How electron beam melting tailors the Al-sensitive microstructure and mechanical response of a novel process-adapted y-TiAl based alloy

David Wimler, Katharina Käsznar, Michael Musi, Christoph Breuning, Matthias Markl, Jozef Keckes, Helmut Clemens, Carolin Körner, Svea Mayer

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung


Additive manufacturing of lightweight intermetallic γ-TiAl based alloys combines process-related freedom of design with material-specific excellent high-temperature properties. Nevertheless, where locally melting the powder by an electron beam, there is a risk that Al evaporates due to its high vapor pressure, causing compositional and microstructural variations. This work investigates the impact of different process parameters on the total and local Al-content as well as the resulting as-built and heat-treated microstructure in a complex multiphase Ti-44.8Al-4.1Nb-0.7W-1.1Zr-0.4Si-0.5C-0.1B (at.%) alloy. The examinations applied are complementary, employing electron microscopy, X-ray spectroscopy and diffraction experiments with synchrotron X-ray radiation, supported by numerical simulations. The mechanical anisotropy of the heat-treated microstructure was analyzed by micro-hardness measurements. The results demonstrate that the amount of γ-TiAl phase decreases with increasing energy input of the electron beam in the as-built and heat-treated microstructure owing to the total and local loss of Al. Besides, the investigations of the crystal orientations within the multiphase alloy reveal a preferred orientation of the γ phase at high energy inputs. This follows from the fact that the preferred γ orientation is inherited through directional solidification of the β phase. The obtained process-microstructure-property relationships show that tailor-made material properties of additively manufactured γ-TiAl components are achievable.

FachzeitschriftMaterials and Design
Ausgabenummer15 December
Frühes Online-Datum20 Okt. 2021
PublikationsstatusVeröffentlicht - 15 Dez. 2021

Bibliographische Notiz

Funding Information:
This research work was conducted within the framework of the BMBF project “NextTiAl” 03XP0088C, Germany, funded by the Federal Ministry of Education and Research. The support of the project partners is gratefully acknowledged.

Publisher Copyright:
© 2021 The Authors

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