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Enhanced strength-ductility synergy and mechanisms of heterostructured Ti6Al4V-Cu alloys produced by laser powder bed fusion.
- Source :
-
Acta Materialia . Sep2023, Vol. 256, pN.PAG-N.PAG. 1p. - Publication Year :
- 2023
-
Abstract
- Limited slip systems of α structure always play a major role in hindering strength-ductility synergy improvement of titanium (Ti) alloys. To overcome the strength-ductility trade-off of Ti alloys, heterostructure is introduced into Ti6Al4V- x Cu (x = 0, 1, 3, 5 wt.%) alloys produced by laser powder bed fusion (LPBF), and the formation mechanism and deformation behavior of heterostructures were investigated. The results showed that the monolithic α' in the LPBF-produced Ti6Al4V- x Cu (wt%) alloys is decomposed into dual α and α" after heat treatment at 600–900 °C through α' → α + Ti 2 Cu → matastable phase → α + α". The multistage transformation of α' to α and α" is driven by thermal activation (temperature > 800 °C), Cu addition and rapid cooling of water quenching. The heterostructure with α and α" in the LPBF-produced Ti6Al4V-5Cu alloy after heat treatment at 800 °C results in high tensile strength (∼1.3 GPa) and large elongation (∼15%). The enhanced strength-ductility synergy is attributed to the decomposition of brittle α' and Ti 2 Cu, as well the soft-hard heterostructure of α" and α. Moreover, the deformation twins (DTs) in α" and the heterogeneous interfaces of α and α" can also improve the strength and ductility of the LPBF-produced Ti6Al4V- x Cu alloys. These findings elucidate the influence of heterostructure (α and α") on strength and ductility, which is helpful for designing Ti alloys with excellent mechanical properties. [Display omitted] [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 13596454
- Volume :
- 256
- Database :
- Academic Search Index
- Journal :
- Acta Materialia
- Publication Type :
- Academic Journal
- Accession number :
- 164926864
- Full Text :
- https://doi.org/10.1016/j.actamat.2023.119112