双级时效对含Sc的Al-Zn-Mg-Zr合金组织与性能的影响

发布时间：2018-03-26 16:37

  本文选题：Al-Zn-Mg-Zr合金　切入点：双级时效　出处：《中南大学学报(自然科学版)》2015年11期

【摘要】：通过慢应变速率拉伸实验(SSR_T)、晶间腐蚀试验、剥落腐蚀实验、室温力学性能测试、电导率测试、维氏硬度测量和透射电子显微分析等手段对2.5 mm厚Al-5.4Zn-2.0Mg-0.25Sc-0.1Zr合金板材在双级时效下的抗应力腐蚀性能(SCC)、抗晶间腐蚀性能(IGC)、抗剥落腐蚀性能(EC)、力学性能、电学性能、显微组织结构及其演变规律进行研究。研究结果表明:合金较适宜的双级时效工艺为120℃/6 h+140℃/20 h,在此工艺条件下合金的抗拉强度R_m、屈服强度R_p、伸长率A和电导率γ分别为553 MPa,534 MPa,12.0%和22.3 MS/m,双级时效后合金晶内为弥散分布的亚稳定强化相η′-MgZn_2,晶界出现粗大不连续分布的平衡相η-MgZn_2,还伴有明显宽化的无沉淀析出带。与单级峰值时效(120℃/24 h)相比,合金晶间腐蚀倾向减小,具有良好的抗剥落腐蚀性能,剥蚀等级为中等剥落腐蚀(EB)级,具有良好的抗应力腐蚀性能。
[Abstract]:Through the slow strain rate tensile test (SSRS), the intergranular corrosion test, the exfoliation corrosion test, the mechanical property test at room temperature, the electrical conductivity test, Vickers hardness measurement and transmission electron microscopy (TEM) were used to study the stress corrosion resistance (SCC), intergranular corrosion resistance (IGC), exfoliation corrosion resistance (ECC), mechanical properties and electrical properties of 2.5mm thick Al-5.4Zn-2.0Mg-0.25Sc-0.1Zr alloy plates under two-stage aging. The microstructure and evolution of the alloy were studied. The results showed that the suitable two-stage aging process was 120 鈩，

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