热暴露对2B25-T3511铝合金力学性能及显微组织的影响  

Effect of heat exposure on mechanical properties and microstructure of 2B25-T3511 aluminum alloy

作　　者：吴秀亮[1] 汝继刚[1] 李超[1] 李惠曲[1] 伊琳娜[1] 王亮[1] 

机构地区：[1]北京航空材料研究院,北京100095

出　　处：《轻合金加工技术》2014年第7期50-55,共6页Light Alloy Fabrication Technology

摘　　要：通过拉伸性能测试和透射电镜(TEM)观察等手段,研究热暴露温度和时间对2B25-T3511铝合金组织和热稳定性的影响。结果表明,当热暴露温度为125℃时,合金的室温抗拉强度变化不大,屈服强度升高,伸长率略有降低。合金的力学性能可以在较长时间内保持稳定,处于欠时效状态。当热暴露温度达到150℃以上时,合金长期处于峰时效的状态,但伸长率降低到11%左右。在175℃下合金经100 h即可达到峰时效状态,屈服强度约427 N/mm2、抗拉强度477 N/mm2,但是随着时间延长合金的性能变化较为缓慢。在200℃条件下进行热暴露时,随着时间的延长,合金的强度持续下降,性能急剧下降。透射电镜分析表明,2B25-T3511铝合金在稳定化处理的过程中均发生S'/S相的析出和粗化。合金强度的降低和伸长率的降低的原因是S'/S相的粗化和晶界无沉淀析出带的宽化。The effect of thermal exposure time and temperature on microstructure and thermal-stability of 2B25-T3511 aluminum alloy was investigated by tensile test and transmission electron microscopy （TEM）. The results show that when thermally exposed at 125℃, the tensile strength doesnt change greatly, the yield strength increases, the elongation slowly decreases, and the mechanical property keeps stable, i. e. under-aged, for a long time. When thermally exposed at 150℃ and above, the alloy is at peak-aged condition for a long time, but the elongation decreases to approximately 11%. When thermally exposed at 175℃, the alloy can reach the peak-aged condition after 100 h, the ultimate tensile strength is approximately 477 N/mm^2, the yield strength is approximately 427 N/mm^2. However, the longer it takes, the more slowly the properties changes. When thermally exposed at 200℃, the strength and properties decrease sharply with increasing of the exposure time. TEM observation suggests that precipitation and coarsening of S＇/S occur when 2B25-T3511 aluminum alloy is under stabilizing treatment. The strength and elongation decreasing of 2B25-T3511 aluminum alloy is caused by the coarsening of S＇/S and the widening of the PFZ.

关 键 词：2B25-T3511铝合金 热稳定性 S’ S相 粗化 无沉淀析出带 

分 类 号：TG146.21[一般工业技术—材料科学与工程]