VISCOSITY OF CuPb, CuPbSn, CuPbSnGa AND CuPbSnGaBi MELTS OF EQUIATOMIC COMPOSITIONS

We investigated the viscosity of CuPb, CuPbSn, CuPbSnGa and CuPbSnGaBi melts of equiatomic compositions by the method of damped torsion vibrations of a crucible. We saw the melts of equiatomic composition as the melts high-entropy. All the investigated melts demonstrated the different temperature dependences of viscosity for heating and cooling. There is an anomalous reduction in viscosity resulted when the melt is heated to a specific temperature. The anomalous behaviour for viscosity we interpreted in terms of melt structure. This structural changes in the melt resulted when the melt is heated to a specific temperature. The microstructure of CuPbSnGaBi ingot of equiatomic composition we investigated using optical microscopy and measurement of microhardness. Collations data of the microstructures with of the microhardness gave three structural components: CuGa2 dendrites, (Sn) + (Bi) + Bi3Pb7 ternary eutectic and rounded Pb inclusions having dimensions of 5 m.

Preparation, Electrical and Electrochemical Characterizations of CuCoNiFeMn High-Entropy-Alloy for Overall Water Splitting at Neutral-pH

High entropy alloys (HEA), the multicomponent (5 or more) alloys with an equiatomic or a near equiatomic composition, provide a unique platform to engineer surface composition and active sites for...

Wetting of Low Carbon Steel by High-Entropy Melts CuSnBiPbGa, CuSnBiPbIn and CuSnBiInCd and Formed Structure of Diffusion Layers

We present a result of a study of reactive wetting of surface of low carbon steel by liquid alloys CuSnBiPbGa, CuSnBiPbIn and CuSnBiInCd of equiatomic composition. Dependences of contact angle and spot diameter of wetted surface on temperature and time were studied. Liquid alloy CuSnBiPbGa begins wetting of surface of steel at 900 °C; spreading rate at higher temperatures increased by 8 times. Liquid alloy CuSnBiPbIn begins wetting surface of steel at 780°C, but spreading speed is almost unchanged with the further increase in temperature. Liquid alloy CuSnBiInCd begins wetting of surface of steel at a temperature of 570°C, and spreading is in a flash in nature. We studied microstructure and chemical composition of diffusion layers, formed at the spreading of liquid alloys of equiatomic composition CuSnBiPbGa, CuSnBiPbIn and CuSnBiInCd on steel surface. In all experiments at boundary with substrate a ductile transition layer of a solid solution of iron-based is formed. The thickness of diffusion layer side depends on the alloy composition. The widest diffusion layers formed for alloy CuSnBiInCd, and the most narrow - for alloy CuSnBiPbGa. We detected in segregations of copper and gallium atoms for bimetallic sample "CuSnBiPbGa+steel", of copper and tin atoms for samples "CuSnBiPbIn+steel" and "CuSnBiInCd+steel" in diffusion layers. The results of these studies have significance for the design of soldering technology and application of protective coatings on steel products.

Влияние изохронных отжигов на поверхностные характеристики лент металлического стекла Ni-=SUB=-50-=/SUB=-Ti-=SUB=-50-=/SUB=-

In this paper we investigated the crystallization of NiTi metallic glass foils of equiatomic composition by XRD and AFM. The initial foil surface which was obtained by the melt spinning method contained only cristalline phases of impurities. Ten-minute annealing at 500°C leads to phase transition in the form of devitrification of Ni50Ti50 phase. The analisys of foil surface geometry included calculation of direct inhomogeneities characteristics, roughness and fractal dimension, as well as the parameters of multifractal fromalism. It was showen that after ten-minute heat treatment at 500°C all above mentioned characteristics have local extrema. In particular there is a minimum of the widths of the singularities spectra which indicates the monofractalization of the system.

Viscosity of CuPb, CuPbSn, CuPbSnGa and CuPbSnGaBi melts of equiatomic compositions

<p class="AMSmaintext">We investigated the viscosity of CuPb, CuPbSn, CuPbSnGa and CuPbSnGaBi melts of equiatomic compositions by the method of damped torsion vibrations of a crucible. We see the melts of equiatomic composition as the melts high-entropy. All the investigated melts demonstrated the different temperature dependences of viscosity for heating and cooling. There is an anomalous reduction in viscosity resulted when the melt is heated to a specific temperature. The anomalous behaviour for viscosity we interpreted in terms of melt structure. This structural changes in the melt resulted when the melt is heated to a specific temperature. The microstructure of CuPbSnGaBi ingot of equiatomic composition we investigated using optical microscopy and measurement of microhardness. Collations data of the microstructures with of the microhardness gave three structural components: CuGa₂ dendrites, (Sn) + (Bi) + Bi₃Pb₇ ternary eutectic and rounded Pb inclusions having dimensions of »5 mm.</p>