Influence of Sintering Temperature on Densification and Nanomechanical Properties of High Entropy Alloy Consolidated via Field Assisted Sintering Technology

This study investigates the influence of sintering temperature on the densification and nanomechanical properties of a Co₁₀Cr₂₀Cu₂₀Mn₂₀Nb₁₀Ni₂₀ high entropy alloy (HEA) consolidated via field-assisted sintering technology (FAST). The HEA was first produced through mechanical alloying of elemental powders using high-energy planetary ball milling to ensure homogeneous elemental distribution prior to consolidation. Thereafter, the alloyed powders were sintered at three different temperatures (850°C, 900°C, and 950°C), and characterized using SEM, XRD, density measurements, and nanoindentation. Results obtained from the characterization reveal a progressive enhancement in densification (from 98.8% to 99.30%) and Vickers hardness (from 343.2 HV to 442.8 HV) with increasing temperature. XRD analysis confirmed the formation of stable FCC, BCC, and Laves phases, with microstructural refinement observed at higher temperatures. Nanoindentation results showed substantial increases in nanohardness (from 1332.7 to 2392.0 MPa) and elastic modulus (from 123.5 to 199.97 GPa) as sintering temperature increased. These improvements are attributed to enhanced diffusion, pore elimination, and grain boundary cohesion. Given these outstanding mechanical attributes, particularly high hardness, stiffness, and phase stability, the optimized HEA is suitable for high-strength structural components, aerospace systems, and wear-resistant applications where mechanical reliability and thermal stability are critical.