MODELING OF MICROCHANNEL BUCKLING DUE TO THERMAL STRESSES DURING DIFFUSION BONDING

摘要

Diffusion bonding has been used as the primary technique for bonding microchannel arrays. In most cases, the diffusion bonding cycle time is the largest cost driver in the fabrication process. The major reason for longer cycle times is slow heating and cooling rates required to avoid warpage within the microchannel array. This paper investigates the warpage of stainless steel (SS) 316L microchannel fins during diffusion bonding believed to be caused by thermal stresses which arise as a consequence of thermal gradients. A finite element model is developed to determine the thermal stresses within a microchannel sample found to warp when exposed to high cooling rates. Model results are compared with analytically calculated critical buckling stresses to determine if the microchannel warpage can be explained by thermal buckling.