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研究了第二级时效工艺对7050铝合金厚板拉伸性能、断裂韧度及电导率的影响,并采用透射电镜及扫描电镜分析其强韧化机理。结果表明:该合金厚板在双级时效的第一级时效条件相同时,随第二级时效温度的升高或时效时间的延长,合金中沉淀相的尺寸和间距增大,合金强度下降,断裂韧度和抗应力腐蚀能力提高,切变和穿晶韧窝混合型断裂方式中的韧窝特征愈加突出,且时效温度对性能的影响较时间明显;在120℃×4 h+165℃×28 h双级时效工艺下合金具有优异的综合性能。
The effects of the second aging process on the tensile properties, fracture toughness and electrical conductivity of 7050 aluminum alloy plate were studied. The mechanism of strengthening and toughening was analyzed by transmission electron microscopy and scanning electron microscopy. The results show that the size and spacing of the precipitates in the alloy increase with the increase of the second aging temperature or the aging time when the first aging conditions of the two - stage aging are the same. The strength of the alloy decreases, Fracture toughness and stress corrosion resistance were improved. The dimple characteristics in the shear fracture and transgranular dimpled mixed fracture mode were more prominent, and the effect of aging temperature on performance was more obvious than that in the time. At 120 ℃ × 4 h + 165 ℃ × 28 h dual-stage aging process alloy has excellent overall performance.