Wear behaviour of T4 and T6 heat treated LM28 composite reinforced with ZrO2 particles by stir casting method

The current study was performed to investigate the metal alloy LM28's wear characteristics, strengthened by fine and coarse ZrO2 were investigated after undergoing thermal treatment with T4 and T6 process. Aluminium degasification tablets were used during the stir casting liquid metallurgy process to produce the composites with less porosity. ZrO2 was employed as fine (10-30 mu m) and coarse (80-120 mu m) particles in a step size of 3% from 0 to 12 wt%. The traditional T4 and T6 HT process was applied to the composite materials (LM28 nZrO(2)). T4 heat treatment involved in elevating the composites to 450 degrees C for 120-180 min before quenching them into the oil and age them naturally for 8-42 days at ambient room temperature. T6 HT was performed in a routine fashion, but also underwent artificial aging at 190-240 degrees C for 3-7 h before normal cooling. When compared to T4 HT process and non-HT composites, the hardness of T6 HT composites gives better results against wear property. The ideal level of hardness and resistance to wear of the composite was found in T6 HT composites when tested with a pin on a disk throughout a range of sliding distances and loads. Scanning electron microscopy demonstrated that T4 HT and non-HT composites suffered more surface damage than T6 HT composites when subjected to the same load and sliding distance. Initially, material was removed by an abrasive wear process, but this shifted to an adhesive one as sliding distance increased. T6 thermal treated composites are ideal for usage in tough conditions as a result of their excellent hardness and resilience to wear.