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

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.%. The tensile tests were carried out at room and elevated temperatures (40, 60 and 100 degreesC). 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. (C) 2004 Elsevier B.V. All rights reserved.