Systematic study of the martensitic transformation in a Cu-Zn-Al alloy. Reproducibility of the thermal energy results and cycling effects

Abstract

A systematic study of the thermal energy released in the martensitic transformation undergone by a monocrystalline alloy of composition 74.41 Cu-18.18 Zn-7.41 Al (wt%) has been made. The values for ΔH in the β → M and M → β transformations have been determined, as a function of the heat treatment and the number of cycles. The experimental results establish that the transformation enthalpy is reproducible when the initial conditions are well determined. For different samples, in thermal cycles 1 to 10, ΔH is approximately constant, and by rapid cycling, the enthalpy of the 100th cycle is slightly smaller. Thermal cycling makes the effects of heat treatment less important and smooths the picture of the transformation dynamic. A qualitative study of several features of the acoustic emission produced during the transformation, as its signal/noise ratio and waveform, has also been carried out. © 1986.