Development of simultaneous process of precursor fabrication and foaming using friction stir welding

Porous aluminum is lightweight and has excellent shock absorption properties. It is expected to be used for automobile parts. In recent years, friction stir welding (FSW) has been used for welding automotive members. We have been attempting to fabricate porous aluminum using FSW. In this study, we placed laminated Al-Si-Cu ADC12 alloy die-casting plates (ADC12 plates) and blowing agent powder into the groove of an SS400 plate, then traversed the top tool on the ADC12 plates to mix the blowing agent powder into the ADC12 plates to fabricate a precursor. After traversing the top tool, we traversed the bottom tool from below the SS400 plate to foam the ADC12 precursor with the frictional heat generated while traversing the bottom tool. It was shown that a precursor can be fabricated at v=10-50 mm/min by traversing the top tool. In addition, the obtained precursor can be sufficiently foamed with fine pores at a bottom-tool traversing speed of v=20 mm/min. © 2021 The Japan Institute of Light Metals.