(1. 中南大學(xué) 輕合金研究院，長沙 410083；
2. 廣西南南鋁加工有限公司，南寧 530031；
3. 中南大學(xué) 有色金屬先進(jìn)結(jié)構(gòu)材料與制造協(xié)同創(chuàng)新中心，長沙 410083)
摘 要: 采用末端淬火試驗、光學(xué)顯微鏡、掃描電子顯微鏡和高分辨透射電子顯微鏡研究時效對7085鋁合金厚板淬火引起的不均勻性影響。結(jié)果表明：峰時效和過時效前進(jìn)行長時間的自然時效提高厚板的均勻性，自然時效、峰時效、過時效、自然時效+峰時效和自然時效+過時效后，兩端硬度下降率分別約為3.5%、8.6%、7.8%、5.3%和5.2%，硬度與冷卻速率的對數(shù)間有較好的線性關(guān)系。隨淬火速率的減小，冷卻過程中平衡相的數(shù)量和尺寸隨之增加，導(dǎo)致厚板不均勻，峰時效和過時效前的長時自然時效有利于慢速淬火處穩(wěn)定GP區(qū)的形成，最終得到數(shù)量更多、分布更均勻彌散和尺寸更細(xì)小的強(qiáng)化相，從而減小兩端的硬度差值，降低淬火引起的不均勻性。
關(guān)鍵字: 7085鋁合金；厚板；淬火；不均勻性；時效；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
