7050合金中铝镍相的细化机制(英文)

Refinement Mechanism Research of Al_3Ni Phase in Ni-7050 Alloy

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 2364MPa(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。

This work investigated the refinement of AI3Ni 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 AI3Ni 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 AI3Ni phase. With the annealing time prolonged, the hardness first increased and then decreased. （2） After multi-step hot/cold roiling, the microscopic structure of composites showed that the size of AI3Ni phase changed progressively, AI3Ni phase was smashed and transformed from original long slab to nearly isometric particles.