表面纳米化对7055铝合金耐磨性能的影响

为了研究表面纳米化对7055铝合金耐磨性能的影响,利用高能喷丸(High Energy Shot Peening, HESP)技术对7055铝合金材料进行表面纳米化处理,在7055铝合金表面获得纳米结构。利用透射电镜分析纳米化前后微观组织的变化,同时对纳米化材料表层进行残余应力及显微硬度测定,并采用球盘磨损试验机研究了纳米化表面对固定载荷条件下7055铝合金材料磨损性能的影响。结果表明：表面纳米化使7055铝合金材料表面发生严重塑性变形,材料表面分布较高幅值残余压应力,最大可达到-369MPa, 残余压应力层深度达0.6mm；纳米化后试样显微硬度较基体提高了50%。摩擦磨损实验表明：表面纳米化从一定程度降低了7055铝合金材料表面摩擦系数,且磨损失重是未处理试样的32%,表明高能喷丸表面纳米化有效改善了7055铝合金材料的耐磨性能。

Effects of Surface Nano-crystallization on Wear Behavior of 7055 Aluminum Alloy

High Energy Shot Peening (HESP) was used to treat the material surface in order to study the effects of surface nano-crystallization of 7055 aluminum alloy on wear behavior. The nano-crystalline layer was obtained on sample surface. TEM was used to analyze the microstructure before and after nano-crystallization, meanwhile, residual stress and micro-hardness were measured on surface, and wear behaviors of nano-crystalline surface were examined by reciprocating wear tester as well. The experiment results show that, HESP caused severe plastic deformation on surface, and there exits compressive residual stress with large magnitude on surface, and the maximum value is -369MPa, meanwhile, the compressive residual stress layer come up to 0.6mm.The micro-hardness increases by 50% compared to matrix. The frictional wear experiments show that, HESP nano-crystallization can apparently decrease friction factor, and the wear loss is only 32% of untreated samples, HESP largely improved the wear-resisting property of 7055 aluminum alloy.