Solutionizing Temperature Effect on the Dry Sliding Wear Performance of Al-7Si-0.3Mg-3Ni Hypoeutectic Alloy

The solutionizing temperature effect on the dry sliding wear performance of cast T 6 heat-treated Al–Si–Mg-Ni hypoeutectic alloy is explored in this work. The alloys were melted and transferred into a pre-heated metallic die using an electric furnace to produce cast rods of ɸ 32 mm × 150 mm in length. The cast alloys were solutionized for 8 h at 450 °C & 540 °C and quenched in water at 30 °C. Furthermore, a 12-h artificial ageing procedure was carried out at 180 °C. Hardness and tribological behaviour for the cast heat-treated rods were evaluated using the Vickers microhardness tester and a pin-on-disk tribometer. The wear test was conducted on the samples for varying loads (5, 8 and 10N) and sliding velocity (0.1, 0.15, 0.2 m/s). It was noted that the hardness value increased from the baseline alloy to the Al–Si–Mg-3Ni alloy subjected to heat treatment at 540 °C. It was also found that when the solutionizing temperature was enhanced, there was a decrease in the value of the specific wear rate and friction coefficient. Moreover, adding 3 wt% of nickel substantially improved the sliding wear performance. The presence of intermetallic such as Al 3 Ni during Ni additions to Al–Mg-Si alloy and spheroidization of silicon, precipitation of intermetallic and eutectic phases during ageing treatment played an essential role in improving the hardness and sliding wear performance. Advanced characterization techniques were used to evaluate the microstructure, wear track, tribo layer, and wear debris and to analyze the wear mechanism of the heat-treated wear test samples.