(1. 中南大学 材料科学与工程学院，长沙 410083； 2. 航天材料及工艺研究所，北京 100076)
摘 要: 采用金相显微镜、透射电镜、扫描电镜及拉伸性能在测试研究0.11% Ce(质量分数)添加对一种Al-Cu-Li系高强铝锂合金薄板T8态时效(5%冷轧预变形+155 ℃时效)组织和力学性能的影响。结果表明：0.11% Ce添加明显降低合金强度，但伸长率略有增加。微量Ce添加可细化铸态晶粒组织及固溶再结晶晶粒组织；而且微量Ce添加未改变铝锂合金中时效析出相的种类，主要强化相仍然为T1相(Al2CuLi)及θ′相(Al2Cu)，但其数量减少。铝锂合金中添加微量Ce，凝固时可形成含Ce且富Cu的Al8Cu4Ce相粒子，在后续均匀化及固溶处理时均难以完全溶解，导致固溶基体中的Cu含量降低，时效时含Cu析出相T1相及θ′相含量减少，合金强度降低。
关键字: 铝锂合金；Ce微合金化；显微组织；强度
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China; 2. Aerospace Research Institute of Materials and Processing Technology, Beijing 100076, China）
Abstract:Through metalloscopy, transmission electron microscopy, scanning electron microscopy and tensile tests, the effect of 0.11% Ce (mass fraction) addition on structures and tensile properties of a high-strength Al-Cu-Li alloy with T8 aging (5% cold rolling pre-deformation and aging at 155 ℃) was investigated. The results show that the addition of 0.11% Ce significantly decreases the strength, but enhances the elongation a little. The cast structure and re-crystallized grains after solution treatment are refined by the Ce addition. The precipitate types does not change with the small addition of Ce, and the aging precipitates are still T1(Al2CuLi) and θ′(Al2Cu) phases, but their amount decreases. As 0.11% Ce is added to the Al-Li alloy, Ce-contained and Cu-rich Al8Cu4Ce particles form during solidification process, which cannot be completely dissolved into the alloy matrix during homogenization and solution process. The concentration of dissolved Cu in solid solution decreases, which decreases the fraction of T1 and θ′ precipitates and lowers the alloy strength.
Key words: Al-Li alloy; Ce micro-alloying; microstructure; strength
