540 SiC粒子とAl_2O_3whiskerハイブリッドMMC破壊強度に及ぼすウィスカの方位の影響(OS7-2 微視構造を有する材料の変形と破壊,OS7 微視構造を有する材料の変形と破壊)

抄録

In this study, the effect of whisker/particle orientation on monotonic and fatigue strength of aluminium cast alloy locally reinforced by SiC particles and Al_2O_3 whiskers are investigated. The material is monotonically and cyclically deformed to failure at room temperature. A significant effect of reinforcement orientation on the monotonic strength and fatigue strength are observed experimentally and numerically. With respect to the stress direction whisker orientation gives significant difference in strength of this material. SEM analysis shows almost all whiskers are transversely debonded when whisker direction is perpendicular to the stress direction and almost all whiskers are broken when the whisker direction is parallel to the stress direction. A three-dimensional single whisker unit cell model of cylindrical shape whisker in the periodic boundary condition is conducted using finite element method (FEM) to describe the overall behavior of the composite. Numerical results is in good agreement with the experimental results.