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采用搅拌铸造方法制造MgAl2O4颗粒增强型AC4C基复合材料。考察MgAl2O4颗粒的尺寸及尺寸的分布对颗粒分散度的影响,并且测试复合材料的微观组织、强度与疲劳性能。5~25μm范围内的MgAl2O4颗粒可以提高复合材料的抗拉强度。疲劳性能测试表明,在250°C、107循环周期内,MgAl2O4颗粒使复合材料的疲劳性能提高27%。在MgAl2O4颗粒周围,观察到了大量位错,产生这种情况的主要原因是MgAl2O4与Al两者之间的热膨胀系数不匹配。在MgAl2O4颗粒周围产生裂纹,但在扩展过程中大量的裂纹发生了转向和弯曲,这有助于材料疲劳性能的提高。
Preparation of MgAl2O4 Particle Reinforced AC4C Matrix Composites by Stirring Casting Method. The effects of the size and size distribution of MgAl2O4 particles on the particle dispersion were investigated. The microstructure, strength and fatigue properties of the composite were also tested. The MgAl2O4 particles in the range of 5 ~ 25μm can improve the tensile strength of the composites. Fatigue performance tests showed that MgAl2O4 particles improved the fatigue properties of composites by 27% at 250 ° C for 107 cycles. A large number of dislocations were observed around the MgAl2O4 particles, the main reason for this is the mismatch in the coefficients of thermal expansion between the MgAl2O4 and Al. Cracks occur around the MgAl2O4 particles, but during the expansion process, a large number of cracks are turned and bent, which helps to improve the fatigue properties of the material.