Structural, Thermal and Mechanical Properties of mechanically alloyed Ni80Co17Mo3 powder mixture

Abstract

This study investigates the evolution of structure and microstructure alongside thermomechanical properties of Ni₈₀Co₁₇Mo₃ alloy powder mixture subjected to high-energy mechanical milling. Scanning electron microscopy observations reveal a consistent particle size reduction to 22 ± 2 μm. X-ray diffraction analysis confirms the formation of an FCC nanostructured solid solution NiCo(Mo) after 6h of milling, with a mean crystallite size ⁓ 56.4 nm and microstrain up to 6.5×10⁻³ % after 72 h. Thermogravimetric analysis manifests a precise mass gain trend, showing a strong correlation (R² = 0.90–0.99) between milling time and compositional changes, with an average activation energy of 70.68 ± 3.5 kJ/mol supporting the thermodynamic modelling results. Due to structural and microstructural modifications associated with mechanical milling, the microhardness significantly increases from 134.00 to 285.00 HV. These findings highlight insights into optimizing nanostructured materials and provide a framework for designing advanced materials for water splitting and aerospace.