新型Al-Mg-Cu铝合金铸锭均匀化过程中相的变化

Microstructural evolution of ingot of A aluminum alloy during homogenization treatment

采用金相、扫描电镜、能谱和DSC分析方法研究了新型Al-Mg-Cu铝合金(以下简称A铝合金)半连续水冷铸锭均匀化处理过程中相的变化。结果表明,A铝合金半连续铸锭的铸态组织中存在大量非平衡凝固的含Al2CuMg和Al2Cu的共晶相,其熔化温度为505℃;在595℃12 h均匀化过程中,该合金铸锭中非平衡凝固共晶相发生溶解,合金中铸造过程形成的非平衡凝固共晶体Al2Cu全部消失,但Al2CuMg相不能完全溶解。

The evolutions of the microstructure and phases of the direct chill semicontinuous casting ingot of A aluminum alloy during its homogenization treatment were studied with metallographic analysis, scanning electrie microscopy（SEM）, energy spectroscopy and differential scanning calorimetry（DSC）. The results showed that： a considerable amount of non-equilibrium eutectics containing Al, Zn, Cu, Mg exist in the direct chill semicontinuous casting ingot of 7B04 super-high strength aluminum alloy, and their melting temperature is 505℃. During homogenization treatment at 495℃ 12 h these eutectics dissolved into the matrix partly, the disappearance of the non-equilibrium euteetics though Al2 Cu phase could be dissolved completely and Al2 CuMg phase could not be dissolved completely.