Post-compaction heat-treatment response of dynamically-compacted Inconel 718 powder

Dynamically-compacted Inconel 718 powder has been heat treated in order to examine the evolution of microstructural recovery and hardness, recrystallization and grain coarsening, and interparticle-adhesion and fracture response. Following dynamic compaction the compacted powders are imperfectly bonded and the material is fairly brittle; the shock wave has caused significant hardening; local microstructures and properties are variable from particle surface to interior. Following annealing at 900 to 1000° C, virtually complete recrystallization occurs giving rise to a material which is softened and has a fine-scale microstructure. Little improvement in fracture response occurs, however, because the oxidized prior-particle surfaces do not weld together. Shock-wave consolidation offers the possibility of producing monolithic, microstructurally-fine materials, providing suitable post-consolidation thermo-mechanical processes are developed to overcome the limited bonding problem.