摘要
采用金相观察、拉伸性能测试及透射电镜分析等手段研究1460铝锂合金的铸态组织、薄板T6态单级时效(160℃)及T8态双级时效(5%预变形,130℃+160℃时效)处理时力学性能及微观组织的演化。研究结果表明:添加微量Sc元素时,凝固时形成Al_3(Sc,Zr)初生相粒子,1460铝锂合金铸锭树枝晶组织被消除,晶粒呈等轴状,粒度较小(20~50mm);而冷轧薄板固溶处理后为细小的带状晶粒组织;1460铝锂合金主要时效析出强化相为d′相(Al_3Li),其次为T1相(Al_2Cu Li),但在时效过程中可能形成q″(q′)(Al_2Cu)过渡相;在时效过程中,时效前期快速析出d￠相;随时效时间延长,d′相长大,并析出q￠￠(q′)过渡相;随着时效时间进一步延长,T1相析出,而q″(q′)过渡相消失;与T6态时效相比,T8态时效时T1相尺寸降低但密度增大,强度提高。
The as-cast structure, mechanical properties and microstructural evolution of 1460 Al-Li alloy sheet during T6 one-step aging at 160 ℃ and T8 two-step aging(5% predeformation followed by aging at 130℃ and then 160 ℃) were investigated by using metallographic microscopy, tensile measurement and tansmission electronic microscopy(TEM).The results show that the dendritic structure of cast ingot is eliminated and equi-axed grains with fine size of 20-50 mm are formed due to the formation of primary crystal particle Al_3(Sc,Zr) during solidification process. Meanwhile, the solutionized sheet is featured with fine elongated grain structure. The main aging precipitate of 1460 Al-Li alloy is d￠(Al_3 Li), but considerable T1(Al_2 Cu Li) phases are also precipitated. Transitional phase of q″(or q￠)(Al_2 Cu) is formed during the aging process. In the under-aging stage, d￠ phases are precipitated rapidly. With the increase of aging time, the transitional phase of q″(q￠) is precipitated. Finally, T1 precipitates are formed and transitional phase of q￠￠(q￠) disappears. Compared to the T6 aging, T1 precipitates with higher population density and smaller size are formed in the T8 aging, the strength of the T8-aged alloy is therefore enhanced.
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2017年第11期2867-2873,共7页
Journal of Central South University:Science and Technology
基金
国家高技术研究发展计划(863计划)项目(2013AA032401)
中南大学教师基金资助项目(2013JSJJ001)~~
关键词
铝锂合金
力学性能
微观组织
Al-Li alloy
mechanical property
microstructure
