First principles study on heterogeneous interfaces of TiCu alloys through aluminum addition

Abstract

This paper investigates the heterogeneous nucleation interface resulting from the addition of Al element to TiCu alloy, focusing on the essential phases Ti2Cu and TiCu. Employing first principles calculations, we explore the refinement mechanism of this interface. Initially, the lattice mismatch between Al/Ti2Cu and Al/TiCu interfaces is calculated to assess the potential for heterogeneous nucleation. Four distinct interfacial types are established following a surface convergence test. The adhesive work (Wad) and Interfacial energy (γ) are computed for each interface to ascertain their crystallization potential. Furthermore, the differential charge density (DCD) and projected density of states (PDOS) for the four interfacial types are determined to analyze bonding characteristics. Results indicate a mismatch degree of 4.09 % for Al (110)/Ti2Cu (110) and 5.29 % for Al (110)/TiCu (110). These values suggest a tendency to form a heterogeneous interface with a coherent lattice, primarily characterized by Cu-Al and Ti-Al metallic bonds. The Al-Ti2Cu interface exhibits a larger nucleation work of 2.23 J/m2 and a smaller interface energy of −53.007 J/m2. This study demonstrates that Al effectively serves as a heterogeneous nucleation center within the Ti2Cu/TiCu system, contributing to substrate phase refinement and strengthening the TiCu alloy. The optimization of these findings provides valuable insights into the alloy's microstructural evolution, facilitating the design and enhancement of advanced materials for diverse applications.