中文摘要：

2060铝锂合金是新一代铝锂合金中具有更低密度及更高强度的典型代表。利用高功率光纤激光填充ER2319焊丝对2060铝锂合金进行了对接试验,借助光学显微镜、扫描电镜、显微硬度测试、拉伸性能测试等手段研究了焊缝形貌和组织特征及焊缝的力学性能等。研究结果表明,焊接稳定性在一定程度上影响焊缝的宏观成形,在合理的焊接工艺下,焊接功率P=3kW与填丝速度w=3m/min保持不变,随着焊接速度的增加,焊缝整体的晶粒尺寸呈现变小的趋势,枝晶臂由繁多变得简单,等轴枝晶的二次枝晶逐渐减少甚至消失;焊缝的平均硬度达到95.7HV,抗拉强度达到了345MPa,分别为母材2060合金的63.0%和65.1%;焊缝的熔合线附近区域是接头的最薄弱环节,拉伸断裂沿熔合线从焊缝的下部向上扩展,断口表现为沿晶界的韧脆混合断裂,焊缝下部的韧性优于焊缝的上部。

英文摘要：

2060 Al Li alloy is one of the typical representatives on a new generation of aluminum lithium alloy with lower densi- ty and higher strength. In this paper, 2060 Al Li alloy was tested by means of high power laser beam welding filled with ER2319 wire. The morphology, microstructure and mechanical properties of the weld were studied by means of optical micro- scope, scanning electron microscope, micro hardness test and tensile test. The results show that, to some certain extent, the welding stability has effects on the formation of the weld. In the reasonable welding process, with the increase of welding speed in welding power P=3 kW and wire filling speed w=3 m/rain, the overall grain size of the weld is becoming smaller and smal- ler, and a wide variety of dendrite arm becomes simple. The second dendrite of the equiaxed dendrite crystals gradually reduced or even disappeared. The average hardness of the weld reaches 95.7 HV, and the tensile strength reaches 345 MPa, which are 63 % and 65.1 % of the base metal 2060 alloy respectively. The area near the fusion line of the weld is the weakest link, and the tensile fracture is extended from the lower part of the weld to the upper part along the fusion line. The fracture morphology be- longs to the mixed fracture of toughness and brittleness along the grain boundary. The toughness of the lower part of the weld is superior to the upper part of the weld.