NbTi-NiTi原位复合材料的约束态相变阻尼

Constraint transformation damping behavior of in-situ NbTi-NiTi composite

为使记忆合金展现宽温域高阻尼特性,采用熔炼、热锻、轧制等手段制备原位自生的NbTi-NiTi记忆合金复合材料。借助NbTi对NiTi的约束,拓宽NiTi相变温度区间,获得宽温域相变阻尼。采用LMR-1低频力学弛豫谱测试机测试样品内耗。完全相变测试结果表明:材料能在很宽的温度范围内展现高阻尼特性,并随着预变形量的增加,马氏体逆相变阻尼峰的峰温随之升高,峰宽也随之增加;预变形后,样品在第一次加热过程中阻尼峰的峰温较高,且峰较宽,而第二次加热,阻尼峰温和宽度都明显降低;测试中材料的动态模量也伴有相同的变化。不完全相变测试结果表明:内耗曲线出现双阻尼峰,而动态模量曲线出现阶梯式升高现象,且内耗曲线和动态模量曲线都展现出温度记忆效应。

In order to obtain high damping capacity within wide temperature window by enlarging the transformation temperature window of NiTi shape memory alloy(SMA) during constraint transformation, an in-situ NbTi-NiTi composite was prepared by vacuum induction melting, hot forging and cold rolling processing. The complete and incomplete constraint transformation damping behavior of the composite was studied by a low-frequency mechanical analyzer LMA-1 testing system. The results show that the predeformed samples can exhibit high damping capacity with in a very wide temperature range, and both the peak temperature and the width of the internal peak increase with the pre-deformation level increasing. In the first heating process, the internal friction peak shows a higher peak temperature and a wider peak temperature range than that of the second heating. During the second heating process, the internal friction peak temperature decreases and the range of the peak becomes narrower than that of the first heating process. The relative modulus curves show the same variation trend. Furthermore, a stepped increasing of relative modulus curve and a peak splitting of damping curve which exhibits the temperature memory effect observed in incomplete constraint transformation.