摘要
热冲压–淬火一体化工艺是复杂形状铝合金薄壁件的先进成形技术,但受限于较长的标准T6处理时间,如2219铝合金需要不短于12 h。本文研究了2219铝合金的快速双级时效热处理工艺,利用高低温模具内时效处理代替标准的T6处理,通过试验研究了不同时效条件对合金力学性能的影响。首先进行了快速双级时效试验研究,探究了第一步时效温度与时间以及第二步时效时间对合金力学性能的影响。结果表明,随着第一步时效温度从220℃提高至305℃,合金的屈服强度和抗拉强度整体呈下降趋势;随着第二步时效时间从0.5 h延长至4 h,合金的强度提高。然后,根据快速双级时效试验结果对时效参数范围进行优化,并以此为依据进行了模内时效工艺试验研究。结果表明,当时效条件为220℃/230℃/240℃×5 min+175℃×4 h时,屈服强度不低于T62态的91%,抗拉强度不低于T62态的100%;当时效条件为240℃×5 min+175℃×4 h时,随着模具接触压强从0.33 MPa提高至1.82 MPa,合金的抗拉强度从393 MPa提高至419 MPa。最后对包含时效条件240℃×5 min+175℃×4 h在内的几组典型时效条件下的试样进行TEM分析,观察了其沉淀相的形态与分布。本文提出的高低温双级时效热处理制度,在保证合金性能的前提下,相较于传统时效工艺(175℃×12 h或175℃×18 h),总时效时长减少超过63%,大幅缩短了高强铝合金薄壁冲压件成形后的时效周期。
The hot-stamping quenching process is an advanced forming technique for thin-walled aluminum alloy parts with complex shapes,but is limited by the long standard T6 treatment time,such as no shorter than 12 h for 2219 aluminum alloy.In this paper,the fast two-step aging heat treatment process of 2219 aluminum alloy was investigated,by aging in dies with high-low temperatures to replace standard T6 treatment,and the effect of various aging conditions on the mechanical properties of the alloy was experimentally investigated.Firstly,the fast two-step aging experimental investigation was carried out to explore the effect of the first-step aging temperature and time,and the second-step aging time on the mechanical properties of the alloy.The results show that the yield and the ultimate strength of the alloy show a whole trend to decrease as the first-step aging temperature increases from 220℃to 305℃and the strength of the alloy increases as the second-step aging time increases from 0.5 h to 4 h.Then,according to the results of the fast two-step aging experiments,the range of the aging parameters was optimized,and based on this,an experimental study of the in-die aging process was carried out.The results show that the yield strength is not lower than 91%of the T62 state and the ultimate strength is not lower than 100%of the T62 state when the aging condition is 220℃/230℃/240℃×5 min+175℃×4 h.When the aging condition is 240℃×5 min+175℃×4 h,the tensile strength of the alloy increases from 393 MPa to 419 MPa as the die contact pressure increases from 0.33 MPa to 1.82 MPa.Finally,the TEM analysis of several sets of specimens of the typical aging conditions including the aging condition of 240℃×5 min+175℃×4 h was carried out to observe the morphology and distribution of the precipitations.The two-step high and low temperature ageing heat treatment process proposed in this paper reduces the total aging time by over 63%compared to the traditional aging process(175℃×12 h or 175℃×18 h)on the premis
作者
曲海涛
陈福龙
何宗仁
石佳瑷
韩玉杰
曹宏东
郑菁桦
QU Haitao;CHEN Fulong;HE Zongren;SHI Jiaai;HAN Yujie;CAO Hongdong;ZHENG Jinghua(AVIC Manufacturing Technology Institute,Beijing 100024,China;Dalian University of Technology,Dalian 116024,China;Nanjing University of Aeronautics and Astronautics,Nanjing 211106,China)
出处
《航空制造技术》
CSCD
北大核心
2024年第6期14-22,共9页
Aeronautical Manufacturing Technology
基金
国家自然科学基金(52105359)。
关键词
2219铝合金
快速双级时效
力学性能
微观组织
沉淀相
2219 aluminum alloy
Fast two-step aging
Mechanical properties
Microstructure
Precipitate phase
