Thermodynamic analysis and microstructural evolution of the W-Mo-Ni-C system produced by mechanical alloying

• Published in: Physica. B, Condensed matter Condensed matter, 2022-11, Vol.644, p.414126, Article 414126
• Main Authors: Castillo Plata, Fredy Josealdo, Rivera Olvera, Jesús Noé, Garibay Febles, V., Diaz Barriga, Lucia Graciela
• Format: Article
• Language: English
• Subjects: Alloy formation; Carbides; Formation enthalpy; Mechanical alloying; Miedema model; Thermodynamic analysis
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2022.414126

In this research, the microstructural evolution of the W-Mo-Ni-C system was studied by conducting a thermodynamic analysis of formation enthalpies using the Miedema model. Samples were synthetized with different milling times of up to 240 h and analyzed using X-ray diffraction to determine the phases that were produced at each stage of the synthesis. The experimental results indicated carbon diffusion into the transition metal lattice, as WC formation was observed at 120 h and NiC formation was observed at 160 h. Nanostructured MoNi3 and MoW alloys were identified at initial stages from 40 h to 120 h, and as carbon diffusion continued, the MoW alloy transformed into WMoC carbide at 200 h. The Miedema model predictions established that the necessary energy for carbide formation is much larger than that for the formation of alloys of transition metals, demonstrating that these alloys must be formed first, which was validated by experimental data. It was found that the mechanical alloying process produced materials that were out of equilibrium. •Miedema model was applied in the determination of formation enthalpy of different carbides produced by mechanical alloying.•Metal-metal interactions are favoured over carbon-metal interactions during the synthesis process.•Bimetallic alloys are generated at initial stages of milling process before carbide’s formation.•The WMoC carbide is formed by carbon solubilization in bimetallic alloy MoW.