The effect of off-stoichiometry on the microstructures and tensile properties of Ni3Al–Ni3V pseudo-binary alloys was investigated by a scanning electron microscope, a transmission electron microscope, Vickers hardness test, and high-temperature tensile test. As the alloy deviates from a just-stoichiometric composition toward Ni-rich one, the microstructures constituted by two ordered phases, Ni3Al and Ni3V changed to those constituted by two ordered phases, Ni3Al and Ni3V, and one disordered phase, Ni solid solution. Also, the deviation from the stoichiometric composition resulted in a decrease in flow strength as well as Vickers hardness and conversely increase in tensile elongation. Higher tensile elongation in the off-stoichiometric alloys was induced by the transition from intergranular fracturing to transgranular fracturing. The trade-off relation in the yield strength (or hardness) versus tensile elongation curve, which was drawn plotting the data obtained from the alloys with different off-stoichiometric compositions, was most excellent at 600 °C but rapidly became worse at high temperatures beyond 600 °C. It was demonstrated that the deviation to the off-stoichiometric composition in the two-phase Ni3Al–Ni3V pseudo-binary alloy system was a useful alloying parameter to improve the balance of the flow strength and tensile ductility.

In the present work, Mo was added to an Al–Si–Mg foundry alloy to study its influence on the evolution of dispersoids during various heat treatments. The microhardness and the elevated-temperature tensile properties and creep resistance were measured to evaluate the contribution of dispersoids. Results showed that the addition of Mo greatly promoted the formation of α-dispersoids. During solution treatment, the formation of α-dispersoids started after 8 h at 500 °C. At high temperature (540 °C), the coarsening of dispersoids with increasing time became predominant. The optimum condition of dispersoids can be reached by 520 °C/12 h or 500 °C/4 h + 540 °C/2 h, leading to the highest differences in microhardness between the Mo-containing alloy and base alloy. The tensile strengths were improved at both room temperature and elevated temperatures, while the elongation at elevated temperature was greatly increased. The creep resistance at elevated temperature is further enhanced due to the Mo addition.

In the present work, a β-Ti alloy (Ti–15V–3Sn–3Cr–3Al) was unidirectionally cold rolled to 80% thickness reduction, followed by recrystallization at two temperatures: (i) 1013 K and (ii) 1053 K. The microstructural developments were studied using light optical microscopy, scanning electron microscopy X-ray peak profile analysis, and electron backscattered diffraction. The bulk texture of deformed and fully recrystallized samples was studied using X-ray diffraction. The deformed microstructures showed the presence of high fraction of shear bands, and these bands were preferentially formed in γ-fiber grains than in the grains with other orientations. Cold rolled β-Ti alloy samples were fully recrystallized in 10 min at 1053 K and in 90 min at 1013 K. Strong α- and γ-fibers were formed after 80% cold rolling, while strong discontinuous γ-fiber (with very strong {111}〈112〉 component) was formed after complete recrystallization. Oriented nucleation was found to be the dominant mechanism for the development of recrystallization texture.

To simulate the effects of hot working parameters on microstructure and flow resistance during dynamic recrystallization (DRX) of a Ni–Cr–Mo-based C276 superalloy, a 2D mesoscopic model has been established using cellular automaton (CA) method. The isothermal hot compression tests were performed on a Gleeble 1500 thermal-mechanical simulator at the temperature range of 1273–1473 K and strain rate range of 0.001–5 s−1. The flow stress behaviors were then obtained and the microstructures of quenching specimen were observed after compression. Then the dislocation density evolution, nucleation and grain growth during hot compression were determined from experiments and integrated to the CA model. The topology of microstructure evolution and deformation resistance were calculated using the developed CA model and compared with the experimental ones. The CA simulation results show reasonable agreements with the experiments, implying the developed CA can capture the effects of processing parameters on the DRX behavior of C276 superalloy.

