The Johnson-Mehl-Avrami Model Applied to Martensitic Kinetics in Ausformed Cooper Based Shape Memory Alloy

Abstract

CuAlNi shape memory alloys which are used as sensors and actuators have also been investigated recently as materials for medicine devices. This study shows the influence of the thermo – mechanical treatments in CuAl13Ni4 shape memory alloy on martensitic transformation kinetics and microstructures. While maintaining a constant 20% degree of deformation, deformation temperature was varied between 800 ^oC and 1000 ^oC. The alloy was investigated by differential scanning Calorimetry (DSC) and optical microscopy. The validity of JMA model to the kinetics analysis was checked. The changes in the microstructure and kinetic transformations have been linked to the evolution of the rolling temperature that introduced high density dislocations in initial phase and changes fraction and interaction between the β₁^’ (18R) and γ₁^’ (2H) martensite coexisting in this shape memory alloy.