摩擦攪拌による炭素鋼S45Cとダイカスト用アルミニウム合金

ADC12接合体の疲労強度特性

抄録

The butt dissimilar joints of die-cast aluminum alloy and carbon steel by means of friction stir welding were prepared for investigating fatigue properties of the joints. The FSW tool used in this study has cemented carbide thread probe and a shoulder with scroll groove made of alloy tool steel. Fatigue tests were carried out under a load-controlled condition with a stress ratio R=-1 and R=0.1 in air at room temperature. From the experimental results, it was found that fatigue strength of the joint at 107 cycles were 117 MPa under R=-1 and 72 MPa under R=0.1, respectively. The fatigue fracture was initiated from the location approximately 6-7 mm distant from the welding interface. This site was thought to be the border between the stir zone and base metal. In the base metal region, a lot of silicon particles were distributed as acicular shape. On the other hand, in the stir zone, silicon particles were distributed as fine grain shape.