In this paper, the hardness and Young’s moduli along the diffusion paths in fcc Ni–X (X = Rh, Ta, W, Re, Os, and Ir) binary diffusion couples were measured by using the nanoindentation technique. Hardness increases gradually from the pure Ni to the fcc Ni–X alloys, except for the Ni–Os system. While the Young’ moduli in fcc Ni–X alloys scatter much larger and do not show noticeable variation with the addition of element X. After that, the CALPHAD models for description of the composition-dependent hardness and Young’s modulus were proposed, and an in-house code was developed. Based on the present experimental data, the CALPHAD-type descriptions for hardness and Young’s modulus in fcc Ni–X (X = Rh, Ta, W, Re, Os, and Ir) systems were obtained. The model-predicted hardness and Young’s moduli of composition dependence agree with the experimental data in general. It is anticipated that the presently obtained CALPHAD-type hardness and Young’s modulus descriptions, together with the previous thermodynamic and atomic mobility databases, can be used for the future alloy design of novel Ni-based superalloys.

In the present work, mechanical, tribological, and electrochemical behaviors of Al Alloy 6061–(0–10) % B4C–(0.25–1.2) % graphene nanoplatelets (GNPs) composites, prepared by a combination of solution mixing and powder metallurgy, were investigated. Properties such as hardness, compressive strength, wear rates, and coefficient of friction (COF) were used to investigate the effects of GNPs on mechanical and self-lubricating tribological behavior. The corrosion resistance of composites was investigated using potentiodynamic polarization and electrochemical impedance techniques. Scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDS), and EDS mapping were employed to study the distribution, the fracture profile, and wear mechanism. The AA 6061–10% B4C–0.6% GNPs composites exhibited sharp increase in hardness and compressive strength and significant decrease in wear rates and COF. However, for GNPs contents exceeding over 0.6 wt%, mechanical properties and wear performances deteriorated. Pulling out of sheared pultruded GNPs was observed during the fracture of composites. Worn surfaces of GNPs-containing composites showed the smeared graphene layer with some macro-cracks exhibiting delamination wear. It was found that the corrosion inhibition efficiency of GNPs was more pronounced in H3BO3 environment than in NaCl solution.

Two rapidly solidified (RS) Mg ribbons with the compositions of Mg97Zn2Gd1 and Mg90Zn5Gd5 (at.%) were first prepared by the planar flow casting method. These RS ribbons were subsequently consolidated by spark plasma sintering (SPS). The use of SPS on the RS ribbons was demonstrated to be an effective processing route to control W-phase precipitation process while keeping fine grains. The size of W-phase particles was less than 200 nm in Mg97Zn2Gd1 alloy and smaller than 500 nm in Mg90Zn5Gd5 alloy. The content of W phase was approximately 34 vol% and 41 vol% in the two SPS bulks, respectively. The compressive properties showed that the yield compressive stress (YCS) and ultimate compressive stress of the Mg97Zn2Gd1 alloy reached 200 MPa and 390 MPa, respectively, and an elongation of 0.24. The corresponding values for the Mg90Zn5Gd5 alloy were 313 MPa, 504 MPa, and 0.14, respectively. Based on the results of the quantitative analysis, W-phase nanoparticles with size less than 100 nm exhibited obviously strengthening effect in the Mg alloys. It highlighted that the W-phase nanoparticles contributed a large proportion of the YCS in the Mg97Zn2Gd1 alloy and a relatively small proportion for that of the Mg90Zn5Gd5 alloy.

A novel solid-clad-by-liquid method was developed to form a 10-m long by 10-mm wide by 80-μm thick Ni–5 at.% W/Ni–9.3 at.% W/Ni–5 at.% W composite tape. Three deformation routes (cold rolling, cold rolling with intermediate annealing, and cold rolling combined with warm rolling) have been investigated in short Ni–5 at.% W/Ni–9.3 at.% W/Ni–5 at.% W composite substrate. To optimize the dynamic continuous annealing parameters for the long composite substrates, air-cooled and furnace-cooled annealing procedures were compared in short Ni–5 at.% W/Ni–9.3 at.% W/Ni–5 at.% W composite substrates. Improved cube texture of 98.7% in a 10-m long by 10-mm wide by 80-μm thick Ni–5 at.% W/Ni–9.3 at.% W/Ni–5 at.% W composite substrate was achieved via warm rolling deformation at 550 °C and two-step dynamic continuous annealing (750 °C for 1 h followed by 1200 °C for 1 h). The yield strength, Curie temperature, and saturation magnetization of 176 MPa, 324 K, and 18 emu/g, respectively, were obtained.

