Dry sliding wear behaviour of Al6061-5%SiC-TiB2 hybrid metal matrix composites synthesized by stir casting process

Functionally graded Al6061-SiC composites are widely used in the manufacturing of bearing surfaces, bushes, gears, cylinder liners, pistons and camshafts. However, due to the poor density and higher level of porosity, the usages of Al6061-SiC composites are limited. The Purpose of the study is to improve the wear behaviour of the Al606l-SiC composites to widen the engineering application of the Al6061 alloy. In this present work, an effort is made to examine the dry sliding wear characteristics on a newly developed hybrid metal matrix composite of Al6061%-5%SiC-x TiB2 (x = 2%, 4%, 6%, 8% and 10 wt%) fabricated by stir casting route. The Wear Rate and Coefficient of Friction were examined using a Pin-on-Disc tribometer at various dry sliding conditions. The results of the experimental studies revealed that with the addition of secondary hard ceramic TiB2 particles, the wear behaviour was found to be significantly improved on the hybrid composite due to the new formation of Mechanically Mixed Layer (Fe2O3 layer). The Coefficient of Friction showed a decreasing trend in the case of varying loads and sliding distances. Conversely, the COF exhibit an increasing trend concerning the sliding velocities. The results have shown that the highly concentrated Al6061-5%SiC-10%TiB2 hybrid composite achieved the least COF values of 0.26, 0.31 and 0.29 at higher applied load (40N), sliding distance (2000 m) and sliding velocity (2.61 m s(-1)) conditions respectively. The worn surface of the hybrid composite indicates fine grooves with minimal abrasion.