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利用旋转弯曲疲劳试验机研究了三种膜厚(10μm、15μm、20μm)的微弧氧化处理LD10铝合金的疲劳性能;采用SEM观察微弧氧化试样的表面、截面以及断口形貌;利用XRD分析微弧氧化试样的表面相组成和表面残余应力。结果表明:微弧氧化膜层由AlSi0.5O2.5非晶相组成,膜层中的微裂纹起源于放电通道(微孔),终止在通道附近区域;膜层附近基体中存在残余拉应力,促使疲劳裂纹在此形成和扩展,导致10μm、15μm、20μm三种膜厚的微弧氧化处理铝合金的疲劳寿命分别下降了63%、75%和65%,疲劳极限分别下降了9.5%、7.9%和9.9%。
The fatigue properties of LD10 aluminum alloy with three kinds of film thickness (10μm, 15μm, 20μm) were investigated by rotating bending fatigue tester. The surface, cross section and fracture morphology of micro-arc oxidation specimen were observed by SEM. The surface phase composition and surface residual stress of microarc oxidation samples were analyzed. The results show that the micro-arc oxidation film consists of AlSi0.5O2.5 amorphous phase, the micro-cracks in the film originate from the discharge channel (micropore) and terminate in the vicinity of the channel. There are residual tensile stress in the matrix near the film, The fatigue life of microalloyed aluminum alloy with thickness of 10μm, 15μm and 20μm decreased by 63%, 75% and 65%, respectively, and the fatigue limit decreased by 9.5% and 7.9% respectively % And 9.9%.