热处理对喷射成形超高强Al-Zn-Mg-Cu系铝合金的影响

Effects of heat-treatment on microstructure and mechanical properties of ultra-high strength spray deposited Al-Zn-Mg-Cu aluminum alloy

研究了2种不同热处理方式对喷射成形超高强度Al Zn Mg Cu系铝合金的显微组织和力学性能的影响。观察了沉积态、挤压态、固溶及时效处理后样品的显微组织,对经时效处理的样品进行了力学性能测试。结果表明:沉积态合金晶粒均匀细小;挤压态合金存在大量的第二相颗粒,为富铜相;固溶处理后,合金出现了再结晶现象。在T6条件下,采用常规470℃单级固溶和时效处理,其抗拉强度仅为710MPa,延伸率为6.5%;采用双级固溶和时效处理,其抗拉强度超过800MPa,延伸率达到9.3%。

The microstructures of as-deposited, extruded and heat treated ultra-high strength aluminum alloys(Al-Zn-Mg-Cu)were investigated. The tensile properties of the heat-treated alloys were tested. The results show that fine and homogeneous grain structure is obtained in as-deposited alloy. However, there are a large amount of Cu-rich particles as determined by energy dispersion spectroscopy (EDX) in as-extruded alloy. The recrystallization occurs in the heat-treated alloy. On the condition of T6 treatment, the ultimate tensile strength of the alloy following single solid-solution treatment is kept on no more than 700 MPa with an elongation of 6.5%. However, the tensile strength of the alloy following dual solid-solution treatment is kept over 800 MPa with an elongation of (9.3%.)