U型ノッチを有するα-Ti単結晶に生ずるすべり変形の有限要素法結晶塑性解析

抄録

The activity of slip deformation in titanium single crystal at a U-shaped notch was numerically analyzed by using a crystal plasticity finite element method. The critical resolved shear stress (CRSS) for slip system is given by the extended Bailey-Hirsch model which includes the effects of lattice friction, work hardening, and the size of microstructure. As the lattice friction stress of each slip system was assumed to be the same values in the high-temperatures, all slip systems were activated at the notch tip with the loading condition of 0.1% in nominal tensile strain. In the region of elastic deformation, strain rate at the notch tip is about 3 times larger than the macroscopic strain rate. In the reason of elastoplastic deformation, the strain rate at the notch tip is about 10 times larger than that in the macroscopic scale. The increase in the strain rate contributes to the increase in the lattice friction stress for the slip deformation. Therefore, in the present study, the plastic deformation at a notch tip was investigated by changing the CRSS for each slip systems, representing the increase in the strain rate.