Search Results (178)

The influence of the copper (Cu) content on the corrosion resistance of 3.5%Ni low-carbon weathering steel was investigated using periodic dry–wet cycle accelerated corrosion tests. The mechanical properties of the steels were assessed via tensile and low-temperature impact tests, while corrosion resistance was evaluated based on weight loss measurements. Surface oxide layers were characterized using three-dimensional laser confocal microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and electrochemical methods. Electron probe microanalysis (EPMA) was employed to examine the cross-sectional morphology of the oxide layer after 72 h of accelerated corrosion tests. The results indicate that the solution state of Cu increased the strength of 3.5%Ni steels but significantly damaged the low-temperature toughness. As the Cu content increased from 0.75% to 1.25%, the corrosion rate decreased from 4.65 to 3.74 g/m² h. However, when there was a further increase in the Cu content to 2.15%, there was little decrease in the corrosion rate. With the increase in the Cu content from 0.75% to 2.15%, the surface roughness of 3.5%Ni weathering steel after corrosion decreased from 5.543 to 5.019 μm, and the corrosion behavior was more uniform. Additionally, the α/γ protective factor of the oxide layer of the surface layer increased from 2.58 to 2.84 with an increase in the Cu content from 0.75% to 1.25%, resulting in the oxide layer of the surface layer being more protective. For 1.25%Cu steel, the corrosion current density of rusted samples is lower (ranging from 1.2609 × 10⁻⁴ A/cm² to 3.7376 × 10⁻⁴ A/cm²), and the corrosion potential is higher (ranging from −0.85544 V to −0.40243 V). Therefore, the rusted samples are more corrosion resistant. The Cu in the oxide layer of the surface layer forms CuO and CuFeO₂, which are helpful for increasing corrosion resistance, which inhibits the penetration of Cl⁻. Full article

The laser damage resistance of optical films holds significant practical importance, as it largely determines both the maximum power output of laser systems and the overall stability of the entire optical assembly. A comprehensive investigation was conducted to examine the influence of both single additives—acetylacetone (ACAC) and diethanolamine (DEA)—and dual-additive systems, specifically ACAC combined with polyethylene glycol 200 (PEG 200) and DEA combined with PEG 200, on TiO₂ film properties and their laser-induced damage behavior under 1064 nm irradiation. It demonstrated that the films fabricated using ACAC exhibited smoother surfaces. Nevertheless, the sol prepared with DEA was more stable, resulting in films with superior optical properties and an enhanced laser-induced damage threshold (LIDT). The incorporation of dual additives further improved the films’ LIDT. Specifically, the film with DEA and PEG 200 achieved the highest LIDT, reaching 21.5 J/cm². Moreover, all films exhibited defect-induced damage, yet distinct damage morphologies were observed across different samples. The single-additive films predominantly displayed stress-type damage patterns, whereas the dual-additive films manifested melting-type damage characteristics. Furthermore, through a combination of experiments and calculations, it was revealed that the reasons why the film with DEA and PEG 200 achieved the highest LIDT were twofold: first, the high thermal conductivity of DEA reduced the maximum temperature at the defect center within the film; second, the long molecular chains of PEG 200 created a looser film structure that better mitigated damage caused by stress and expansion during laser irradiation. This study presents a promising approach to enhancing the LIDT through the strategic selection of additives with high thermal conductivity while simultaneously incorporating organic compounds with long molecular chains to develop effective dual-additive films. Full article

Interpenetrating phase composites (IPCs) have demonstrated tremendous potential across various fields, particularly those based on triply periodic minimal surface (TPMS) structures, whose uniquely interwoven lattice architectures have attracted widespread attention. However, current research on the dynamic mechanical properties of such IPC remains limited, and their impact resistance and damage mechanisms are yet to be thoroughly understood. In this study, a novel design of two volume fractions of IPCs based on the TPMS IWP configuration is developed using Python-based parametric modeling, with the Ti6Al4V alloy TPMS scaffolds fabricated via selective laser melting (SLM) and the AlSi12 reinforcing phase through infiltration casting. The influence of Ti alloy volume fraction and strain rate on the dynamic mechanical behavior of the Ti/Al IPC is systematically investigated using a split Hopkinson pressure bar (SHPB) experimental setup. Microscopic characterization validates the effectiveness and reliability of the proposed IPC fabrication method. Results show that the increasing Ti alloy volume fraction significantly affects the dynamic mechanical properties of the IPC, and IPCs with different Ti alloy volume fractions exhibit contrasting mechanical behaviors under increasing strain rates, attributed to the dominance of different constituent phases. This study enhances the understanding of the dynamic behavior of TPMS-based IPCs and offers a promising route for the development of high-performance energy-absorbing materials. Full article

