空化超声滚压对7075铝合金表面质量的影响

Effect of cavitation ultrasonic rolling on surface quality of 7075 aluminum alloy

目的 为了研究超声滚压加工过程中空化效应对零件表面质量的影响,方法 以车削后的7075-T6铝合金为加工对象,进行空化超声滚压和普通超声滚压工艺对比试验,使用表面粗糙度仪测量加工后的工件表面粗糙度,采用显微硬度计测量工件表面显微硬度,并用超景深测量仪测量工件表面微观形貌。结果 结果表明,普通超声滚压和空化超声滚压均能降低滚压加工后的工件表面粗糙度,增大表面显微硬度。随着静压力增大,两种超声滚压加工方式获得的表面粗糙度均呈逐渐降低趋势,而表面显微硬度均呈逐渐增大趋势。超声滚压加工通过削峰填谷作用使工件表面变光滑。相对于普通超声滚压,空化超声滚压的空化效应引起的冲击波和微射流可以进一步促进材料表层的塑性流动,使工件表面经空化超声滚压加工后能获得更低的表面粗糙度和更高的显微硬度,更加平整。在本文试验条件下,空化超声滚压加工后的表面粗糙度最低可达0.038μm,表面显微硬度最高可达210.07 HV0.1。相同静压力下,空化超声滚压加工相较于普通超声滚压加工,表面粗糙度最大可降低42.2%,表面显微硬度最大可提升2.6%。结论 试验证实了在超声滚压加工过程中引入空化效应可进一步提高工件表面强化质量。

Objectives To explore the influence of cavitation effect on the surface quality of parts in ultrasonic rolling processing,Methods the comparison tests including cavitation ultrasonic rolling and ordinary ultrasonic rolling were carried out on 7075-T6 aluminum alloy after turning.The surface roughness of the processed workpiece was measured by a surface roughness meter,the surface microhardness was measured by a microhardness tester,and the surface micro-morphology was measured by a large depth-of-field ultracompact microscope.Results The results showed that,both ordinary ultrasonic rolling and cavitation ultrasonic rolling could reduce the surface roughness and increase the surface micro-hardness of the workpiece after rolling processing.With the increase of the static load in the two ultrasonic rolling processing methods,the surface roughness of workpieces decreased gradually and the surface microhardness increased gradually.Ultrasonic rolling processing made the workpiece surface smoother through the beneficial effect of peak cutting and valley filling.Compared with ordinary ultrasonic rolling,the shock wave and micro-jet caused by cavitation effect could further promote the plastic flow of the material surface layer,which could produce lower surface roughness and higher micro-hardness after cavitation ultrasonic rolling processing,with a much more flatter surface of the workpiece.Under the test conditions of this study,the surface roughness after cavitation ultrasonic rolling processing could be as low as 0.038 μm,and the surface micro-hardness could be as high as 210.07 HV0.1.Under the same static load,the surface roughness after cavitation ultrasonic rolling processing could be reduced by up to 42.2% and the surface hardness could be increased by up to 2.6% when compared with the ordinary ultrasonic rolling processing.Conclusions It was proved that the introduction of cavitation effect in the ultrasonic rolling processing could further improve the surface strengthening quality.