Al-8.9Zn-2.0Mg-1.8Cu合金固溶及时效处理过程中组织性能演变研究  

Microstructure and property evolution during solution and aging treatments of an Al-8.9Zn-2.0Mg-1.8Cu alloy

作　　者：汤林志 温凯 程韬潜 李锡武 李志辉 TANG Lin-zhi;WEN Kai;CHENG Tao-qian;LI Xi-wu;LI Zhi-hui(Southwest Aluminium(GROUP)Co.,LTD.,Chongqing 401326,China;State Key Laboratory of Nonferrous Metals and Processes,China GRINM Group Co.,LTD.,Beijing 100088,China;GRIMAT Engineering Institute Co.,LTD.,Beijing 101407,China)

机构地区：[1]西南铝业(集团)有限责任公司,重庆401326 [2]中国有研科技集团有限公司有色金属材料制备加工国家重点实验室,北京1000882 [3]有研工程技术研究院有限公司,北京101407

出　　处：《世界有色金属》2024年第10期1-4,共4页World Nonferrous Metals

基　　金：国家重点研发计划项目课题(2023YFB3710502)。

摘　　要：固溶处理可使7xxx系合金获得过饱和固溶体,并在时效阶段析出强化相,最终获得高的综合性能。本试验研究了Al-8.9Zn-2.0Mg-1.8Cu合金在固溶及时效处理过程中的组织及力学性能演变,并在此基础上确定了优选的固溶和时效处理制度。研究结果表明:470℃~480℃固溶处理1h后,合金中的Mg(Zn,Cu,Al)_2相完全回溶,仅有富Fe相残留;延长470℃固溶处理时间,富Fe相无明显变化,合金拉伸性能基本相当。合金适宜的固溶处理制度为475℃/1h。单级时效过程中,随着时效时间的延长,合金硬度初期迅速升高,后期表现平稳,整体上呈现出升高的趋势;单级时效温度越高,其初期增长越快,数值也更大。合金强度的演变规律与硬度类似。随着时效时间的延长,电导率呈现升高的趋势;时效温度越高,电导率越大。120℃时效时,随时效时间延长,合金的晶内析出相的尺寸增大,析出相尺寸分布范围变宽,主要析出相由时效初期的GPⅠ区、GPⅡ区和η'相转变为GPⅡ区、η'相和η相。适宜的峰时效制度确定为120℃/48h。Solution treatment enables 7xxx series alloys to achieve a supersaturated solid solution,which precipitates strengthening phases during aging,ultimately resulting in high comprehensive properties.This experiment studied the evolution of the microstructure and mechanical properties of an Al-8.9Zn-2.0Mg-1.8Cu alloy during solution and aging treatments,and based on these findings,optimized solution and aging treatment regimes were determined.The results indicated that after solution treatment at 470℃~480℃for 1 hour,the Mg(Zn,Cu,Al)2 phase in the alloy completely dissolved,with only Fe-rich phases remaining.Extending the solution treatment time at 470℃showed no significant change in the Fe-rich phases,and the tensile properties of the alloy remained essentially unchanged.The suitable solution treatment regime for the alloy was determined to be 475℃/1h.During single-stage aging,with the extension of aging time,the hardness of the alloy initially increased rapidly and then stabilized,showing an overall increasing trend.The higher the single-stage aging temperature,the faster the initial increase and the higher the values.The evolution of the alloy strength followed a similar pattern to that of hardness.With prolonged aging time,the electrical conductivity showed an increasing trend;the higher the aging temperature,the greater the electrical conductivity.During aging at 120℃,as the aging time increased,the size of the matrix precipitates in the alloy grew,and the size distribution range of the precipitates widened.The main precipitates transitioned from GPI zone,GPII zone andη'phase in the early stage to GPII zone,η'phase andηphase.The suitable peak aging regime was determined to be 120℃/48h.

关 键 词：7XXX系铝合金 固溶处理 时效处理 组织性能 

分 类 号：TG166.4[金属学及工艺—热处理]