变形铝合金激光熔覆工艺研究

为应用激光熔覆法修复涡桨发动机螺旋桨叶腐蚀损伤，利用CO2连续激光器在LYl2基材表面进行铝基合金粉末熔覆试验。分析了激光功率、扫描速度和光斑直径等工艺参数对熔覆效果的影响，观测了熔覆层的组织特征与性能。结果表明，要获得表面平整、内部无明显缺陷的熔覆层，存在激光功率阈值；熔覆层高度和熔深以及稀释率随激光功率的增加而增大，随扫描速度而降低；熔覆层的宽度主要取决于光斑直径。熔覆层组织为均匀细小的等轴晶，靠近基体界面的位置有较大尺寸的柱状晶存在，晶轴与熔合线垂直，尺寸可达20gm以上。熔覆层的显微硬度在100～110HV之间，较基体降低约30％。

Research on Laser Cladding of Deformed Aluminum Alloy

For repairing the aluminum alloy component of aircraft by laser cladding, an experiment of laser cladding on LY12 substrate was carried out using a continuous CO2 laser beam with AI based powder in the argon atmosphere. The effects of processing parameters on the cladding layer were examined, and the layer microstructure was investigated. It was found that there was a threshold of laser power to get a sound layer with smooth appearance and no apparent inside poles and cracks. The cladding height and penetration into the substrate increased as the laser power going up and reduced when the scanning speed increased; the width of layer was dependent on the laser beam diameter. The microstructure of the layer consisted of equiaxial crystal dispersed in the layer and columnar grains, whose axial direction near the substrate was perpendicular to the interface The microhardness of the layer was a little lower than that of LY12 substrate