Effects of powder size segregation on tensile properties of Ti-5Al-2.5Sn ELI alloy powder

Ti-5Al-2.5Sn ELI pre-alloyed powders were prepared by electrode induction melting gas atomization process, and Ti-5Al-2.5Sn ELI alloy was prepared through hot isostatic pressing route. Five different HIPed preforms of Ti-5Al-2.5Sn ELI alloy were prepared. Five HIPed performs were prepared by the same hot isostatic pressing, powder filling and taping parameters except various original powder size distribution ranges. Powder size segregation usually occurred during powder filling and long-time taping and its influence on alloy properties were both studied. The results show that, in the first group of HIPed preforms prepared by typical powder filling and taping parameters, the air contents of the five preforms are almost the same, while the largest grain size difference is about 10 μm; no obvious difference is found on tensile properties of different samples. While in HIPed preforms prepared by long-time taping and powder filling process, cryogenic tensile properties of samples from the top of the capsule deteriorate significantly due to powder size segregation phenomenon.