(1. 東北大學軋制技術(shù)及連軋自動化國家重點實驗室，沈陽 110819；
2. 燕山大學國家冷軋板帶裝備及工藝工程技術(shù)研究中心，秦皇島 066004；
3. 東北大學材料電磁過程研究教育部重點實驗室，沈陽 110819；
4. 廣西先進鋁加工創(chuàng)新中心有限責任公司，南寧 530007)
摘 要: 在鑄造冷卻速率分別為1.4 ℃/s與5.7 ℃/s的條件下制備了Al-Mg-Si-Mn鋁合金鑄錠，對鑄錠進行了430 ℃、6h超低溫均勻化，對均勻化后的合金樣品進行了等軸熱壓試驗。結(jié)果表明：水冷銅模樣品中的共晶組織含量更少且尺寸更小。均勻化熱處理后，大量α-Al(Fe, Mn)Si彌散相在鋁基體中析出，水冷銅模樣品的彌散相數(shù)量密度高于砂模樣品。等軸熱壓過程中，水冷銅模樣品具有更高的變形應(yīng)力，原因是其α-Al(Fe, Mn)Si相數(shù)量密度更高，產(chǎn)生了更強的顆粒強化效應(yīng)；砂模樣品的邊裂傾向更嚴重，原因是砂模樣品中的粗大共晶組織更容易引起變形過程中的局部應(yīng)力集中。
關(guān)鍵字: 鋁合金；鑄造冷卻速率；α-Al(Fe, Mn)Si彌散相；熱加工性能
（1. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China;
2. National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinghuangdao 066004, China;
3. Key Laboratory of Electromagnetic Processing of Materials, Ministry of Education, Northeastern University, Shenyang 110819, China;
4. Guangxi Advanced Aluminum Processing Innovation Center Co., Ltd., Nanning 530007, China）
Abstract:Al-Mg-Si-Mn aluminum alloys were cast with different cooling rates of 1.4 ℃/s and 5.7 ℃/s, respectively. Ultra-low temperature homogenization at 430℃ for 6h was applied, followed by uniaxial hot compression tests to verify the hot workability. The results show that the water-cooled copper moldsample possesses a lower eutectics structure with a smaller size than the sand moldsample. After homogenization, a large amount of α-Al(Fe, Mn)Si dispersoids precipitate, and the number density of dispersoids in the water-cooled copper mold sample is greater than that in the sand mold sample. The water-cooled copper mold sample exhibits higher engineering stress levels during hot compression due to the enhanced dispersoids strengthening effect than that in sand mold sample. The edge cracks in water-cooled copper mold is less severe owing to the much finer initial eutectics generating depressed the risk of crack growth thanthat in the sand mold sample.
Key words: aluminum alloy; casting cooling rate;α-Al(Fe, Mn)Si dispersoid; hot workability
