(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(diǎn)實(shí)驗(yàn)室，長沙 410083)
摘 要: 通過末端淬火的方法研究7055鋁合金厚板的淬透性，采用透射電子顯微鏡對(duì)微觀組織進(jìn)行分析。結(jié)果表明：該合金板材的淬透深度可達(dá)45 mm，使其淬透的冷卻速率需大于230 ℃/min；隨著冷卻速率的減小，淬火過程析出平衡相的數(shù)量和尺寸增加，時(shí)效后析出的η′ 沉淀強(qiáng)化相的數(shù)量減少，晶界無沉淀析出帶寬度增加；在所研究的冷卻速率范圍內(nèi)，時(shí)效后鋁合金板材的硬度、晶界無沉淀析出帶寬度與冷卻速率的對(duì)數(shù)均呈線性關(guān)系。
關(guān)鍵字: 7055鋁合金厚板；末端淬火；淬透性；微觀組織
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China）
Abstract:The hardenability of a 7055 aluminum alloy plate was studied by end quenching test, the microstructure was investigated by transmission electron microscopy. The results show that the hardened depth is about 45 mm for the plate and the corresponding cooling rate is about 230 ℃/min. With decreasing the cooling rate, the number and size of quench-induced equilibrium phase increase, the number of η′ strengthening precipitates decreases and the width of precipitate free zone near grain boundaries increases. In the range of the studied cooling rates, the relationships among the hardness, width of precipitate free zone near grain boundaries and logarithm of cooling rate are linear.
Key words: 7055 aluminum alloy plate; end quenching; hardenability; microstructure
