Investigation of the influence of Ni and Cu additions on the wear behavior of spray formed Al-15Si alloy at elevated temperature

The aim of this study is to develop a novel class of alloy material using spray forming process, which is a rapid solidification process that produces refined, equiaxed microstructures with low segregation. In the present study, the effects of adding Ni and Cu on the dry sliding wear behavior of the spray formed Al-15Si alloy at different elevated temperatures were investigated and compared with the cast Al-15Si alloy. Al-15Si and Al-15Si-4Ni-2Cu alloys were prepared by spray forming and conventional casting methods. The microstructure of the alloys was examined using optical and scanning electron microscopy (SEM) and energy dispersive X-rays. The hardness was measured using a Vickers hardness tester. Dry sliding wear tests at room temperature, 25 °C, 100 °C, 200 °C, and 300 °C were performed on a pin-on-disc tribometer at different loads (10, 20, 30, 40, 50 N) and a sliding velocity of 1.0 m/s. The microstructure of the spray-formed Al-15Si-4Ni-2Cualloy show fine, spherical form of primary Si, eutectic Si phases and fine dispersion of intermetallic particles. The spray-formed alloys display higher hardness values compared to the cast alloys and the spray formed Al-15Si-4Ni-2Cu alloy show a hardness almost 24% higher than the spray formed binary alloy. Lower wear rate and coefficient of friction were obtained in the Al-15Si-4Ni-2Cu alloy at all the normal loads and elevated temperatures. The spray formed alloys emerge as a better wear resistant material than the cast alloys at elevated temperatures. Although oxidative, abrasive and delamination wear mechanisms were found in the alloys manufactured by both the technique but severe plastic deformation was observed only in the cast alloys