Modeling of the Formation of Stress-Induced ω Phase in Metastable β Titanium Alloys

M. Knapeka, J. Kozlíka, J. Čapeka, b, H. Seinerc, J. Šmilauerováa, M. Janečeka aCharles University, Department of Physics of Materials, Ke Karlovu 5, 12116 Prague, Czech Republic bCzech Academy of Sciences, Nuclear Physics Institute, Řež 130, 25068 Řež, Czech Republic cCzech Academy of Sciences, Institute of Thermomechanics, Dolejškova 5, 18200 Prague, Czech Republic

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Titanium alloys are materials with exceptional properties including high specific strength, extreme corrosion resistance, and biocompatibility. Among them, metastable β titanium alloys are a prospective group exhibiting complex phase transformations which can be employed to improve the performance of the material. Microstructural mechanisms controlling phase transformations in these alloys are not completely understood. In this work, we propose a continuum-based model describing non-diffusional, displacive, reversible β→ω phase transformation which leads to a formation of stress-induced ωdef phase. The proposed model utilizes a well-developed mathematical theory of martensitic phase transitions based on the Cauchy-Born hypothesis, and reformulates this theory to describe the crystallographic mechanism of β→ωdef phase transformation. The model evaluates compatibility criteria at the interfaces between β and ωdef phases in relation to the external stress and provides conditions for the formation of ωdef phase.

DOI:10.12693/APhysPolA.134.769 PACS numbers: 46.05.+b, 64.60.-i, 81.05.Bx