Molecular Dynamics Simulation of Ti and Ni Particles on Ti Substrate in the Cold Gas Dynamic Spray (CGDS) Process

Abstract

This paper presents simulation of molecular dynamics for the deposition of Titanium (Ti) and Nickel (Ni) particles on Ti substrate during Cold Gas Dynamic Spray (CGDS) process. The influencing factors of the deposition process, such as particle incident velocity, particle size and particle temperature are taken into consideration. Ti and Ni were selected because of their potential applications in the aerospace, marine and bio-medical industries. CGDS is preferred because it is a state of the art technique by which coatings are created without significant heating of the sprayed powder. In CGDS, particles are accelerated to supersonic velocities using a high speed gas stream. However, there are inherent difficulties in relating particle deposition characteristics with influencing factors of the deposition process. Moreover, there is limited literature on molecular dynamics simulation of CGDS process. For this reason, this paper develops a simulation process for Ti and Ni particles under influence of many factors using molecular dynamics. In this process, particles are allowed to interact for a short time, giving a view of their motion. The trajectories of these particles are determined by numerically solving the Newton's equations of motion for a system of interacting particles, in which the forces between the particles are defined. The results of the simulation process show that higher incident velocities and larger particle sizes result in stronger interface between the particle and the substrate. Further, higher temperatures of the substrate and particles improve the bond strength.