Melting Point of Ti, Ti3Al, TiAl, and TiAl3 Nanoparticles Versus Their Diameter in Vacuum and Liquid Aluminum: Molecular Dynamics Investigation

The dependence of the melting point of Ti, Ti3Al, TiAl, and TiAl3 nanoparticles on temperature in vacuum and an aluminum matrix has been studied using the molecular dynamics method. It has been found that the melting point of all nanoparticles drops with a decrease in their diameter, the decrease being proportional to the surface area/volume ratio. The melting points of Ti, Ti3Al, and TiAl nanoparticles in the aluminum matrix turn out to be lower than those of the same particles in vacuum. This is explained by interface smearing and disordering because of interdiffusion. For TiAl3 nanoparticles, the result is radically different: the aluminum sheath influences the melting point of the nanoparticle insignificantly in this case. As the diameter of the particles grows both in vacuum and in aluminum, their melting points tend to the same value. This is because when particles became coarser, interdiffusion smears the surface and it becomes to play a minor role.