Dry sliding wear and friction studies on AlSi10Mg–fly ash–graphite hybrid metal matrix composites using Taguchi method

The aim of the investigation is to study the influence of parameters such as sliding distance, sliding speed, load and fly ash content on dry sliding wear loss and coefficient of friction (COF) of AlSi10Mg–Fly ash–graphite hybrid composites using Taguchi method. A pin-on-disc wear testing equipment was used to conduct the dry sliding wear tests on the hybrid composite produced through the liquid metallurgy route. Signal to noise ratio response analysis and analysis of variance were used to investigate the influence of parameters, and correlation between the parameters was established by multiple linear regression models. It was determined that sliding distance was the most dominant factor influencing the wear and COF of hybrid composites. There was a decrease in wear with increases in sliding speed and fly ash content. However, the COF of composites increased with increasing load, but decreased with increases in sliding distance, sliding speed and fly ash content. At higher sliding speeds, a mechanically mixed layer (MML), containing fractured fly ash particles and oxides of aluminium and iron form between the pin and the counterface. This MML helps to reduce the chance of direct metallic contact, thereby lowering the wear loss and COF. Multiple linear regression models were developed which could be effectively used to predict the wear loss and COF of the hybrid composites. Abrasive wear was the dominant wear mechanism at low loads and when the load was increased to 26·98 N, the wear mechanism changed to mixed abrasion–delamination wear with a drastic increase in the wear loss of the hybrid composite. Mild oxidative wear was predominant at high sliding speeds (3 m s⁻¹) and lower loads.