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采用脉冲激光焊接方法对SiCW/ 6 0 6 1Al复合材料进行焊接试验。研究了试件表面处理状态、保护气体、激光输出功率、焊接速度、激光脉冲频率等工艺参数对焊接质量的影响规律。试验结果表明 ,激光输出功率和焊接速度对焊缝的显微组织和焊接质量都有较大的影响 ,激光脉冲频率的变化对焊接质量有一定的影响 ,而试件表面的处理状态对焊接质量影响不大。同时发现 ,利用N气代替Ar气也取得了较好的保护效果。利用扫描电镜和透射电镜对焊缝进行显微观察 ,从微观角度分析了焊缝接头强度损失的机理 ,认为焊接时SiC晶须与基体Al发生反应而烧损及生成较脆的界面反应物是造成接头强度下降的重要原因。提出了临界硅活度α[Si]min的概念 ,成功实现了铝基复合材料SiCW/ 6 0 6 1Al的激光焊接。
The welding experiment of SiCW / 6 0 6 1Al composite was carried out by pulsed laser welding. The effects of the surface treatment conditions, shielding gas, laser output power, welding speed and laser pulse frequency on the welding quality were studied. The experimental results show that the laser output power and welding speed have a great influence on the microstructure and welding quality of the weld. The change of the laser pulse frequency has a certain influence on the welding quality. However, Has little effect. Also found that the use of N gas instead of Ar gas also achieved good protection. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the weld seam microstructure, and the mechanism of strength loss of weld joint was analyzed from the microscopic point of view. It is concluded that SiC whisker reacts with matrix Al and burns out and produces relatively brittle interface reactant Cause the joint strength of the important reasons. The concept of the critical silicon activity α [Si] min is put forward and the laser welding of SiC / 6 0 6 1Al aluminum matrix composites is successfully achieved.