Refinement Mechanism Research of Al3Ni Phase in Ni-7050 Alloy

摘要:

在7050合金的基础上，使用铸锭冶金工艺制备镍含量为5%，10%的2种复合材料，研究Al3Ni相的细化机制。通过硬度测试，金相观察，SEM，DSC等测试手段分析其组织及性能。结果表明该材料的硬度在T6时效后分别达到1918 MPa(5%镍)和2364 MPa(10%镍)，高于7050合金(1800 MPa)。材料断口观察结果显示，器断裂机制主要为Al3Ni相的沿晶脆性断裂及与基体界面分离2种断裂模式。退火及轧制工艺对材料性能的影响主要为：长时间退火处理可使Al3Ni相明显细化，并使其球化。随着退火时间的延长，材料的硬度先增加后减小；经过多道次的冷轧/热轧工艺，Al3Ni沉淀相逐步细化，由长棒状被破碎为大小相似的颗粒

Abstract:

This work investigated the refinement of Al3Ni phase in Ni-7050 composite, which was prepared by the melting reaction with two different components, 5% and 10% Ni added in 7050 aluminium alloy. Hardness tests, metallographic observation, SEM and DSC were used to analyze the structures and performances. The results show that the hardness of the two composites was obviously increased to 1918 and 2364 MPa after T6 aging. Fracture analysis shows that the fracture mechanism was mainly Al3Ni brittle fracture and interfaces debond. Experiments were designed to investigate the influences of annealing/rolling treatment on structures and properties of the composites. The results indicated: (1) Long time annealing treatment could induce refinement and spheroidization of the Al3Ni phase. With the annealing time prolonged, the hardness first increased and then decreased. (2) After multi-step hot/cold rolling, the microscopic structure of composites showed that the size of Al3Ni phase changed progressively, Al3Ni phase was smashed and transformed from original long slab to nearly isometric particles