攪拌領域を拡張させたFSWによるS45C/ADC12接合体の疲労強度特性

抄録

The butt dissimilar joints of carbon steel JIS-S45C and die-cast aluminum alloy ADC12 by means of friction stir welding with extended stir zone by friction stir processing were prepared for investigating fatigue properties of the joints. The joints of ADC12 and ADC12 with extended stir zone were also prepared for comparison in fatigue properties. Fatigue tests were carried out under a load-controlled condition with a stress ratio R=-1 in air at room temperature. From the experimental results, it was found that in case of the conventional S45C/ADC12 joints, fatigue fracture were initiated around the border between the region where the silicon particles were distributed as acicular shape and the region where the silicon particles were distributed as fine grain shape. In case of the joints of ADC12 and ADC12 with extended stir zone, fatigue fracture also occured around the border between two types of state in the silicon particles. On the other hand, in case of the joints of ADC12 and ADC12 with extended stir zone, there were cases fatigue fracture occured at welding interface. The reason was thought to be the growth in intermetallic compound at welding interface by extending stir zone process.