固溶制度对Al-5.6Cu-1.7Mg-0.2Zr-0.1Sr-0.6Ti合金挤压材组织性能的影响

通过金相组织分析、扫描电子显微镜分析、X射线衍射、硬度、电导率、室温拉伸性能、断后伸长率和抗晶间腐蚀等微观组织观察及性能表征，研究了四种不同固溶制度对Al-5.6Cu-1.7Mg-0.2Zr-0.1Sr-0.6Ti合金微观组织和性能的影响。结果表明：随着固溶温度的升高，合金中的晶粒逐渐变大；当固溶温度低于520℃时，合金中的未溶相的数量和尺寸随着固溶温度的升高而减小；当固溶制度为510℃×2 h+520℃×2 h时，合金中的未溶相开始增多，合金出现轻微过烧，断后伸长率及抗晶间腐蚀性能变差，但抗拉强度最高，达到了490.14 MPa。合金的位错强度和位错贡献值随着固溶温度的升高而减小，合金中的强化效果主要来源于固溶强化和时效析出强化。合金在T6状态下，(490℃×2 h+500℃×2 h)和(500℃×2 h+510℃×2 h)两种不同固溶制度下的抗拉强度和断后伸长率等力学性能和抗晶间腐蚀性能都较优，这两种固溶制度均是适合Al-5.6Cu-1.7Mg-0.2Zr-0.1Sr-0.6Ti合金的固溶制度。

Effect of solid-solution treatment on microstructure and properties of extruded Al-5.6Cu-1.7Mg-0.2Zr-0.1Sr-0.6Ti alloy

The effects of four solid-solution treatments on the microstructure and properties of Al-5.6Cu-1.7Mg-0.2Zr-0.1Sr-0.6Ti alloy were studied herein by metallographic structure analysis,SEM(Scanning Electron Microscope) analysis、X-Ray Diffraction,hardness,conductivity,room temperature tensile properties, elongation after fracture and intergranular corrosion resistance. The results show that the grain size increases and with an increase in the solution temperature. The size and quantity of insoluble phase in the alloy decrease with increasing solution temperature when the temperature is less than 520 ℃. When the solid treatment is 510 ℃ for 2 h and then at 520 ℃ for 2 h, the insoluble phase in the alloy begins to increase, and the alloy appears slight overburning, the elongation after fracture and intergranular corrosion resistance become worse, but the tensile strength reaches the highest as 490.14 MPa. The dislocation strength and dislocation contribution decrease with an increase in the solution temperature. The strength effect in the alloy is mainly attributed to the solution strengthening and aging precipitation strengthening.Two different solid-solution treatments (route a:490 ℃ for 2 h and then at 500 ℃ for 2 h; route b: 500 ℃ for 2 h and then at 510 ℃ for 2 h) both can guarantee the mechanical properties(strength and elongation) and intergranular corrosion resistance of the alloy under T6 aging are good; therefore,both of the solid-solution treatments are suitable for preparing Al-5.6Cu-1.7Mg-0.2Zr-0.1Sr-0.6Ti alloy.