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Our study investigated the reinforcing effect of submicron-sized (100–500 nm) Al0.5CoCrCuFeNi high-entropy alloy particles (HEAps) on the tensile properties of Al matrix composites. The HEAps were refined to the submicron-sized level via a thermal plasma process to maximize reinforcing efficiency by increasing specific surface (i.e., interface) area. The Al/HEA composites were produced by hot rolling of mechanically milled Al/HEA composite powder. The microstructural analysis demonstrated that the HEAps were uniformly dispersed within the Al matrix by forming a sound interface without interdiffusion brittle intermetallic layers or any noticeable voids. Moreover, the addition of 2 vol% HEAps resulted in a simultaneous increase in both yield strength from 355 to 403 MPa and tensile elongation from 1.3 to 3.3%. As a result, the composite experienced a synergistic effect due to the combination of intrinsic strengthening to promote uniform plastic deformation and extrinsic strengthening to mitigate plastic instability and crack propagation.

The nano-precipitates with minimal misfit strengthen Al–Zn–Mg alloys by impeding dislocation motion. However, grain boundary precipitates (GBPs) are known to have a completely incoherent relationship with the matrix, making them less effective in strengthening the alloys. Instead, GBPs are recognized for preoccupying elements such as Zn or Mg, thereby diminishing the quantity of nano-strengthening phases. GBPs significantly influence the deformation and fracture behaviors of Al–Zn–Mg alloys by accelerating stress localization and crack formation. In this study, we investigated how the accumulation of dislocations in the GBP areas leads to stress localization and subsequent cracking, using micropillar tests and crystal plasticity finite element method (CP-FEM) analysis. The dislocation pile-up in the GBPs causes stress localization around the grain boundaries, inducing crack initiation and leading to intergranular fracture. These findings enhance our understanding of the role of GBPs in the deformation and cracking of Al–Zn–Mg alloys and may pave the way for new concepts in managing GBPs.

The development of thermally conductive lightweight materials holds paramount importance for optimizing heat dissipation in automobile components. This study investigated three distinct techniques for coating graphene onto 6061 Al plates: direct, aluminum nitride (AlN)-aided, and poly-vinyl-alcohol (PVA)-aided coatings. The direct coating approach, via dipping into a graphene suspension, resulted in nonuniform graphene distribution due to the poor wettability of Al with graphene. AlN formation on the surface of a 6061 Al plate before graphene dip coating (AlN-aided coating) considerably improved the wettability of the surface with graphene. When using the PVA-aided coating method, 6061 Al plate was treated with PVA, followed by immersion in a graphene oxide (GO) suspension, achieving uniform GO coverage. This was facilitated by strong bonding between functional groups formed on the plate through treatment with PVA and those present on the GO surface. Directly coated samples exhibited a bonding strength of ∼1 MPa, whereas the samples coated using AlN- and PVA-aided methods showed bonding strengths of ∼3 and ∼10 MPa, respectively. Furthermore, AlN- and PVA-aided coatings improved thermal conductivity by ∼5.6% and ∼8.5%. This study proposes a facile and effective graphene-derivative coating process to improve the heat dissipation of Al-based materials.

Unlike diffusion-mediated chemical short-range orders (SROs) in multi-principal element alloys, diffusionless SROs and their impact on alloys have been elusive. Here, the authors show the formation of strain-induced SROs by crystalline lattice defects, upon external loading at 77 K.

Although the Inconel 706 alloy has been developed to reduce the manufacturing cost for mass production, the effect of post-heat treatment on the deformation mechanisms of this alloy system has not been well investigated yet. In this study, the effect of heat treatment conditions on the plastic deformation behavior of the Inconel 706 alloy was analyzed. The size of the coherent γ'/γ'' co-precipitates in the sample subjected to 3-step aging (3STEP) is larger than that in the sample subjected to 2-step aging (2STEP). However, the yield strength of 3STEP is lower than that of 2STEP due to the precipitate-free zone near its η phase which reduces the volume fraction of the γ'/γ'' co-precipitates. The coarsened η phase in 3STEP also acts as a crack initiation site, inducing intergranular fracture. Meanwhile, serrated flows were observed in the tensile stress-strain curve of 2STEP tested at a high temperature condition, which resulted in ductility degradation. The present result indicates that the different heat treatment conditions for the Inconel 706 alloy affect the morphology of the precipitate in the matrix, which can be attributed to their deformation behaviors.

This paper proposes a novel method to impart intelligence to metal parts using additive manufacturing. A sensor-embedded metal bracket is prototyped via a metal powder bed fusion process to recognise partial screw loosening or total screw missing or identify the source of vibration with the assistance of artificial intelligence (AI). The digital metal bracket can recognise subtle changes in the screw fixation state with 90% accuracy and identify unknown sources of vibration with 84% accuracy. The von Mises stress distribution in the prototyped metal bracket is evaluated using a finite element analysis, which is learned by AI to match the real-time deformation analysis of the metal bracket in augmented reality. The proposed prototype can contribute to hyper-connectivity for developing next-generation metal-based mechanical components.

