中文摘要：

通过显微组织分析、室温及高温力学性能测试、XRD和SEM分析等方法,研究了稀土Pr对Al5 Mg合金的显微组织、凝固区间和室/高温力学性能的影响。实验结果表明,Al5Mg合金中加入稀土Pr使合金凝固区间变窄,细化了合金组织;Pr的加入净化了合金组织,减少了合金组织杂质缺陷,提高了合金性能;Pr的加入对合金有固溶和强化相强化作用,β-Al（11）Pr3强化相具有较高的高温稳定性能,提高了合金的高温性能。

英文摘要：

Effects of Pr on microstructure,solidification interval and room/high temperature mechanical properties of of Al-5Mg alloy were studied by microscopic analysis,room/high temperature mechanical property test,SEM and X-ray analysis methods.Experiments show that rare earth Pr can narrow the solidification interval and refine the microstructure and improve its tensile properties at both room temperature and high temperature.The addition of Pr can purify the microstructure and reduce the impurity and defects,and improve the performance of alloy.The rare earth Pr plays an important role on both solid solution strengthening and phase reinforcement.β-Al11Pr3 strengthening phase has high heat stability,and can improve the high temperature properties of the alloy.