Advanced Engineering Materials最新文献

ZGH451, a directionally solidified Ni-based superalloy designed for additive manufacturing, has garnered significant attention in the realm of next-generation turbine blades. Welding the ZGH451 superalloy is crucial for promoting its practical application. In this study, transient liquid phase (TLP) bonding is applied to weld ZGH451 superalloy produced through directed energy deposition. A Ni-based interlayer alloy powder is developed and prepared via thermodynamic calculation, with the interlayer subsequently characterized using differential thermal analysis. TLP bonding is conducted at 1200 °C for 4 h. The influence of the preset gap on the joint microstructure and mechanical properties is examined. The microstructure of the TLP bonding joints comprises athermally solidified zones (ASZ), isothermally solidified zones, and diffusion-affected zones. The ASZ width significantly increases with the growing preset gap. A preset gap not exceeding 100 μm enables complete isothermal solidification of the joints. Particularly, joints with a preset gap ranging from 0 to 30 μm demonstrate optimal reliability, exhibiting a tensile strength of up to 1375 MPa at room temperature, which is 12% higher than the room temperature strength of the base metal (BM), and a tensile strength of 983 MPa at 760 °C, surpassing 86% of the BM's strength at the same temperature.

Advancements in polymers have made significant contribution in diverse application-oriented fields. The multidisciplinary application of polymers generates a range of strategies, which is applicable in a wide range of biomedicines. Polymeric compounds such as hydrogels have been explored globally as a potent biomaterial that can furnish essential attributes due to their three-dimensional (3D) soft and highly hydrophilic polymeric network. These hydrogels have been used extensively in various applications due to their biocompatible, biodegradable, and biosorption nature. However, they have some limitations, owing to their soft nature, low mechanical properties, and unsatisfactory degradation profile. Therefore, there is a need to develop novel, stronger, and more durable hybrid hydrogels with enhanced biocompatible and multifunctional properties. The current review gives a broad spectrum of hybrid hydrogels with its importance and significance. Further, the review highlights the strategies of generation of hybrid hydrogels reinforced with nanomaterials, biomaterials, and nanobiocomposites along with their advantages and disadvantages. The review also features various applications of these hybrid hydrogels in the field of biomedicines, photocatalysis, agriculture, and food industry over the last 5 years. This review will give a comprehensive overview to researchers working in the field of hybrid hydrogels development.

The splash of molten Ag under arc erosion is the major reason for the failure of Ag-based contact materials. Changing the size of the molten pool may manipulate the splash process and suppress the arc erosion. Herein, the size effect by fabricating a SnO₂ network with pores smaller than the typical Ag molten pool is investigated. Silver is subsequently infiltrated into the SnO₂ network to form Ag–SnO₂ interpenetrating contact materials. It is found that the SnO₂ network with small pore sizes separates the Ag matrix into smaller regions, reducing the melting volume. Compared with the particle-dispersed one, the interpenetrating composite decreases ≈90% mass loss and temperature rise, as well as provides superior microstructure stability. This finding demonstrates a promising way to improve the arc erosion resistance of contact materials by tailoring the size of molten pool, benefiting long-lifetime contact materials for smart grid applications.

In this study, experiments and finite element modeling (FEM) are performed to study the tensile mechanical properties of SiC particle-reinforced 6061 Al-matrix composites (SiC_p/6061Al) at various volume fractions (VFs) of SiC_p. The Young's modulus, yield strength, and tensile strength of SiC_p/6061Al display an overall upward trend with the increment of the VF of SiC_p. The fracture analysis results demonstrate that the fracture of SiC_p/6061Al is a hybrid of matrix fracture, reinforcement fracture, and interface debonding. An algorithm is developed to construct the mesostructure of particle-reinforced composites, based on the random sequential absorption algorithm. The VFs of the particles of the representative volume element (RVE) model constructed using the novel algorithm are as high as 42%. The tensile mechanical properties of SiC_p/6061Al are predicted by replacing the irregular particle reinforcements in SiC_p/6061Al with spherical particles in the RVE model. Comparisons reveal that the stress–strain curves obtained via experiment and FEM are highly consistent in the elastic-plastic stage, which verifies the effectiveness and rationality of the novel algorithm.

To meet the strength requirements of aluminum/polytetrafluoroethylene (Al/PTFE) in practical applications, tungsten (W) whisker is added into the traditional formula Al/PTFE (26.5%/73.5%) to improve the dynamic compressive strength of the reactive material. Mechanical properties of reactive material specimens prepared by sintering are tested. In the results, it is shown that the dynamic compressive strength of Al/PTFE-reactive material reinforced by tungsten whisker with volume fraction of 13.1% can reach 141 MPa at strain rate of 1800 s⁻¹. The constitutive model of dynamic compression for tungsten-whisker-enhanced Al/PTFE-reactive material is constructed, and the results are basically consistent with the experimental results. The quantitative impact energy release of reactive material specimens under vacuum environment are performed by using the two-stage light gas gun loading system, and the quantitative impact release energies of Al/PTFE-reactive material reinforced by tungsten whisker under different whisker percentage content and diameter are obtained.

