Appraisal of tribological properties of A356 with 20% SiC composites under dry sliding condition

The goal of this research work is to assess the tribological properties of A356 alloy reinforced with 20 wt% SiC composite prepared by liquid metallurgy route. A356 alloy and A356 with 20 wt% SiC composites were manufactured through three different casting techniques such as gravity die casting, stir casting and stir cum squeeze casting. The fabricated castings exhibit improved hardness value of around 680 MPa, 840 MPa and 950 MPa for A356 alloy, A356 with 20 wt% SiC stir cast composite and A356 with 20 wt% SiC stir with squeeze cast composite, respectively. Further, an ultimate tensile strength of 256 MPa, 298 MPa and 331 MPa was obtained for A356 alloy, A356 with 20 wt% SiC stir cast composite and A356 with 20 wt% SiC stir with squeeze cast composite, respectively. The tribological properties of prepared samples were tested using a pin-on-disk tribometer at room temperature under dry sliding condition. The wear results explained that the wear rate and coefficient of friction started to increase with the function of load (10-40 N) under both the sliding distance of 1000 m and 2000 m. The squeeze cast A356 with 20 wt% SiC composite produced less wear rate and a higher coefficient of friction when compared to other samples. This was attributed to effective embedding, bonding and load-carrying capacity of SiC particles over the A356 matrix. This result indicates improved adhesive properties and abrasion resistance in the squeeze cast A356 with 20 wt% SiC composite. Further, the worn surface morphology of squeeze cast samples was examined using a scanning electron microscope to observe mild adhesive wear and damages due to the delamination effect.