挤压铸造制备高体积含量SiCp/2024Al复合材料

High Volume Fraction SiC Particles Reinforced 2024Al Composite Prepared by Squeeze Casting

采用干压成形将200μm与10μm的SiC颗粒按不同配比混合制得多孔陶瓷预制体,当粗、细颗粒质量比为8∶2时,预制体相对密度达到最大值75%。采用挤压铸造工艺制得陶瓷含量为75%的SiC/2024Al复合材料,研究了预制体氧化处理对复合材料力学性能的影响。未氧化处理的预制体经挤压铸造所得的复合材料抗弯强度达到288MPa,断裂韧性达到8.7MPa.m1/2;预制体经氧化处理后所得的复合材料的相对密度、抗弯强度和断裂韧性较未氧化处理的有所降低,但硬度变化不大,HRA约为70。复合材料失效破坏的主要机制是SiC大颗粒解理断裂和小颗粒与金属基体界面解离。

High volume fraction composites were produced by infiltrating liquid aluminium into preforms made by mixing and packing SiC particles with average diameters of 200 and 10μm. The maximum particle volume fraction 75% （volume fraction） was obtained for a mixture having 80% （mass fraction） of coarse particles. The influence of preform＇s oxidation treatment on mechanical properties of the composites was studied. The results showed that the bending strength and fracture toughness of the composite which was fabricated from the un-oxidation treatment preform were 288MPa and 8.7MPa · m^1/2 respectively. The relative density of the composite after oxidation treatment was lower, so as to the bending strength and toughness. But the oxidation treatment has little effect on the hardness of the composite, and the hardness of both composites was about HRA 70. The main failure mechanisms of the composite were the crack of the coarse particle and the debonding of the interface between fine particle and the matrix.