Search Results (1,606)

Pre-hospital use of whole blood is becoming increasingly prevalent in EMS and military medicine. Technologies to store, transport, warm up, and transfuse the blood are now available, and the outcome of whole blood transfusion seems to be superior to infusion of crystalloid solutions or plasma and at least equivalent to packed cells with plasma. The auto-transfusion tourniquet (A-TT^®, Oneg HaKarmel Ltd., Tirat Carmel, Israel) is a non-invasive device that shifts the patient’s own blood from the legs to the core and blocks its reentry. The A-TT consists of an elastic ring made of a stainless-steel coil, wrapped by an elastic sleeve and pulling straps. When rolled up the leg(s), it squeezes the soft-tissues’ blood into the central circulation, and the ring stops the return of blood to the leg. The application time of the A-TT is less than 20 s per leg, and the A-TT transfers more than 500 mL of blood from each leg to the core. The auto-transfused blood is of the patient’s own type, has full oxygen carrying capacity, is normothermic, and is not anticoagulated. The device can be applied by a trained first responder, even during transport, and its use can be titrated to avoid overshooting the patient’s blood pressure. The device can be kept on the leg for up to 2 h, and as such, can serve as a bridge to blood or a bridge to definitive care. This paper is a hypothesis-generating review that defines the potential role of the A-TT in settings where blood is not available and is a call for others to help generate more data. Full article

Cobalt–chromium (CoCr) alloys have gained significant importance in the field of medical implants due to their outstanding combination of mechanical strength and excellent wear and corrosion resistance. Compared with other state-of-the-art materials, such as stainless steel or titanium, CoCr alloys typically exhibit superior fatigue strength, which is particularly advantageous for implants and components exposed to long-term repetitive loading. The present study investigates the feasibility of using commercially available CoCr alloy powders in the Laser Powder Bed Fusion (PBF-LB/M) process for the fabrication of biomedical implants. Microstructural characterization of the PBF-LB/M-manufactured CoCr samples revealed a dense, refined cellular–dendritic microstructure with a high degree of densification, characteristic of the rapid solidification associated with the PBF-LB/M process. The evaluation of mechanical performance, wear behavior, and corrosion resistance provides valuable insights into the suitability of these alloys for biomedical applications, especially in the design of complex implants requiring enhanced durability and long-term reliability. Furthermore, compression testing highlighted the influence of layer orientation on mechanical properties, emphasizing the importance of strategic prototyping and building orientation selection in the PBF-LB/M process. Tribological behavior assessed under dry sliding conditions demonstrated a significantly reduced coefficient of friction and lower wear rate compared to a conventional 316L stainless steel, which is frequently used in similar applications. Corrosion resistance was evaluated by potentiodynamic polarization measurements in Ringer electrolyte, showing that the PBF-LB/M-fabricated CoCr samples exhibit good corrosion resistance in environments resembling physiological fluids. Overall, the PBF-LB/M technique represents a promising manufacturing route for next-generation CoCr biomedical implants, particularly for orthopedic and dental applications. Beyond the biomedical field, the findings of this study also support the potential extension of PBF-LB/M-processed CoCr alloys to industrial sectors requiring high wear and corrosion resistance, including aerospace and automotive applications. Full article

Fiber Bragg grating (FBG)-based sensors are increasingly used for temperature and strain monitoring in both fission and fusion facilities, whereas their long-term mechanical reliability under intense γ–neutron fields remains insufficiently understood. Although radiation-resistant FBGs and optical fibers have demonstrated tolerance to fast-neutron fluences approaching 10²⁰ n/cm², the post-irradiation behavior of complete sensor assemblies, including their metallic packaging and joining regions, has received much less attention. This work presents methodology and results of assessing the post-irradiation mechanical properties of packaged FBG-based temperature and strain sensors. The investigated sensors were based on Cu-coated FBGs embedded in 316L stainless-steel bodies and joined using STEMET-1101 brazing filler metal. The sensors were irradiated in the cores of the IVG.1M and WWR-K research reactors to fast-neutron fluences of 4.5 × 10¹⁷ and 1.8 × 10²⁰ n/cm², with absorbed γ-doses of 29.1 MGy and 2.3 GGy, respectively. After decay storage and hot-cell disassembly, tensile testing, microhardness measurements, and SEM–EDS analysis were performed. The results demonstrate that the investigated metal-packaged FBG sensor of this design retained mechanical integrity under high-fluence reactor irradiation. Full article

