Combinatorial Deposition of Ultrathick Ta-W-Au-Bi High-Entropy Alloys for Next-Generation Hohlraums by Direct-Current Magnetron Sputtering

Protection against microbiologically influenced corrosion (MIC) is critical for materials used in aquatic environments, as MIC accelerates material degradation and leads to faster structural failure. Copper (Cu) has the potential to substantially improve the MIC resistance in alloys. In this study, high-entropy alloy (HEA) coatings containing Cu were deposited using DC (Direct Current) magnetron sputtering to enhance the corrosion resistance and mechanical properties of various substrates. Two CuCrFeMnNi HEA compositions in the form of bulk alloys and PVD (Physical Vapor Deposition) coatings, with 5% and 10% Cu, were analyzed for their microstructural, mechanical, and anticorrosive characteristics. Deposition parameters were varied to select the optimal values. Microstructural evaluations using SEM-EDS (scanning electron microscopy and energy dispersive X-ray spectroscopy), XRD (X-ray diffraction), and AFM (atomic force microscopy) revealed uniform, dense coatings with good adhesion composed of dendritic and interdendritic BCC (body-centered cubic) and FCC (face centered cubic) structures, respectively. Microhardness tests indicated improved mechanical properties for the samples coated with developed HEAs. The coatings exhibited improved corrosion resistance in NaCl solution, the 10% Cu composition displaying the highest polarization resistance and lowest corrosion rate. These findings suggest that Cu-containing HEA coatings are promising candidates for applications requiring enhanced corrosion protection.

This study investigated the impact of different bismuth (Bi) contents on the mechanical properties, melting point, and corrosion resistance of tin-copper (Sn-Cu) series alloys (Sn-0.7Cu). Furthermore, Sn-0.7Cu-xBi alloys with different Bi contents (x = 0, 3, 6, 9, 12, 15 wt%) were prepared through a traditional casting process. The composition and microstructure of the alloy were characterized via X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The impact of Bi on the mechanical properties, melting point, and corrosion resistance of Sn-0.7Cu alloy was analyzed, reaching a peak at 12 wt% Bi. Furthermore, beyond this concentration, the mechanical properties of the alloy exhibited a decline. The corrosion resistance of Sn-0.7Cu-xBi alloys increased with increasing Bi content. However, when the Bi content was >12 wt%, owing to the aggregation of Bi in the alloy, the corrosion resistance of the alloy decreased.

Bi2Te3 thin films were deposited onto polyamide sheets with direct current (DC) or radio frequency (RF) magnetron sputtering techniques. The films were prepared using a Bi2Te3 target at a varying pre-heating temperature from 150 to 350 °C. It was observed that the type of plasma excitation and pre-heating temperature can significantly change the composition, preferred orientation, crystallinity, and thermoelectric properties of the films. The pre-heat treatment significantly affected the non-stoichiometric composition. In addition, it was shown that crystallinity and (0 0 l) planes were enhanced in the DC sputtered coatings at a high pre-heating temperature. The maximum power factor of 3.5 × 10−3 W/m K2 at 285 °C was obtained for the films deposited using DC magnetron sputtering and a pre-heating temperature of 350 °C. The carrier concentration and mobility of the film were 5.40 × 1020 cm−3 and 13.04 cm2/V s, respectively. Compared with an ordinary Bi2Te3 film, the power factor of such film has been greatly increased. The results indicated that DC magnetron sputtering can enhance the (0 0l ) plane orientation in the Bi2Te3 film.

We have studied the structural and electrical properties of bismuth-modified lead zirconate titanate thin films. Specimens with various Bi contents, (Pb1−3/2xBix) (Zr0.52 Ti0.48) O3 (PBZT) thin films, were prepared on a Pt-coated Si wafer by the sol–gel method. Ferroelectricity confirmed by the measurement of dielectric constant and P–E hysteresis loop was found for specimens below x = 0.25, in which the values of both dielectric constant and remanent polarization were decreased with increasing Bi contents. The behaviors of the electrical properties with Bi content corresponded to the structural changes by increasing non-ferroelectric cubic phase with increasing Bi contents, which was thought to be due to the vacancies in Pb-sites created by the substitution of Bi into Pb.

Enhanced multiferroic properties of Bi0.85Nd0.15FeO3 ceramics with excess Bi2O3

Effect of Bi contents on key physical properties of NiO NPs synthesized by flash combustion process and their cytotoxicity studies for biomedical applications

The epitaxial growth, structural, and optical properties of GaSb1–xBix alloys have been investigated. The Bi incorporation into GaSb is varied in the range 0 < x ≤ 9.6% by varying the growth rate (0.31–1.33 μm h−1) at two growth temperatures (250 and 275 °C). The Bi content is inversely proportional to the growth rate, but with higher Bi contents achieved at 250 than at 275 °C. A maximum Bi content of x = 9.6% is achieved with the Bi greater than 99% substitutional. Extrapolating the linear variation of lattice parameter with Bi content in the GaSbBi films enabled a zinc blende GaBi lattice parameter to be estimated of 6.272 Å. The band gap at 300 K of the GaSbBi epitaxial layers decreases linearly with increasing Bi content down to 410 ± 40 meV (3 μm) for x = 9.6%, corresponding to a reduction of ∼35 meV/%Bi. Photoluminescence indicates a band gap of 490 ± 5 meV at 15 K for x = 9.6%.

