喷射成形7055铝合金MIG焊接头组织与力学性能

Microstructure and mechanical property of welded joint of spray forming 7055 aluminum alloy by MIG welding process

对喷射成形和热挤压工艺制备的7055铝合金进行MIG焊焊接试验。对焊接接头组织及其力学性能进行了研究,试验结果表明:焊缝组织主要为树枝状晶,熔合区靠近焊缝一侧为柱状晶,靠近热影响区一侧为等轴晶,热影响区为粗大的等轴晶组织;接头的抗拉强度为112.5 MPa,焊接系数约为0.68;拉伸断口扫描观察显示,接头的断裂特征呈现为韧性断裂和脆性断裂。

7055 aluminum alloy was welded with MIG welding process, which was made by the way of spray forming and hot extrusion. The mechanical properties and microstructure of the welded joint were studied. The results showed that the crystallizing morphology on the weld was dendrites, and close to the side of the fusion area were columnar crystals, close to the side of HAZ was equiaxed grains, the thick of equiaxed grains was the characteristic of HAZ. The tensile strength of the welded joint reached 112.5 MPa, and the welding coefficient was about 0.68. SEM observation indicated that the fracture surface morphology of joint presented the obvious mix fracture characteristic of ductilefracture and brittle fracture.