Tribological behavior of ZK60Gd alloy reinforced by SiC particles after precipitation hardening

Abstract

In this research, the effect of precipitation hardening on the tribological behavior of the ZK60Gd/SiC composite was studied. For this purpose, ZK60Gd alloy containing with 5 and 10 wt% SiC were produced with stir casting method. The microstructure characterization of the samples showed the wide distributions of Mg7Zn3 and Gd(Mg0.5Zn0.5) precipitates were formed during casting. The results of hardness measurement after precipitation hardening at different temperatures showed that the hardness peck was obtained at 175 °C. The wear tests with different loads (10, 40, 60, 90, and 120 N) and velocities (0.1, 0.3, 0.6, and 0.9 m/s) were performed on the as-cast and heat treated sample at 125, 175, and 225 for 12 h. Between the different precipitation hardening conditions, the precipitation hardened samples at 175 °C had the highest hardness values and least wear rate. The sample containing 10% reinforcement had the least wear rate between the unreinforced alloy and the composites. The results showed that abrasive, adhesive, delamination, MML, and fatigue wear mechanisms were the dominant wear mechanisms for the composite samples. In contrast, the dominant wear mechanism for the unreinforced samples was abrasive, adhesive, delamination, MML, and plastic deformation.

Keywords

• Precipitation hardening
• Composite
• Gadolinium
• Mg-Zn-Zr-Gd
• Wear map