Traditional energy sources such as fossil fuels can cause environmental pollution on the one hand, and on the other hand, there will be a shortage of diminishing stocks. Recently, a variety of new energy sources have been proposed by scientists, such as nuclear energy, hydrogen energy, wind energy, water energy, and solar energy. There are already many technologies for converting and storing energy generated from new energy systems, such as various storage batteries. One of the keys to the commercialization of these new energy sources is to explore new materials. Researchers have performed a lot of research on new energy material preparation, mechanical properties, radiation resistance, energy storage, etc. However, new energy metal materials are still unable to combine radiation resistance, good mechanical properties, excellent energy storage, and other characteristics. There is still a lack of breakthrough materials with better performance or more stable structure. Recently, researchers have discovered that high-entropy alloys have become one of the most promising new energy metal materials. Because it not only has high energy storage and high strength, but also has high stability and high radiation resistance, and is easy to form a simple phase, the prediction of phases in high-entropy energy alloys is very critical, and the generation of designed phases in high-entropy energy alloys is a very important step. In this study, three machine learning algorithms were used to predict the generated phase classification in high-entropy alloys, namely, support-vector machine (SVM) model, decision tree (DT) model, and random forest (RF) model. The models are optimized by grid search methods and cross-validated, and performance was evaluated with the aim of significantly improving the accuracy of generative phase prediction, and the results show that the random forest algorithm has the best prediction ability, reaching 0.93 prediction accuracy. The ROC (receiver operating characteristic) curve of the model shows that the random forest algorithm has the best classification of solid-solution (SS) phases, where the classification probabilities AUC (area under the curve) area for amorphous phase (AM), intermetallic phase (IM), and solid-solution phase (SS), respectively, are 0.95, 0.96, and 1, respectively, , which can predict the generated phases of high-entropy energy alloys well.

Wear behavior of high entropy alloys containing soft dispersoids (Pb, Bi)

Development of cost-effective high-entropy alloys with superior mechanical properties

Structure and tribological behavior of (AlCrNbSiTiV)N film deposited using direct current magnetron sputtering and high power impulse magnetron sputtering

It was found that a large orthorhombic anisotropy is induced in (EuBi) 3 Fe 5 O 12 garnet films grown on (110) NdGG substrates. The Bi content is controlled by regulating the melt composition and the supercooling temperature. Gyorgy's parameter B = ?2(Ku + K p ) increases linearly with the Bi content. The main part of B was found to be growth-induced. Gyorgy's parameter A = K p - K u is very small and almost independent of the Bi content. The growth- and stress-induced parts of A were found to be considerably larger, but of opposite sign, and were found to compensate each other almost completely, although their respective absolute values increased with increasing Bi content. The following were obtained as the magnetic properties of the (Eu 1·8 Bi 1·2 ) 3 Fe 5 O 12 film: saturation magnetization 4?Ms = 1560 G, uniaxial anisotropy K u = 1.6 × 105 erg/cm3, in-plane anisotropy K p = 1.6 × 105 erg/cm3, quality factor Q = 1.7, material length l = 0.06 ?m and wall mobility ?w ?? o = 19 ms?1Oe?1. Such film might be useful as 0.5-?m bubble material for current access devices.

Developments of high strength Bi-containing Sn0.7Cu lead-free solder alloys prepared by directional solidification

The effect of the Bi content on the formation of intermetallic compounds (IMCs) layers between the Sn-xBi-0.9Zn-0.3Ag lead-free solder (with x = 1, 2, 3 and 4, in weight percent, hereafter) and Cu substrate was investigated. The structure of the IMC layer in the soldered interface varies apparently with increasing the Bi content. When the Bi content is 1 wt%, the interface soldered is consisted of CuZn and Cu6Sn5 IMC layers, which are separated by an intermediate solder layer. As the Bi content increases, the spalling phenomenon tends to disappear. Moreover, the layer between the Sn-2Bi-0.9Zn-0.3Ag solder and Cu substrate is thicker than others. The evolution of the soldered interfacial structure could be attributed to the existence of Bi.

In this study the effect of three different nickel concentration on the microstructure, hardness and corrosion properties of high entropy alloys (HEAs) from AlCrFeCoNi system as an alternative material for medical instruments fabrication was investigated. The analyzed HEAs were AlCrFeCoNix obtained by vacuum arc remelting from high purity raw materials and having nickel atomic ratio x = 1.0, 1.4 and 1.8. The microscopy examination revealed the dendritic morphology for the reference alloy (AlCrFeCoNi) and that the extent of the interdendritic areas increased with the concentration of nickel while Cr was more segregated in the interdendritic areas than in dendrites. Hardness values decreased as the percentage of nickel increased due to the dissolution of the precipitates in a nickel-rich matrix and consequently the formation of continuous solid solutions. The corrosion properties of the synthesized HEAs were evaluated using a potentiodynamic polarization method. The alloys were immersed in Simulated Body Fluid during one week and the corrosion parameters were recorded. The low corrosion rates, low corrosion currents and high polarization resistance attest the good stability of these HEAs in simulated biological environment indicating their possible use for surgical and dental instruments.