粉末冶金法制备混杂增强铝基复合材料及其组织性能研究

发布时间：2018-05-20 01:10

  本文选题：粉末冶金 + 铝基复合材料　； 参考：《湖南大学》2015年硕士论文

【摘要】：颗粒增强铝基复合材料具有高比刚度、高耐磨性、热稳定性等优异的力学性能,制备工艺相对简单,技术成熟,在汽车、航天航空、电子等领域有非常重要的应用。微米/纳米颗粒混杂增强铝基复合材料具有更优异的综合性能,是目前铝基复合材料领域的重点研究方向之一。本文采用粉末冶金法制备微米/纳米颗粒混杂增强铝基复合材料,分析并优化混合粉末压制工艺、烧结工艺,在此基础上,制备出Si C(微米级)-Ti B2(纳米级)双相混杂增强铝基复合材料,并与单一Si C颗粒和Ti B2颗粒增强铝基复合材料进行性能对比研究分析,通过密度与硬度分析、拉伸试验、XRD与SEM等表征分析,对所制备的铝基复合材料组织性能进行了深入研究。冷压成型时复合材料的致密度随着冷压压力的增加而升高,冷压压力750MPa时,5%Si Cp/Al-Si致密度可达到93.68%,进一步提高压制压力,致密度无明显增加。复合材料的孔隙率随着烧结温度的升高而减少,冷压坯料在640℃烧结并保温40min条件下获得的铝基复合材料致密度最高,可达到92%以上。对单一颗粒和混杂颗粒增强铝基复合材料来说,随着增强颗粒体积含量的增加,铝基复合材料的硬度、拉伸强度等性能总体呈现上升趋势,Si C颗粒增强、Ti B2颗粒增强以及Si C-Ti B2混杂增强铝基复合材料的最佳的增强颗粒体积含量分别为5%、1.5%、5%Si C-1.5%Ti B2。相对于Si C、Ti B2单相增强铝基复合材料,Si C-Ti B2混杂增强铝基复合材料的性能有一定程度的提高。5%Si C-1.5%Ti B2双相混杂增强铝基复合材料的维氏硬度为53.39,抗拉强度为158MPa。颗粒增强铝基复合材料断裂为混合断裂机制,当颗粒与界面的结合较好时,颗粒增强铝基复合材料的主要断裂机制为基体的韧性断裂、颗粒断裂和颗粒与界面撕裂;当颗粒与界面结合较差时,主要的断裂机制为基体的塑性断裂以及增强颗粒从基体界面的脱离。
[Abstract]:Particle reinforced aluminum matrix composites have excellent mechanical properties such as high specific stiffness, high wear resistance and thermal stability. The preparation process is relatively simple and the technology is mature. It has very important applications in automotive, aerospace and electronic fields. Micron / nanocrystalline hybrid reinforced aluminum matrix composites have better comprehensive properties and are one of the key research directions in the field of aluminum matrix composites. In this paper, micron / nano-particle hybrid reinforced aluminum matrix composites were prepared by powder metallurgy method. The compaction process and sintering process of mixed powder were analyzed and optimized. Sic (micrometer scale) two-phase hybrid reinforced aluminum matrix composites were prepared and compared with single sic particles and TiB2 particle reinforced aluminum matrix composites. The density and hardness of the composites were analyzed by density and hardness analysis. The microstructure and properties of the aluminum matrix composites were studied by tensile test, SEM and so on. The density of composites increases with the increase of cold pressing pressure, and the density of 5Si Cp/Al-Si can reach 93.68 when cold pressing pressure 750MPa. The compaction pressure is further increased, but the density does not increase obviously. The porosity of the composites decreases with the increase of sintering temperature, and the density of aluminum matrix composites sintered at 640 鈩，

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