中文摘要：

采用半连续铸造法制备Al-6.8Mg-0.3Mn和Al-6.8Mg-0.3Mn-0.4Er（质量分数,%）两种合金铸锭。合金铸锭经均匀化处理—多道次热轧成4mm薄板;研究不同退火温度下微量Er对Al-Mg-Mn合金微观组织与力学性能的影响。结果表明：添加微量Er能显著提高Al-Mg-Mn合金强度,改善合金强度和塑性的配合,能明显提高合金的抗再结晶能力和室温力学性能;Al-Mg-Mn-Er合金板材经300℃退火1h后可获得理想的综合力学性能,其σb、σs与ψ分别为421MPa,310MPa和18.3%。

英文摘要：

Both AI-6.8 Mg-0.3Mn and A1-6.8Mg-0.3Mn-0.4Er （mass fraction/% ） alloy ingots were prepared with semi-continuous casting process, and the alloy ingots were rolled into 4mm thick sheets after homogenization treatment and muhipass hot roiling. The effect of Er on microstructure and mechanical properties of A1-Mg-Mn alloy sheets at different annealing temperatures were investigated. The results show that the addition of minor Er can improve the strength of the A1-Mg-Mn alloy significantly as well as the coordination between strength and plasticity of the alloy. Besides, the ability of anti-recrystallization and mechanical properties at room temperature are largely enhanced. Finally by annealing at 300℃ for lh, the A1-Mg-Mn-Er alloy sheet obtains the optimum application values of σb , σs and ψ, which are 421MPa, 310MPa and 18.3% respectively.