Abstract
β-Titanium alloys demonstrate unique properties, especially their low elastic modulus, good balance of strength and ductility, and strong heat treatment response. In this study, pre-alloyed powder of a β-Ti-alloy Ti–34Nb–13Ta–5Zr-0.3O (TNTZO) was processed using Laser Powder Bed Fusion (LPBF). Dense builds that demonstrate a full β microstructure with limited texture were achieved following process optimisation, with an elastic modulus of 56.5 GPa, tensile strength of 756 MPa, elongation-to-failure of 20 %, and recoverable strain of 1.3 %. Due to the high oxygen content, the β→α′′ deformation induced transformation was supressed, which resulted in a typical elastic-plastic stress-strain behaviour unlike the double-yielding behaviour typically experienced in superelastic Ti-alloys. The alloy was particularly sensitive to ageing heat treatments that resulted in needle α-precipitation, with tensile strengths exceeding 950 MPa, elastic modulus of ∼80 GPa, and recoverable strain of 1.5 %, yet at the expense of a reduced elongation-to-failure of 9 %. Transmission electron microscopy and electron backscattered diffraction investigations revealed the deformation mechanism was slip-dominated with no trace of twinning or stress induced phase transformation.
Original language | English |
---|---|
Article number | 146617 |
Journal | Materials Science and Engineering: A |
Volume | 905 |
Early online date | 6 May 2024 |
DOIs | |
Publication status | Published - 1 Jul 2024 |
Bibliographical note
AcknowledgementThe authors acknowledge The Egyptian Ministry of Higher Education & Scientific Research and The British Council (Newton-Mosharafa Fund) represented by The Egyptian Bureau for Cultural & Educational Affairs in London.
Keywords
- Additive manufacturing
- Titanium alloys
- Microstructure
- Mechanical properties