323 機械的・熱的負荷を受ける NiTi/ポリカーボネイト形状記憶合金複合材料の変形挙動と破壊過程

Abstract

Composites containing NiTi shape memory alloy long-Fiber, short-fibers or Ti long-fiber in a Polycarbonate matrix have been fabricated by the injection molding technique. In the shape memory alloy (SMA) composites, two kind of NiTi fibers showing the shape memory effect (SME) and the psuedoelasticity (PE) at room temperature are used. Fracture behaviro under uniaxial tension and deformation behavior under thermo-mechanical loading are examined on the composites. The obtained results are as follows : (1) The stress-strain relation up to the final fracture of the SMA composites showed the repeated up-and-down of the stress which corresponds to the necking of the specimen, fiber fracture and matrix fracture. (2) The strain for the initiation of necking and the strain for the fiber or matrix fracture in the SMA composites were higher than those in the Ticomposite. This is attributed to the unique stress-strain relations accompanied by the stress-induced martensitic transformation of the SMA fibers. (3) The SMA composite containing PE fiber exhibited the psuedoelastic deformation under tensile loading-unloading. (4) The SMA composite containing SME fiber exhibited the contraction by heating after tensile loading-unloading, but the compressive residual stress in the matrix expected in this process was not remarkable.