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    表面机械滚压及滚压道次对7075铝合金组织和耐磨性能的影响

    Effect of Surface Mechanical Rolling and Rolling Passes on Microstructure and Wear Resistance of 7075 Aluminum Alloy

    • 摘要: 对7075铝合金分别进行一道次、三道次、五道次表面机械滚压处理(SMRT),研究了表面机械滚压及滚压道次对合金显微组织、显微硬度及耐磨性能的影响。结果表明:SMRT后试验合金的表层发生变形,表面粗糙度增加,表面晶粒细化,形成由表及里晶粒尺寸增大的梯度结构;表层显微硬度升高,且由表及里呈逐渐降低的梯度分布;平均摩擦因数和磨损率降低,耐磨性能提高。随着滚压道次增加,试验合金的变形层厚度增加,表面粗糙度增大,表面平均晶粒尺寸减小,表面显微硬度升高,平均摩擦因数和磨损率下降,耐磨性能提升。表面机械滚压处理后,主要磨损机制由磨粒磨损转变为疲劳磨损和磨粒磨损的复合形式;随着滚压道次增加,剥落现象减轻,犁沟与磨屑减少。

       

      Abstract: 7075 aluminum alloy was subjected to surface mechanical rolling treatment (SMRT) with one, three, and five passes, respectively. The effects of SMRT and the number of rolling passes on the microstructure, microhardness, and wear resistance of the alloy were investigated. The results show that after SMRT, the surface layer of the test alloy was deformed, surface roughness increased, and surface grains were refined, forming a gradient structure with grain size increasing from the surface toward the interior; the surface microhardness was increased, exhibiting a gradually decreasing gradient distribution from the surface to the interior; the average friction coefficient and wear rate were reduced, and the wear resistance was improved. As the number of rolling passes increased, the deformation layer thickness of the test alloy increased, surface roughness increased, surface average grain size decreased, surface microhardness increased, average friction coefficient and wear rate decreased, and wear resistance was further enhanced. After SMRT, the wear mechanism transitioned from abrasive wear to a combined mode of fatigue wear and abrasive wear. With the increase of rolling passes, spalling was reduced, and both plowing grooves and wear debris decreased.

       

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