High-temperature dry sliding wear behaviour of pre-aged 3-step T6-treated Al7075 hybrid matrix composite

Abstract

AbstractThe focus of current work is to narrow the understanding of high-temperature dry sliding wear behaviour of Al7075 and its composite, which contains Si3N4 and 2 wt.% granite powder and is pre-aged and T6-treated in 3-steps. The composite is prepared by conventional stir casting. The time to attain peak hardness at 100°C, 120°C and 150°C is taken as the basis to fix the duration of each step in 3-step aging process. The alloy and composite were initially pre-aged and are followed by 3-step T6 treatment. The alloy and composite hardness due to this heat treatment were 185.6 and 197.6 VHN respectively. Further the treated alloy and composite were subjected to temperature dependent isothermal dry sliding wear by choosing the operating temperature as 35°C, 70°C, 140°C and 210°C. The results showed that, average wear rate of alloy was more as compared to composite for each of the temperature and normal load. An inverse relation is noticed among hardness and wear rate. But wear rate was found to vary in direct relation to the temperature. Also the co-efficient of friction showed an increasing trend with increase in temperature. It is found to be noticeably high for alloy than the composite for all temperature and normal load.

Keywords

• composite
• step aging
• hardness
• high temperature wear
• SEM