Crystal Plasticity Simulation of Cyclic Behaviors of AZ31B Magnesium Alloys via a Modified Dislocation-Twinning-Detwinning Model.

In this study, a probabilistic model within the dislotwin constitutive framework of DAMASK (the Düsseldorf Advanced Material Simulation Kit) was established to describe the cyclic loading behaviors of AZ31B magnesium alloys. Considering the detwinning procedure within the twinned region, this newly developed dislocation-twinning-detwinning model was employed to accurately simulate stress-strain behaviors of AZ31B magnesium alloys throughout tension-compression-tension (T-C-T) cycle loading. The investigations revealed that the reduction in yield stress during the reverse loading process was attributed to the active operation of twinning and detwinning modes.

Simulation of Friction Stir Welding of AZ31 Mg Alloys.

Friction stir welding has been extensively applied for the high-quality bonding of Mg alloys. The welding temperature caused by friction and plastic deformation is essential for determining the joint characteristics, especially the residual stress and weld microstructure. In this work, a modified moving heat source model was proposed by considering the variations in heat generation caused by friction shear stress at both the side and bottom surfaces of the tool.

Laser Welding of Titanium/Steel Bimetallic Sheets with In Situ Formation of Fe(CoCrNiMn)Ti High-Entropy Alloys in Weld Metal.

Due to the notable disparities in the physical and chemical characteristics between titanium and steel, the direct fusion of titanium/steel bimetallic sheets results in a considerable formation of fragile intermetallic compounds, making it difficult to achieve excellent metallurgical welded joints. In this study, a multi-principal powder of CoCrNiMn was designed and utilized as a filler material in the welding of the TA1/Q345 bimetallic sheet. It was expected that the in situ formation of Fe(CoCrNiMn)Ti high-entropy alloys would be achieved using the filler powders, combined with the Ti and Fe elements from the melting of the TA1 and Q345 so as to restrain the generation of Fe-Ti IMCs and obtain the promising welded joints of the TA1/Q345 bimetallic sheet.

Elucidating the origin of catalytic activity of nitrogen-doped carbon coated nickel toward electrochemical reduction of CO.

Converting CO into valuable chemicals and fuels through clean and renewable energy electricity provides a way to achieve sustainable development for human societies. In this study, carbon coated nickel catalysts (Ni@NCT) were prepared by solvothermal and high-temperature pyrolysis methods. A series of Ni@NC-X catalysts were obtained by pickling with different kinds of acids for electrochemical CO reduction reaction (ECRR).

Effective Removal of Fe (III) from Strongly Acidic Wastewater by Pyridine-Modified Chitosan: Synthesis, Efficiency, and Mechanism.

A novel pyridine-modified chitosan (PYCS) adsorbent was prepared in a multistep procedure including the successive grafting of 2-(chloromethyl) pyridine hydrochloride and crosslinking with glutaraldehyde. Then, the as-prepared materials were used as adsorbents for the removal of metal ions from acidic wastewater. Batch adsorption experiments were carried out to study the impact of various factors such as solution pH value, contact time, temperature, and Fe (III) concentration.

HO modified peanut shell-derived biochar/alginate composite beads as a green adsorbent for removal of Cu(II) from aqueous solution.

In this study, a novel composite bead (MPB-ALG) was prepared by encapsulating HO modified peanut shell-derived biochar (MPB) into alginate matrix through a facile method. The structure and properties of prepared materials were characterized using FTIR, BET, SEM, and XPS. Batch adsorption experiments were performed to compare the Cu(II) adsorption performance of MPB, plain alginate beads (ALG), and MPB-ALG.

Transient Liquid Phase Diffusion Bonding of NiAl Superalloy with Low-Boron Nickel-Base Powder Interlayer.

As a technology for micro-deformed solid-phase connection, transient liquid phase (TLP) diffusion bonding plays a key role in the manufacture of heating components of aero engines. However, the harmful brittle phase and high hardness limit the application of TLP diffusion bonding in nickel-based superalloys. In this paper, a new strategy in which a low-boron and high-titanium interlayer can restrain the brittle phase and reduce the hardness of the TLP-diffusion-bonded joint is proposed.

Adsorption Performance of Methylene Blue by KOH/FeCl Modified Biochar/Alginate Composite Beads Derived from Agricultural Waste.

In this study, high-performance modified biochar/alginate composite bead (MCB/ALG) adsorbents were prepared from recycled agricultural waste corncobs by a high-temperature pyrolysis and KOH/FeCl activation process. The prepared MCB/ALG beads were tested for the adsorption of methylene blue (MB) dye from wastewater. A variety of analytical methods, such as SEM, BET, FTIR and XRD, were used to investigate the structure and properties of the as-prepared adsorbents.

Microstructure evolution and grain refinement of ultrasonic-assisted soldering joint by using Ni foam reinforced Sn composite solder.

