Study of the stabilization of a Cu-Zn-Al shape memory alloy under stress

The influence of tensile stresses coupled with temperature cycling has been determined on a Cu-Zn-Al shape memory alloy that transforms above room tem perature. It is shown that the application of increasing stresses during th ermal cycles leads to an increasing martensite stabilization. The repeated thermal cycling with constant stress as well as slow temperature rates incr ease the stabilization. This phenomenon is attributed to a pinning of auste nite-martensite interfaces by vacancies. This hypothesis is confirmed by th e comparison of experiments with continuous and with stepwise temperature v ariations.