Synthesis of high entropy alloy FeCoNiCuAl and investigation of enthalpy effect in phase separation

Nearly two decades have passed since the discovery of high-entropy alloys, an idea of alloying that has encouraged materials engineering scientists to explore unusual alloy compositions and multicomponent alloy systems. To increase the performance of this group of alloys in various fields of application, controllable synthesis with favorable phases is required. Based on this, in this research, with the aim of synthesizing a two-phase high entropy alloy based on the principles of thermodynamics, theoretical calculations were performed in the first step, and after feasibility from a theoretical point of view, elemental powders of iron, cobalt, nickel, and copper were used in the solid state method. And high purity aluminum was selected and mechanically mixed and alloyed. Sampling was done from the mechanical alloying chamber at consecutive times of 10, 20, 30, 40 and 50 hours. These samples were characterized by X-ray diffraction (XRD) technique and it was observed that after 50 hours, this alloy has two-phase FCC crystal structure. In this way, the experimental tests confirmed the thermodynamic calculations. Also, the images of the elemental map analysis showed that after 50 hours of mechanical alloying, all elements of the high entropy alloy were completely uniformly dispersed in the field and a uniform solid solution structure was formed. Finally, some insights into the challenges and future prospects in this emerging research field are provided.