Abstract An effective method for obtaining large amounts of metal nanoparticles (NPs) encapsulated by carbon layers through upcycling from floating‐catalyst aerosol chemical vapor‐deposited carbon nanotubes is demonstrated. NPs with diameters of less than 20 μm are selectively extracted from the synthesized carbon assortments through sonication, centrifugation, and filtration. The particles show an aggregation behavior owing to the π–π interaction between the graphitic carbon shells surrounding the iron carbides. By controlling the degree of the aggregation and arrangement, the light scattering by the gap‐surface plasmon effect in perovskite solar cells is maximized. Application of the NPs to the devices increased the power conversion efficiency from 19.71% to 21.15%. The short‐circuit current density (JSC) trend over the particle aggregation time accounts for the plasmonic effect. The devices show high stability analogue to the control devices, confirming that no metal‐ion migration took place thanks to the encapsulation.

The core challenge in directed energy deposition is to obtain high surface quality through process optimisation, which directly affects the mechanical properties of fabricated parts. However, for expensive materials like Ti-6Al-4V, the cost and time required to optimise process parameters can be excessive in inducing good surface quality. To mitigate these challenges, we propose a novel method with artificial intelligence to generate virtual surface morphology of Ti-6Al-4V parts by given process parameters. A high-resolution surface morphology image generation system has been developed by optimising conditional generative adversarial networks. The developed virtual surface matches experimental cases well with an Fréchet inception distance score of 174, in the range of accurate matching. Microstructural analysis with parts fabricated with artificial intelligence guidance exhibited less textured microstructural behaviour on the surface which reduces the anisotropy in the columnar structure. This artificial intelligence guidance of virtual surface morphology can help to obtain high-quality parts cost-effectively.

Herein, eco‐friendly natural acids inspired by nature, namely, acetic acid, formic acid, lactic acid, and citric acid on their capability of functioning as a p‐dopant for the carbon nanotube transparent electrode in silicon‐based planar heterojunction solar cells, are tested. From the result, lactic acid shows the multifunctional effect of p‐doping with excellent doping stability as well as antireflection. The doping effect and its stability are investigated by diverse methods, such as van der Pauw four‐probe measurement as well as Raman, photoelectron yield, and absorption spectroscopy. The sheet resistance decreases by 22.1% when carbon nanotube films are doped by lactic acid and the doped films are stable for more than 20 days. The antireflection effect of lactic acid coating is confirmed by atomic force microscopy, ellipsometry, computational analyses, and reflectance spectroscopy. The power conversion efficiency of carbon nanotube‐laminated silicon solar cells improves from 8.2% to 10.3% by using nature‐inspired lactic acid. Such a great improvement is ascribed to not only the p‐doping and antireflection effects but also the passivation effect of lactic acid on the Si surface defect sites as evidenced by both the Fourier‐transform infrared and the Quasi‐steady‐state photoconductance lifetime measurements.

The effects of nanoprecipitations on the mechanical properties of Al-Zn-Mg-Cu alloys after GBF (gas bubbling filtration) and EMS (electromagnetic stirring) casting were investigated. Dendritic cell structures were formed after GBF processing, while globular dendritic structures were nucleated after EMS processing. Equiaxed cell sizes were smaller in the EMS-processed specimens compared to the GBF-processed specimens, confirmed by EBSD (electron backscatter diffraction) analysis. Nanoprecipitations of η′ phases inside of dendrites were observed by TEM (transmission electron microscope), and other Fe-bearing compounds were located in the dendritic boundaries. The yield strength of the T4 and T6 heat-treated specimens was close to 400 MPa and 500 MPa, respectively. Fractographic analysis was performed to investigate the effect of precipitations on tensile fracture.

The current study utilized a two-step laser power bed fusion (LPBF) method to create a heterostructured material (HSM) composed of STS316L and Inconel 718. STS316L enhances ductility, while Inconel 718 improves strength. We examined the tensile deformation behavior of HSMs and found that stress is mainly localized in the cell or grain boundary area. The volumetric ratio of Inconel 718 to STS316L in the HSM affects the tensile properties, although the structural design is crucial for improving tensile strength. Fractographic analysis revealed that fracture occurred and propagated at the STS316L and Inconel 718 interface, with evident unmelted powders due to insufficient energy density. Achieving an optimized process parameter is necessary to ensure a reliable chemical joining which increases the mechanical properties of HSM. [ABSTRACT FROM AUTHOR]