搅拌摩擦加工制备纳米RE/Al2O3增强铝基复合材料

铝基复合材料因其优异的物理性能及机械性能已得到广泛应用.文中通过在2219-O铝合金内部添加不同比例的RE/Al₂O₃纳米粉末，利用搅拌摩擦加工技术，制备铝基复合材料.并对搅拌区进行金相、拉伸、硬度、SEM，EDS和XRD等试验.结果表明，搅拌区金属在搅拌头强烈的搅拌摩擦作用下发生显著的塑性变形和连续动态再结晶，形成细小的等轴晶粒，并具有明显的洋葱环组织.复合材料的抗拉强度为母材的163%、屈服强度为母材的195%，同时硬度也明显增加.但是不同稀土比例对金属基复合材料的组织形貌和力学性能影响不大.大块复合材料制备过程粉末添加及隧道型缺陷的控制是关键.

Preparation of nano RE/Al2O3 reinforced aluminum matrix composite material by friction stir processing

Aluminum based composite materials have been widely used for its excellent physical and mechanical properties. RE/Al₂O₃ nano powders were added into 2219-O aluminum alloy and the composite materials were prepared by friction stir processing. Meanwhile, the microstructure and properties of the specimen were analyzed and tested by using metallographic, tensile, hardness, SEM, EDS and XRD methods. The results show that, the stir zone metal occurs obviously plastic deformation and continuous dynamic recrystallization under strong friction stir. Besides, fine equiaxed grain and onion rings structure are found in the stir zone. The tensile strength of the composite material can reach 163% and yield strength can reach 195% of matrix ones. Meanwhile, the hardness of the composite material obviously increases, but the rare earth content has little influences on the microstructure and mechanical properties of matrix composites. The key issue to prepare the composite material is how to control the powder addition and tunnel defects.