Additively manufactured (AM) parts have been applied in many areas with the risk of cavitation erosion (CE), and pores are common defects in AM metals. However, the role of pores in CE is still unclear, and a systematic investigation is needed. In this study, 316L stainless steel was selected as a model material and produced using laser powder bed fusion; the porosity was 6.4%. The morphological evolution of various pores during CE was investigated via electron backscatter diffraction and scanning electron microscopy. It was found that material removal easily occurred around large polygonal pores. The critical size for large polygonal pores was estimated to be between 13 and 20 μm. For narrow pores, concavity first appeared around the pores during CE, and then the narrow pores closed. Small spherical pores with sizes of 3–9 μm showed strong resistance to CE, and no damage occurred within the 60 min CE period. The main reason that different pores played different roles in CE was analyzed. Finally, factors for improving the CE resistance of AM metals were suggested. The research results are helpful for understanding the CE behaviors of AM metals and porous materials. Full article

The permeability of porous asphalt pavements is a critical skid resistance indicator that directly influences driving safety on wet roads. To ensure permeability (water infiltration capacity), it is necessary to assess the degree of clogging in the pavement. This study proposes a permeability evaluation model for porous asphalt pavements based on 3D laser imaging and deep learning. The model utilizes a 3D laser scanner to capture the surface texture of the pavement, a pavement infiltration tester to measure the permeability coefficient, and a deep residual network (ResNet) to train the collected data. The aim is to explore the relationship between the 3D surface texture of porous asphalt and its permeability performance. The results demonstrate that the proposed algorithm can quickly and accurately identify the permeability of the pavement without causing damage, achieving an accuracy and F1-score of up to 90.36% and 90.33%, respectively. This indicates a significant correlation between surface texture and permeability, which could promote advancements in pavement permeability technology. Full article

The aim of the study was to assess the mechanical and material properties of porous titanium capsules, produced by 3D printing via the DMLS (Direct Metal Laser Sintering) technique based on their potential application as carriers for anticancer drugs. The study used capsules made from the Ti-6Al-4V alloy, and analyzes the impact of geometric parameters, structural features, and printing angles (0°, 45°, and 90°) on their compressive strength. A total of 36 capsules were tested, 18 of type KTD and 18 of type KTM, each in two loading directions. The surface roughness and damage characteristics resulting from mechanical loading have also been evaluated. Statistical analysis of the results was performed using Student’s t-test. The results show that the capsules printed at an angle of 45° are characterized by the highest compressive strength, while their resistance significantly exceeds the values typical of human bone tissue. Additionally, the observed damage does not lead to the formation of sharp edges or loose fragments, which confirms the safety of their use in the body. The high surface roughness promotes tissue integration and limits capsule migration after implantation. The analyses confirm the potential of 3D-printed titanium capsules as effective and safe drug carriers in personalized anticancer therapy. Full article

Cu-5wt%TiC coatings were fabricated by high-speed laser cladding on the 7075 aluminum alloy substrate using various scanning speeds to improve its current-carrying wear resistance. The effects of scanning speed on the microstructure, phase, hardness, and current-carrying tribological properties of the coating were investigated using a scanning electron microscope, an X-ray diffractometer, a hardness tester, and a wear tester, respectively. The results show that the increase in scanning speed accelerates the coating’s solidification rate. Among the samples, the coating comprised of equiaxed crystals prepared at 149.7 mm/s presents the best quality, but solidification speeds that are too rapid lead to elemental segregation. The hardness of the coating also decreases with the increase in scanning speed. The coating prepared at 149.7 mm/s exhibits the best wear resistance and electrical conductivity. The wear rate of the coating prepared at 149.7 mm/s at 25 A was 4 × 10⁻³ mg·m⁻¹, respectively. During the current-carrying friction process, the presence of thermal effects and arc erosion cause the worn track to be prone to oxidation, adhesion, and plastic deformation, so the current-carrying wear mechanisms of coatings at 25 A include adhesive wear, oxidation wear, and electrical damage. Full article

