界面改性对SiC/Al双连通复合材料力学性能的影响

Effect of Interfacial Modification on Mechanical Properties of the Co-continuous SiC/Al Composites

采用真空气压浸渗技术制备Si C/Al双连通复合材料,研究了Si C_(3D)/Al复合材料压缩强度的应变率效应,以及Si C骨架表面氧化时间对复合材料压缩和弯曲强度的影响规律。结果表明:Si C/Al双连通复合材料抗压缩强度有显著的应变率硬化效应(10^(-3)~10 s^(-1)),最高增幅可达25%。Si C骨架表面氧化可以进一步提高复合材料抗压缩强度,Si C骨架1200℃氧化6 h后所对应的复合材料具有最高的抗压缩强度,在应变率为10^(-3) s^(-1)时,其抗压缩强度相比于未氧化处理的复合材料提升幅度达10%;其原因是,氧化处理改变了Si C/Al的界面特征,从而影响了复合材料的断裂行为。但是,Si C骨架氧化处理几乎没有改变复合材料的抗弯强度。

The novel co-continuous SiC/Al composites were prepared by a vacuum-infiltration technique.The effects of strain rates and surface oxidation modification of 3D-SiC preforms on the mechanical properties of co-continuous SiC/Al composites were investigated.The results show that the strain rate hardening effect of the co-continuous SiC/Al composites is obvious,and there is the maximum increment of 25%in compressive strength at strain rate from 10^(-3) s^(-1) to 10 s^(-1).Furthermore,the compressive strength of the SiC_(3D)/Al composites are also improved by surface oxidation modification of SiC preforms,and the maximum increment is observed in the composite with 3D-SiC preform at 1200℃for 6 h.Its compressive strength is about 10%higher than that of the SiC_(3D)/Al composite without surface oxidation modification at 10^(-3) s^(-1),which suggests that the surface oxidization modification for SiC preforms can play an important role in the fracture behaviours of the SiC_(3D)/Al composites due to the improvement of SiC/Al interfacial characteristics.But the three-point bending strengths of SiC_(3D)/Al composites are not sensitive to surface oxidization modification.