摘要
采用硬度测试、电导率测试、室温拉伸、TEM观察、DSC分析以及剥落腐蚀实验,研究了非等温时效对7B50铝合金热轧厚板的微观组织及耐蚀性能的影响。结果表明:经过480℃、1 h固溶后室温水淬火,再经1℃/min的加热速率升温至215℃后立即炉冷至室温的非等温时效,7B50铝合金的晶内析出相细小弥散,晶界相粗大断续。合金抗拉强度可达605 MPa,剥落腐蚀等级可达EB,综合性能优于单级等温峰时效(T6)和双级等温过时效(T76),与回归再时效(RRA)态性能类似。非等温时效技术实现了短流程操作,且取消等温保温的措施更适用于厚板的时效热处理。
Due to the temperature rising or cooling stage in thick plate, non-isothermal ageing has been the research hotspot of heat treatment for Al-Zn-Mg-Cu alloy thick plate. It is possible to replace the isothermal ageing by non-isothermal one because of the high efficiency and practicability. As one of the Al-Zn-Mg-Cu alloy, 7B50 aluminum alloy and its thick plate have supposed to manufacture the wing in "Yun-20" big plane. In this work, hardness test, electrical conductivity test, room temperature tensile test,DSC analysis, exfoliation corrosion test and TEM observation were used to study the influence of non-isothermal ageing on microstructure and corrosion resistance of 7B50 aluminum alloy hot rolling thick plate.Results revealed that, after 480 ℃, 1 h solution and quenched in room temperature water, followed by ageing from room temperature to 215 ℃ at 1 ℃/min heating rate, and furnace cooling to room temperature immediately, the inner precipitates of 7B50 aluminum alloy are fine and dispersed while the ones on grain boundary are coarsened and discontinuous. The tensile strength and exfoliation corrosion grade reached to 605 MPa and EB level, respectively. Comprehensive performance of 7B50 aluminum alloy are excellent overall those of isothermal peak ageing(T6) or isothermal double stages over ageing(T76), but similar to that of retrogression and re-ageing(RRA) treatment. The non-isothermal ageing realized the short process preparation and the measure removing isothermal stage is more suitable for thick plates.
作者
李吉臣
冯迪
夏卫生
林高用
张新明
任敏文
LI Jichen;FENG Di;XIA Weisheng;LIN Gaoyong;ZHANG Xinming;REN Minwen(School of Materials Science and Engineering,Jiangsu University of Science and Technology,Zhenjiang 212003,China;School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;School of Materials Science and Engineering,Central South University,Changsha 410083,China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2020年第9期1255-1264,共10页
Acta Metallurgica Sinica
基金
国家自然科学基金项目No.51801082
江苏省自然科学基金项目No.BK20160560
江苏省大学生创新创业训练计划项目No.201910289095Y。
关键词
7B50铝合金
非等温时效
强度
剥落腐蚀性能
7B50 aluminum alloy
non-isothermal ageing
strength
exfoliation corrosion property
作者简介
李吉臣,男,1997年生,硕士生;通讯作者:冯迪,difeng1984@just.edu.cn,主要从事高强航空铝合金的强韧化研究。
