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基于第一性原理计算方法探讨了铝合金应力/应变时效的可能机制,综合评估了时效温度和外加应力/应变对Al-Sc合金中Al3Sc固溶边界和Al-Cu合金中Al/θ’’界面能的潜在影响。计算结果表明:在传统时效过程中引入外加拉应力/应变,声子态密度在高态区有红移现象,可以明显降低溶解熵;同时,导致相图中固溶线上移,表明外加拉应力/应变可降低Al3Sc在Al-Sc合金中的极限固溶度,从而增加析出相的最大可能体积分数。外加应力/应变对Al-Cu合金中不同取向的Al/θ’’界面形成能有不同程度的影响,这种差别可以通过泊松效应进一步放大,从而影响到Al-Cu合金中析出相的择优取向。这2种机制在应力/应变时效中均可能发挥重要作用。
Based on the first-principles calculation method, the possible mechanism of stress-strain aging of aluminum alloy was discussed. The influences of aging temperature and applied stress / strain on the Al3Sc / Al alloy interface in Al-Sc alloy and the Al / The potential impact of interface energy. The results show that the addition of tensile stress / strain during the traditional aging process results in a red shift of the phonon state density in the high-state region, which can obviously reduce the entropy of dissolution. At the same time, Stress / strain can reduce the ultimate solid solubility of Al3Sc in Al-Sc alloys and increase the maximum possible volume fraction of precipitates. The addition of stress / strain has different effects on the Al / θ "interface formation in different orientations in Al-Cu alloys. This difference can be further amplified by the Poisson effect, which affects the preferential precipitation of Al-Cu alloy orientation. Both of these mechanisms may play an important role in stress / strain aging.