Hot Isostatic Pressing (HIP) is a process used to make compact heat exchangers. The search of a compromise between time, pressure and temperature, for a HIP cycle aiming at attaining fully bonded interfaces while preserving the designed shape of the compact heat exchanger, may lead to numerous experimental failed assemblies. Modelling of diffusion bonding occurring during the cycle might significantly reduce these runs.

Void closure kinetic is the focus of the present study. Most literature models require a unique cavity representative of an interface in terms of bonded area fraction. Through the weak coupling of mechanics (finite elements resolution) and diffusion phenomena (finite differences resolution), the herein numerical model is a step toward the simulation of the closure of a variety of voids along an interface by diffusion bonding. The model is confronted to experimental kinetic closure statistics of isolated voids resulting from interrupted hot pressing cycles.