The segregation behavior of elements at the Ti/TiFe coherent interface: First-principles calculation

The segregation behavior of elements at the Ti/TiFe coherent interface were studied by first-principles calculation. The effect of elements on nucleation, growth, and coarsening of the TiFe precipitate were analyzed by calculation of segregation energy, interfacial energy and diffusion rate. The results show that Ni, Co, Cu, V and Mo atoms have the obvious tendency to segregate towards the interface. Cr and Mn prefer to accumulate in the TiFe precipitate while Al to be energetically more favorable to enrich in Ti matrix. The mechanism of the above different segregation phenomena of the elements at the coherent Ti/TiFe interface was also analyzed and the corresponding thermodynamic driving force was proposed. The interfacial segregation results in the reduction of interface energy. Titanium alloys containing with V and Co elements are more conducive to the nucleation of TiFe precipitate from the Ti matrix. The coarsening of TiFe precipitate is effectively modified by addition of the Co, Ni and Al.