Role of Site-selective Doping on Melting Point of CuTi Alloys: A Classical Molecular Dynamics Simulation Study

TL;DR

This study uses classical molecular dynamics simulations to explore how site-selective doping of Ti in Cu affects the melting point of CuTi alloys, revealing that atomic arrangement influences thermal stability.

Contribution

It demonstrates that site-specific substitution of Ti in Cu can tune the melting point, explaining experimental non-monotonous trends through atomic arrangement effects.

Findings

Melting point decreases linearly with random Ti doping.

Selective site doping causes non-monotonous melting point variation.

Atomic arrangement influences melting point variability.

Abstract

Effect of site-selective substitution of Ti in Cu on the thermal stability of CuTi alloy is investigated using classical molecular dynamics simulations with Embedded Atom Method potentials. It has been observed experimentally that melting point of all the naturally occurring stable phases of CuTi alloys do not show a definite trend with gradual increase in Ti concentration. To understand the phenomenon, super cells of CuTi alloy are constructed where Cu atom is substituted by Ti randomly and at selective sites. For random substitution, the melting point decreases linearly with increase in Ti concentration. A non-monotonous dependence is seen when Cu atoms at selective sites are replaced by Ti. For a particular doping concentration, the melting point shows a wide range of variation depending on the order of atomic arrangement, and can be fine tuned by selecting the sites for substitution. The variations in melting points in different cases are explained in terms of the peak height, width and position of the corresponding radial distribution functions. Finally, it is verified that initial structures of the naturally occurring CuTi alloys are responsible for the non-definite trend in their melting points.