Influence of bismuth on the microstructure, hardness and dry sliding wear behavior of magnesium silicide reinforced magnesium alloy composite

The modification effect of bismuth (Bi) on in-situ-formed magnesium silicide (Mg$_2$Si) reinforced magnesium-aluminium (Mg–Al) alloy is investigated using optical microscope, scanning electron microscope and X-ray diffraction. Processing of the in-situ composite was carried out through a stir casting technique. The size of Mg$_2$Si is significantly refined and the optimal modification effect was obtained when the Bi content in the composite is 1.4 %. A slight decrease in hardness values and increase in wear resistance were observed in the study with bismuth addition.