粒子強化型アルミニウム基複合材料の微視変形過程のSEM内その場観察

抄録

In order to directly observe microscopic behavior of particles, matrix and their interfaces of particle reinforced metal matrix composites during static loading, the in situ tensile test in the scanning electron microscope equipped with a deformation stage was examined for the Al₂O₃ particle reinforced aluminum matrix composite produced with the melt stirring method. Two types of sheet tensile specimens were investigated, the one has a small hole in the center of the general tensile specimen and the another is reduced in width with a round radius. The stress and strain distributions in their specimens were analyzed by an FEM calculation and compared with observed microcracks distribution. It is possible to observe only microstructural degradation owing to structural defects without the influence of stress localization by using the latter specimen, because the stress distribution in the center part is almost homogeneous in the specimen. Some microcracks owing to the interface debonding and the particle fracture are found at early loading point before maximum loading. The microcracks do not propagate in the matrix because of its ductility, but a number of new microcracks are initiated during increasing load.