ポリプロピレン－銅メッシュ複合材料の塑性変形過程における不均一変形の評価

Abstract

To improve the plastic instability of a thermoplastic polymer composite under cold forming, a copper mesh was filled into the polypropylene (PP). PP-Cu mesh composite plate specimens with the Cu mesh inclined in various directions were formed by the compression molding of the PP pellet and Cu mesh. First, the tensile behavior of Cu meshes with the angles of 0/90°, 15/75°, 30/60° and 45° to the tensile direction was examined. The maximum stress decreased gradually with increasing Cu mesh angle to the tensile direction because the Cu wires rotated in the tensile direction. The anisotropic response was also confirmed for the PP-Cu mesh composite, and the anisotropy was emphasized for composites with the higher volume fractions of the Cu mesh. The decrease in the nominal stress, which is often seen in the tensile deformation of the thermoplastic polymer, almost disappeared for the composite specimen with the Cu mesh at the angle of 45° to the tensile direction. Also, the deformation concentration in the specimen was effectively suppressed by reducing the deformation resistance in the early stage of deformation and by increasing the strain hardening after yielding.