(江蘇大學(xué)先進(jìn)制造與現(xiàn)代裝備技術(shù)工程研究院，鎮(zhèn)江 212013)
摘 要: 研究預(yù)回復(fù)對固溶-T652處理超高強(qiáng)鋁合金Al-12.5Zn-3.6Mg-1.2Cu-0.2Zr-0.06Sr擠壓材組織與性能的影響。結(jié)果表明：合金在固溶-T652處理前預(yù)回復(fù)處理((250 ℃，24 h)+(300 ℃，6 h)+(350 ℃，6 h)+(400 ℃，6 h))能明顯提高合金的位錯(cuò)密度，顯著細(xì)化合金晶粒(平均晶粒尺寸從11.14 μm下降到5.25 μm)，降低晶界平均角度(從17.81°下降到12.57°)，提高低角度晶界所占比例(由66.2%提高到76.4%)，但硬度和強(qiáng)度略有下降。預(yù)回復(fù)處理能顯著改善合金的抗晶間腐蝕性能，最大晶間腐蝕深度由247.7 mm降為138.0 mm。定量分析結(jié)果表明：合金強(qiáng)度的降低可歸因于時(shí)效沉淀強(qiáng)化效果的降低；抗腐蝕性能的提高可歸因于低角度晶界比例的提高和晶界析出相的粗化。
關(guān)鍵字: 超高強(qiáng)；鋁合金；預(yù)回復(fù)；擠壓材；顯微組織；腐蝕性能
（Engineering Institute of Advanced Manufacturing and Modern Equipment Technology,
Jiangsu University, Zhenjiang 212013, China）
Abstract:The effect of pre-recovery treatment on microstructure and properties of Al-12.5Zn-3.6Mg-1.2Cu- 0.2Zr-0.06Sr aluminum alloy extrusion treated by solid solution –T652 treatment was studied. The results show that the pre-recovery treatment ((250 ℃, 24 h)+(300 ℃, 6 h)+(350 ℃, 6 h)+(400 ℃, 6 h)) can improve the dislocation density of the alloy significantly, refine the grain size (from 11.14 to 5.25 μm), reduce the average angle grain boundaries (from 17.81° to 12.57°) and increase the percentage of low angle grain boundaries (from 66.2% to 76.4%), but reduce the hardness and tensile strength slightly. Pre-recovery treatment enhances inter-granular corrosion performance, the maximum corrosion depth decreases from 247.7 μm to 138.0 μm. Quantitative analysis results show that the decrease of the alloy strength can be attributed to the decline of aging precipitation strengthening. The promotion of corrosion resistance can be due to the improvement of the proportion of low angle grain boundary and the coarsening of precipitates.
Key words: ultra high strength; aluminum alloy; pre-recovery; extrusion; microstructure; corrosion performance
