Al-Si/Al-Mn复合连铸坯料均匀化热处理研究

Uniform Heat Treatment of Direct Chill Continuous Casting Al-Si/Al-Mn Clad Slab

摘要:

对Al-Si/Al-Mn复合连铸坯料通过不同热处理温度和保温时间进行了均匀化热处理研究，并对均匀化热处理后的微观组织、硬度和微观成分分布进行了分析。结果表明：Al-Si/Al-Mn复合连铸坯料经过均匀化热处理后，Al-Si合金一侧的微观组织由粗大的网状结构转化成点状或短棒状混合组织，Al-Mn合金一侧微观组织趋于均匀一致，复合界面处的界限更加明显；均匀化热处理后Al-Si合金硬度有明显下降，但对Al-Mn合金的影响较小；微观元素分布分析表明均匀化热处理后溶质元素更加均匀，在复合界面处溶质元素出现互扩散现象，特别是Mg元素扩散后复合界面模糊；综合分析表明，Al-Si/Al-Mn复合连铸坯料在480 ℃保温15 h后效果最佳。

Abstract:

The uniform heat treatment of direct chill continuous casting Al-Si/Al-Mn clad slab was investigated with different temperatures and time, and the microstructure, hardness and solute distribution of the uniform heat treated samples was studied. The results show that the coarse net-work compounds of Al-Si alloy change into spot and short-bar compounds, the Mn element distribution is more uniform, and the interface of Al-Si/Al-Mn clad slab is clearer because of element solution. The hardness of Al-Si alloy is reduced after the treatment, but the hardness of Al-Mn alloy is not sensitive to temperatures and time of the uniform heat treatment. The elemental EPMA mappings show that the distribution of solute elements are more uniform, and elements are diffused on the interface of Al-Si/Al-Mn clad slab, especially Mg element becomes not obvious on the interface after uniform heat treatment. It can be concluded that the best Al-Si/Al-Mn clad slab is obtained when the uniform heat treating temperature is 480 oC and the time is 15 h.