【摘要】 以Al-Al₂O₃-B₂O₃为反应体系,采用接触反应法制备了原位自生Al₁₈B₄O₃₃w/6061复合材料,利用XRD和SEM对复合材料分别进行物相分析及微观形貌观察,对比6061基体材料,研究了Al₁₈B₄O₃₃晶须对复合材料硬度和耐磨性能的影响。结果表明,采用接触反应法,利用Al-Al₂O₃-B₂O₃反应体系可直接在6061基体材料中原位自生针状Al₁₈B₄O₃₃晶须,Al₁₈B₄O₃₃晶须直径为0.1～2μm,晶须伴生于Mg元素。经T6热处理后,Al₁₈B₄O₃₃w/6061复合材料的硬度为HB 132.7,较6061基体提高了27.4%,硬度的提高机制为位错强化和细晶强化。Al₁₈B₄O₃₃w/6061复合材料的比磨损率和平均摩擦系数分别为1.96×10^-8 kg/（N·m）和0.221,较6061基体下降了12.11%和22.46%。采用原位自生工艺制备的Al₁₈B₄O₃₃w/6061复合材料,晶须与基体材料之间的润湿性和界面结合强度良好,且晶须本身强度高,在磨损时能够起到支撑作用,减小了基体的应变和磨损,有效地提高了复合材料的耐磨性。更多还原

【Abstract】 In situ Al₁₈B₄O₃₃w/6061 composites were prepared by contact reaction method using Al-Al₂O₃-B₂O₃ as reaction system. The phase analysis and micro-morphology observation of the composites were carried out by XRD and SEM respectively. The effect of Al₁₈B₄O₃₃ whisker on the hardness and wear resistance of the composites was studied by comparing 6061 matrix. The results show that the needle-like Al₁₈B₄O₃₃ whiskers could be directly in situ formed in 6061 matrix by the Al-Al₂O₃-B₂O₃ reaction system. The diameter of Al₁₈B₄O₃₃ whiskers was 0.1-2 μm, and the whiskers formation were associated with Mg element. After T6 heat treatment, the hardness of Al₁₈B₄O₃₃w/6061 composite was HB 132.7, which was 27.4% higher than that of 6061 matrix. The mechanism of hardness improvement was dislocation strengthening and fine grain strengthening. The specific wear rate and average friction coefficient of Al₁₈B₄O₃₃w/6061 composites were 1.96×10^-8 kg/（N·m） and 0.221, respectively, which were 12.11% and 22.46% lower than that of 6061 matrix. Al₁₈B₄O₃₃w/6061 composites prepared by in-situ processing had good wettability and interfacial bonding strength between whiskers and matrix, and the strength of whiskers themselves was enough high, which could play a supporting role during wearing, reducing the strain and wear of the matrix, and effectively improving the wear resistance of composites.更多还原