纳米SiC增强纯Al基复合材料的微观组织和力学性能

与采用微米尺度SiC颗粒为增强相制备的Al基复合材料相比,以纳米SiC颗粒为增强相制备的Al基复合材料具有更加优异的力学性能,可极大提高SiC增强Al基复合材料的服役可靠性及应用范围。采用传统粉末冶金方法制备纳米SiC颗粒增强纯Al基复合材料,研究烧结温度和增强相体积分数对复合材料微观结构和力学性能的影响。研究表明,烧结温度和增强相体积分数均对复合材料的微观结构和力学性能有重要影响。随烧结温度升高,复合材料中的残留微孔减少,密度和强度均得到显著提高。含体积分数为3%纳米SiC颗粒的复合材料在610℃具有最高的强度,进一步提高纳米SiC颗粒的含量并不能提高材料的力学性能,这主要是由于当纳米SiC颗粒的体积分数超过3%时将出现明显的团聚,从而降低强化效应。

Microstructures and mechanical properties of nano-sized SiC particle reinforced pure Al based composites

Compared to the composites reinforced by micro-sized SiC particles, the composites reinforced by nano-sized SiC particles possess much better mechanical properties, which can greatly improve the operational reliability and serviceable range of the materials. The effects of the sintering temperature and the volume fraction of the reinforcements on the microstructure and mechanical properties were investigated for nano-sized SiC reinforced composites manufactured by the powder metallurgy route. The results show that both factors have significant effects on the microstructures and mechanical properties of the composites. With increasing the sintering temperature, less residual pores exist in the composite, and both the density and strength are improved. The composite reinforced with 3% nano-sized SiC sintered at 610℃ possesses the highest strength among the composites. However, further increasing the volume faction of SiC particles cannot obtain higher strength. The strengthening effects of nano-sized SiC in the composite reinforced by more than 3% SiC particles become weak due to the agglomerations of the SiC particles.