Advanced Engineering Materials最新文献

Composite Metal Foam Behavior

In article number 2401267, Afsaneh Rabiei and Aman Kaushik present a numerical approach to study the performance of composite metal foam (CMF) under compression using smooth particle hydrodynamics modeling of entrapped air inside the porosities of CMF. The numerical and experimental results agree well, opening room to further the fluid–solid interaction study of entrapped air inside the porosities of CMF to effectively predict its performance under a variety of loading scenarios.

Room Temperature Thermal Energy Storage

In article number 2400012, Michael D. Toomey, Jaswinder Sharma, and co-workers demonstrate the first example of wet-spun PCM fibers comprised of a polymer sheath and a salt hydrate core for thermal energy storage applications. Fibers produced using this scalable production method achieve enthalpies of melting of ca. 130 J/g, melting onset at 29°C, and supercooling of 4.8°C while retaining 96.5% of its phase change capacity after 1000 cycles.

Spherical Hexagonal Boron Nitride

In article number 2401027, Seog-Young Yoon, Seunghyup Lee, and co-workers propose a synthetic strategy for submicron-scale spherical hexagonal boron nitride (s-BN) particles using a droplet-based morphology control method. s-BN exhibits superior fluidity, allowing for homogeneous dispersion and alignment within the polymer matrix. s-BN can be applied to thermal management by overcoming the limitations of conventional shapes while preserving its original advantages.

Microreactor-Assisted Soft Lithography

In article number 2401112, Chih-hung Chang and co-workers demonstrate a novel microreactor-assisted soft lithography process to deposit nanostructures with multiscale 3D geometric shapes and fabricate p-n heterojunction with n-type ZnO and p-type CuO. Factors determining the printing process are studied based on COMSOL simulation and experimental results. This novel process enables the scalable fabrication of complicated functional nanostructures on the desired regions using low-cost and facile solution-based methods.

Touch-Spun Nanofibers

In article number 2401022, P. Ravi Selvaganapathy and co-workers present gelatin-zein composite nanofibers formed at high throughput through collectorless touch spinning

Polymer foams and cellular solids have gained significant interest due to their enhanced properties. This study introduces a novel approach by employing foamed fused filament fabrication printing of cellular solids. A composite polylactic acid filament containing chemical blowing agents is used to create structures with varying micro relative density, which is examined through scanning electron microscopy and tensile testing, with comparisons made to a Mori Tanaka analytical model and representative volume elements investigation. Two different types of cellular solid structures, specifically body-centered cubic and Gyroid triple periodic minimal surface structures, have been created with different thicknesses and printed at various temperatures. This is done to attain a range of micro- and macroporosity, leading to samples with equal total relative densities. Compression tests, coupled with finite element analysis, provide insights into the influence of each type of porosity. The fabricated specimens exhibit compressive strengths ranging from 1.07 to 79.14 MPa and elastic moduli ranging from 0.064 to 3.35 GPa. The findings suggest that porous structures relying on macroporosity exhibit higher compressive strength, while those relying on microporosity demonstrate more appealing energy absorption properties, particularly under stresses approaching the plateau region.

This work focuses on understanding the defect-related electronic transport in cadmium sulfide (CdS) thin films, and finds thermal treatment as an efficient tool to tailor its intrinsic defect charge carrier concentration for optimum visible-light photodetection performance. The radio frequency (RF)-sputtered CdS thin-films show a substantial decrease in measured dark-current by three orders of magnitude (μA to nA) with an increase in substrate deposition temperature (T_s) from room-temperature (RT) to a maximum of 400 °C. With increase in T_s, the current conduction behavior changes from Ohmic (at RT) to Schottky-behavior (T_s ≥ 100–400 °C). The decrease in dark-current and the crossover from Ohmic to Schottky electronic transport behavior, pointed to a decrease in defect-density charge carrier concentration, with increased T_s. Additionally, post-deposition thermal annealing of CdS thin films also is found to result in a similar decrease in dark-current (μA to nA). The photo-to-dark-current ratio of CdS thin-film visible-light photodetectors increased by two-orders of magnitude, and its dynamic response time decreased by an order of magnitude via. thermal engineering. The thermal-annealing treatment possibly reduced the defect-related trap-sites, which enables a reliable and faster photo-switching response for CdS thin-film-based visible-light photodetectors.

Thin-film transistors (TFTs) have been studied for their high mobility and stability to facilitate the development of TFT-based touch sensors and electronic devices. A metal capping (MC) layer on the back channel of Si–Zn–Sn–O(SZTO) TFTs has been proposed to improve the electrical properties. MC, when adopted on the channel layer, has low resistance, leading to an improvement in the mobility of the TFT. The mobility of Ti/Al MC TFT has improved from 20.7 to 37.9 cm² V⁻¹ s compared to the pristine TFTs. Applying a potential voltage to the MC layer sensitively modulates the I–V characteristics of the TFT. The present study applies a voltage of 60 mV, similar to that of the human body, to MC-TFTs to explore their possibilities as human touch sensors. The sensitivity and the energy bandgap modulation are also discussed.

This study explores the potential of periodic open cellular structures (POCS) that combine the auxetic and the shape memory effect (SME) with the aim of enhancing heat transfer in catalytic tubular reactors. On the one hand, these structures exhibit a negative Poisson's ratio, contracting perpendicular to the load axis under compression, driven by the rotation of nodes generating complex stress fields. On the other hand, the shape memory alloy (SMA) Nitinol (NiTi) with a reversible strain of up to 8% produced via electron beam powder bed fusion (PBF-EB) shows extraordinary material properties with a high degree of freedom in structure design. The study conducts finite element method simulations and experiments to design POCS with tailored properties. Compression tests on less expensive Ti-6Al-4V POCS compared to NiTi POCS validate the simulative parameter study applied to fabricate novel auxetic hexagonal reentrant structures from NiTi with a unique stacking order and curved struts. The aim of this part of the study is to offer a pathway to design a NiTi auxetic POCS based on validated simulations. Further, it explains the interactions between geometrical parameters and mechanical properties of cellular reentrant NiTi structures. An optimized auxetic NiTi POCS achieved a Poisson's ratio of −1.

Adv. Eng. Mater. 2024, 26, 2400950, https://doi.org/10.1002/adem.202400950

In Figure A3 the top left subfigure should be replaced as it is a duplicate of the center top subfigure. In the below figure, the top left subfigure of Figure A3 is replaced.

We would also like to make an adjustment to the text in section 3.4 Crack Path to better match the new image. In the first paragraph under section 3.4 Crack Path, the text should read:

The difference in crack path between the undeformed material PD0 and PD1 is small. Both show an inclined crack growth, but the crack propagates at a slightly shallower angle for PD1. However, as the degree of predeformation increases to PD3, a marked difference is observed. The crack now propagates closer to the direction of the microstructure alignment resulting from the predeformation, leading to a transverse fracture. For both duplicate PD3 test bars and one of the PD1 test bars, the final fatigue crack length prior to fracture is much shorter compared to the other cases. This indicates that at certain combinations of predeformation, crack geometry, and loading, the effective critical stress intensity is reached at shorter crack lengths.