搅拌摩擦焊工艺参数对铸造AlSi14合金焊接接头性能的影响

摘要

The microstructures, mechanical properties and fracture morphology of AlSi14 high silicon aluminum alloy friction stir welded joints with different welding parameters were investigated. The results show due to the occurrence of dynamic recrystallization, the grain of nugget zone is very fine. Thermo-mechanically affected zone is close to nugget zone and the elongated microstructure appears at a higher speed. Compared with the base metal, the grain size ofαphase and the eutectic Si grains in the heat affected zone is increased. With 1300 r/min of tool rotational speed and 100 mm/min of the welding speed, the tensile strength of the joint can reach 92% that of the base metal. The fracture occurs in the heat affected zone of the advancing side, and the fracture is a mixture mode of brittle and gliding fracture. The micro-hardness of the joint is approximately the shape of the saddle, the hardness of the base metal is higher, and it is lower near the heat affected zone.%研究了采用不同焊接工艺参数时铸造AlSi14高硅铝合金搅拌摩擦焊接头的微观组织、力学性能及断口形貌.结果表明,焊核区组织由于发生动态再结晶,晶粒非常细小;热力影响区紧靠焊核区,在较高转速时出现被拉长的组织;热影响区基体α相及共晶Si晶粒尺寸相对于母材均有所增加.在搅拌头转速为1300 r/min、焊速为100 mm/min时,获得的接头抗拉强度可达到母材的92%;断裂发生在前进侧热影响区,断裂方式是韧性与脆性的混合型断裂;接头显微硬度近似呈"马鞍"形分布,在热力影响区附近硬度低于母材硬度.