PRECIPITATION PHENOMENA IN FRICTION STIR WELDED 6000-SERIES ALUMINIUM ALLOY WITH PAINT-BAKE-HARDENING RESPONSE

摘要

Recently, the 6000-series aluminium alloy with paint-bake-hardening response has been used in automotive industry for outer panels. In the car-body production, there is a possibility that friction stir weld of this alloy is subjected to press forming, followed by bake-hardening process. Therefore, distributions of local mechanical properties and bake-hardening responses, and effect of introduced strain on bake-hardening response should be understood in the weld. In the present study, changes in the precipitate distribution associated with hardness profile during bake-hardening process were investigated in the weld. Additionally, effect of strain on bake-hardening response in the weld was also examined.