| Abstract Scope |
The micro cold spray process (MCS) is a manufacturing process capable of depositing thick films of ceramics at room temperature. Films are formed by impacting solid micron-scale particles at high enough velocities that they deform, stick and form dense films. A particular challenge is determining the required impact velocities for film formation; particles impacting below a critical velocity bounce off the substrate without sticking and excessive particle velocities result in erosion rather than film formation. Studying appropriate impact velocities and their associate deformation mechanisms experimentally is not possible because of the extremely high strain rates, short impact times, and fine particle sizes used in MCS. We demonstrate that molecular dynamics simulations can be used to study deformation mechanisms under conditions relevant to MCS. Results show that pressure-induced phase transformations, dislocation initiation and propagation, and amorphization and viscous flow are responsible for deformation. Applications to nuclear energy systems will be discussed. |