Abstract Plasmonic color arises from the resonance interaction between light and the metallic surface of nanostructures. Unlike conventional dye-based technologies, plasmonic color offers several advantages, including sub-wavelength resolution, vibrant hues and long-term stability without fading. These properties make plasmonic color promising for applications in multifunctional pattern coloration, anti-counterfeiting labels, and high-density data storage. However, current plasmonic color printing techniques often rely on costly and complex equipment. In this study, we present a novel, reversible plasmonic color-printing technology that combines laser shock processing with heat treatment, providing a highly efficient method for color printing. The results demonstrate that vivid plasmonic colors can be dynamically and reversibly controlled by modulating the geometrical dimensions and crystallinity of the nanostructure. Moreover, through molecular dynamics simulations, the underlying physical mechanism behind the reversible reshaping of metallic nanoparticles is explored in detail. This innovative approach holds significant potential for applications in plasmonic sensors, energy harvesters, and nanolithography systems.

Abstract The present research focuses on the hot deformation behavior, microstructure, texture evolution, and fracture mechanisms of wire arc additively manufactured Inconel 625 alloy. The deposited material exhibits columnar, cellular, and dendritic grain structures, with grain widths ranging between 10 to 40 μm and lengths extending up to 150 μm. Deformation characteristics were studied across a temperature range of 700 to 900°C. At medium temperatures, distinct serrations were observed, transitioning from B-type to C-type as the temperature increased. At elevated temperatures, B-type serrations reappeared, attributed to interactions between C14-Ni2Nb Laves phases and mobile dislocations, as revealed by TEM analysis. Conversely, C-type serrations were associated with the nucleation and growth of deformation twins. Grain size and boundaries under varying deformation temperatures were examined using EBSD and TEM, which revealed occurrence of dynamic recrystallization (DRX). It was observed that preferred orientation for DRX nucleation in the Inconel 625 alloy is along the <001> direction. At 900°C, recrystallized grains were prominent, with EBSD results confirming both discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX), where CDRX acted as a secondary nucleation mechanism. Below 900°C, cracks primarily nucleate due to stress concentrations near Nb-rich phases. At 900°C, crack initiation was influenced by slip band impingement at grain boundaries combined with stress concentrations around Nb-rich phases. The high-temperature deformation behavior of WAAM-deposited Inconel 625 is strongly influenced by the interplay of DDRX and CDRX mechanisms.

Abstract Biomass–fungi composites offer renewable, biodegradable, and energy-efficient alternatives to conventional petroleum-derived plastic materials. These composites are produced by combining lignocellulosic biomass with filamentous fungal mycelium, which naturally binds and interconnects biomass particles into products. Their mechanical, thermal, and acoustic properties can be tailored through fungal strain selection, substrate composition, and processing conditions, making them suitable for applications in packaging, construction, furniture, and insulation. The integration of biomass–fungi composites into additive manufacturing has further expanded their potential, enabling the fabrication of products with complex shapes. However, printing biologically active mixtures introduces unique challenges, including control of rheological behavior, maintenance of fungal viability, and optimization of interlayer bonding. This review summarizes recent progress in the bioink formulation, pre-/post-processing, and 3D printing of biomass–fungi composites, highlighting the relationships between feedstock preparation, printing parameters, and resulting structural and functional properties. Finally, it outlines opportunities to enhance printability, scalability, and emerging functionalities, providing a roadmap for advancing biomass–fungi composite materials toward industrial applications.

Abstract Lasers are widely applied in modern industries, ranging from subtractive machining to additive manufacturing. Pulsed laser technology has significantly advanced precision machining, particularly for hard or refractory materials that are challenging to process using conventional methods. Cemented carbides exemplify such materials, serving as essential components in cutting tools and wear-resistant parts. In practice, these carbides are frequently coated to enhance wear resistance and extend service life. Previous studies show that nanosecond lasers could improve the performance of coated cemented carbides but induced microscale thermal side effects. Femtosecond lasers can minimize these effects, reducing issues like melting and pore formation. This study examines the surface and mechanical integrity of femtosecond-laser-machined cemented carbides with subsequent PVD coating. Vickers hardness, micro-scratch testing, and post-scratch topographical analysis were applied to evaluate coating performance and surface integrity. Results show that femtosecond laser processing minimally alters surface integrity, causing only slight changes in roughness, morphology, and microstructure. It enhances hardness and scratch resistance compared to untreated samples. In particular, low-energy processing, especially with perpendicular sliding across laser-induced features, further boosts coating performance.

Abstract Surface severe plastic deformation (SSPD) techniques have been widely used to enhance the surface integrity and mechanical performance of metallic materials via modifying surface microstructures and introducing compressive residual stress. In this study, we applied an electro-magnetic (EM) compound field to assist a deformation-based surface strengthening technique known as ultrasonic nanocrystal surface modification (UNSM). EM assisted UNSM outperforms its electric- or magnetic-assisted counterparts by producing a synergistic effect during processing, which leads to significant improvements in the surface hardness and the depth of the compressive residual stress layer in Ti64. X-ray diffraction (XRD) analysis and viscoplastic self-consistent (VPSC) modeling further revealed that the EM field promotes the activation of <c+a> dislocations, which facilitates strain accommodation and weakens crystallographic texture. These findings provide new insights into plasticity control of hard-to-deform metals, with promising implications for advanced forming and surface treatment technologies.

