Effect of Mn as Fe corrector on microstructure and adhesive wear of eutectic Al-Si Piston alloy

Al-Si alloys are most preferred choice for applications such as piston, engine block, etc. Formation of needle shaped P-phase is direct fallout of presence of Iron in Piston alloys. The elements such as Mn change the morphology of needle shaped compounds to Chinese script type. In this paper, the effect of Manganese as Iron corrector on microstructure and wear behavior of cast AI-Si alloy has been reported. Sliding wear behavior of eutectic alloy Al-12Si-1Cu-0.1Mg for 2 levels of Iron was investigated with variations in Fe/Mn ratio. Sliding wear behavior has been evaluated at four normal loads of 5, 20, 50 and 70 N and sliding speeds of 2 m/s by using pin-on-disk test configuration against heat treated EN31 steel counter-surface at room temperature. Worn pin surfaces were examined by scanning electron microscopy (SEM) for analyzing wear mechanisms. The wear mechanism has been found to be mild oxidative type for both alloys in entire range of loads used in the study. No transition to severe metallic wear was observed at higher loads. Hardness of the alloy shows a significant increase only in alloy with 2.0 wt.% Fe with addition of Manganese. In general, wear rates show significant reduction in both alloys with addition of Mn with minimum at Fe/Mn =1 for alloy with 1.2 wt.% Fe and at Fe/Mn =2 for alloy with 2.0 wt.% Fe.