Effect of Silicon on Mechanical and Wear Properties of Aluminium-Alloyed Gray Cast Iron

Influence of Si on mechanical and wear properties of Al-alloyed gray cast iron has been investigated in this work. The Si content is varied from 1.27 to 2.1% in five different alloys with nearly 2% Al additions. Alloy with 2.1% Si and 1.9% Al shows maximum ferrite matrix with highest flake volume (17.3%). It also has the lowest hardness and strength. Rest of the alloys with Si content equal to or less than 1.7% and 2% Al content shows maximum pearlite matrix with higher hardness and strength. They have also shown a tendency for oxide formation and reduced wear during sliding probably due to higher friction heat and lower heat dissipation tendency due to lower flake volume and Al addition which reduces thermal conductivity of the matrix. The same oxide layer was not evident in alloy with 2.1% Si and 1.9% Al alloy having the highest flake volume (17.3%).