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采用硬度与电导率测试、拉伸试验、金相(OM)观察、X射线衍射(XRD)分析、晶间腐蚀和剥落腐蚀(EXCO)试验,研究了不同热处理工艺(固溶-T6时效,固溶-预压缩-T6时效,预回复-固溶-预压缩-T6时效和预回复-固溶-预压缩-T76时效)对含锆锶复合微合金化的Al-10.78Zn-2.78Mg-2.59Cu-0.221Zr-0.0465Sr高强铝合金组织与性能的影响。结果表明:在T6(120℃×24 h)时效制度下,预回复和预压缩均能提高位错强化,并且预回复能显著抑制再结晶;与固溶-预压缩-T6相比,预回复-固溶-预压缩-T6工艺能在不降低强度的情况下,提高抗晶间和剥落腐蚀性能(最大晶间腐蚀深度从125μm减少到91μm,剥落腐蚀从EB级提高到EA级);预回复-固溶-预压缩-T76状态下,合金强度低至600 MPa,但电导率高达31.58%ICAS,较T6时效下的抗腐蚀性能明显改善。经研究表明,Al-10.78Zn-2.78Mg-2.59Cu-0.221Zr-0.0465Sr高强铝合金挤压材在预回复-固溶-预压缩-T6时效工艺下的综合性能最佳。
The effects of different heat treatment processes (solid solution-T6 aging, solidification-solidification) on the mechanical properties and mechanical properties were studied by means of hardness and conductivity test, tensile test, OM observation, XRD analysis, intergranular corrosion and exfoliation corrosion (EXCO) Al-10.78Zn-2.78Mg-2.59 with zirconium-strontium composite micro-alloying has been successfully prepared by sol-precompression-T6 aging, pre-restoration-solutionizing-precompression- Effect of Cu-0.221Zr-0.0465Sr High-Strength Aluminum Alloy on Microstructure and Properties. The results show that both pre-recovery and pre-compression can enhance the dislocation strengthening under the aging system of T6 (120 ℃ × 24 h), and the pre-recovery can significantly inhibit the recrystallization. Compared with the solution-precontracted-T6, - The solution-pre-compression-T6 process increases the resistance to intergranular and exfoliation corrosion (the maximum intergranular corrosion decreases from 125 μm to 91 μm and the exfoliation corrosion increases from the EB level to the EA level) without preconditioning; Under the condition of solution-solution-pre-compression-T76, the strength of the alloy is as low as 600 MPa, but the conductivity is as high as 31.58%, and the corrosion resistance of the alloy is significantly improved as compared with that under T6 aging. The research shows that the comprehensive performance of Al-10.78Zn-2.78Mg-2.59Cu-0.221Zr-0.0465Sr high-strength aluminum alloy extruded material in the pre-recovery-solution-precompression-T6 aging process is the best.