新型高强Al-Cu-Li-Mg-Ag合金的时效工艺研究  

Study on aging process of new high-strength Al-Cu-Li-Mg-Ag alloy

作　　者：郝一玄 牛凤姣 马子博 郭亚杰[1] HAO Yixuan;NIU Fengjiao;MA Zibo;GUO Yajie(School of Materials Science and Engineering,Chang'an University,Xi'an 710061,China;Modern Engineering Training Center,Chang'an University,Xi'an 710061,China)

机构地区：[1]长安大学材料科学与工程学院,陕西西安710061 [2]长安大学现代工程训练中心,陕西西安710061

出　　处：《兵器材料科学与工程》2025年第1期26-33,共8页Ordnance Material Science and Engineering

基　　金：国家自然科学基金(52101007);陕西省重点研发计划一般项目(2024GX-YBXM-352)。

摘　　要：Al-Cu-Li合金为析出强化型铝合金,因高比强度、耐腐蚀、抗疲劳性好等特点,广泛应用于航空航天等领域。第三代铝锂合金通过增大Cu/Li比提升力学性能,却与铝锂合金减质量初衷相背离,因此在尽可能保持Li元素占比的同时使合金展现更高的性能是目前研究的热点。有鉴于此,本文在典型的第三代铝锂合金AA2195的基础上降低了Cu含量,自制新型Al-3.18Cu-0.89Li-0.37Mg-0.15Ag(质量分数)合金,通过显微硬度测试和拉伸性能测试对比研究不同时效工艺下该型合金的时效行为和性能演化规律,并基于透射电子显微镜(TEM)分析不同时效工艺下的相析出,包括析出相的组成、主要强化相析出占比与尺寸变化。结果表明:在单级时效时,时效温度的升高使析出相更细小弥散,抑制δ'相生成,提高了T_(1)相占比并增大了其径厚比,使人工时效到达峰值的时间提前,合金强度提高。自然时效使后续人工时效时T_(1)相和δ'/θ'/δ'相增多,显著提高了T_(1)相的径厚比,抑制了δ'相和σ相的析出,晶界无析出带不明显,相对于单级时效,屈服强度提高12%,抗拉强度提高9%,伸长率略有下降,峰值硬度不变,合金综合性能更优良。Al-Cu-Li alloys are precipitation-strengthened aluminium alloys,which are widely used in aerospace and other fields due to their high specific strength,corrosion resistance and good fatigue resistance.The third-generation Al-Li alloys enhance the mechanical properties by increasing the Cu/Li ratio,which was contrary to the original intention of Al-Li alloys to reduce the mass,so it is a hotspot of research to made the alloys show higher properties while maintaining the Li element ratio as much as possible.In view of this,this article reduced the Cu content on the basis of the typical third-generation aluminum lithium alloy AA2195,and self-made a new Al-3.18Cu-0.89Li-0.37Mg-0.15Ag(mass fraction)alloy.The aging behavior and performance evolution of this type of alloy under different aging processes were compared through microhardness testing and tensile performance testing.The phase precipitation under different aging processes was analyzed based on transmission electron microscopy(TEM),including the composition of precipitated phases,the proportion and size changes of main strengthening phases.The results show that during single-stage aging,the increase in aging temperature makes the precipitated phase finer and more dispersed,inhibits the formation ofδ'phase,increases the proportion of T_(1) phase and its diameter to thickness ratio,advances the time for artificial aging to reach the peak,and improves the alloy strength.Natural aging leads to an increase in T_(1) phase andδ'/θ'/δ'phase during subsequent artificial aging,significantly improving the diameter to thickness ratio of T_(1) phase and suppressing the precipitation ofδ'phase andσphase.There is no obvious precipitation zone at the grain boundary.Relative to single-stage aging,the yield strength increases by 12%,the tensile strength increases by 9%,the elongation slightly decreases,the peak hardness remains unchanged,and the overall performance of the alloy is better.

关 键 词：铝合金 时效温度 析出相 力学性能 

分 类 号：TG166.3[金属学及工艺—热处理]