Hot extrusion experiments were conducted on Al–5.50Zn–2.35Mg–1.36Cu (wt%) alloy under various temperatures and extrusion speeds. Results indicated that dynamic recovery occurred at low temperature and then dynamic recrystallization was triggered at higher temperature or speed. High billet temperature reduced the grain size and increased the volume fraction of Al23CuFe4 and AlMgZn. When the extrusion speed was enhanced to 0.5 mm/s, the peak of MgZn2 phase diminished in the results of X-ray diffraction. The strong brass and S components appeared in all the extruded specimens. Texture intensity gradually decreased with increasing temperature and the fraction of texture components was also significantly affected by the extrusion parameters. The extruded alloy exhibited the highest ultimate tensile strength of 350.2 MPa at 480 °C and 0.5 mm/s and the best elongation of 16.78% at 520 °C and 0.1 mm/s. Moreover, the extrusion speed had more significant effects on the tensile properties than that of the temperature.

The improvement of hydrogen embrittlement (HE) is a key problem for transition-metal silicides. Although C40 TMSi2 disilicides are attracted candidates for ultrahigh-temperature applications, the HE mechanism of TMSi2 is unclear. Importantly, the role of hydrogen on the structural configuration, elastic modulus, and hardness of TMSi2 is entirely unknown. To reveal the HE, we study the role of hydrogen in TMSi2 (TM = Nb, Mo, and W) based on the first-principles calculations. Four H-doped sites are considered in detail. The calculated results show that hydrogen is favorable to occupy the octahedral interstitial site because the C40 TMSi2 layered structure is favorable to absorb hydrogen. H-doping results in lattice expansion of c-axis compared with the a-axis and b-axis. H-doping obviously reduces the elastic modulus and hardness of TMSi2 due to the interaction between hydrogen and TMSi2. In addition, H-doping changes the electronic properties of MoSi2 and WSi2.

Nano-forms of copper oxides (CuO and Cu2O) are potential candidates in the field of energy conversion and storage. Low temperature and controlled growth of three-dimensional nanostructured hierarchical assembly of CuO over Cu2O is reported here with demonstrated advantage in energy conversion and storage applications. Electrodeposited Cu2O is partially oxidized in an alkali bath to two different forms of hierarchical nanostructures (HNS): CuO/Cu2O and CuO:Cu(OH)2/Cu2O. Randomly oriented nanorods and nanoflakes with high surface area tussock-like nanostructure are formed during oxidation at room and at elevated temperatures, respectively. The nanoflake morphology exhibits a high surface area of 85.82 m2/g and sufficient ion percolation pathways, leading to an efficient electrode–electrolyte interface for electrochemical energy devices. A favorable conduction and valence band alignment in the HNS with respect to water redox level along with fast electron diffusion time of 0.8 μs make it an ideal photocathode.

Iron sulfides have attracted much interests for their potential as anode materials in energy storage devices in view of their low costs, and environmentally benign and high theoretical capacities. Among them, Fe1−xS is relatively rarely investigated. In this work, Fe1−xS@rGO has been synthesized using a facile in situ hydrothermal method. After wrapped by rGO, the morphology of Fe1−xS particles changes from hexagonal flakes to irregular particles with much smaller sizes. As the anode material for lithium ion batteries, Fe1−xS@rGO exhibits excellent lithium storage ability. It can deliver an initial discharge capacity of 1575.5 mA h/g in the potential window of 0.005–3 V, and a reversible capacity of 907.8 mA h/g can be maintained after 200 cycles at 100 mA/g. Its improved electrochemical performance can be attributed to the effect of enhanced contact area and shortened Li+ ion transport distance because of rGO’s contribution.

A supercapacitor electrode featured with a voltage self-stabilizing capability is demonstrated by growing indium tin oxide (ITO) nanowires on Ni foam. The ITO nanowires with a single crystal structure are prepared by using magnetron sputtering technique, and they can act as an active electrode material. Charging–discharging experiments are performed under different current densities, demonstrating a good rate capability. Using properly designing top and bottom double connection circuits, part of the electrode can be used as a resistance switch. An electrode that can function as a supercapacitor and a resistance switch is fabricated. Detailed characteristics confirm that the device not only exhibits high performance as a supercapacitor but also has good characteristics of resistance switching (RS). The specific capacitance is 956 F/g at the scanning rate of 10 mV/s, and the switching ratio as a bipolar resistance switch is as high as 102. The stabilization time of discharging voltage is nearly doubled longer than that without any RS function, revealing the potential application of our devices, which can be used as a supercapacitor with voltage self-stabilizing.

