Xiaoyu Ding

Enhancing the strength–ductility synergy of Inconel 718 alloy is critical for its reliable use in high-performance components such as aero-engine turbines. In this study, Inconel 718 was fabricated via laser-directed energy deposition (LDED), and a heterogeneous structure comprising alternating heat-treated and untreated deposited zones was produced through interlayer laser heat treatment followed by double aging. Compared with traditional heat treatment samples, the interlayer laser heat-treated alloy exhibits an excellent combination of strength and ductility, with an average tensile strength of 1152 MPa and an elongation of 16.11%. Strengthening is mainly attributed to precipitation and grain refinement in the heat-treated zones, while enhanced ductility results from preferential deformation in the untreated zones and crack-resistant heterogeneous interfaces, collectively achieving an optimized strength–ductility synergy. These findings demonstrate that heterogeneous structuring effectively enhances the mechanical performance of deposited Inconel 718 alloy layer.

The increasing prevalence of emerging contaminant (EC) in aquatic environments has raised significant public concern, owing to their environmental persistence and potential ecological risks even at trace concentrations. This study evaluated a novel and environmentally sustainable strategy for enhancing EC removal in sequencing batch reactors (SBRs) through the addition of Aspergillus niger mycelial pellets (MPs). An optimal MPs-to-sludge inoculum ratio of 3:1 (w/w) was identified as for promoting aerobic granular sludge (AGS) formation and improving contaminant elimination. Two lab-scale SBRs, R1 (Test, with MPs) and R0 (Control, without MPs), were operated over 90 days to assess systems performances. Results showed that MPs supplementation in R1 considerably accelerated aerobic granulation and increased biomass retention. Notably, diclofenac sodium (DCF) removal efficiency in R1 reached an average of 68.8%, representing a 14% improvement over R0. Simultaneously, R1 demonstrated even higher removal efficiencies for COD (94.2% vs. 93.7%), total nitrogen (69.5% vs. 66.3%), and total phosphorus (94.4% vs. 90.1%) compared to the control R0. Mechanistic investigations through morphological analysis, extracellular polymeric substance (EPS) quantification, enzyme activity assays, and 16S rRNA gene sequencing revealed that the superior performance in R1 was attributed to the synergistic effects of larger granular structures (411 μm vs. 165 μm), enhanced biomass retention, elevated EPS and enzyme production, and increased microbial diversity. In conclusion, the integration of fungal mycelial pellets into SBRs provides an effective and green strategy for enhancing the removal of emerging contaminant from wastewater.

The growing aging population and the increasing incidence of traumatic injuries have jointly intensified the clinical demand for bone repair materials and technologies. Tantalum (Ta) and titanium (Ti) alloys are widely used in clinical orthopedics—such as joint replacements, cranial implants, and spinal implants—due to their excellent biocompatibility and mechanical properties. Notably, tantalum exhibits outstanding biological performance, including superior osseointegration and antibacterial properties. In recent years, researchers have focused on fabricating tantalum coatings on titanium and its alloys to combine the advantages of both materials. Various coating techniques have been developed, including chemical vapor deposition, magnetron sputtering, vacuum plasma spraying, and selective laser melting (SLM). However, these methods still present limitations such as limited bonding strength, poor controllability of pore size and porosity, and mismatched elastic modulus. In this study, a Ta/Ti6Al4V composite porous structure with uniform pores was successfully prepared using SLM. The structure achieved metallurgical bonding between the two materials, with a bonding strength of up to 447.3 MPa and a compressive yield strength ranging from 66.1 to 87.4 MPa. Thanks to the fully porous design, the elastic modulus was significantly reduced (1.9–2.9 GPa), matching that of human bone tissue; in vitro experiments confirmed that its overall biocompatibility is comparable to that of pure Ta. Corrosion resistance tests demonstrated that the Ta/Ti6Al4V composite porous structures exhibit good chemical stability in simulated body fluid. The Ta/Ti6Al4V composite porous structures show promising potential as an orthopedic implant.

