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采用拉伸测试、TEM和电导率测试等方法,研究回归再时效(RRA)处理中预时效处理对喷射成形7075合金组织及性能的影响.结果表明,采用120℃,16 h的欠时效预处理比120℃,24 h峰值时效预处理和120℃,32 h过时效预处理更有利于在回归处理过程中合金晶内析出相的回溶,比120℃,8 h的早期预时效处理更有助于晶界相在再时效处理后断续分布.120℃,16 h预时效处理的合金经RRA处理后,其抗拉强度和屈服强度分别为782和726 MPa,均高于T6峰值时效和常规回归再时效水平;电导率为22.7MS/m,晶界析出相断续分布,合金抗腐蚀性能优良.
The effects of pre-aging treatment on the microstructure and properties of spray-cast 7075 alloy were studied by means of tensile test, TEM and conductivity test.The results showed that under the condition of 120 ℃, 16 h under-aging pretreatment Compared with 120 ℃, 24 h peak aging pretreatment and 120 ℃, 32 h overage pretreatment, it is more conducive to the precipitation of alloy precipitates during the regression process than the 120 ℃, 8 h early pre-aging treatment more Which will contribute to the intermittent distribution of the grain boundary phase after re-aging treatment.The tensile strength and yield strength of the pre-treated alloys at 120 ℃ and 16 h after RRA treatment are 782 and 726 MPa, respectively, which are higher than those of T6 peak aging and Conventional regressive re-aging level; electrical conductivity of 22.7MS / m, the grain boundary precipitates are intermittently distributed, the alloy has excellent corrosion resistance.