高速固相接合した2024アルミニウム合金スタッドと6N01アルミニウム合金板の界面組織と機械的性質

Abstract

2024-T3 aluminum alloy studs were welded to 6N01-T6 aluminum alloy plates by using an advanced high-speed solid-state joining method. Plastic deformation of a projection was promoted with increasing discharge voltage. As the result, joining area and joint strength increased. Fracture stress was about 300 MPa in all discharge voltage. In the case of thin plate, the outside region was subjected to higher temperature than the inside region, which caused asymmetrical deformation. In contrast, the deformation was symmetrical in the case of thick plate, because temperature similarly rose in both inside and outside. This resulted in the increased joining area and joint strength with increasing plate thickness. Vickers hardness profile was also measured across the weld interface. The softened zone was appeared at the 6N01-T6 aluminum alloy plate adjacent to the weld interface. Hardness of the softened zone was recovered to that of 6N01-T6 aluminum alloy after post-weld aging. This result indicated that softening was caused by dissolving β″precipitates in the aluminum matrix due to the welding heat input.