Formation of coarse-grained inter-particle regions during hot isostatic pressing of nanocrystalline powder

In a compact that was hot isostatic pressed (HIPped) using nanostructured Al-5083/SiCp composite powder prepared by cryomilling, coarse-grained (reinforcement-free) inter-particle regions were observed. These coarse-grained regions formed via elemental diffusion towards the inter-particle pores during the HIPping process. This finding can well explain the bimodal grain-size distribution reported for various HIP-consolidated nanocrystalline metals.