The optimization and the engineering development of additive manufacturing (AM) products both require accurate, non-destructive techniques to extract their mechanical performances. The Instrumented Indentation Test (IIT) has such a potential, although it currently lacks standard procedures that are suitable for analyzing materials which are affected by internal residual stress (RS). Additionally, nanoindentation testing suffers from the presence of indentation size effects (ISE), which hamper the possibility of correlating the measured mechanical performance at different indentation depths or peak loads using the standard indentation hardness (H_IT) and modulus (E_IT). This paper presents a novel IIT methodology that is based on new indentation parameters, namely the loading stiffness rate (LSR) and the rate-derived hardness (H_R), which are then used to assign the desired mechanical performances of an L-PBF 316L austenitic stainless-steel alloy obtained via multiload/multiscale IIT strategy. The mean values of LSR, H_R, H_IT, and E_IT on the macroscale were 57.3 ± 1.4 GPa, 2.33 ± 0.059 GPa, 2.41 ± 0.13 GPa, and 201 ± 7.8 GPa, respectively, whereas on the nanoscale they were 56.1 ± 5.1 GPa, 2.30 ± 0.21 GPa, 3.00 ± 0.36 GPa, and 219 ± 24 GPa, respectively. Unlike the standard H_IT, the new indentation parameters of the nano- and macro-IITs are within the standard deviation, proving their ISE-free property. The obtained E_IT was slightly higher than the reference Young’s modulus (~190 GPa) of the 316L stainless steel. The loading secant stiffness versus depth plot can be used to assess the susceptibility of RS to relax during indentation, which is an important performance factor for the engineering design of AM components. The successful correlation that has been found between electron backscatter diffraction (EBSD) analysis (in terms of crystal anisotropy, grain size, and dislocation density) and nanoindentation testing at three subregions of the core zone of the investigated deposit confirms the validity of the proposed methodology. The proposed methodology is a step towards the full determination of the three Ps, that is, process, properties, and performance of advanced AM products. Full article

To meet the combined requirements of high strength, intrinsic corrosion protection, and cost effectiveness for bridge cable wires, 316L/SWRH82B stainless-steel/high-carbon-steel clad wire rods were manufactured under industrial hot rolling conditions. Three initial rolling temperatures of 1000, 1024, and 1047 °C were investigated through metallographic observation, quantitative image analysis, EPMA characterization, SEM fractography, and tensile testing, with 15 specimens tested for each temperature group. The EPMA results, together with the metallographic observations, were used to evaluate carbon diffusion, interfacial elemental redistribution, and decarburization. As the initial rolling temperature increased from 1000 to 1024 and 1047 °C, the decarburized-layer thickness on the SWRH82B side increased from 7.42 ± 1.28 µm to 11.31 ± 1.74 µm and 18.15 ± 1.76 µm, respectively, whereas the carburization-affected-zone thickness on the 316L side increased from 48.36 ± 2.73 µm to 63.04 ± 3.06 µm and 68.73 ± 3.65 µm, respectively, demonstrating pronounced asymmetric interfacial reaction–diffusion. The average tensile strengths of the three groups were 1120.07, 1146.27, and 1152.28 MPa, with corresponding standard deviations of 14.83, 4.55, and 13.34 MPa and coefficients of variation of 1.32%, 0.40%, and 1.16%, respectively. Among the tested conditions, the 1024 °C group exhibited the lowest tensile-strength standard deviation and coefficient of variation, indicating the best tensile stability and mechanical consistency. Although the 1047 °C group achieved the highest average tensile strength, it also exhibited reduced cladding thickness uniformity and renewed mechanical scatter. All 45 tensile specimens were fractured on the SWRH82B side without obvious macroscopic interfacial delamination, indicating that the interface was not the preferential macroscopic fracture path under the present uniaxial tensile-loading condition. However, the intrinsic interfacial bonding strength was not directly quantified in this work. Therefore, 1024 °C is identified as the preferred initial rolling temperature for the specific billet geometry and industrial rolling conditions examined in this work, rather than a universally applicable value. The present study is limited to as-hot-rolled clad wire rods; corrosion performance, multi-pass cold drawability, and the final performance of bridge cable wires after drawing remain to be experimentally validated. Full article

