Relationship between microstructure and dry wear behavior of compo-cast nano-SiC(p) + micro-Gr((p))/Zn-35Al-1.2Mg-0.2Sr composite under different chilling conditions

摘要

In the present experimental research, the compo-casting process was employed to fabricate Zn-35Al-1.2Mg-0.2Sr composite alloy reinforced with nano-SiC(p) + micro-Gr((p)) particles and the water-cooling control system casting was applied to realize the effects of different chilling conditions on the as-synthesized material. Also, dry sliding wear experiments were performed to study the wear behavior of Zn-35Al-1.2Mg-0.2Sr composite alloy. Moreover, the effects of nano-SiC(p) + micro-Gr (p) addition on wear behavior of the as-prepared composite at different wear temperatures were analyzed. It was noticed that the abrasive resistance of Zn-35Al-1.2Mg-0.2Sr composite alloy was dependent on the percentage and the dendritic arm spacing of the wearable Al-rich alpha-phase as well as on the distribution of nano-SiC(p) + micro-Gr((p)) particles. With the increase in cooling rate during casting, the dendritic arm spacing of the alpha-phase decreased apparently. Further, with the increase in wear temperature, the percentage of the wearable Al-rich alpha-phase, especially for the specimen cooled under a full cooling mode, started to increase significantly. The specimen cooled under a full cooling mode manifested excellent high-temperature abrasive resistance. Furthermore, the tensile strength of the as-cast composite increased with the increase in cooling rate during casting, and it could be attributed to the refined microstructures and the distribution of nano-SiC(p) + micro-Gr((p)) particles.