Substitution Behavior of Elements in CoZr-with Consideration of Lattice Relaxation

摘要

The substitution behavior of some alloying elements in CoZr is investigated using the discrete variational Xα cluster method. The method proposed by the author to predict the substitutionbehavior is amended to consider the local lattice relaxation. A diagram is drawn based on the binding energies of clusters with alloying elements taking either Co or Zr site. Two straight lines on the diagram separate the alloying elements into three groups with different substitutionbehavior. The elements above the upper line will take Zr sites and those below the lower line will take Co sites regardless of the composition. The substitution behavior of elements in between the two Iines will be afFected by the alloy composition. The concept of site competition and step ordering is proposed.