【作者】 章照；

【导师】 赵玉涛；

【作者基本信息】 江苏大学 ， 钢铁冶金， 2006， 硕士

【摘要】 本文研究开发了Al-K₂ZrF₆-B₂O₃原位反应新体系，采用熔体反应法成功制备了（ZrB₂+Al₂O₃+Al₃Zr）／Al及（ZrB₂+Al₂O₃+Al₃Zr）／A356复合材料，对复合材料的微观组织、凝固行为、反应机制、力学性能进行了研究。 XRD和电子探针分析的结果均表明，Al-K₂ZrF₆-B₂O₃原位反应生成的增强相颗粒为ZrB₂、Al₂O₃和Al₃Zr。以SEM分析对原位反应生成的颗粒大小及分布均匀性进行了评价，结果表明：其颗粒平均尺寸约为1～4μm，颗粒偏聚程度较小。工艺参数对凝固组织的影响研究表明：Al-K₂ZrF₆-B₂O₃体系制备复合材料的最佳工艺参数为：起始反应温度在850±20℃，反应时间为15min，反应物K₂ZrF₆与B₂O₃摩尔配比为2∶1，反应物的加入量应不超过铝液质量分数的20％为宜。 （ZrB₂+Al₂O₃+Al₃Zr）p／Al复合材料的室温拉伸强度随颗粒体积分数的增加而增大，但延伸率先升后降。当增强相颗粒体积分数为8vol％时，复合材料的力学性能为：σ_b=152.3MPa，σ_s=112.3MPa，较基体分别提高95.2％和167.3％。（ZrB₂+Al₂O₃+Al₃Zr）p／A356复合材料的抗拉强度和屈服强度均随颗粒体积分数的增加而提高。当增强相颗粒体积分数为8vol％时，该复合材料的力学性能为：σ_b=341.6MPa，σ_s=283.2MPa，较基体A356合金分别提高了53.3％和68.4％。但是其延伸率则一直呈下降趋势。 在载荷58.8N、滑动速度0.42m／s的干滑动磨损条件下，（ZrB₂+Al₂O₃+Al₃Zr）p／Al复合材料耐磨性随着颗粒体积分数的增加而提高，磨损时间为120min时基体材料的磨损量为122.2mg而8vol％（ZrB₂+Al₂O₃+Al₃Zr）p／Al的磨损量为59.2mg，基体材料的磨损量是复合材料的2.1倍；（ZrB₂+Al₂O₃+Al₃Zr）p／A356复合材料的耐磨性明显高于基体A356合金的耐磨性，且复合材料耐磨性随着颗粒体积分数的增加而提高。磨损时间为120min时A356基体材料的磨损量为82.2mg，而8vol％（ZrB₂+Al₂O₃+Al₃Zr）p／A356材料的磨损量仅为31.2mg，A356基体材料的磨损量是复合材料的2.6倍。随着磨损时间的加长，（ZrB₂+Al₂O₃+Al₃Zr）P／A356复合材料的耐磨性越来越优于基体A356合金。在滑动速度0.42m／s，每一载荷下滑动时间为60min时，复合材料和基体的磨损量都随外加载荷的增大而增大，但复合材料的磨损量随载荷的增大幅度远小于基体。复合材料的瞬变载荷要比基体合金更多还原

【Abstract】 (ZrB₂+Al₂O₃+Al₃Zr)/Al and （ZrB₂+Al₂O₃+Al₃Zr）/A356 matrix composites were firstly prepared from the novel Al-K₂ZrF₆-B₂O₃ system via in-situ melt reaction. The microstructure, solidification behaviors, reaction mechanism and mechanical properties of the as-prepared composites were investigated.XRD, EPA and SEM show that ZrB₂, Al₂O₃ and Al₃Zr reinforcement particulates have been obtained; the reinforcement particulates were distributed nearly uniformly in the matrix and the average size was about 1-4μm. The best processing parameters of the Al-K₂ZrF₆-B₂O₃ composites according to the surface analysis of the solidifying structure were described as follows: the initial reaction temperature is 850±20℃, the reaction time 15 min., the mole ratio to the reactant K₂ZrF₆ and B₂O₃ 2:1 and the additional amounts of the reactants no exceeding 20% in weight than the total of the aluminum molten.The tensile strength of the （ZrB₂+Al₂O₃+Al₃Zr）_p/Al composites increase with the increase of the volume fraction, the elongation increase firstly and then decrease. When the volume of particulate is 8vol%, σ_b and σ_s increase by 95.2% and 167.3% to the aluminum matrix, reaching 152.3 and 112.3MPa, respectively. The tensile and yield strength of the （ZrB₂+Al₂O₃+Al₃Zr）_p/A356 composites increase with the increase of the volume fraction and the elongation decrease. When the volume of particulate is 8vol%, σ_b and σ_s increase by 53.3% and 68.4% to the aluminum matrix, reaching 341.6 and 283.2MPa, respectively.The wear resistance of the as-prepared Al and A356 matrix composites increases with the increase of the volume fraction under the following dry sliding condition at room temperature: 58.8N load and 0.42m/s sliding rate of speed. When the sliding time is 120min., the wear mass of the pure aluminum and A356 alloy is 2.1 fold and 2.6 fold to 59.2mg and 31.2mg for the 8vol% （ZrB₂+Al₂O₃+Al₃Zr）_P/Al and （ZrB₂+Al₂O₃+Al₃Zr）p/A356 composites, reaching 122.2mg and 82.2mg, respectively.With the sliding time increase, the （ZrB₂+Al₂O₃+Al₃Zr）p/A356 composites showed better wear resistance than that of the A356 alloy. The wear mass of the composites and the matrix increase with the increase of the forcing load under the sliding conditions: 0.42m/s sliding rate of speed and 60min. sliding time with the same load. The更多还原