Wear and corrosion behaviour of multiple pass friction stir processing on aluminium alloy 6061 embedding with B 4 C particles

In this research, surface modification was carried out on aluminium alloy 6061 through friction stir processing by embedding surface with B4C particles. Three different samples namely, AA6061 with only stir processing (sample 1), friction stir processed by B4C with single pass (sample 2) and by B4C multi-pass (sample 3) were developed to study the wear, corrosion and microstructural properties. The modified surfaces were characterised by carrying out using optical and scanning electron microscopes. Pin-on disc method was employed to study the wear rate on these stir processed samples. Corrosion behaviour of three stir processed samples was characterised in a 3.5 wt.% NaCl solution at 10 mV/s scan rate. From microstructural analysis, the dark zones with onion rings were seen at the nugget zone in sample 2, whereas uniform distribution with clear grain boundaries were observed in sample 3. From wear test, the wear rate for sample 1 was higher when compared with other two samples. From corrosion test, corrosion rate of sample 2 was observed to be 1.469 mm/year which is lower than sample 1 (2.868 mm/year) and sample 3 (6.127 mm/year). Corrosion resistance of sample 2 was greatly improved due to proper mechanical mixing of B4C particles.