Metal oxides are promising candidates as the anodes of next-generation lithium ion batteries. However, the low electronic conductivities hinder their practical applications. Herein, through a facile calcination process using ammonium bicarbonate (NH4HCO3) as the N source, the nitrogen heteroelement was introduced into the ZnO/CoO micro-/nanospheres, which greatly improves the conductivity of the composites. As the lithium-ion battery anode, the N-doped ZnO/CoO micro-/nanosphere demonstrates much enhanced electrochemical performance. It displays a high initial capacity of 911.8 mA h/g at a current density of 0.2 A/g and long-term cycling stability, with a reversible capacity of 977.8 mA h/g remained after 500 cycles at a current density of 1 A/g. Furthermore, the N-doped ZnO/CoO composite presents an outstanding rate performance, with 605 mA h/g remained even at 5 A/g. The excellent electrochemical properties make N-doped ZnO/CoO micro-/nanospheres a promising candidate as high-performance anodes for next-generation rechargeable LIBs.

The physicochemical properties and broad applications of graphene have been extensively studied, but its preparation method is still a bottleneck, and it cannot simultaneously meet the requirements of low process cost and high quality of products in the time being. In this article, the redox potential was employed to control the quality of graphene prepared from graphene oxide by chemical reduction. The effects of the initial redox potential on the productivity, microscopic morphology, and structural and intrinsic properties of graphene were investigated. Results showed that there was an optimum initial redox potential range between −1200 and −1180 mV. In such a range could the graphene with a high yield be obtained, and layers of graphene products could be stabilized at 1 or 2 layers. Therefore, the redox potential could be used as an effective parameter instead of trying to design orthogonal tests to determine the optimal conditions and control the synthesis of graphene.

Heterogeneous photocatalytic oxidation technology is currently a technology with the potential to solve environmental pollution and energy shortages. The key to this technology is to find and design efficient photocatalysts. Here, a series of inorganic coordination polymer quantum sheets (ICPQS)@graphene oxide (GO) composite photocatalysts are synthesized by adding GO to the synthesis process of ICPQS: {[CuII(H2O)4][CuI4(CN)6]}n. These composite photocatalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, cyclic voltammetry, scanning electron microscopy, transmission electron microscopy, Zeta potential, and N2 adsorption/desorption isotherms. The photocatalytic degradation of methylene blue showed that the activity of ICPQS@GO composite photocatalysts is better than that of ICPQS. Among ICPQS@GO composite photocatalysts, the 10.6% ICPQS@GO composite photocatalyst has the best activity, which can reach 3.3 mg/(L min) at pH 3. This method of loading low–specific surface area photocatalysts onto GO to improve photocatalytic performance indicates the direction for the synthesis of highly efficient photocatalysts.

The development of stable and effective earth-abundant metal oxide electrocatalysts is very crucial to improve competence of water electrolysis. In this study, iron manganite (FeMnO3) nanomaterials were synthesized as an affordable electrocatalyst for water oxidation reactions. The structural and chemical properties of FeMnO3 nanomaterials were studied by transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray, X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma-optical emission spectrometry, and Brunauer–Emmett–Teller analyses. The microscopy analyses show that the synthesized material has wire morphology, and assembly of approximately 70 nm nanocrystallites forms the wires. XRD patterns confirmed the bixbyite structure of FeMnO3. The potential utility of the synthesized FeMnO3 nanowires (NWs) as an electrocatalyst for oxygen evolution reaction (OER) was investigated in alkaline medium. The FeMnO3 NW modified fluorinated tin oxide (FTO) electrodes demonstrated promising OER activity with onset potential of 1.60 V versus reversible hydrogen electrode and overpotential of 600 mV at 10 mA/cm2 catalytic current density. FeMnO3 NW modified FTO electrode was also observed to be stable during long-term constant potential electrolysis. Therefore, this new material can be considered as a cost-effective alternative to noble metal electrocatalysts for water oxidation and other possible catalytic reactions.