铝合金的激光熔覆修复

通过对航空航天用超高强7050铝合金进行激光熔覆修复的实验研究,探讨了激光熔覆修复铝合金的可行性。实验采用5kWCO2连续激光器作为加热源,在惰性气体保护隔离箱中,对7050铝合金的板状试样进行了激光单道熔覆、多道搭接熔覆、多层堆积熔覆的实验研究。得到优化的激光熔覆工艺参数,制备了激光熔覆修复试样,并观察了不同激光熔覆区的微观组织以及拉伸断口形貌。实验结果表明,优化激光熔覆工艺参数是:激光功率密度为1.84×104～2.12×104W/cm2,扫描速度为5mm/s,送粉量为1.8～2.4g/min,搭接宽度为1.5mm。采用优化工艺参数熔覆,基底和熔覆区形成良好的冶金结合,熔覆后工件表面平整且基底没有变形。同时,采用干燥的氩气加强对激光熔池的保护可以有效消除铝合金激光熔覆中的缺陷。

Laser Cladding Reparation of Aluminum Alloy

Experiment of repairing aluminum (Al) alloy 7050 (Al 7050) by laser-cladding techniques was investigated. A 5 kW CO2 laser was used as the heat source. Experiemnts of single trace cladding, multi-trace overlapping cladding, and multi-layer cladding were performed on the Al 7050 plates shielded in a closed box with inert gas. A set of optimized laser-cladding repairation parameters for damaging Al 7050 samples were found, and the microstructures in different cladding regions and micro-appearances of fracture surface were studied. The optimized laser-cladding repairation parameters were laser power of 1.84×104～2.12×104 W/cm2, scanning speed of 5 mm/s, powder feeding rate of 1.8～2.4 g/min, and overlapping width of 1.5 mm. With the optimized repairing parameters, the cladding zone displayed a superior metallurgical bonding with its substrate, the repaired sample surface appeared smooth without any substrate distortion, and the defect formation in the cladding zone was effectively prevented by strengthening shielding of the molten pool with dry argon.