Regensburg 2019 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 12: Poster session I

MM 12.36: Poster

Montag, 1. April 2019, 19:15–20:45, Poster C

Brute force composition scanning with a CALPHAD database to find low temperature bcc high entropy alloys — •Peter Klaver, Darko Simonovic, and Marcel Sluiter — Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628CD Delft, The Netherlands

We used Thermo-Calc CALPHAD calculations to determine the stable phases of AlCrMnNbTiV, AlCrMoNbTiV, AlCrFeTiV and AlCrMnMoTi alloys. A five- or six-dimensional grid is constructed, with stable phases calculated at each grid point. Three million compositions were calculated, resulting in ~20000 compositions consisting of a single disordered bcc phase down to 800 K. By filtering out compositions with a single disordered phase, composition islands of high entropy alloys are determined. The sizes and shapes of such islands provide information about which element combinations have good high entropy alloy forming qualities as well as about the role of individual elements within an alloy. We determined which compositions lie near the centers of these islands and thus remain high entropy islands under small composition changes. These compositions make good candidates for experimental verification. The search for high entropy islands can be conducted under constraints, e. g. requiring a minimum amount of Al and/or Cr to promote oxidation resistance. It is also possible to look for alloys consisting of two different disordered phases. The high entropy forming qualities of AlCrMnNbTiV and AlCrMoNbTiV are relatively good, those of AlCrFeTiV are poor, while those of AlCrMnMoTi are poor at 800 K but quickly become better with increasing temperature.