添加镍颗粒的铝/钛异种材料电阻焊接头力学性能及显微组织分析

使用三相次级整流电阻焊机对LY12铝合金/TC4钛合金进行电阻点焊，并在板材中间添加了镍颗粒. 结果表明，最佳工艺参数为电极压力3.03 kN，预热脉冲焊接电流7.5 kA/10 cyc(1 cyc=0.02 s)，焊接脉冲焊接电流12.1 kA/45 cyc，缓冷脉冲焊接电流7.5 kA/10 cyc，接头的最大拉剪力为7.12 kN. 铝合金侧熔核的显微组织为细小的等轴晶，钛合金侧熔核的显微组织为针状马氏体，IMC层由靠近铝合金侧的一层1～2 μm厚的NiAl3和在钛合金/铝合金之间散乱分布着的TiAl3共同构成.

Microstructure and mechanical properties of joint of titanium alloy/aluminum alloy by resistance spot with Ni particles

Resistance spot welding is used to weld LY12 aluminum alloy /TC4 titanium alloy with Ni particles by 3-phase DC resistance welding machine. The results show that the optimal parameters of welding joint with Ni particles are as follows. The electrode pressure is 3.03 kN, the welding current in the first pulse is 7.5 kA, and the welding time in the first pulse is 10 cyc (1 cyc=0.02 s). The welding current in the second pulse is 12.1 kA, and the welding time in the second pulse is 45 cyc. The welding current in the third pulse is 7.5 kA, and the welding time in the third pulse is 10 cyc. The maximum tensile shear strength of the welding joint with Ni particles is 7.12 kN. The microstructure of aluminum alloy side of nuclear fusion is coarse columnar crystal,and the microstructure of titanium alloy side of nuclear fusion is coarse acicular martensite. The main component of the IMC layer is a layer of 1～2 μm thick planar NiAl3 which is close to the aluminum side, and white massive TiAl3 in scattered distribution between titanium alloy and aluminum alloy in the welding joint with Ni particles.