7A04铝合金深冷处理的组织和性能研究

The Study of Cryogenic Process in 7A04 Aluminum Alloy

对7A04铝合金试样分别采取普通固溶处理和固溶加深冷处理,并在不同的温度下进行人工时效。结合金相组织,硬度、抗拉强度和冲击韧性的测试值对比两组工艺,分析深冷处理对7A04铝合金时效金相组织和力学性能的影响。结果表明:深冷处理能使7A04铝合金在晶粒内外产生大量析出相,并形成较为均匀的弥散分布。7A04铝合金固溶+深冷处理的理想时效温度为120℃,时效16 h,峰值时效硬度为190 HB,最高抗拉强度为679 MPa,与普通固溶处理相比分别提高了24.1%和26.9%,韧性略有提高,具有较高强韧性。

Treat the 7A04 aluminum alloy specimens with conunon solution and solution combined with cryogenic treatment, fo llowed by aging at different temperalures. Then analyze the impact of various heat treatment processes on the properties of 7A04 alloy through the methods of metallographie observation, hardness test, tensile strength test, impact toughness test. The resuhs shows that cryogenic treatment can make 7A04 aluminum alloy produce more homogeneous and larger amount of second phase particles. The ideal aging temperatm~ of solution combining cryogenic treated 7A04 aluminum alloy is 120℃, with the time of 16h. The highest hardness and toughness are 190HB and 679MPa. Compared with common solution treatment,the hardness increases by 24. 1% ,while strength is improved by 26.9%, toughness is slightly higher. The strength and toughness both are at a relatively high level.