【作者】 韩娟娟； 郑伟； 王广春；

【Author】 Han Juan-juan;Zheng Wei;Wang Guang-chun;Shandong University;Shandong Jianzhu University;

【机构】 山东大学； 山东建筑大学；

【摘要】 通过宏微观尺度下的纯铜圆柱镦粗实验,分别研究了试样尺寸、平均晶粒尺寸、模具表面粗糙度对干摩擦条件下微塑性成形摩擦尺寸效应的影响。研究结果表明:随着试样尺寸的增加,接触面上的摩擦因子逐渐增大。引入试样直径尺寸与平均晶粒尺寸的比值t研究微成形过程摩擦尺寸效应的变化,结果表明:当t小于0.7尤其是小于0.2时,随着t值的减小,接触面上摩擦因子的变化幅度增大,摩擦的尺寸效应程度增大;而当t大于0.7时,随着t的增加摩擦因子的变化不大,尺寸效应逐渐消失。同时研究了模具表面粗糙度对接触面上的摩擦因子的影响,结果表明:随着模具表面粗糙度的增加,接触面上的摩擦因子逐渐增大。试样尺寸越小,接触面上的摩擦因子对模具表面粗糙度变化越敏感。同时随着模具表面粗糙度的增大,摩擦的尺寸效应程度降低。更多还原

【Abstract】 In this work, the cylindrical upsetting experiments of pure copper under macro and micro scale were carried out and the effects of specimen size, grain size and tool surface roughness on dry friction in micro-forming process were studied. In order to study the mechanism of the size effect on friction behavior, the ratio of specimen size D to grain size d(t=D/d) is introduced as a scale parameter. A higher friction factor on the contact surface is found as the ratio t is higher in the experimental results. The effects of tool surface roughness on friction behavior were also studied through the upsetting tests under disks in different surface roughness in our work. And a rising trend of friction factor on the contact surface is observed with the increasing of tool surface roughness. The increase ratio of friction factor is chosen to study the effects of tool surface roughness on friction. It turns out that the increase ratio of friction factor is larger for the smaller specimen and the degree of friction size effect decreases with the increasing of tool surface roughness.更多还原