(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083； 2. 航天材料及工藝研究所，北京 100076)
摘 要: 采用金相顯微鏡、透射電鏡、掃描電鏡及拉伸性能在測試研究0.11% Ce(質(zhì)量分?jǐn)?shù))添加對一種Al-Cu-Li系高強(qiáng)鋁鋰合金薄板T8態(tài)時效(5%冷軋預(yù)變形+155 ℃時效)組織和力學(xué)性能的影響。結(jié)果表明：0.11% Ce添加明顯降低合金強(qiáng)度，但伸長率略有增加。微量Ce添加可細(xì)化鑄態(tài)晶粒組織及固溶再結(jié)晶晶粒組織；而且微量Ce添加未改變鋁鋰合金中時效析出相的種類，主要強(qiáng)化相仍然為T1相(Al2CuLi)及θ′相(Al2Cu)，但其數(shù)量減少。鋁鋰合金中添加微量Ce，凝固時可形成含Ce且富Cu的Al8Cu4Ce相粒子，在后續(xù)均勻化及固溶處理時均難以完全溶解，導(dǎo)致固溶基體中的Cu含量降低，時效時含Cu析出相T1相及θ′相含量減少，合金強(qiáng)度降低。
關(guān)鍵字: 鋁鋰合金；Ce微合金化；顯微組織；強(qiáng)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
