采用平均粒径为800 nm的超细SiC颗粒作为增强体,制备含SiC体积分数为15%的铝基复合材料,研究烧结温度和强压处理对复合材料微观组织和力学性能的影响.研究表明,提高烧结温度可有效加速复合材料的致密化,与520℃下烧结制备的复合材料相比,610℃下烧结制备的复合材料具有更高的密度和较低的孔隙度,从而具有更高的硬度.610℃下烧结制备的复合材料的硬度为83.9 HBS,远高于520℃烧结制备的复合材料的硬度(53.7 HBS).这主要是由于烧结温度的提高可加速原子扩散,有利于Al粉之间以及Al粉与SiC颗粒之间的结合,并改善界面结合情况.研究还表明,强压处理可以有效提高复合材料的致密度和降低孔隙的体积分数,610℃下烧结制备的复合材料经强压处理以后的密度为2.68 g/cm3,接近于理论密度(2.78 g/cm3),且硬度可达121 HBS,抗拉强度、屈服强度和伸长率分别可达177.6 MPa、168.6 MPa和3.97%.%Al based composites reinforced by 15vol% ultrafine SiC particles were fabricated using 800 nm sized SiC particles as the raw materials. The effects of the sintering temperature and severe compression treatment on the microstructures and mechanical properties of the composites were investigated. The results indicate that increasing the sintering temperature can effectively accelerate the densification of the composites. Compared to the composite sintered at 520℃, the composite sintered at 610℃ has higher density, lower porosity and higher hardness. The hardness (HB) of the composite sintered at 610℃ is 83.9 HBS, much higher than that (53.7 HBS) of the composite sintered at 520℃. This is due to the fact that increasing the sintering temperature can accelerate the atom diffusion, and thus help the consolidation of the Al powders, and Al powder and SiC powder to improve the interfacial bonding. It has also been shown that severe compression treatment can effectively increase the density of the composites and decrease the volume fraction of the pores. The density of the composite prepared by sintering under 610℃ and severe compression treatment is 2.68 g/cm3, which is very close to the theoretic density of the composite (2.78 g/cm3). The hardness of the composite can reach 121 HBS, and the tensile strength, yield strength and ductility can reach 177.6 MPa, 168.6 MPa and 3.97%, respectively.
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