Abstract
This feasibility study examines the additive manufacturing of Ti–48Al–2Cr–2Nb preforms in a quest to make more complex engine components from this promising but hard to machine, brittle material. The preforms are built using the electron beam melting technique; hot isostatic pressing (HIP) was performed as the only post-process. Microstructural characterizations were carried with scanning electron microscopy techniques, X-ray diffraction and X-ray computed tomography while mechanical properties were obtained via tensile testing. We exploited computational thermodynamic modeling (widely known as CALPHAD) approach to investigate the phase stability pertinent to Nb and Cr modified TiAl. Defect-free structures were obtained in the HIPed condition with mechanical behavior comparable to/better than traditionally manufactured counterparts. Equiaxed duplex microstructures were achieved in the as-built condition that were sustained post-HIP. The effect of the build conditions and phase transformation kinetics on the observed microstructures is discussed. The microstructure-mechanical behavior relationship is also discussed.
Original language | English |
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Article number | 100284 |
Journal | Materialia |
Volume | 6 |
DOIs | |
State | Published - Jun 2019 |
Funding
This work was sponsored by the U.S. Department of Energy , Office of Energy Efficiency and Renewable Energy , Vehicle Technologies Office , Propulsion Materials Program. Research at the Manufacturing Demonstration Facility (MDF) was sponsored by the U.S. Department of Energy , Office of Energy Efficiency and Renewable Energy , Advanced Manufacturing Office , under contract DE-AC05-00OR22725 with UT-Battele, LLC.
Funders | Funder number |
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U.S. Department of Energy | |
Advanced Manufacturing Office | DE-AC05-00OR22725 |
Office of Energy Efficiency and Renewable Energy |
Keywords
- Additive manufacturing
- CALPHAD
- Scanning electron microscopy (SEM)
- Titanium aluminide
- X-ray computed tomography
- X-ray diffraction