Numerical investigation of the physical vapor deposition of titanium

The electron beam physical vapor deposition (EB-PVD) of titanium is modeled using the Direct Simulation Monte Carlo (DSMC) technique and a collisionless Line Of Sight (LOS) method. In the EB-PVD process, titanium atoms are evaporated from a molten pool, and are accelerated collisionally to a deposition surface. The electronic excitation of the vapor is shown to be significant at the temperatures of interest. The electronic energy mode is modeled in the DSMC method, and a collisional energy exchange model is considered to model the energy exchange between the electronic and translational energy modes. Energy transfer between these modes is found to affect the flow significantly. The effect of electronic energy on the vapor deposition modeling is quantified through comparisons between simulations which include and exclude the electronic energy mode. The computed flow field properties show good agreement with experimental measurements when electronic energy is considered. Good agreement is also achieved between the computed and experimentally measured deposition profiles. A sensitivity analysis is carried out to assess the effect of some physical parameters on the flow field. The deposition profile is seen to be affected by the collision cross section of the vapor species, but is not significantly affected by minor changes in the sticking coefficent at the wall, or the shape of the evaporating surface.; The near collisionless nature of the flow prompted the development of the LOS method for the analysis of the EB-PVD process. The LOS algorithm is validated through comparisons with a collisionless DSMC simulation. The importance of collisions on the expansion and the deposition is shown. Hybrid DSMC-LOS techniques are developed to capture the collisional physics of the flow accurately, while providing a significant savings in computational cost. The hybrid method is shown to provide a faster and more efficient way of modeling the EB-PVD process.