(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 中南大学 教育部有色金属材料科学与工程重点实验室，长沙 410083)
摘 要: 通过末端淬火的方法研究7055铝合金厚板的淬透性，采用透射电子显微镜对微观组织进行分析。结果表明：该合金板材的淬透深度可达45 mm，使其淬透的冷却速率需大于230 ℃/min；随着冷却速率的减小，淬火过程析出平衡相的数量和尺寸增加，时效后析出的η′ 沉淀强化相的数量减少，晶界无沉淀析出带宽度增加；在所研究的冷却速率范围内，时效后铝合金板材的硬度、晶界无沉淀析出带宽度与冷却速率的对数均呈线性关系。
关键字: 7055铝合金厚板；末端淬火；淬透性；微观组织
（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
