Phase formation, microstructure and deformation behavior of heavily alloyed TiNb- and TiV-based titanium alloys
- Authors
- Publication Date
- Aug 22, 2018
- Source
- Lirias
- Keywords
- Language
- English
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- Unknown
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Abstract
© 2018 Elsevier B.V. The effect of chemical composition on microstructure and mechanical properties of heavily alloyed beta-titanium Ti-Nb(V)-Cu-Co-Al alloys was studied. The alloys were fabricated by casting into a water-cooled copper crucible employing relatively high cooling rates. The microstructure of these alloys consists of primary micrometer-sized bcc-structured (bcc – body centered cubic) dendrites surrounded by a minor amount of intermetallic phases. The morphology and volume fraction of the intermetallic phases are strongly affected by the alloys’ chemical composition. Particularly, the solubility of Cu and Co in the bcc dendrites of Ti-V-Cu-Co-Al is lower compared to that of Ti-Nb-Cu-Co-Al leading to a higher volume fraction of the intermetallic phase in the latter alloy. The high mechanical strength of the Ti-Nb(V)-Cu-Co-Al alloys (yield strength up to 1430 MPa) is mainly attributed to their multiphase nature and solid solution hardening of the supersaturated bcc-structured dendrites. Moreover, the large compressive plastic deformability supported by pronounced strain-hardening reaches several tens of percent. The alloys exhibit a significant strength asymmetry between compressive and tensile loadings, namely, they are weak and brittle under tensile loading. The tensile brittleness is associated with the lattice distortion in the bcc-structured dendrites as well as crack initiation at the interdendritic precipitates. / sponsorship: The authors are grateful to S. Donath, F. Ebert and M. Frey for technical assistance. I.V.O. is thankful to IFW Dresden where this work was initiated. Funding by the European Research Council (ERC) under the ERC Advanced Grant INTELHYB (grant ERC-2013-ADG-340025) is gratefully acknowledged. (European Research Council (ERC)|ERC-2013-ADG-340025) / status: Published