In this investigation, ultrasonic-assisted soldering at 260 °C in air produced high strength and high melting point Cu connections in 60 s using Ni foam reinforced Sn composite solder. Systematically examined were the microstructure, grain morphology, and shear strength of connections made with various porosities of Ni foam composite solders. Results shown that Ni foams as strengthening phases could reinforce Sn solder effectively.

Investigation of the Tribological Behavior and Microstructure of Plasma-Cladded Fe-Cr-Mo-Ni-B Coating.

In this study, an Fe-Cr-Mo-Ni-B coating was prepared using plasma cladding on Cr5 steel substrate. The microstructure, phase evolution and tribological performance of the Fe-Cr-Mo-Ni-B coating were investigated. The microstructure is mainly composed of MoFeB, FeB, α-Fe, γ-Fe and MoB.

Microstructural Characteristics and Hardness Enhancement of Super Duplex Stainless Steel by Friction Stir Processing.

In the present study, microstructural evolution and hardness of the friction stir processed (FSPed) SAF 2507 super duplex stainless steel fabricated at a rotational speed of 650 rpm and a traverse speed of 60 mm/min were investigated. A scanning electron microscope (SEM) equipped with an electron backscatter diffraction (EBSD) detector was used to study the microstructure of the stir zone. The grain sizes of austenite and ferrite in the FSPed 2507 were found to be smaller (0.

Effect of Dynamic Preheating on the Thermal Behavior and Mechanical Properties of Laser-Welded Joints.

The high cooling rate and temperature gradient caused by the rapid heating and cooling characteristics of laser welding (LW) leads to excessive thermal stress and even cracks in welded joints. In order to solve these problems, a dynamic preheating method that uses hybrid laser arc welding to add an auxiliary heat source (arc) to LW was proposed. The finite element model was deployed to investigate the effect of dynamic preheating on the thermal behavior of LW.

Wire + Arc Additive Manufacturing and Heat Treatment of Super Martensitic Stainless Steel with a Refined Microstructure and Excellent Mechanical Properties.

Due to the advantages of relatively low cost, increased energy efficiency, increased deposition rate, and the capacity to create medium to large scale components, wire + arc additive manufacturing (WAAM) has gained growing interest. Super martensitic stainless steel (SMSS) combines outstanding strength, ductility, and corrosion resistance, making it a great option for WAAM. In the present work, an SMSS component was successfully produced by WAAM.

Visible-light-driven photocatalytic N fixation to nitrates by 2D/2D ultrathin BiVO nanosheet/rGO nanocomposites.

Photocatalytic nitrogen fixation is a promising approach owing to its environmental friendliness and cost-effectiveness. The 2D/2D BiVO/rGO hybrid developed in this study exhibits a high nitrate-production rate of 1.45 mg h g and an apparent quantum efficiency (QE) of 0.

Preparation of Graphene Oxide/LaTiO Composites with Enhanced Electrochemical Performances for Supercapacitors.

A series of graphene oxide (GO)/lanthanum titanate (LaTiO LTO) fiber composites were prepared through a hydrothermal method. The LTO fibers were homogeneously dispersed between the GO sheets. The structure and micromorphology of the GO/LTO composites were systematically studied.

Preparation and Properties of an Ultrahigh-Energy-Density Aqueous Supercapacitor with a Superconcentrated Electrolyte and a Sr-Modified Lanthanum Zirconate Flexible Electrode.

Although supercapacitors are considered to play a vital role in flexible electronic devices, there are still some problems that need to be overcome, such as low energy density and narrow electrochemical stability windows in aqueous electrolytes. Herein, we have successfully synthesized a series of Sr-modified LaZrO (LZO-) nanofibers as a new electrode material by a facile electrospinning technique. To determine the best doping sample, the changes in structures and electrochemical performances of LaZrO (LZO-) nanofibers with various Sr contents are investigated carefully.

Mechanistic Insights into the Electrochemical Reduction of CO and N on the Regulation of a Boron Nitride Defect-Derived Two-Dimensional Catalyst using Density Functional Theory Calculations.

Electrochemical reductions of CO (ECRR) and N (ENRR) can not only reduce CO emissions in the air but also make use of N and HO, the most extensive resources on earth, to produce high value-added chemicals, which has become one of the hot research directions. In this study, the formation energy () and dissolution potential () of 96 two-dimensional catalysts derived from different defect sites of monoclinic crystal boron nitride (BN) were calculated, and the catalysts with thermodynamic and electrochemical stability were selected. The suitable catalysts for producing HCOOH (Ga/In@N-BN), CO (Sn@BN), and CHOH (Co@N-BN) by ECRR and NH (Fe@BN) by ENRR were predicated based on a selective calculation method.

Nano-Mechanical Properties and Creep Behavior of Ti6Al4V Fabricated by Powder Bed Fusion Electron Beam Additive Manufacturing.

Effects of scanning strategy during powder bed fusion electron beam additive manufacturing (PBF-EB AM) on microstructure, nano-mechanical properties, and creep behavior of Ti6Al4V alloys were compared. Results show that PBF-EB AM Ti6Al4V alloy with linear scanning without rotation strategy was composed of 96.9% α-Ti and 2.