Effect of Grain Refinement on Microstructure and Wear Behavior of Cast Al-7Si Alloys
The present work deals with the study of wear of Al-7Si alloys without and with the addition of grain refiners
such as, Al-5Ti-1.25C, Al-5Ti-0.8C and Al-5Ti-1B individually. Grain refiner additions have shown grain
refinement in the cast Al-7Si alloys. Microstructures showed morphological changes in a- Al phases from
dendrite to equiexed. These changes in structure showed improvement in wear resistance of Al-7Si alloys.For
this, pin-on-disc test has been performed on Al-7Si alloy samples with varying addition level of grain refiners.
The worn-out surfaces of the samples were characterized by SEM studies in order to understand the wear
mechanism of Al-7Si alloys against steel disc. Worn-out surfaces of Al-7Si alloys pins exhibited different surface
morphologies. Although it has been found that wear mechanism was same for both without and with grain
refined Al-7Si alloys. However untreated samples exhibits higher wear loss than that of grain refined samples. It
was noticed that with addition of grain refiner, the samples gave smaller debris particles.
This showed less wear loss during such conditions.