Effect of Ce on Hot Tearing Sensitivity of As-Cast Al-Cu-Mg-Y Alloy.

The effect of rare earth Ce on the hot tearing sensitivity of the Al-Cu-Mg-Y alloy is studied by using a self-made multi-channel "cross" hot tearing test device. Based on hot tearing sensitivity, solidification temperature, shrinkage force and microstructure of the as-cast Al-4.4Cu-1.5Mg-0.15Zr-0.15Y alloy with different contents of Ce, the influence regularity and mechanism of rare earth Ce on the hot tearing are systematically studied. The results show that the hot tearing resistance of the alloy is evidently improved due to grain refinement and the increase of feeding capacity of liquid phase in the later stage of solidification with addition of Ce. The average grain size, the HTS₁ value and the CSC value of the alloy firstly decrease and then increase with the content of Ce increases from 0 to 2.5 wt.%. Compared with the alloy without Ce, the average grain size of the alloy with addition of 1.0 wt.% Ce reduces from 150.04 to 90.23 μm. The fluidity and hot tearing resistance of the alloy are significantly enhanced owing to the generated Al₈Cu₄Ce phase. Furthermore, when the Ce content exceeds 1.0 wt.%, which leads to the microstructure coarsening and the rise of the hot tearing sensitivity of the alloy compared with addition of 1.0 wt.%. [ABSTRACT FROM AUTHOR]