Temperature Resistance of Mo3Si: Phase Stability, Microhardness, and Creep Properties

Abstract

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.

Effect of the Si Content on the Dry and Wet Sliding Wear Behavior of the Developed Ti-15Mo-(0-2) Si Alloys for Biomedical Applications

“…The percentage of the strength enhancement of the Ti15Mo-2Si alloy reaches a value of 16.64% over the alloy without Si content (the Ti-15Mo alloy). In Ti-alloys, strength can be influenced by factors such as alloy composition, processing methods, heat treatments, and the presence of various strengthening mechanisms like solid solution strengthening, precipitation hardening, and grain refinement [40]. Si can play a significant role in the grain refining of β-Ti alloys, which can lead to improved mechanical properties according to the Hall-Petch equation [41,42].…”

High-Temperature Behavior of Metals

“…The effects of microstructure or microstructural stability, either directly correlated to the manufacturing process, or induced by heat treatment or by prolonged high temperature exposure simulating service, have also been considered in other contributions: for the two Al-SiMg alloys differently produced and heat treated by Gariboldi et al [5] and Paoletti et al [6], for the friction stir welded Mg alloy WE54 studied by Álvarez-Leal et al [7], for the dynamic recrystallization in martensitic steels changes reviewed by Derazkola et al [8], the Ni-based alloys investigated by Llizzi et al [9] and Engels [10], and finally the Mo-Si alloys investigated by Krauss et al [11].…”

“…The paper by Krauss et al [11] underlined the effect of microstructure and the need for a clear understanding of it in a different way. Clear differences have been demonstrated between the creep properties of Mo, Mo solid solution, Mo5SiB2 and some Mo-Si-B alloys, these latter candidate materials for future gas turbine engines operating at temperatures exceeding those possible for Ni-based alloys.…”

Effects of Fe/Si Stoichiometry on Formation of Fe3Si/FeSi-Al2O3 Composites by Aluminothermic Combustion Synthesis

“…Transition metal silicides have been promising for a wide range of applications including microelectronic transistors, high-temperature structural components, thin film coatings, thermoelectrics, spintronic devices, and catalysts [1][2][3][4][5][6]. Of many transition metal silicides, iron silicides exhibit magnetic, semiconducting, metallic, and insulating characteristics, depending on different crystalline structures [7,8].…”