钛/铝激光焊接的微观组织及力学性能

Microstructure and Mechanical Properties of Laser Welded Ti/Al Alloys

采用3 kW光纤激光偏置铝侧焊接的方式,完成了TC4钛合金和6082铝合金的连接。测试了接头的宏微观组织及力学性能特征,通过有限元方法对接头的温度场分布及钛/铝结合界面的热循环曲线进行了模拟。研究结果表明,钛/铝激光偏置焊接可获得无裂纹、无气孔,具有良好拉伸强度的接头,钛试板在焊接过程中发生部分熔化,端面变得不平整。在凝固过程中,钛/铝结合界面会形成一个厚度较薄的钛/铝金属间化合物层,其主要相为TiAl_3。拉伸试验表明,接头的最高抗拉强度为153 MPa,是铝基材强度的72.9%;接头的断裂模式为脆性解理断裂,断裂发生在金属间化合物层位置,引起断裂的脆性相为TiAl和TiAl_3。

The welding of TC4 Ti alloy and 6082 Al alloy is realized by 3 kW fiber laser offset welding on Al sheets. The macro- and micro-structures and mechanical properties of joints are tested. The temperature field distribution of joints and the thermal cycling curves at Ti/Al interfaces are simulated by the finite element method. The results show that the joints without cracks and porosity and with good tensile strength can be obtained by Ti/Al laser offset welding. During the welding process, the Ti substrate is partially melted and its surface becomes uneven. In the solidification process, there occurs a thin intermetallic compound layer at the Ti/Al bonding interface, whose main phase is TiAl3. The tensile test show that the maximum tensile strength of joints is 153 MPa, 72.9% that of Al substrate. The fracture mode of joints is a brittle cleavage one. The fractures occur in the intermetallic compound layer, and brittle phases which cause the fracture are TiAl and TiAl3.