形状记忆材料中二类相界面的研究

Study of Two Types of Interface in Shape Memory Materials

在经过训练处理具有双程形状记忆效应的记忆合金材料中,相变变体(或相界面)可分为2类:择尤取向的变体(界面)和自协作的变体(界面).择尤取向界面运动提供可逆的形状记忆效应.外应力可以促进或抑制择尤取向界面运动,改变其相变平衡温度,但对自协作界面无重要影响.2类变体的比例与合金类型和训练工艺有关,对Cu-Zn-A1合金弹簧,择尤取向变体占总变体的65%.

In shape memory alloys exhibiting two-way shape memory effect(TWSM),the martensitic variants(or phase interface)may be classified into pref-erred orientational variant and accommodating variant.Measurements of electricalresistivity,memory recovery strain and in-situ X-ray diffraotion show that theTWSM is caused only by the motion of orientated variants and the transformationtemperature of the orientated variant are higher than those of the accommodatingvariant.The proportion of the two types of variant depends on the alloy species,training process etc.For the Cu-Zn-Al memory alloy used in our investigation,the volume fraction of the preferred orientational variant is about 65%.Appliedstress may promote or restrain the motion of orientated interface,thereby affectingthe shape recovery temperature,but the stress has no significant effect on the motionof the accommodating interfaces.