Sintering mechanisms of ultrafine Cr2AlC MAX phase powder

This investigation aims to understand the sintering mechanisms of high purity ultrafine Cr2AlC MAX phase powder. Green compacts were sintered using vertical dilatometer system and the sintering data were analyzed through different sintering models to determine possible dominating mechanism. Activation energies and frequency factors estimated through the grain boundary diffusion models were found to be unusually higher than normally reported values on most polycrystalline materials. Activation energies (301 and 419 kJ/mol) and frequency factors obtained through the volume diffusion mechanism were found to be closure to that of self-diffusion of chromium as well as chromium diffusion in many multi elements systems; indicating volume diffusion to be a possible sintering mechanism, where chromium seems to play a decisive role. However, it should be noted that the present result needs to be verified, once the diffusion data on pure Cr2AlC phase would be available in future. (C) 2016 Elsevier Ltd. All rights reserved.