heat-transfer problems involving melting or solidification is adopted and applied to the martensitic transformation of a Ni-Ti shape memory alloy ring. This ring is deformed at low temperature and heated to recover its high temperature shape. The evolution of the temperature field inside the ring during the transformation is plotted. The influence of the latent heat on the recovery time is shown.