7075铝合金搅拌摩擦连接性能分析

Performance Analysis of 7075 Aluminum Alloy Friction Stir Connection

采用单道对接连接的形式对7075铝合金进行搅拌摩擦连接试验,研究了不同参数下的微观组织和性能。结果表明:连接区中心与前进侧热机影响区分界线较为明显,与后退侧的分界线不明显。固定旋转速度为1000 r/min,随着进给速度从100 mm/min增大到300 mm/min,连接区抗拉强度先增大后减小,当进给速度为200 mm/min时,抗拉强度最高,达到了487.3 MPa,是母材的89.4%,当进给速度为300 mm/min时,抗拉强度较低,但也达到了母材的78.8%。连接区横截面维氏硬度呈“W”形分布,连接区中心硬度高于热影响区硬度,但低于母材硬度。各试样的磨损机理为黏着磨损和磨粒磨损,其中试样2的摩擦系数与磨损量均为最小,耐磨性最高。

The friction stir joint test of 7075 aluminum alloy was carried out in the form of single channel butt joint,and the microstructure and properties of 7075 aluminum alloy were studied under different parameters.The results show that the boundary between the center and the forward side of the connection zone is obvious,but the boundary between the center and the backward side is not obvious.The fixed rotation speed is 1000 r/min.As the feed speed increases from 100 mm/min to 300 mm/min,the tensile strength of the connection areas first increases and then decreases.When the feed speed is 200 mm/min,the tensile strength reaches 487.3 MPa,which is 89.4%of the base material.When the feed speed is 300 mm/min,the tensile strength is low,but it also reaches 78.8%of the base material.The Vickers hardness in the cross section of the connection zone is"W"shape distribution,and the hardness in the center of the connection zone is higher than that in the heat affected zone,but lower than that in the base material.The wear mechanism of each sample is adhesive wear and abrasive wear,among which the friction coefficient and wear amount of sample 2 are the smallest,and the wear resistance is the highest.