Microstructural characterization of Ti-6Al-4V machining chips after remelting and severe deformation

The present work was initiated to recycling the machining chips of Ti-6Al-4V alloy as part replacement of titanium sponge and expensive alloying materials for manufacturing Ti-alloy ingots. The technology includes a two-step processing route involving an initial remelting of machining chips into ingot by vacuum-induction melting furnace followed by conversion of the ingot into slab by severe hot working processes (forging and large strain hot rolling). Optical microscope was used to investigate the microstructures. The results show that when deformation process is carried out in the alpha + beta-phase field, a much finer alpha+ beta-structure can be obtained, because the primary alpha-phase limits the growth of the beta-phase. Both the primary alpha-phase and beta-phase deform simultaneously and the beta grains are easier to recrystallize. (C) 2008 Elsevier Ltd. All rights reserved.