搅拌摩擦焊修复ZL210铸造铝合金组织与性能分析

Microstructure and mechanical properties of ZL210 casting Al alloy repair using friction stir welding

鉴于铸件中存在不可避免的缺陷,以ZL210合金为研究对象,对搅拌摩擦焊修复技术进行试验研究,重点分析转速对修复接头微观形貌和力学性能的影响.结果表明,当转速过低时,修复区容易出现孔洞缺陷;在合理的焊接参数组合下可得到无缺陷的焊核区,其由细小的等轴晶组成.修复区的显微硬度呈"W"分布,热影响区的宽度随转速增加而增加.另外,随着转速的增加,修复区的抗拉强度先增加后减小;当转速为1 500 r/min,修复区的抗拉强度和断后伸长率达到最大值,分别为318 MPa和11.8%.断裂形貌表明修复后材料呈现典型的韧性断裂.

In view of the unavoidable defects in casting structure,friction stir welding( FSW) was performed to repair ZL210 casting Al alloy. Effects of rotational speeds on microstructures and mechanical properties were mainly investigated.The experimental results showed that the cavity defect appeared in stir zone( SZ). The defect-free SZ could be attained under reasonable welding parameters and was featured by fine and equiaxed grains. The hardness distribution of repaired region presented W-shape,and the width of heat affected zone( HAZ) increased with the increasing of the rotational speed. In addition,with the increase of rotational speed,the tensile properties of repaired region firstly increased and then decreased. The maximum tensile strength and elongation of repaired region were attained at1 500 r/min and the values were 318 MPa and 11. 8% respectively. The fracture surface morphologies showed the ductile fracture of repaired region.