Variation Rule of the Primary Powder Boundaries During the Densification

The variation of the boundaries of the plasma rotation electron process (PREP) Ti-5Al-2.5Sn powder has been studied. This study concludes that the change of primary powder boundaries (PPB) is related to the sintering temperature, pressure, holding-time and the resistance to deformation of the material, especially the sintering temperature. The boundaries (PPB) have experienced a complicated variation from deformation, and breakdown to aggregation during HIPing. This is due to the composition segregation, oxidation and enrichment of the impurities, and the existence of these substances degrade the interface binding force of the materials. In order to eliminate the above influence, it is necessary and effective to increase the temperature and extend the holding time reasonably.