Abstract Diamond turning is a mainstream technology for fabricating microstructured surfaces with high form fidelity. However, traditional systems utilizing either the slow slide servo (SSS) or fast tool servo (FTS) are constrained by inherent trade-offs between the stroke capacity and control bandwidth of a single servo axis, restricting achievable machining performance. To address these limitations, this work proposes a novel discrete Fourier transform-based parallel tool servo (DFT-PTS) diamond turning process, enabling coordinated control within a dual-stage feed drive system. In the proposed process, the initial tool trajectory is decomposed into low- and high-frequency components using the DFT and its inverse, with the low-frequency trajectory assigned to the SSS axis and the high-frequency trajectory to the FTS axis. A frequency response data-based simulation procedure is developed to determine the optimal cut-off frequency for trajectory decomposition. Experimental results on a three-axis ultra-precision machine tool equipped with a customized FTS axis show that the proposed DFT-PTS process significantly improves tracking performance. When applied to turning composite microlens arrays, the DFT-PTS process achieves a 49% reduction in peak-to-valley form error and a 52% reduction in root-mean-square form error compared with conventional geometry-based trajectory decomposition methods. These results confirm that the proposed method can simultaneously improve machining accuracy and efficiency, offering strong potential for industrial applications in ultra-precision manufacturing of microstructured optical surfaces.

Abstract The Microscale Selective Laser Sintering (μ-SLS) system is a microscale powder bed fusion (PBF) technology capable of producing fine-resolution, high aspect ratio copper interconnect structures for use in semiconductor packaging and MEMS fabrication. Despite these capabilities, the feature resolution of the μ-SLS system is currently limited by unwanted heat transfer in the nanoparticle bed during laser sintering. A full part-scale thermal model has been developed to predict the thermal evolution in the sintering particle bed in response to a given laser exposure pattern and sintering duration. A thin copper particle layer is modeled atop a thick glass substrate to simulate the sintering domain, and previously developed nanoparticle property relationships allow the model to capture material property changes that accompany nanoparticle sintering. The model is used to predict both temperature change and part densification in response to a variable laser exposure pattern. These temperature and part predictions provide the information needed to pre-optimize laser exposure patterns and reduce unwanted heat spread and sintered part error.

Abstract Achieving high-throughput production without sacrificing quality remains a critical challenge in extrusion-based additive manufacturing. Traditional approaches rely on real-time sensing for feedback control of process parameters that indirectly reflect printing quality. Many extrusion printers lack online monitoring systems, making such closed-loop solutions to direct quality control impractical. This article proposes a framework which enables adjustments of kinematic parameters such as printing speed and acceleration along different regions of printing paths to compensate for defects. To make this planning process computationally feasible, this article discovers and leverages process knowledge that links fast printing-induced defects to infill slicing patterns. This insight enables a targeted, localized search for compensation strategies, drastically reducing the design space for planning. A two-scale adjustment for compensation is developed to reduce the printing time. At a global scale, the method identifies how the base setting affects the spatial distribution of defects. At a local scale, it adjusts the base setting in regions prone to defects. The cloud framework enables the sharing of Bayesian models to achieve compensation using just very limited user-provided samples. It rapidly updates printing plans and estimates defect regions, optimal compensation, and production time. Our case studies show that local-scale compensation through speed adjustment in different part designs and commercial printers reduces the printing time by an average of 54% without introducing infill defects. Moreover, the proposed two-scale compensation through cloud-based model adaptation achieves reductions of up to 65%.

Abstract Enhancing stiffness of thin-walled workpieces is essential to suppress chatter during milling, and applying pre-bending on workpieces is an effective method to achieve this. A semi-analytical dynamic model based on the variational method is developed to uncover how pre-bending curvature and direction modulate dynamic stiffness and milling stability. A fixture-based pre-bending technique is then applied to maintain the workpiece in its bent configuration during milling. Numerical analysis confirms the stiffness enhancement is generally applicable across various geometries, with the first natural frequency increased in all simulated cases and the increase exceeding 110% in high aspect ratio cases. Stability simulations indicate that pre-bending expands the stable spindle-speed range, easing parameter selection under uncertainty. Experimental results show a transition from an unstable to a stable milling state at a spindle speed of 8000 rpm. The results validate the established dynamic model and demonstrate that applying pre-bending technique, with theoretically guided selection of curvature and direction, significantly improves milling stability.

Abstract With the growing demand for lightweight and high-strength structures in fields such as aerospace and automotive engineering, aluminum alloy/steel (Al/steel) hybrid structures, combining the low density of Al with the high strength of steel, have gained widespread applications. Focusing on Al–steel friction welding, this review explores metallurgical evolution and control methods in this solid-state joining process characterized by low heat input and high joint strength. However, significant differences in physical and metallurgical properties often lead to interfacial challenges, including the formation of brittle intermetallic compounds, residual stresses, and structural inhomogeneities. This review highlights research advances made over the past decade in thermomechanical regulation, interfacial metallurgical optimization, and novel assisted welding techniques. Furthermore, strategies such as geometric interface design, interlayer insertion, and the development of novel three-body friction welding configurations are discussed as effective methods to improve joint quality and reliability. It also identifies the key challenges in quality control for welding large-scale components and in evaluating the service performance of dissimilar joints. Overall, this review provides valuable control strategies and outlines future research directions for achieving high-reliability Al/steel friction welds.