热压与放电等离子体烧结两种工艺制备Al2O3/Cu复合材料

由机械合金化法(MA)制得纳米级Al₂O₃颗粒弥散镶嵌于微米级Cu颗粒表面的复合粉末, 利用球形化工艺改善所制得复合粉的形貌及粒度范围, 分别采用热压法(HP)和放电等离子体烧结(SPS)法制备Al₂O₃/Cu复合材料。通过测试密度、 电导率、 抗弯强度及SEM复合粉形貌和烧结体断口分析、 微区成分分析, 对比研究了Al₂O₃质量分数分别为0%、 0.5%、 1.0%、 1.5%时Al₂O₃/Cu复合材料的物理、 力学和电学性能。结果表明: 不同制备工艺下随着Al₂O₃含量增加, 材料的抗弯强度先增后降, 电导率除受杂质影响外, 还受材料缺陷的影响, 故变化规律不明显, 对于Al₂O₃含量相同的Al₂O₃/Cu复合材料, 采用SPS法制备的复合材料的致密度、 抗弯强度及电导率均高于HP法; 在弯曲应力下两种制备方法所得复合材料均发生延性断裂。

Al2O3/Cu composite fabricated by hot pressing and spark plasma sintering

The composite powders, in which the nano-Al2O3 particles are dispersed on the micrometer copper particles, were prepared by the mechanical alloying(MA). The shapes and size distributions of the composite powders were improved by the spherical process. The nanometer Al2O3/Cu composites were individually fabricated by the hot pressing (HP) and spark plasma sintering (SPS). The properties of the sintered composites with Al2O3 mass fractions of 0%, 0.5%, 1.0% and 1.5% were investigated, including density, electric conductivity and bending strength. The microstructures of the composite powders and fractures of the sintered samples were analyzed by SEM and the element analysis of micro-area. The results show that the bending strength of the composites increases and then decreases while the electric conductivity varies randomly with the increase of Al2O3 mass fraction. The SPS is superior to the HP, comparing the density, bending strength and electric conductivity of the composites with the same Al2O3 mass fraction. The ductile fracture occurs under bending loading.