Zn-Cu-Ti合金搅拌摩擦焊与激光焊接头组织与性能对比研究

通过金相显微镜、扫描电镜和显微硬度测试等分析手段,研究了Zn-Cu-Ti合金搅拌摩擦焊接头与激光焊接头的组织和性能。结果表明,Zn-Cu-Ti合金搅拌摩擦焊接头主要分为母材区、热机影响区、焊核区,其显微组织分别为纤维组织、拉伸弯曲变形组织、细小的晶粒;接头各区域硬度分布为:母材区>热机影响区>焊核区;接头的抗拉强度153.8 MPa,延伸率为6.7%,发生偏向脆断的准解理断裂。激光焊接头主要分为母材区、熔合区、焊缝区,焊缝区中心位置上下表面有凹坑,其内部有多条排列规则且形状近似抛物线的熔合线,并存在较明显的夹杂;接头各区域硬度分布为:母材区<熔合区<焊缝区;接头的抗拉强度为110.3 MPa,延伸率仅为4.7%,发生脆性断裂。

Contrastive Analysis of the Microstructure and Properties of the Joints Prepared by Friction Stir Welding and Laser Welding for Zn-Cu-Ti Alloy

The microstructure and properties of the joints of Zn-Cu-Ti alloy prepared by friction stir welding (FSW) and laser welding were investigated by means of OM, SEM and micro-hardness testing. The results showed that the FSW joint was mainly divided into parent material zone (PMZ), thermal-mechanically affected zone (TMAZ) and weld nugget zone (WNZ), being of fiber structure, tensile and bending deformation structure, as well as fine and dense grain structure, respectively. Moreover, the hardness distribution of each part of the joint was in the following order: PMZ>TMAZ>WNZ. In addition, the FSW joint had the tensile strength of 153.8 MPa and the elongation of 6.7%, and the quasi-cleavage fracture trending toward brittle was observed. While the laser welded joint was mainly divided into PMZ, fusion zone and weld zone. The weld zone had tiny dents on the upper and lower part of surfaces. There were many fusion lines in regular arrangement with shape similar to parabola, and some obvious inclusions in the weld zone. The hardness distribution of each part of the joint was in the following order: PMZ