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。
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.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2016年第9期1823-1831,共9页
The Chinese Journal of Nonferrous Metals
基金
国家重点基础研究发展计划资助项目(2012CB619500)
国家国际科技合作专项项目(2014DFA50210)~~
关键词
7085铝合金
厚板
淬火
不均匀性
时效
淬火析出相
7085 aluminum alloy
thick plate
quench-induced
inhomogeneity
aging
precipitation
