Formation and characterization of self-lubricated carbide layer on AA6082 Al-Mg-Si aluminum alloy by electrical discharge alloying process

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.