Abstract

In this work, the Al–Cu–Mg alloy with different Y (0–0.2 wt%) and Ce (0.5–1.5 wt%) are designed. The effect of mixed addition of Y and Ce on the grain structure and hot tearing for Al–4.4Cu–1.5Mg–0.15Zr alloy was investigated using "cross" hot tearing mould. The results indicate that as rare earth Y and Ce increases, the grain size becomes finer, the grain morphology changes from dendrite to equiaxed grain, and effectively reduce the hot tearing sensitivity coefficient (HTS₁) and crack susceptibility coefficient (CSC) of the alloy. With the increase of Ce element (0.5–1.5 wt%), the hot tearing susceptibility of the alloy decreases first and then increases. With the increase of Y element (0–0.2 wt%), the hot tearing sensitivity of the alloy decreases. When the content of rare earth is 0.2 wt% Y + 1.0 wt% Ce, the minimum HTS₁ value and CSC value of the alloy are 68 and 0.53, respectively. Rare earth Ce refines the alloy microstructure, shortens the feeding channel, and reduces the hot tearing initiation. Meanwhile, the rare earth Y can form Al₆Cu₆Y phase at the grain boundary, improve the feeding capacity of the alloy. Therefore, appropriate addition of rare earth Y and Ce can effectively reduce the hot tearing tendency of the alloy.

中文翻译：

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Y、Ce微合金化对铸态Al-Cu-Mg合金显微组织和热裂的影响

摘要

在这项工作中，设计了具有不同Y（0-0.2 wt%）和Ce（0.5-1.5 wt%）的Al-Cu-Mg合金。利用“十字”热裂模具研究了Y和Ce混合添加对Al-4.4Cu-1.5Mg-0.15Zr合金晶粒结构和热裂的影响。结果表明，随着稀土Y和Ce的增加，晶粒尺寸变细，晶粒形貌由枝晶转变为等轴晶，有效降低合金的热撕裂敏感性系数(HTS ₁ )和裂纹敏感性系数(CSC) 。随着Ce元素(0.5~1.5 wt%)的增加,合金的热裂敏感性先降低后增加。随着Y元素(0-0.2 wt%)的增加，合金的热撕裂敏感性降低。当稀土含量为0.2wt%Y+1.0wt%Ce时,合金的最小HTS _{1值和CSC值分别为68和0.53。}稀土Ce细化了合金组织，缩短了补缩通道，减少了热裂萌生。同时，稀土Y可在晶界形成Al ₆ Cu _{6 Y相，提高合金的补缩能力。}因此，适当添加稀土Y和Ce可以有效降低合金的热裂倾向。