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采用粉末冶金法制备50%Si/Al(质量分数,下同)复合材料,利用金相显微镜(OM)、万能试验机和扫描电镜(SEM)对材料的组织不均匀性及性能稳定性进行了研究。结果表明:在不同混料条件下,50%Si/Al复合材料能够轻易达到宏观均匀,组织之间的区别在于微区不均匀性。对于50%Si/Al复合材料而言,微区域大小为75μm×70μm所反映的组织微区不均匀性规律与断裂韧性稳定性的变化趋势相吻合。而断裂韧性的稳定性与组织的微区不均匀性相关,因此选取大小为75μm×70μm的微区域能够较好地反映材料的微区不均匀性。相比较而言,4种不同混料工艺中,最佳混料工艺为混料24 h,球料比1∶1。组织微区不均匀性对于断裂韧性稳定性影响最为突出,对抗弯及抗拉强度稳定性的影响并不明显。
The 50% Si / Al (mass fraction, the same below) composites were prepared by powder metallurgy method. The microstructures and properties of the composites were characterized by OM, universal testing machine and scanning electron microscope (SEM) the study. The results show that under different mixing conditions, the 50% Si / Al composites can easily achieve macroscopical homogeneity, and the difference between the microstructures lies in the heterogeneity of the microstructure. For the 50% Si / Al composites, the microstructure heterogeneity reflected by the size of 75μm × 70μm coincides with the trend of fracture toughness stability. However, the stability of fracture toughness is related to the heterogeneity of the microstructure. Therefore, the micro-area with the size of 75μm × 70μm can reflect the micro-area heterogeneity of the material well. In comparison, among the four different compounding processes, the best compounding process is mixing for 24 h and the ratio of aggregate to aggregate is 1: 1. The microstructure heterogeneity has the most prominent influence on the fracture toughness stability, but has no obvious effect on the bending and tensile strength stability.