The preparation of coatings by atmospheric plasma spraying gives rise to complex physical processes, which present challenges to the study of plasma jet characteristics and particle in-flight behavior. Herein, a 3D numerical model that integrates multiple physical phenomena, including electromagnetism and thermal and gas dynamics, to simulate the heating, acceleration, and melting of particles under the thermal–mechanical effect, is developed. Meanwhile, yttria-stabilized zirconia (YSZ) coatings are prepared under varying process parameters. The DPV-2000 system is employed for the diagnosis of particle velocity, surface temperature, and diameter. Following comparison, the simulation exhibits errors of 4.5% and 14.8% for the maximum temperature and velocity, respectively. An increase in current intensity from 500 to 600 A results in a rise in the proportion of particles exhibiting temperatures above the melting point (2963 K), from 75.1 to 93.4%, accompanied by an increase in average velocity of ≈16.6%. As the spraying distance increases from 60 to 100 mm, the proportion of particles melting decreases from 93.5 to 66.3%, and the average velocity decreases by ≈9.2%. This work will provide a theoretical foundation for the optimization of process parameters to adjust particle behavior and melting state, thus achieving an optimal spraying effect.

The precise manipulation of microdroplets on solid surfaces is crucial for the practical application and future development of microfluidic control technology. Traditionally, methods to achieve precise control over microdroplets often involve complex fabrication processes. Herein, the control of surface wettability is achieved based on the light- and heat-responsive shape memory effect of the microstructure. An innovative superhydrophobic shape-memory material with a simplified and efficient manufacturing process is proposed to precisely control microdroplets through surface wettability switching. Firstly, microplates with shape-memory effects are manufactured using 4D printing technology and polylactic acid as the base material. Then, a mixture of carbon black and epoxy resin is sprayed onto the surface for superhydrophobic modification, resulting in a contact angle of up to 165°. The addition of carbon black endows the surface with excellent photothermal conversion effects. Anisotropy and photothermal response studies are incorporated. Through periodic heating, pressing, and deformation, the microplate array exhibits controllable wettability switching. Based on the shape-memory effect of polylactic acid, the superhydrophobic surface has adjustable adhesion and is successfully applied to microfluidic platforms and microdroplet size screening. This innovative material and process offer significant potential for advancing the field of microfluidic control technology.

In this study, it is attempted to achieve a balanced enhancement of strength and ductility in warm-rolled Fe–30.5Mn–8Al–1.0C (wt%) lightweight austenitic steel through aging treatment. Samples are warm rolled at 350 °C with different reductions of 25%, 45%, and 65%, followed by aging at 600 °C for 10 min. In the results, it is indicated that the 65% reduction sample exhibits an exceptional performance with well-balanced ultimate tensile strength (1610.3 ± 1.2 MPa) and total elongation (16.2% ± 0.6%). Such an excellent strength–ductility match is primarily attributed to deformation twinning, shear band refinement, and κ-carbide precipitation strengthening, which collectively contribute to an improved work-hardening capacity. In this study, the efficacy of combined warm-rolling and aging treatments in optimizing the mechanical properties of Fe–Mn–Al–C steel is highlighted.

The superplastic deformation behavior of 2 mm Ti60 sheet is studied, and the constitutive equation of superplastic deformation is established. The results show that when the strain rate is 5.00 × 10⁻³ s⁻¹ and the temperature is 950 °C, the maximum superplastic elongation reaches 400%. Through the analysis of the true strain–true stress curve, it is found that the average apparent activation energy (Q) is 490.783 kJ mol⁻¹ and the average strain rate sensitivity (m) is 0.49. Dynamic spheroidization (DG) promotes the transformation of lath α phase to equiaxed α phase. Dynamic recrystallization (DRX) promotes the generation of high-angle grain boundaries (θ > 15°). After deformation, the strength of R-type textures changes significantly. From the grip to the tip, the strength of R-type texture gradually weakens, which is mainly caused by the rotation of grains during deformation. The deformation mechanism of Ti60 sheet is dominated by grain boundary sliding, and is coordinated by grain growth, DG, DRX, dislocation motion, and grain rotation.

Laser powder bed fusion (LPBF) involves depositing, melting, and solidifying metal powder particles layer by layer to create 3D components. In this study, a deep fundamental understanding on how process parameters—laser power, scan speed, and hatch spacing—affect the melt pool, densification, microstructure, hardness, and thermal behavior of 420 stainless steel (420SS) parts produced by such technology is provided. The conducted investigation considers five levels of laser power and hatch spacing, and four scan speeds. Optimal single tracks, based on geometry and profile, are achieved with laser powers between 40 and 80 W and a scan speed of 10 mm s⁻¹. In the multitrack analysis, it is indicated that a dense, smooth surface is obtained with a hatch spacing of 250 μm, corresponding to an overlapping rate of ≈30%. The 420SS samples show high densification (≈99%) and low surface roughness (≈3.62 μm). The microstructure consisted of martensite laths and retained austenite. The hardness and thermal conductivity of the samples are measured at 540 HV and 15.3 W m⁻¹ K⁻¹, respectively. In this study, the understanding of the process–structure–property relationships in LPBF of 420SS is expanded.