High-Entropy FeCoNiB<sub>0.5</sub>Si<sub>0.5</sub> Alloy Synthesized by Mechanical Alloying and Spark Plasma Sintering
Kaouther Zaara,
Mahmoud Chemingui,
Sophie Le Gallet,
Yves Gaillard,
Lluisa Escoda,
Joan Saurina,
Joan Josep Suñol,
Frédéric Bernard,
Mohamed Khitouni,
Virgil Optasanu
Affiliations
Kaouther Zaara
Laboratoire de Chimie Inorganique, UR 11-ES-73, Université de Sfax, B.P. 1171, Sfax 3018, Tunisia
Mahmoud Chemingui
Laboratoire de Chimie Inorganique, UR 11-ES-73, Université de Sfax, B.P. 1171, Sfax 3018, Tunisia
Sophie Le Gallet
Laboratoire Interdisciplinaire Carnot de Bourgogne, ICB, UMR 6303 CNRS, Université de Bourgogne Franche Comté, BP 47870, 21078 CEDEX Dijon, France
Yves Gaillard
Franche-Comté Electronique Mécanique Thermique et Optique—Sciences et Technologies, FEMTO-ST, UMR 6174 CNRS, Université de Bourgogne Franche Comté, 25000 Besançon, France
Lluisa Escoda
Department of Physics, Campus Montilivi, University of Girona, 17071 Girona, Spain
Joan Saurina
Department of Physics, Campus Montilivi, University of Girona, 17071 Girona, Spain
Joan Josep Suñol
Department of Physics, Campus Montilivi, University of Girona, 17071 Girona, Spain
Frédéric Bernard
Laboratoire Interdisciplinaire Carnot de Bourgogne, ICB, UMR 6303 CNRS, Université de Bourgogne Franche Comté, BP 47870, 21078 CEDEX Dijon, France
Mohamed Khitouni
Laboratoire de Chimie Inorganique, UR 11-ES-73, Université de Sfax, B.P. 1171, Sfax 3018, Tunisia
Virgil Optasanu
Laboratoire Interdisciplinaire Carnot de Bourgogne, ICB, UMR 6303 CNRS, Université de Bourgogne Franche Comté, BP 47870, 21078 CEDEX Dijon, France
A FeCoNi(B0.5Si0.5) high-entropy alloy with the face-centered cubic (FCC) crystal structure was synthesized by mechanical alloying and spark plasma sintering (SPS). Phase evolution, microstructure, morphology and annealing behaviors were investigated. It was found that a single FCC solid solution appears after 50 h of milling. The grain size was 10 nm after 150 h of milling. Microstructure parameters were calculated by the Rietveld fitting of the X-ray Diffraction patterns. Magnetic characterizations of milled and annealed powders at 650 °C for 1 h were investigated. The heat treatment improves the magnetic properties of the milled powders by enhancing the saturation magnetization value from 94.31 to 127.30 emu/g and decreasing the coercivity from 49.07 to 29.57 Oe. The cohabitation of the FCC phase with the equilibrium crystalline phases observed after annealing is responsible of this magnetic softening. The as-milled powder was also consolidated by spark plasma sintering at 750 and 1000 °C. The obtained specimen consolidated at 750 °C improved the coercivity to 25.06 Oe and exhibited a compressive strength of 1062 Mpa and Vickers hardness of 518 ± 14 HV, with a load of 2 kN. The nanoindentation technique with the Berkovich indentor gave hardness and indentation elastic modulus of 6.3 ± 0.3 Gpa (~640 HV) and 111 ± 4 Gpa for samples consolidated by SPS at 750 °C.
