Microstructure features of high-entropy equiatomic cast AlCrFeCoNiCu alloys

The structural and phase transformations that take place in the cast high-entropy equiatomic alloy AlCrFeCoNiCu after solidification, homogenizing heat treatment, and cooling have been studied. Analytical transmission microscopy, scanning electron microscopy, X-ray energy dispersive spectroscopy, and X-ray diffraction analysis were used to conduct the studies. The elastic modulus, nano-, and microhardness have been measured. The alloy decomposition has been found to occur with the precipitation of no less than six nanoscale phases with different morphologies, structures (A2, B2, L12), and chemical compositions. All the nanophases are multicomponent solid solutions enriched with several elements, which indicates the pronounced elemental and phase nanomodulation over the alloy volume. © 2013 Pleiades Publishing, Ltd

Specific features of cast high-entropy AlCrFeCoNiCu alloys produced by ultrarapid quenching from the melt

Results of studying structural and phase transformations that occur in the cast high-entropy equiatomic AlCrFeCoNiCu alloy after ultrarapid quenching from the melt in an inert atmosphere (RQM) and various isothermal treatments are presented for the first time. The investigations have been performed using analytical, transmission and scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction structure and phase analyses, as well as measurements of the nanohardness, microhardness, and elastic moduli. It has been found that an ultrafine-grained structure is formed in this alloy during RQM. Already during quenching and, especially, during subsequent annealing, the alloy undergoes decomposition, which is accompanied by the precipitation in the bcc (B2) matrix of some nanosized phases, predominantly of equiaxed morphology, both atomically ordered (B2) and disordered (A2), with various chemical compositions. All nanophases are multicomponent solid solutions and are enriched in a few elements, which leads to a pronounced nanomodulation of the elemental and phase compositions over the alloy bulk, identified, in particular, from the presence of satellites in the vicinity of some reflections in selected-area electron diffraction patterns. © 2013 Pleiades Publishing, Ltd

Влияние быстрой закалки расплава и мегапластической деформации на структуру и свойства высокоэнтропийных сплавов системы AlCoCrCuFeNi

В данной работе было исследовано влияние быстрой закалки расплава (методами спиннинга и сплэтинга (скорость охлаждения расплава ~ 105 и 106 К/с соответственно)) и мегапластической деформации под давлением на структуру и свойства высоко энтропийных сплавов системы AlCoCrCuFeNi

The effects of electron irradiation and fluoride salt melt ZrF₄ – NaF on mechanical properties of Hastelloy N type alloys

NSC KIPT has cast Hastelloy N type alloys that are to be used in molten-salt reactors (MSR). A study was made on the collective effects of exposure to electron irradiation and melt of sodium and zirconium fluorides at the temperature 650°С for 700 hours on mechanical properties of those alloys.В ННЦ ХФТІ виплавлені сплави типу Хастелой Н, які призначені для роботи в рідинно-сольових реакторах. Досліджувалася сумісна дія опромінення електронами і розплаву фторидів натрію і цирконію при температурі 650°С протягом 700 г на механічні властивості зразків із сплавів типу Хастелой Н.В ННЦ ХФТИ выплавлены сплавы типа Хастеллой Н, которые предназначены для работы в жидкосолевых реакторах. Исследовалось совместное воздействие облучения электронами и расплава фторидов натрия и циркония при температуре 650°С в течение 700 ч на механические свойства образцов из сплавов типа Хастеллой Н