高性能铝基复合材料的颗粒分布及界面结合

采用常规粉末冶金和高能球磨粉末冶金法制备了B4Cp/Al复合材料，研究了B4C颗粒分布与界面结合特点、形成机制以及对材料性能的影响。结果表明，17％（体积分数）B4Cp/6061Al复合材料的屈服和抗拉强度分别为415MPa和470MPa，比常规粉末冶金复合材料分别提高了69％和70％。微观分析表明，高能球磨粉末冶金复合材料中B4C颗粒均匀分布、颗粒与基体之间存在近百纳米厚度的界面层，界面层由呈带状且有序分布的微细铝晶粒和弥散分布的纳米颗粒组成。高能球磨过程中，铝粉末在钢球表面形成冷焊层，B4C不断被挤入而均匀化是实现颗粒均匀分布的主要机制；球磨过程中铝粉末表面氧化层破碎暴露出新鲜铝表面且与镶嵌与铝粉末中的B4C颗粒形成界面结合是获得良好界面结合复合材料的重要条件

Distribution of Particles and Interfacial Bonding of Advanced Aluminium Matrix Composites

B 4C particles reinforced aluminium matrix composites were successfully fabricated by traditional powder metallurgy(CPM) and high energy ball milling powder metallurgy(HEBM PM) respectively. The characteristics and forming mechanism of B 4C particle distribution and interfacial bonding and the effect of particle distribution and interfacial bonding on the HEBM PM composites were investigated. Test results indicated that, the yield and ultimate tensile strength of 17vol% B 4C p/6061Al composites fabricated by the HEBM PM were 415 MPa and 470 MPa, increased by a factor of 69% and 70% respectively compared with that of 17vol% B 4C p/6061Al composites fabricated by the CPM. Microstructural analysis showed that, spatial distribution of B 4C particles in composites made by the HEBM PM was uniform, and there was an interface zone between B 4C particles and Al matrix, which was composed of superfine Al grains in ordered banding distribution and particle like substances of nano metre size. The chief mechanism of particle even distribution is that aluminium particles form a cold weldings zone on steel balls and B 4C was squeezed into cold welding zone constantly during the high energy ball milling process. Forming an interfacial bonding between B 4C particles embedded in matrix and aluminium with fresh surface during the milling is an important requirement for obtaining composites with good interfacial bonding.