Effect of different Al contents on the microstructure, tensile and wear properties of Zn-based alloy

摘要

The effect of different Al contents on the microstructure, hardness, tensile properties and wear behavior of Zn-based alloys was examined. The alloys were prepared by conventional melting and casting route with different Al contents namely, 8, 12 and 27 wt. percent. The tensile tests were carried out at room and elevated temperatures (40.60 and 100 deg C). The wear tests were carried out on pin on ring apparatus at a linear speed of 0.65 m s~(-1) over a load range of 10 - 100 N. Higher hardness and strength were obtained by increasing Al content, however, the ductility decreased. Zn-Al alloys showed a reduction in strength and increase in ductility with increasing temperature. Higher strength at elevated temperature was also observed with increasing Al content in the Zn-Al alloys. In addition, the wear resistance increased with the increase of Al content and weight loss increased with increasing loads. The improved tensile properties and wear resistance of the Zn-Al alloys are due to change in the microstructure of the Zn-based alloy as the Al content increases where microstructure of Zn-8Al alloy consists of coarse eta-Zn rich dendrite and alpha + eta eutectoid colonies. Also, the microstructure of Zn-12Al reveals finer eta-Zn rich, but more eutectoid colonies than Zn-8Al. while microstructure of Zn-27Al has alpha-Al rich dendrites surrounded by alpha + eta eutectoid.