The escalating demands of industrial applications, particularly those involving severe wear, temperature, and corrosive environments, present significant challenges for the long-term strength of critical components, often fabricated from high-value materials such as super duplex stainless steel alloys. Super duplex can withstand the corrosive environment (in particular, crevice corrosion and pitting damage) and maintain mechanical integrity sufficient for high-pressure pumping applications such as seawater injection and crude oil. Conventional repair methodologies frequently result in component rejection due to process-induced distortions or detrimental phase transformations, contributing to substantial material waste and hindering the adoption of circular economy principles. This research addresses this issue by developing and validating a novel repair process utilizing laser metal deposition (LMD) additive manufacturing. The research focuses on establishing optimized process parameters to ensure the salvaging and restoration of damaged super duplex components while preserving their requisite mechanical integrity and corrosion resistance, in accordance with industry standards. Comprehensive characterization, including microstructural analysis, chemical composition verification, hardness profiling, and mechanical fatigue testing, confirms the efficacy of the LMD repair process. This work demonstrates the potential for extending the service life of critical components, thereby promoting resource efficiency and contributing to a more sustainable and resilient industrial paradigm. Full article

Calcium fluoride (CaF₂) crystals are widely utilized in deep-ultraviolet (DUV) lithography due to their excellent optical properties. The laser-induced degradation and damage of CaF₂ crystals is a critical concern that restricts its extended application. Impurities of CaF₂ crystal are considered a key factor affecting its laser resistance. Establishing the quantitative relationship and mechanism of impurity content impacting the degradation and damage characteristics of CaF₂ crystal is essential. This study investigated the characteristics of different impurity contents affecting the degradation and laser-induced damage thresholds (LIDTs) of CaF₂ crystals under X-ray and 193 nm pulsed laser irradiations, and quantitatively analyzed the degradation process and mechanism. Our findings demonstrate that impurities at ppm levels significantly diminish the transmittance of CaF₂ crystals across various wavelengths following X-ray irradiation. In contrast, these impurities have a negligible effect on the LIDT test results, suggesting distinct damage mechanisms between X-ray and laser irradiation. This study provides valuable insights for optimizing the CaF₂ crystal fabrication process and enhancing irradiation resistance. Full article

Long-term stability and laser-induced damage resistance of optical components in the UV region are critical for enhancing their performance in UV high-power laser applications. This study evaluates the laser-induced damage threshold (LIDT) of commercially available UV optical windows with anti-reflective (AR) coating, produced through various coating techniques and designed for high-power lasers. A third-harmonic (343 nm) wavelength with good beam quality was generated in the picosecond regime to investigate the LIDT of optical components. The LIDT for each sample was measured under controlled conditions and compared based on their coating techniques. The sample coated with Al₂O₃/SiO₂ through ion beam sputtering has the best LIDT value, of 0.6 J/cm², among the tested samples, based on the hundred-thousand-pulses methodology. The damage threshold curve and the corresponding damage morphology are discussed in detail, and these findings provide insights into the durability and susceptibility of UV optics for advanced laser systems available in the market. Full article

Leukemia is a malignant tumor of the hematopoietic system. Approximately 15% of adult leukemias are chronic myeloid leukemias (CMLs), and this incidence increases annually. The BCR-ABL oncoprotein drives the initiation, promotion, and progression of CML. Although tyrosine kinase inhibitors (TKIs) are first-line therapies for CML, BCR-ABL-mediated drug resistance limits their clinical efficacy and patient prognosis. Perillaldehyde (PAE), a monoterpene and primary volatile oil from perilla, is a promising small-molecule candidate for degrading BCR-ABL and has potential medical applications. The molecular mechanism showed that PAE regulated the expression of autophagy- and apoptosis-related proteins in K562 cells. Confocal laser observation showed that PAE damaged the mitochondrial membrane potential and induced ROS generation. Further evaluations indicated that PAE targeted HSP70 and inactivated the phosphorylation of BCR-ABL, thereby inhibiting its downstream proteins. This study may produce a lead compound for CML therapy as PAE may be an effective treatment for further exploration. Full article

