(1.中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
2. 中南大學(xué) 教育部有色金屬材料科學(xué)與工程重點實驗室，長沙 410083)
摘 要: 采用示差掃描量熱法(DSC)，研究2E12鋁合金在190 ℃時效過程中施加強電場(±9 kV/cm)對合金析出的動力學(xué)的影響，并探討電場影響合金時效過程的微觀機理。結(jié)果表明：時效時施加強電場促進(jìn)了合金中Ⅰ型S相向Ⅱ型S相的轉(zhuǎn)變，使得析出峰提前；未施加電場的合金樣品具有更高的過飽和度、析出焓、析出相體積分?jǐn)?shù)及析出速率；強電場作用降低合金中空位與溶質(zhì)原子之間的結(jié)合能，進(jìn)而降低S相析出激活能。根據(jù)DSC結(jié)果對S相析出激活能進(jìn)行Kissinger方法和普適積分法計算發(fā)現(xiàn)，時效過程中施加電場與未施加電場相比，S相激活能分別降低7.9~12.7 kJ/mol和6.8~22.6 kJ/mol。
關(guān)鍵字: 2E12鋁合金；S相；電場；時效；示差掃描量熱法；動力學(xué)
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China）
Abstract:The influence of electric field (±9 kV/cm) on the aging kinetics and mechanism of 2E12 aluminum alloy during aging at 190 ℃ were investigated by differential scanning calorimetry (DSC). The results show that the transformation of S phase from type Ⅰ to type Ⅱ is promoted by applying electric field. The S phase formation peak in DSC curves under electric field shifts to a lower temperature. The supersaturation degree, formation enthalpy, volume fraction of precipitates and precipitation rate of aged alloy without electric field are higher than those with electric field. The bonding energy between the vacancy and solute atom is decreased by introducing electric field, causing lower activation energies of S phase formation. Based on the DSC results, the activation energies of S phases with electric field in aging are 7.9 −12.7 kJ/mol and 6.8−22.6 kJ/mol lower than those without electric field calculated by the method of Kissinger and general integration measurement, respectively.
Key words: 2E12 aluminum alloy; S phase; electric field; aging; differential scanning calorimetry; kinetics
