2018-Sustainable Industrial Processing Summit
SIPS2018 Volume 5. Zehetbauer Intl. Symp. / SISAM

Editors:F. Kongoli, S. Kobe, M. Calin, J.-M. Dubois, T. Turna
Publisher:Flogen Star OUTREACH
Publication Year:2018
Pages:154 pages
ISBN:978-1-987820-90-4
ISSN:2291-1227 (Metals and Materials Processing in a Clean Environment Series)
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    Diffusive and Displacive Phase Transformations Driven by High Pressure Torsion

    Boris Straumal1; Askar Kilmametov2; Olga Kogtenkova3; Andrey Mazilkin2; Brigitte Baretzky2;
    1INSTITUTE OF SOLID STATE PHYSICS RAS, Chernogolovka, Russian Federation; 2KARLSRUHE INSTITUTE OF TECHNOLOGY (KIT), Eggenstein-Leopoldshafen, Germany; 3INSTITUTE OF SOLID STATE PHYSICS, Chernogolovka, Russian Federation;
    Type of Paper: Invited
    Id Paper: 302
    Topic: 42

    Abstract:

    The influence of high pressure torsion (HPT) on the diffusive and displacive phase transformations in sustainable advanced materials has been studied. In diluted Cu-based binary alloys the HPT drives the competition between deformation-driven precipitation and dissolution of precipitates. The dynamic equilibrium between these two processes is reached already after 1.5-2 anvil rotations. The composition of Cu-matrix in this equifinal state is equal to that which can be reached in equilibrium after long annealing at a certain temperature T<sub><i>eff</i></sub>. T<sub><i>eff</i></sub> in diluted Cu-based binary alloys increases with increasing activation enthalpy of diffusion of a second component and its melting temperature Tm [1, 2].
    In Cu-Al-Ni shape memory alloys, HPT leads to the combination of displacive (austenite-martensite) and diffusive (decomposition of supersaturated solid solution) phase transitions. On the one hand, the HPT of these alloys led to the precipitation of α1-phase in the Al-pure alloy and to the precipitation of γ1-phase in the Al-rich one (as if they were annealed at an effective temperature T<sub><i>eff</i></sub> = 620-20°C). As a result of this precipitation, the matrix in the first alloy was enriched and in the second one depleted in Al. The resultant composition change in the Cu-rich matrix changed also the route for the martensitic transformations. After HPT, both alloys contained mainly β'3 martensite with a certain amount of γ'3 martensite. Thus, the HPT-driven diffusive transformations (precipitation of α1- and γ1-phase) influence the followed displacive (martensitic) transformation [3].
    The combination of displacive and diffusive phase transitions has been observed also under HPT of Ti-Fe and Ti-Co alloys [4].

    Keywords:

    Advanced materials; Surfaces and interfaces;

    References:

    [1] B.B. Straumal, V. Pontikis, A.R. Kilmametov, A.A. Mazilkin, S.V. Dobatkin, B. Baretzky, Acta Mater. 122 (2017) 60-1.
    [2] B.B. Straumal, A.R. Kilmametov, A. Korneva, A.A. Mazilkin, P.B. Straumal, P. ZiA�ba, B. Baretzky, J. Alloys Comp. 707 (2017) 20-26.
    [3] B.B. Straumal, A.R. Kilmametov, G.A. Lopez, I. Lopez-Ferrero, M.L. No, J. San Juan, H. Hahn, B. Baretzky, Acta Mater. 125 (2017) 274-285.
    [4] A. Kilmametov, Yu. Ivanisenko, A.A. Mazilkin, B.B. Straumal, A.S. Gornakova, O.B. Fabrichnaya, M.J. Kriegel, D. Rafaja, H. Hahn, Acta Mater. 144 (2018) 337-351.

    Cite this article as:

    Straumal B, Kilmametov A, Kogtenkova O, Mazilkin A, Baretzky B. (2018). Diffusive and Displacive Phase Transformations Driven by High Pressure Torsion. In F. Kongoli, S. Kobe, M. Calin, J.-M. Dubois, T. Turna (Eds.), Sustainable Industrial Processing Summit SIPS2018 Volume 5. Zehetbauer Intl. Symp. / SISAM (pp. 53-54). Montreal, Canada: FLOGEN Star Outreach