(1. 東北大學(xué) 軋制技術(shù)及連軋自動化國家重點實驗室，沈陽 1108192；
2. 燕山大學(xué) 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. 廣西先進(jìn)鋁加工創(chuàng)新中心有限責(zé)任公司，南寧 530007)
摘 要: 采用真空離心鑄造工藝制備了7055鋁合金鑄管坯，通過金相觀察(OM)、掃描電鏡(SEM)、電子探針(EPMA)分析以及硬度測試研究了鑄管坯的微觀組織與力學(xué)性能。結(jié)果表明：鑄管坯組織呈梯度分布，從管坯的外層到內(nèi)層金屬間化合物面積比例、平均尺寸以及晶粒尺寸逐漸增加，晶粒形狀由外層的細(xì)小等軸晶逐漸過度到內(nèi)層的粗大枝晶，溶質(zhì)元素濃度以及硬度逐漸增加；經(jīng)均勻化熱處理后，從管坯外層到內(nèi)層析出相T相含量逐漸增加，合金外層和中層的硬度略有降低，而內(nèi)層硬度大幅下降。為保證組織均勻性和性能的穩(wěn)定性，該管坯厚度以不超過12 mm為宜。
關(guān)鍵字: 7055鋁合金；T相；真空離心鑄造；微觀組織；硬度
（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, Qinhuangdao 066004, China;
3. Guangxi Advanced Aluminum Processing Innovation Center Co., Ltd., Nanning 530007, China）
Abstract:The 7055 aluminum alloy casting tube was prepared by vacuumed centrifugal casting process, and the microstructure and mechanical properties of the tube were studied by metallographic observation (OM), scanning electron microscope (SEM), electron probe microanalysis (EPMA) and hardness test. The results show that the as-cast microstructure presents gradient distribution. From the outer layer to the inner layer, the area fraction, average size and grain size of intermetallic compounds gradually increase, the grains gradually transit from equiaxed grains in the outer layer to dendrites in the inner layer, and the element content and hardness also gradually increase. After homogenization heat treatment, the precipitated phase (T phase) increases gradually from the outer layer to the inner layer of the tube, while the hardness of the outer layer and the middle layer of the alloy decreases slightly, while the hardness of the inner layer decreases greatly. In order to ensure the uniformity of microstructure and stable performance, the thickness of the tube should not exceed 12 mm.
Key words: 7055 aluminum alloy; T phase; vacuumed centrifugal casting; microstructure; mechanical properties
