MECHANICAL ALLOYING WITH PARTIAL AMORPHIZATION OF FE–CR–CO–NI–MN MULTICOMPONENT POWDER MIXTURE AND ITS SPARK PLASMA SINTERING FOR COMPACT HIGH-ENTROPY MATERIAL PRODUCTION

Abstract

This paper presents the results of studying the mechanical alloying (MA) effect on the surface morphology, microstructure and atomic-crystal structure of multicomponent Fe–Cr–Co–Ni–Mn powder mixture particles. The following materials were used as initial components: radio-engineering carbonyl iron powder (R-10 with an average particle size d = 3,5 μm), nickel powder (NPE-1, d = 150 μm), cobalt powder (PK-1u, d <71 μm), chromium powder (PH-1М, d <125 μm) and manganese powder (MR0, d <400 μm) were used. MA of the prepared mixture was carried out in the AGO-2 water-cooled mechanical activator using 9 mm steel balls with an acceleration of 90 g in air. Alloying time varied between 5 and 90 minutes. The ratio of ball mass to the mass of the mixture was 20 : 1. X-ray patterns of the initial and alloyed mixtures and the sample obtained by sintering were made on the DRON 3M diffractometer on FeKα radiation in the range of angles 2θ = 30°÷100°. The particle microstructure of the mixtures and compact sample section after sintering was studied by scanning electron microscopy. It is found that no peaks of the initial components are present on the X-ray pattern of the mixture after 90 minutes of mechanical activation, but there are peaks corresponding to the γ-Fe-based solid solution phase having a face-centered crystal lattice with an amorphous phase content increased by 20 %. A compact single-phase material was obtained by spark plasma sintering at 800 °С for 10 minutes from the mixture after 90-minute alloying. Material density was 7,49 kg/cm3, specific electrical resistivity was 0,94÷0,96·10–6 ·m, microhardness was 306÷328 kg/mm2, and the phase was distributed uniformly throughout the volume.