(1. 中南大学 轻合金研究院，长沙 410083；
2. 广西南南铝加工有限公司，南宁 530031；
3. 中南大学 有色金属先进结构材料与制造协同创新中心，长沙 410083)
摘 要: 采用末端淬火试验、光学显微镜、扫描电子显微镜和高分辨透射电子显微镜研究时效对7085铝合金厚板淬火引起的不均匀性影响。结果表明：峰时效和过时效前进行长时间的自然时效提高厚板的均匀性，自然时效、峰时效、过时效、自然时效+峰时效和自然时效+过时效后，两端硬度下降率分别约为3.5%、8.6%、7.8%、5.3%和5.2%，硬度与冷却速率的对数间有较好的线性关系。随淬火速率的减小，冷却过程中平衡相的数量和尺寸随之增加，导致厚板不均匀，峰时效和过时效前的长时自然时效有利于慢速淬火处稳定GP区的形成，最终得到数量更多、分布更均匀弥散和尺寸更细小的强化相，从而减小两端的硬度差值，降低淬火引起的不均匀性。
关键字: 7085铝合金；厚板；淬火；不均匀性；时效；淬火析出相
（1. Light Alloy Research Institute, Central South University, Changsha 410083, China;
2. Alnan Aluminium Inc., Nanning 530031, China;
3. Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation
Center, Central South University, Changsha 410083, China）
Abstract:The influence of aging on the quench-induced inhomogeneity of 7085 aluminum alloy thick plate was investigated by means of end-quench test, optical microscopy(OM), scanning electron microscopy(SEM) and high resolution transmission electron microscopy(HRTEM) . The results show that the homogeneity can be improved by long time natural aging before peak aging and overaging. The hardness drop percentages after aging treatments of natural aging, peak aging, overaging, natural aging+ peak aging and natural aging+overaging are about 3.5%,8.6%,7.8%,5.3%, 5.2%, respectively, from spray end to the other one. There is a good linear relationship between hardness and logarithm of cooling rate. With the decrease of cooling rate, more equilibrium η phase with larger size precipitates during the cooling process, causing inhomogeneity of the thick plates. While the long time natural aging before peak aging and overaging is favorable for the formation of stable GP zones at slowly-cooled locations, and consequently more amount of dispersed and fine hardening precipitates are obtained, giving rise to lower hardness drop percentage and inhomogeneity caused by cooling.
Key words: 7085 aluminum alloy; thick plate; quench-induced; inhomogeneity; aging; precipitation
