Interaction mechanism between void and interface grain boundary in diffusion bonding

The interaction process between void and migrating interface grain boundary (IGB) in the bonding interface of 1Cr11Ni2W2MoV steel joints produced by diffusion bonding has been examined, and the corresponding interaction mechanism was analysed. The results showed that there were two cases occurring in void-IGB interaction by comparing the IGB velocity with void velocity: if the IGB velocity exceeded the void velocity, the void would separate from the IGB and be trapped inside the grain; otherwise, the void would attach to and migrate with the IGB. It was also found that the void-IGB interaction was related to the radius of void. The bigger voids easily separated from the migrating IGB, while the smaller voids tended to attach to it. The approximate theoretical values of critical radius of voids for separation/attachment were derived, and they agreed well with the experimental values obtained.