放电合金化工艺在 AA6082 Al-Mg-Si 铝合金表面涂覆自润滑碳化物层的形成和表征

摘要

The surface modification on the AA6082 Al−Mg−Si aging-hardenable aluminum alloy was investigated by electrical discharge alloying (EDA) process. Kerosene, used as a dielectric fluid, was pyrolytically decomposed into carbon for the formation of a self-lubricated carbide layer on the aluminum alloy surface during EDA process. Transmission electron microscopy (TEM) image found that the self-lubricated carbide layer was a multi-phase material with carbides and graphite. As a result, the EDA-modified aluminum alloy had a negligible wear rate of ~2´10−4 mg/m (c. f. ~1.1´10−2 mg/m for aluminum alloy substrate). Notably, a new characteristic was found that the EDA-processed carbide layer was a soft magnet, which improved the electromagnetic interference (EMI) shielding performance of the alloy.%采用放电合金化工艺对 AA6082 Al−Mg−Si 时效硬化铝合金进行表面改性。在放电合金化过程中，作为工作液的煤油热解成碳，从而形成附着于合金表面的自润滑碳化物层。TEM 结果表明，合金表面形成的自润滑碳化物层为由碳化物和石墨组成的多相材料。因此，经放电合金化改性铝合金的摩损率极小，约为2×10−4 mg/m，而铝合金基体的磨损率约为1.1×10−2 mg/m。显然，在铝合金表面经放电合金化形成的碳化物为一种能改善合金抗电磁干扰性能的软磁体。