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采用硬度测试、透射电镜(TEM)和差示扫描量热分析(DSC)等方法,研究了多级断续时效对高Cu/Mg比Al-Cu-Mg-Ag-Zr合金组织和性能的影响。结果表明,断续时效第二级低温时效对合金硬度无明显影响,第三级高温时效对硬度影响较大,随着时间的延长,硬度先增大且在160℃时效20 h左右达到最大值后减小。透射电镜和DSC证明在断续时效的不同阶段,合金的沉淀析出特征:在第一阶段高温时效中,Ω相和θ’相同时析出,两种析出相的数量无明显差别;在第二阶段低温时效中,θ’相持续析出,无明显的Ω相析出特征;在第三阶段高温再时效中,Ω相和θ’相同时析出长大,Ω相为主要强化相,θ’相相对较少。
The effects of multi-stage intermittent aging on microstructures and properties of high Cu / Mg ratio Al-Cu-Mg-Ag-Zr alloys were investigated by hardness test, transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) . The results show that the second stage of intermittent aging has no significant effect on the hardness of the alloy, and the third stage of high temperature has a significant effect on the hardness. With the extension of time, the hardness first increases and reaches the maximum at about 20 h After the decrease. Transmission electron microscopy and DSC showed that the precipitation characteristics of the alloy during different stages of intermittent aging: In the first stage of high temperature aging, when the Ω phase and θ ’are the same, the amount of precipitation is no significant difference; in the second stage In the low temperature aging, the θ ’phase is precipitated continuously with no obvious precipitation characteristics of the Ω phase. In the third stage of high temperature re-aging, the phases of Ω and θ’ are precipitated and grown, the phase of Ω is the main strengthening phase and the phase of θ ’ less.