Preliminary Results for Dissimilar Titanium Alloy Diffusion Bonding Using a Surface Roughness Finite Element Model

Diffusion bonding is a valuable solid state welding process that is heavily utilized by the aerospace industry. When performed properly it can produce nearly defect free welds that mate large surfaces together based on the key parameters of time, temperature, pressure, material properties, and surface characteristics. Previous diffusion bonding models have always had a major shortcoming in that while they can model the time, temperature, and pressure accurately, they fail to incorporate the actual surface geometry involved and therefore can only estimate the initial conditions of the model. This study attempts to remedy this deficiency by incorporating initial void geometry determined by measured surface profiles that are combined with finite element plasticity models. The void geometry is then implemented stochastically in a bonding model for both similar and dissimilar titanium alloys which is then compared with published experimental data.