The influence of a heat treatment on the tribological performance of a high wear resistant high Si Al-Si alloy weld overlay

A high silicon (Si)-containing aluminum-silicon (Al-Si) alloy surface weld overlay, deposited on 319 Al alloys, has been developed at Oak Ridge National Laboratory (ORNL) in order to improve surface-dependent properties, like resistance to wear. The overlay deposition process relies on standard techniques for Al manufacturing, therefore no unusual equipment is required. Microscopic examination of the high Si Al-Si weld overlays show a fine cutectic microstructure containing large Si particles, with the overall microstructure characteristics of a hypereutectic Al-Si alloy, similar to 390 Al alloy. The deposition process is versatile enough to be able to place the overlay in critical areas where high wear resistance is needed, thus reducing the overall cost of a component. In order to quantify the wear resistance of the high Si Al-Si overlays, they have been evaluated alongside 390 Al alloy which exhibits high wear resistance. Pin-on-disk (POD) wear tests have been performed on heat-treated (HT) and non-heat-treated specimens consisting of the high Si Al-Si overlays deposited on 319 Al alloy, bulk 390 Al alloys, and bulk 319 Al alloys. The high Si Al-Si weld overlay shows potential as a replacement of bulk 390 Al alloy for applications requiring high wear resistance.