Temperature Resistance of Mo<sub>3</sub>Si: Phase Stability, Microhardness, and Creep Properties
Olha Kauss,
Susanne Obert,
Iurii Bogomol,
Thomas Wablat,
Nils Siemensmeyer,
Konstantin Naumenko,
Manja Krüger
Affiliations
Olha Kauss
Faculty of Mechanical Engineering (FMB), Institute of Material and Joining Technology (IWF), Otto von Guericke University (OVGU) Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany
Susanne Obert
Institute for Applied Materials (IAM-WK), Karlsruhe Institute of Technology (KIT), Engelbert-Arnold-Straße 4, 76131 Karlsruhe, Germany
Iurii Bogomol
Faculty of Physical Engineering (IΦΦ), Department of High-Temperature Materials and Powder Metallurgy (BTM<span style="font-variant: small-caps">t</span>aПM), National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute” (NTUU “KPI”), Peremogy Ave. 37, 03056 Kyiv, Ukraine
Thomas Wablat
Faculty of Mechanical Engineering (FMB), Institute of Material and Joining Technology (IWF), Otto von Guericke University (OVGU) Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany
Nils Siemensmeyer
Faculty of Mechanical Engineering (FMB), Institute of Material and Joining Technology (IWF), Otto von Guericke University (OVGU) Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany
Konstantin Naumenko
Faculty of Mechanical Engineering (FMB), Institute of Mechanics (IFME), Otto von Guericke University (OVGU) Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany
Manja Krüger
Faculty of Mechanical Engineering (FMB), Institute of Material and Joining Technology (IWF), Otto von Guericke University (OVGU) Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany
Mo-Si-B alloys are one of the most promising candidates to substitute Ni based superalloys in gas turbines. The optimization of their composition can be achieved more effectively using multi-scale modeling of materials behavior and structural analysis of components for understanding, predicting, and screening properties of new alloys. Nevertheless, this approach is dependent on data on the properties of the single phases in these alloys. The focus of this investigation is Mo3Si, one of the phases in typical Mo-Si-B alloys. The effect of 100 h annealing at 1600 °C on phase stability and microhardness of its three near-stoichiometric compositions—Mo-23Si, Mo-24Si and Mo-25Si (at %)—is reported. While Mo-23Si specimen consist only of Mo3Si before and after annealing, Mo-24Si and Mo-25Si comprise Mo5Si3 and Mo3Si before annealing. The latter is then increased by the annealing. No significant difference in microhardness was detected between the different compositions as well as after annealing. The creep properties of Mo3Si are described at 1093 °C and 1300 °C at varying stress levels as well as at 300 MPa and temperatures between 1050 °C and 1350 °C. Three constitutive models were used for regression of experimental results—(i) power law with a constant creep exponent, (ii) stress range dependent law, and (iii) power law with a temperature-dependent creep exponent. It is confirmed that Mo3Si has a higher creep resistance than Moss and multi-phase Mo-Si-B alloys, but a lower creep strength as compared to Mo5SiB2.
