Segregation of Mg at TiB2/Al interface mitigating the Zr-poisoning effect

Interfacial segregation can modify a substrate's heterogeneous-nucleation potency.In Al alloys inoculated with TiB 2 , for instance, Zr segregation degrades TiB 2 's nucleation potency and causes the loss of grain refinement, a phenomenon termed the Zr-poisoning effect.Here we use grain-refining tests to demonstrate that the addition of Mg can revive grain refinement from the Zr-poisoning effect.Using advanced transmission electron microscopy, we identify the segregation of Mg at the TiB 2 /Al interface, which causes the disappearance of the poisoning Ti 2 Zr two-dimensional compound (2DC).In its place, atomic layers of a nature close to the Al solid, which we term "Allike layers", develop, rendering the TiB 2 potent again to catalyse the nucleation of α-Al.Thereby, Mgsegregation-modified TiB 2 particles are reactivated for heterogeneous nucleation of Al grains.Apart from a mitigation of the Zr-poisoning effect, this work may shed further light on the manipulation of heterogeneous nucleation by atomic engineering of the nucleating substrate.