Effect of erbium (Er) on the hot cracking behaviour of Al-5Cu alloy

In this paper, the effect of Er on the hot cracking behaviour of Al-5Cu alloy is investigated by the means of wedge moulds, differential hot analyzer, optical microscope, and scanning electron microscope. The results show that the percentage of intergranular low-melting-point eutectic structure is increased by approximately 8% on average per 0.3 wt-% Er additions. The increase of low-melting-point eutectic structure enhances the fluidity of the liquid film in the late solidification stage, resulting in the improvement of the hot cracking resistance of the alloy. Moreover, the Al-5Cu-0.6Er alloy has the best hot cracking resistance under wedge-shaped copper casting experiments.