Microstructure and Wear Property of Zn-Al Alloy Reinforced with Carbonized Rice Husks
Zn-Al composites with carbonized rice husks were prepared by permanent mould. Microstructure and wear property of Zn-Al composites were measured under the condition of as-cast heated at 375 °C and 430 °C corresponding to solid and semi-solid range. The microstructure of as-cast, heated at 375 °C and 430 °C were different. The microstructure of as-cast Zn-Al alloy revealed primary a dendrites (α) and eutectoid α+η (α,rich Al, η rich Zinc)phases. The microstructure of ZA alloy with carbonized rice husks was fine dendrites for heated at 375 °C and second and third dendrites were almost dispersed. After semi-solid treatment, the microstructure of Zn-Al composites presented quasi-round or round and large with time prolonger. The hardness of Zn-Al composites rose with carbonized rice husks and increased slightly by heat treatment. Wear resistance of Zn-Al composites with carbonized rice husks improved significantly and increased with carbonized rice husks. But at the same amount of carbonized rice husks the wear resistance of the composite varied little regardless of being in the state of as-cast or heat treatment.