Publication

Abstract : The effect of thermal treatment on microstructure and tribological behavior of Al-7Si/ZrSiO4 reinforced composites has been investigated. Composites with 5, 10 and 15 vol.% of ZrSiO4 particles were produced using stir casting process. Produced composite samples were then further subjected to T6 heat-treatment by subjecting the cast samples for solution treatment for 4 h at 540 °C followed quenching in water and artificial ageing at 170 °C for 5 h. Microstructure of the composite samples revealed uniform distribution of ZrSiO4 particles. Hardness of the T6 thermal treated samples was found to be superior to that of Al-7Si alloy and hardness of the composite samples increased with increase in wt.% of ZrSiO4 particles. Non heat treated alloy and composite reinforced with 15 wt% of ZrSiO4 possessed a maximum hardness of 68 BHN and 110 BHN respectively. Whereas T6 heat treated Al-7Si alloy and composite reinforced with 15 wt% of ZrSiO4 exhibited a maximum hardness of 84 BHN and 146 BHN respectively. T6 treated composites exhibited superior resistance to wear, when compared to the base alloy. As cast Al-7Si alloy exhibited maximum wear rate of 14.3 × 10−3 mm3 /m, where as non heat treated 15 wt.% ZrSiO4 reinforced composites exhibited a wear rate of 7.6 × 10−3 mm3 /m and wear rate was found to further reduce to 4.0 × 10−3 mm3 /m by T6 treatment. SEM images of the wear tested samples showed the adhesive wear and abrasive wear as the dominant wear mechanisms.