应力诱发马氏体相变滞后的研究

HYSTERESIS IN STRESS-INDUCED MARTENSITIC TRANSFORMATION

用Landau-Devonshire自由能理论可描述形状记忆合金伪弹性行为随温度变化的规律:温度上升,滞后环位置提高,滞后面积减小;到达临界温度T_c后,滞后全部消失。可是对CuZnAl单晶系统测定结果显示:滞后环位置随温度升高而升高,但滞后面积在一定温度范围内,却基本不变。对滞后环内变化规律的研究结果指出,滞后大小取决于应力诱发马氏体量的多少,马氏体量越多,则滞后面积越大。

A simple model based on the Landau-Devonshire theory is capable of simulating the pseudoelastic hysteresis behaviour, i. e., the hysteresis becomes smal- ler with increasing temperature and disappears at a critical temperature. The exper- imental results obtained from CuZnAl memory alloy singleicrystalline specimens show that the width of the hysteresis loop does not change significantly with tem- perature, while the size of the interior loops of hysteresis strongly depends on the martensitic phase fraction induced from austenite.