Mechanism to produce high performance by combining shape memory alloy fibers and its application to material development

为了阐明形状记忆合金纤维与常规材料相结合产生独特性能的机理，开发新型功能复合材料，对形状记忆合金复合材料在热机械载荷作用下的变形行为进行了数值分析和实验测试。所得结果总结如下.基于剪切滞后模型，建立了一个预测形状记忆合金复合材料在热机械载荷作用下变形的力学模型。基于该模型对形状记忆合金复合材料的变形进行了数值分析，探讨了形状记忆合金复合材料独特性能的机理和可能性.以NiTi纤维和聚碳酸酯为原料，采用注射成型工艺制备了形状记忆合金复合材料。研究了复合材料在单轴拉伸下的断裂行为和在热机械载荷下的变形行为。结果表明，形状记忆合金复合材料除了具有形状记忆效应和伪弹性变形外，还具有较高的强度和塑性、基体中产生残余压应力、加热收缩等特性，其独特的性能是由形状记忆合金纤维的形状记忆效应和伪弹性行为与弹性、塑性和塑性相互作用而产生的。基体的弹塑性和粘塑性行为。并对制备具有独特性能的复合材料提出了建议。

In order to make clear the mechanism to produce unique performance by combining shape memory alloy fibers to the conventional materials and to develop new functional composite, numerical analysis and experimental tests on the deformation behavior of shape memory alloy composites have been carried out under thermo-mechanical loading. Obtained results are summarized as follows.1. Amechanical model, which can predict the deformation of shape memory alloy composites under thermo-mechanical loading, was developed based on the shear-lag model. Numerical analysis based on this model was carried out on the deformation of shape memory alloy composites, and mechanism and possibility of unique performance of the composites was discussed.2. Shape memory alloy composites was fabricated by injection molding technique using NiTi fibers and polycarbonate. Fracture behavior under uniaxial tension and deformation behavior under thermo-mechanical loading were examined on the composites. It is found that the composites show the high strength and ductility, creation of compressive residual stress in matrix, contraction by heating, in addition to the shape memory effect and psuedoelastic deformation.From the above results, it is found that the unique performance of the shape memory alloy composites is produced by interaction between the shape memory effects and psuedoelastic behavior of the shape memory alloy fibers and the elastic, elasto-plastic and visco-plastic behavior of the matrix. Furthermore, many suggestions to produce the composite with unique performance were obtained.