Site preference of transition-metal elements in L10-TiAl: A first-principles study

TL;DR

This study investigates how transition-metal elements prefer specific lattice sites in L10 TiAl alloys, revealing that temperature, composition, and electron count influence site occupancy, with implications for alloy design.

Contribution

It combines first-principles calculations and statistical models to analyze transition-metal site preferences in TiAl, highlighting the effects of temperature and alloy composition.

Findings

Site preference varies with temperature and stoichiometry.

Transition metals tend to occupy Al sites as d-electron count increases.

Temperature and alloy composition significantly influence site occupancy.

Abstract

The site preference of 3d (Ti-Cu), 4d (Zr-Ag) and 5d (Hf-Au) transition-metal elements in L10 TiAl is studied using a combination of first-principles supercell calculations and the statistical mechanical Wagner-Schottky model. Our key finding is that both temperature and alloy stoichiometry can strongly affect the site occupancy behavior of ternary alloying elements in L10 TiAl. We further predict that the tendency of transition metals to occupy the Al sites in TiAl increases with increasing d-electron number along a series.