High-Temperature Phase Transformations in Multicomponent Fecocrnival Alloy

M.Karpets,
     
S.Yu.Makarenko
 

I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Omeliana Pritsaka str.,3, Kyiv, 03142, Ukraine
Powder Metallurgy - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2016, #05/06
http://www.materials.kiev.ua/article/2200

Abstract

The phase transformations proceeding in real time in as-cast high-entropy FeCoCrNiVAl alloy are studied using high-temperature in situ X-ray diffraction in a helium atmosphere at 293–1273 K. In initial state, this alloy is a single-phase BCC solid solution ordered according to B2 type. It is found for the first time that a tetragonal σ-phase of CrFe type forms at 1073 K on the surface of the alloy. The surface layer of the σ-phase is ~22 µm in thickness. The influence of annealing on changes in phase composition of the high-entropy alloy is analyzed. Microstructure of the alloy is studied using scanning electron and optical microscopy. The microhardness and effective Young’s modulus of the high-entropy alloy are determined at room temperature.


σ-PHASE, HIGH-ENTROPY ALLOY, HIGH-TEMPERATURE IN SITU X-RAY DIFFRACTION, MICROHARDNESS, MICROSTRUCTURE, SOLID SOLUTION