摩擦攪拌によるS45C/A6063接合体の強度特性におよぼす応力比の影響

抄録

The butt dissimilar joints of Al-Mg-Si alloy A6063 and carbon steel S45C by means of friction stir welding (FSW) were prepared for investigated the effect of stress ratio on the fatigue properties of the joints. Fatigue tests were carried out under a condition of stress ratio R=-1. From the experimental results, it was found that the fatigue strength at 10⁷ cycles of the joint was around 80 MPa. This fatigue strength was significantly higher than that under the condition of stress ratio R=0.1. Two types of fatigue fracture occurred in this study. The first one was fracture at boundary between the lower hardness region and base material in A6063, and the last type was fracture around the welding interface. This tendency was similar to the results under the condition of R=0.1. Furthermore, plastic deformation around the fracture surface for the condition of R=-1 was not so significant as compared to that under the condition of R=0.1.