Synergistic Impact of Mechanical Alloying Duration and Spark Plasma Sintering Temperature on Microstructure and Properties of CoCrFeNiMn High-Entropy Alloys

This study successfully synthesized the CoCrFeNiMn high-entropy alloy (HEA) using a two-step powder metallurgy approach: mechanical alloying (MA) followed by spark plasma sintering (SPS). The research investigated the effects of processing parameters, specifically MA duration and SPS temperature, on the alloy's microstructure, densification, and mechanical properties. X-ray diffraction (XRD) analysis after ۲۵ hours of MA (ball-to-powder ratio of ۱۰:۱) confirmed the formation of a single-phase face-centered cubic (FCC) solid solution. Scanning electron microscopy (SEM) images revealed significant powder particle refinement, with average particle sizes decreasing from initial micrometers to sub-micrometer ranges. The alloyed powders were then consolidated via SPS at temperatures of ۸۰۰°C, ۹۰۰°C, and ۱۰۰۰°C (۴۰ MPa, ۱۰ min in argon). Detailed analysis of the sintered samples showed relative densities ranging from ۹۵.۷۸% to ۹۶.۷۷%, with the highest density (۹۶.۷۷%) achieved at ۱۰۰۰°C. Vickers microhardness measurements exhibited a peak hardness of ۴۴۶ HV at ۹۰۰°C, with a decrease to ۴۲۰ HV at ۱۰۰۰°C, primarily due to grain growth. This research establishes the combined MA and SPS approach as effective for producing high-density, high-hardness HEAs, underscoring the critical role of processing parameters in tailoring their final properties.

کلیدواژه ها:

High-entropy alloys (HEAs) ، Mechanical alloying ، Spark plasma sintering (SPS) ، Microstructural refinement ، Vickers hardness