中文摘要：

文章以石墨粉末作为固体润滑剂，在不同接触压力和粉末层厚度下，对铝合金进行了一系列塑性拉延摩擦试验，得到了铝合金在粉末润滑条件下的摩擦系数和表面膜特性，并对塑性成形过程粉末润滑机理进行了分析。结果表明：爬行现象是润滑膜破坏的主要原因，该现象随着接触压力的增大而加剧；适当增加粉末层厚度可以有效降低润滑膜的损伤，但不是粉末量越多越好，最佳厚度随使用工况而变化；不同粉末层厚度下，表面膜的典型破坏形式有所区别；摩擦系数随着接触压力的增加而减小，随着粉末层厚度的增加而增加。

英文摘要：

By using graphite powder to lubricate the sliding contact interface during strip drawing, the friction tests on the aluminum alloy were performed under different contact pressures and with differ- ent thickness of powder layer. The friction coefficient and the characteristics of surface film of the alu- minum alloy were measured during or after experiments. The mechanism of particle flow lubrication in sheet metal forming was also studied. The results indicate that the surface film is mainly damaged by crawl phenomenon which is intensified with the increase of contact pressure. To increase the thick- ness of the powder layer appropriately can reduce the damage of the lubricant film, but too much graphite does not mean better, the optimum thickness varies with the change of operation condition. The typical damage behavior of the surface film changes with different thickness of powder layer. The friction coefficient deceases with the increase of contact pressure and increases with the increase of the thickness of powder layer.