The antimicrobial and antibiofilm efficacy of two Ocimum basilicum L., essential oils sourced from Colombia (BEOC) and Italy (BEOI), was evaluated against multidrug-resistant fish isolates of Salmonella enterica subsp. salamae, Bacillus thuringiensis, and Bacillus oceanisediminis—species for which such activity has not been previously reported. Using a fish-based model system (FBMS), we found that BEOI, rich in linalool (69.86%), exhibited stronger antimicrobial activity than camphor-dominated BEOC (24.61%). The antimicrobial effects of both EOs were strain- and concentration-dependent, with minimum bactericidal concentration (MBC) 3.75–15.0 µL/mL for BEOI and 15.0–30.0 µL/mL for BEOC. Pure linalool showed even greater potency (MBC: 0.0125 to 0.025 µL/mL). Confocal laser scanning microscopy revealed that BEOI induced severe membrane damage (27% of the cells within 1 h), ultimately leading to the death of 96% of the cells after 24 h. Biofilm formation, assessed in both FBMS and tryptone soy broth (TSB), was strain-dependent, with FBMS promoting higher biofilm production than TSB. Moreover, significant differences in biofilm morphotypes were observed, with the morphotype PDAR (pink dry and rough), characterized by only cellulose, being the most frequently exhibited by the strains (7/15), while BDAR (brown dry and rough), characterized by only curli, was the least expressed (7/15); the remaining strains presented morphotype RDAR. In addition, the strains in polystyrene surfaces accumulated more biomass than stainless steel 304. Notably, BEOI and linaool significantly reduced biofilm formation across all strains, with a reduction of 90% in S. enterica subsp. salamae strains (TJC19 and TJC21. These strains with the RDAR phenotype likely contribute to their strong biofilm-forming capacity. Our findings highlight BEOI’s potential as a natural anti-biofilm agent in food processing environments, offering a promising strategy to combat multidrug-resistant bacteria biofilm-related challenges in the food industry. Full article

To address the graphitization of diamond induced by high temperatures during laser cladding of diamond-reinforced composites, this study proposes a laser cladding method utilizing Inconel 718 (IN718) nickel-based alloy as a transition layer which has a lower melting point than the substrate of 45# steel. And then, in order to analyze the detailed characteristics of the samples, scanning electron microscopy (SEM), EDS, Raman spectral analyzer, super-depth-of-field microscope, and friction tests were used. Experimental study and the test results demonstrate that the IN718 transition layer enhances coating performance through dual mechanisms: firstly, its relatively low melting point (1392 °C) reduces the molten pool’s peak temperature, effectively suppressing thermal-induced graphitization of the diamond; on the other hand, simultaneously it acts as a diffusion barrier to inhibit Fe migration from the substrate and weaken Fe–C interfacial catalytic reactions. Microstructural analysis reveals improved diamond encapsulation and reduced interfacial sintering defects in coatings with the transition layer. Tribological tests confirm that samples with the transition layer L exhibit lower friction coefficients and significantly enhanced wear resistance compared to those without. This study elucidates the synergistic mechanism of the transition layer in thermal management optimization and interfacial reaction suppression, providing an innovative solution to overcome the high-temperature damage bottleneck in laser-clad diamond tools. Full article

With rapid advancements in agricultural mechanization, enhancing the wear resistance and lifespan of rotary tiller blades is crucial for boosting productivity. This study examines how surface textures affect the friction and wear of 65Mn steel in quartz sand slurry. The results show that laser processing treatment significantly improves the wear resistance of 65Mn steel blades through the lubrication effect due to the wear debris capturing ability of the laser-processed micro-pits. Samples with surface textures processed using a laser scanning speed of 200 mm/s exhibit the best anti-wear property under loads of both 70 N and 100 N, reducing the wear loss by approximately 44.19% and 36.22%, respectively, compared to the non-textured samples. With the applied load increase to 100 N, laser-processed textures can still reduce wear damage but with an impaired anti-wear effect due to the gradually flattening of some textures due to long-term friction and crush damage by high load conditions. These findings help to augment wear resistance and prolong the operational lifespan of 65Mn steel rotary tiller blades, thereby contributing to a more robust understanding of the tribological enhancements achievable through the laser surface texturing process. Full article

Background: Composite resin veneers have gained popularity due to their affordability and minimally invasive application as biomimetic restorations. However, long-term clinical challenges, such as discoloration, wear, and reduced fracture resistance, necessitate their replacement over time. Ceramic veneers, particularly feldspathic and lithium disilicate, offer superior esthetics and durability, as demonstrated by studies showing their high survival rates and enamel-preserving preparation designs. However, while ceramic veneers survive longer than composite resin veneers, ceramic veneers may need to be removed and replaced. Reports vary for using Er:YAG (erbium-doped yttrium aluminum garnet) lasers for the removal of existing veneers. Methods: A review was conducted to evaluate the effectiveness of removing restorative materials with an Er:YAG laser. A clinical study was included, highlighting the conservative removal of aged composite resin veneers using the Er:YAG laser. This method minimizes enamel damage and facilitates efficient debonding. Following laser application, minimally invasive tooth preparation was performed, and feldspathic porcelain veneers were bonded. Results: The review showed positive outcomes whenever the Er:YAG laser was used. In the case study, after a 3-year follow-up, the restorations exhibited optimal function and esthetics. Conclusions: Laser-assisted debonding provides a safe and predictable method for replacing failing composite veneers with ceramic alternatives, aligning with contemporary biomimetic principles. Full article