(1. 中南大學 材料科學與工程學院，長沙 410083；2. 三一重工股份有限公司 泵送研究院，長沙 410100)
摘 要: 測定2A14合金連續(xù)冷卻轉(zhuǎn)變動力學曲線(CCT圖)，并對該曲線進行應(yīng)用研究。通過DSC分析和SEM組織觀察確定2A14合金合理的固溶溫度，采用動態(tài)電阻法測得固溶后合金連續(xù)冷卻過程的電阻—溫度曲線，根據(jù)曲線斜率變化判斷相變信息，繪制2A14合金的CCT圖，利用透射電鏡(TEM)觀察連續(xù)冷卻過程中合金的組織轉(zhuǎn)變。結(jié)果表明：2A14合金適宜的固溶溫度為505 ℃；隨著冷卻速度的增加，相變開始溫度先降低，在達到某冷卻速度時驟升，然后持續(xù)增加；相變主要集中在140~380 ℃的溫度區(qū)間發(fā)生，抑制相變發(fā)生的臨界冷卻速度稍大于38.5 ℃/s；在實驗范圍內(nèi)，20 mm厚的2A14合金板適宜采用60 ℃或100 ℃水淬，參考所測CCT圖制定分級淬火工藝，可以在最大限度減小淬火應(yīng)力的同時，抑制第二相的析出。
關(guān)鍵字: 2A14合金；連續(xù)冷卻轉(zhuǎn)變動力學曲線(CCT圖)；原位電阻；相變；冷卻速度
2A14 aluminum alloy and its application
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Institute of Pumping, SANY Heavy Industry Co., Ltd., Changsha 410100, China）
Abstract:The continuous cooling transformation (CCT) curve of 2A14 aluminum alloy and its application were studied. The solutionizing temperature was ascertained by DSC analysis and SEM observation. Electrical resistance—temperature curves of 2A14 alloy in the continuous cooling processes after solid solution treatment were obtained by in-situ resistance measurement. Messages of the phase transformation were judged by analyzing the slope change of the obtained curves. The CCT diagram for Al-Cu-Mg alloy was plotted. The microstructure evolution during the cooling was examined by TEM observation. The results show that the appropriate solid solution temperature is 505 ℃. The phase transformation starting temperature decreases with the increase of cooling rates when the cooling rate is slow, but when the cooling rate is a little higher the phase transformation starting temperature increases suddenly. The phase transformation mainly takes place between 140 and 380 ℃. The critical cooling rate for preventing the phase transformation is above 38.5 ℃/s. It is better for 2A14 plates with the thickness of 20 mm to quench by 60 ℃ or 100 ℃ water. Interrupted quenching process can be established according to the tested CCT diagram to decrease quenching stress utmost and inhibit the precipitation of the secondary phases at the same time.
Key words: 2A14 alloy; continuous cooling transformation (CCT) curve; in-situ electrical resistance; phase transformation; cooling rate
