La对Al-Li合金时效组织和断裂韧性的影响

来源期刊：中南大学学报(自然科学版)1992年第5期

论文作者：郑子樵 赵永庆 尹登峰 梁叔全 谭澄宇

文章页码：546 - 550

关键词：Al—Li合金; 稀土元素; 微观组织; 断裂韧性

Key words：Al-Li alloys; Lanthanum; microstructures; fracture toughness

摘    要：通过电镜观察和断裂韧性测量,研究了稀土元素La对Al-Li-Cu-Mg-Zr合金微观组织和断裂韧性的影响。实验结果表明,在Al-Li合金中存在Fe,Si,Na等元素在晶界的偏聚,添加少量La可减少这些杂质在晶界的偏聚。同时,La的加入抑制δ′相的生长,减少S′相的析出,延缓时效过程,并且减少晶界无析出带宽度。因此,添加少量La提高了Al-Li合金的断裂韧性。

Abstract: The effect of minor La on the microstructure and fracture toughness of Al-Li-Cu-Mg-Zr alloys was studied by electron microscope observation and the mea-surement of toughness. The results showed that some impurities, such as Fe, Siand Na, segregated to the grain boundaries in Al-Li alloys, the addition of minorLa to Al-Li alloys decreased the segregation of these impurities. La can delay the growth of δ' precipitates, decrease the density of S' precipitates and the width of grain boundary precipitation free zones. Therefore, the toughness of Al-Lialloys containing minor La was improved.