MICROSTRUCTURE AND PROPERTIES OF IN SI TU Zn MATRIX COMPOSITESREINFORCED BY Mg2Si AND Si USING CENTRIFUGAL CASTING
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摘要: 采用热模金属型工艺, 离心铸造Zn-27Al-9.8Mg-5.2Si 和Zn-27Al-6.3Mg-3.7Si 合金, 获得了内层聚集大量块状初生Mg2Si 、少量初生Si, 中层不含初生Mg2Si 和初生Si, 外层含有初生Mg- Si 和初生Si 的自生锌基复合材料。离心铸造Zn-27Al-3.2Mg-1.8Si 合金, 获得了不含初生Mg2Si 和初生Si 的单层材料。考察了复合材料的组织形貌, 检测了复合材料的硬度和耐磨性, 分析了复合材料的断裂模式。结果表明: 复合材料的内层因聚集大量的初生Mg2Si 和初生Si 具有较高的硬度和较优的耐磨性。复合材料的断裂方式为脆性断裂, 含共晶Mg2Si 和共晶Si 的中层在断裂中比含块状初生Mg2Si 和初生Si 的内层经历了更多的塑性变形。Abstract: In situ three-layer surface composites of Zn-27Al-9.8Mg-5.2Si and Zn-27Al-6.3Mg-3.7Si alloys wereobtained by using preheated metal mould cent rifugal casting1 The surface composites possess the microst ructureaccumulating lot s of blocky primary Mg2Si and a small amount of blocky primary Si in the inner layer, accumulatingprimary Mg2Si and primary Si in the outer layer, and without primary Mg2Si and primary Si in the middle layer1 Butonly single layer material without primary Mg2Si and primary Si was obtained in cent rifugally cast Zn-27Al-3.2Mg-1.8Si alloy. Microst ructures of cent rifugally cast Zn-27Al-Mg2Si alloys were investigated, The hardness, wearability and f racture mode of the composites were also analysed, The result s show that the hardness and wear resistanceof the composites depend mainly on the dist ribution of the primary Mg2Si and primary Si along the radial direction1The inner layer of the composite shows the highest hardness and best wear resistance1 The f racture mode of thecomposite is primarily brittle1 The middle layer of the composite exhibit s more deformation than the inner layer during the f racture1
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Keywords:
- cent rifugal casting /
- Zn alloy /
- Mg2Si /
- Si /
- in situ surface composites
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