Er在Al-Cu-Mg-Ag合金中的 存在形式及其均匀化工艺

来源期刊：中南大学学报(自然科学版)2006年第6期

论文作者：李云涛 刘志义 夏卿坤 余日成

文章页码：1043 - 1047

关键词：Al-Cu-Mg-Ag合金;铒; Al₈Cu₄Er; Al₂Cu;均匀化

Key words：Al-Cu-Mg-Ag alloy; Er; Al₈Cu₄Er; Al₂Cu; homogenization

摘    要：采用扫描电镜观察、X射线衍射物相定性分析,研究元素Er在Al-Cu-Mg-Ag合金中的存在形式及其均匀化工艺。研究结果表明: Er元素主要以Al₈Cu₄Er相形式存在于铸态合金晶界,少量固溶于α-Al中; Al₈Cu₄Er相作为Al₂Cu相的形核质点,与Al₂Cu相共生于晶界,形成典型的枝晶偏析;与Al₂Cu相相比, Al₈Cu₄Er相为难溶相,使得合金均匀化温度升高,成为均匀化过程中工艺的制约因素;采用420℃×6 h+510℃×24 h+520℃×6 h均匀化制度处理后, Al₈Cu₄Er相回溶至基体,合金晶界变薄,均匀化效果明显。

Abstract: Al-Cu-Mg-Ag alloys without/with rare earth Er with mass fraction of 0.25% were prepared. X-ray diffractometry(XRD), scanning electron microscopy(SEM) and energy dispersivespectrometry(EDS) were used to investigate the form of the rare earth elements Er in the prepared alloys and the following homogenization. The results show that Al₈Cu₄Er phase and a small quantity of solid solution inα-Al are the main forms of Er in the as-cast alloys. As the nucleus of heterogeneous nucleation of Al₂Cu phase solidification, Al₈Cu₄Er phase forms intergrowth with Al₂Cu phase at the grain boundary. Interdendritic segregation of Al₈Cu₄Er phase and Al₂Cu phase at grain boundAary has an influence on homogenizing process. The adopted homogenizing parameter is a three stage annealing of 420℃×6 h+510℃×24 h+520℃×6 h. Following the homogenizing process, Al₈Cu₄Er phase and Al2Cu phase are dissolved back into α-Al and the grain boundary becomes thinner.