Material Properties of TiAl Alloy with High Nb Content Produced by the Additive Manufacturing Technology of Electron Beam Melting

摘要

From pre-alloyed powders, samples of the third generation Ti-46Al-2Cr-8Nb alloy were produced by the additive manufacturing technology of Electron Beam Melting. The major benefits of the process are near-net-shape manufacturing, freedom of design and high material efficiency. Using optimized process parameters, samples with low residual porosity (≤ 1 %) and low oxygen pick-up were realized. The material was subsequently hot isostatically pressed in the (α+γ) phase field in order to further reduce porosity and recrystallize the massive material to a homogeneous, rather fine equiaxed microstructure. Further heat treatment was applied to tailor either a duplex microstructure with specific lamellar ratio or a fully lamellar microstructure.