Síntese e caracterização da liga de alta entropia CoCrCuFeNi por moagem mecânica

Abstract

High entropy alloys are a new class of materials. This dissertation deals with high entropy alloys synthesized utilizing mechanical alloy. Elementary powders (Co, Cr, Cu, Fe, and Ni) are ground in planetary and high-energy ball mills, in both, with process control agent (stearic acid and toluene). Elementary powders are taken out at particular time intervals for the phase analysis through an X-ray diffractometer. The particle morphology was scrutinized by Scanning electron microscopy. The phase analysis through an X-ray diffractometer reveals the formation of a face-centered cubic (FCC) phase. The decrease in the size of the crystallite is observed, by the Rietveld method, with the increase of the milling time. When analyzing the process variables, we found that the combination of the high energy ball mill and toluene as the process control agent was the best result. The high entropy alloy was obtained in 5 hours, and toluene prevented contamination of the CoCrCuNiFe alloy both by the action of oxygen present in the atmosphere and by the materials that make up the tungsten carbide vial set with balls.