The insufficient bond strength between a rigid ceramic bracket and an enamel leads to bracket detachment and orthodontic treatment failure. In this work, a laser-based engineering route with high controllability, high efficiency, and low cost is applied to texture ceramic brackets with surface microstructures to introduce mechanical retention for improved bonding between ceramic brackets and enamels. The influence of the structural features of surface microstructure on the shear bond strength (SBS) of laser-textured ceramic brackets with enamels is systematically studied. The maximum SBS value of 575 ± 25.16 N is obtained for a ceramic bracket that is textured with a surface grid pattern that has a grid size of 80 μm and a groove depth of 37 μm. This SBS value is about four times higher than an untreated bracket. A bracket-resin-enamel model is established to theoretically understand the stress distribution and mechanical behavior of the system under a shear load. The theoretical simulation results evidence concentrated stress at the groove area, suggesting the formation of mechanical retention. The development of a laser surface texturing method to improve the bonding strength of ceramic brackets could promote the bonding reliability of ceramic brackets in orthodontic treatment.

Laser-induced plasma-assisted deposition (LIPAD) is an efficient and low-cost method for processing thin films on transparent substrates, but it is difficult to control in terms of edge evenness, chemical composition homogeneity, and geometric precision. Here, a donor target of stainless steel 316 is used in the LIPAD process to fabricate a homogenous thin film on a glass plate. The effects of laser parameters on the structural and chemical characteristics of the films are systematically investigated. The experimental results show that the density of spherical particles reduces and the particle size shrinks as laser scanning distance increases. The influence of laser scanning distance on the chemical structures of LIPAD films is studied by Raman spectroscopy and x-ray diffraction. Microgratings with precisely defined size are fabricated from the LIPAD thin films by a laser subtractive patterning step, and grating constants retrieved from the optical diffraction experiment match well with the measured strip spacing, envisioning the feasibility of LIPAD in efficient production of microgratings.

The extremely harsh environment of the high temperature plasma imposes strict requirements on the construction materials of the first wall in a fusion reactor. In this work, a refractory alloy system, WTaVTiZr_x, with low activation and high entropy, was theoretically designed based on semi-empirical formula and produced using a laser cladding method. The effects of Zr proportions on the metallographic microstructure, phase composition, and alloy chemistry of a high-entropy alloy cladding layer were investigated using a metallographic microscope, XRD (X-ray diffraction), SEM (scanning electron microscope), and EDS (energy dispersive spectrometer), respectively. The high-entropy alloys have a single-phase BCC structure, and the cladding layers exhibit a typical dendritic microstructure feature. The evolution of microstructure and mechanical properties of the high-entropy alloys, with respect to annealing temperature, was studied to reveal the performance stability of the alloy at a high temperature. The microstructure of the annealed samples at 900 °C for 5–10 h did not show significant changes compared to the as-cast samples, and the microhardness increased to 988.52 HV, which was higher than that of the as-cast samples (725.08 HV). When annealed at 1100 °C for 5 h, the microstructure remained unchanged, and the microhardness increased. However, after annealing for 10 h, black substances appeared in the microstructure, and the microhardness decreased, but it was still higher than the matrix. When annealed at 1200 °C for 5–10 h, the microhardness did not increase significantly compared to the as-cast samples, and after annealing for 10 h, the microhardness was even lower than that of the as-cast samples. The phase of the high entropy alloy did not change significantly after high-temperature annealing, indicating good phase stability at high temperatures. After annealing for 10 h, the microhardness was lower than that of the as-cast samples. The phase of the high entropy alloy remained unchanged after high-temperature annealing, demonstrating good phase stability at high temperatures.

Combining the advantages of a wet chemical method and spark plasma sintering, carbide-doped materials W-1wt%TiC and W-1wt%ZrC were prepared. Microstructural evolution in W-1wt%TiC and W-1wt%ZrC under irradiation of 5 keV He⁺ at 600 °C to fluences up to 5.0 × 10²¹ ions/m² with ion flux of about 8.8 × 10¹⁷ ions/m²s was investigated by transmission electron microscopy (TEM). The dislocation loop number density of W-1wt%TiC was higher than that of W-1wt%ZrC, but the average loop size of the W-1wt%TiC was in average smaller. There were no observable helium bubbles in W-1wt%TiC and W-1wt%ZrC, exhibiting higher radiation resistance to He⁺ compared to pure W. He⁺ pre-damaged and undamaged W-1wt%TiC and W-1wt%ZrC samples were irradiated by 5 keV D₂⁺ to estimate the D retention in doped W materials. The irradiation damage impact of He⁺ on deuterium retention was examined by a method of thermal desorption spectroscopy (TDS). Compared with the undamaged samples, it was illustrated that D₂ retention of W-1wt%TiC and W-1wt%ZrC increased after He⁺ pre-irradiation.