激光熔覆对铝合金疲劳性能的影响

对模拟腐蚀损伤的铝合金试样表面进行了激光熔覆填充处理,分析了激光熔覆层的显微组织,并对熔覆试样和基材试样进行了疲劳寿命对比实验。结果表明,表面激光熔覆会显著降低材料的疲劳性能,在99%可靠度的前提下,熔覆试样的安全寿命比基材试样有所降低。其主要影响因素有熔覆层底部的枝晶、重熔区内的缺陷和熔覆层内的拉应力。经过表面机械冲击后,疲劳性能得到显著提高,提高幅度为244%,疲劳断口形貌表明,熔覆层有明显的疲劳特征。

Effect of Laser Cladding on Aluminum Alloy Fatigue Properties

Laser surface cladding is used to repair corrosion damage of Aluminum alloy that is used on propeller of aeronautical engine. Four-group specimens were tested for the comparison of the fatigue life during two-step-experiment. The effect on fatigue properties of the laser cladding layer of Aluminum alloy were discussed. The results show that the dendrite, micro pore and tensile stress of cladding layer are the factors to reduce fatigue properties; the fatigue life of laser cladding specimens is shorter than substrate material specimen. Using mechanical shocking process on every cladding layer will improve fatigue properties; the fatigue life of shocked specimens is about 3.44 times the length of the claddings.