Phase transformation pathways in a Ti-5.9Cu alloy modified with Fe and Al

Thomas Klein, Duyao Zhang, Ella Staufer, Torben Boll, Christian Schneider-Broeskamp, Christian Edtmaier, Martin Schmitz-Niederau, Jelena Horky, Dong Qiu, Mark Easton

Research output: Contribution to journalArticlepeer-review

5 Citations (SciVal)

Abstract

Titanium alloys have been gaining importance in various industries due to their advantageous combination of strength, low density, excellent corrosion/oxidation resistance, and superior mechanical properties at elevated temperatures. Recently, eutectoid Ti–Cu alloys have been explored as promising candidates for advanced processes. This work investigates the effects of Fe and Al on a Ti-5.9Cu alloy using multi-scale characterization techniques. While Fe acts as a β-stabilizing element (despite being a sluggish eutectoid former), Al acts as an α-stabilizer. This work focuses on the effects of combined addition of these elements, studied in different heat treatment conditions. The results show that a fine, equiaxed microstructure is obtained in the binary Ti-5.9Cu alloy, whereas the addition of 2 wt% Fe, or 2 wt% Fe combined with 2 wt% Al to the Ti-5.9Cu alloy deteriorates the effect of grain refinement and coarse, columnar grains result and a small amount of β-phase is retained. Further, the microstructure resulting from the eutectoid decomposition is altered dramatically from a lamellar pearlitic in the binary alloy to a lath-like α-phase with diverse decomposition products in the ternary and quaternary alloys accompanied by increasing hardness values. Evaluation of the α misorientation suggests that a substantial amount of non-Burgers α is present in the Ti-Cu alloy in contrast to the results of the ternary and quaternary alloys. The observed Cu-rich intermetallic compound was identified as Ti2Cu phase with off-stoichiometric composition. Results obtained explain how adding either Fe or Fe and Al leads to substantial hardening.
Original languageEnglish
Pages (from-to)4978-4985
Number of pages8
JournalJournal of Materials Research and Technology
Volume27
Early online date7 Nov 2023
DOIs
Publication statusPublished - 1 Dec 2023

Funding

Technical assistance by I. Baumgartner, R. Hellstern, A. Arnoldt (all LKR) and M. Weinhard (KNMFi) is greatly appreciated. The authors acknowledge the facilities, and the scientific and technical assistance of the RMIT Microscopy & Microanalysis Facility (RMMF), a linked laboratory of Microscopy Australia, enabled by NCRIS and at the Karlsruhe Nano Micro Facility (KNMFi, www.knmf.kit.edu), with proposal no 2022–028031387.

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