The corrosion resistance of metallic materials is closely related to their service environment. In ammonia-based desulfurization post-treatment systems, 316L stainless steel, 2507 duplex stainless steel, and TA2 commercially pure titanium are widely used as candidate materials for key components such as desulfurization heat exchangers. In this study, the pitting corrosion behavior of 316L, 2507, and TA2 was investigated in simulated ammonia desulfurization post-treatment solutions with different pH. The results show that increasing solution acidity leads to a decrease in the capacitive arc radius and polarization resistance, while the donor concentration and pitting susceptibility of the three materials increase. Under the same pH condition, TA2 exhibits the highest stability and corrosion resistance, followed by 2507, whereas 316L shows the poorest corrosion resistance. The composition of the TA2 passivation film (TiO₂) does not change as the pH of the simulated solution is modified. With increasing solution acidity, the relative XPS peak-area fraction of TiO₂ in TA2 increases, indicating that TiO₂ remains the dominant component of the passive film. In contrast, the relative contents of Cr- and Mo-containing oxides/hydroxides in 316L and 2507 decrease, and MoO₃ is replaced by MoO₂ under acidic conditions. These changes suggest weakened passive-film stability and reduced protection of the substrate. Full article

This study investigates titanium oxynitride (TiO_xN_y) coatings deposited by reactive magnetron sputtering on 316L stainless steel substrates in an Ar–N₂–O₂ gas mixture at a fixed N:O ratio of 1.6. The coatings were deposited under three reactive magnetron sputtering regimes with Ar flow rates of 33, 28, and 26 sccm and corresponding substrate biases of −50, −100, and −150 V, respectively, while the N₂ and O₂ flow rates were kept constant at 10 and 6 sccm. The coatings exhibited a dense microstructure, with thicknesses ranging from 2.13 to 5.51 μm. X-ray diffraction analysis revealed the formation of a multiphase structure comprising TiN, TiO_xN_y, and TiO. The deposition regime had a significant influence on the functional properties of the coatings. The lowest friction coefficients (µ ≈ 0.26–0.28) and stable tribological behavior were characteristic of the Ar26 sample. The highest corrosion resistance was observed for the Ar28 sample, with a corrosion current density of i_corr = 2.82 × 10⁻⁷ A/cm² and a corrosion rate of v_corr = 0.00573 mm/year. All coatings exhibited hydrophilic surface behavior, with contact angles of 50–57°, which may be relevant for further evaluation in biomedical surface applications. Thus, the structure and functional properties of TiO_xN_y coatings can be regulated by selecting an appropriate deposition regime, including the Ar flow rate, relative reactive gas fraction, and substrate bias. However, additional biological tests, including cytotoxicity, hemocompatibility, endothelialization, and platelet adhesion studies, are required before conclusions about vascular implant applicability can be made. Full article

Aiming at non-uniformity in the vertical direction in the polishing effect on stainless steel after plasma electrolytic polishing (PEP), this paper took 304 L stainless steel as the research object. Under an ammonium sulfate electrolyte system with a mass fraction of 2.5 wt%, PEP was carried out utilizing different placement methods for the anode and electrolyte temperatures, and the causes of non-uniformity in the polishing process were explored. Experimental results demonstrate that the vertical polishing inhomogeneity originates from the upward movement of unruptured bubbles at the sample bottom. Under the combined effects of electrolyte internal pressure and bubble buoyancy, a vapor-gas envelope (VGE) featuring a thick upper part and thin lower part forms near the sample surface. This enhances plasma-related physicochemical reactions at the sample bottom and consequently raises the polishing rate. The vertical polishing unevenness can be alleviated by adjusting the electrolyte temperature. Non-uniformity could be improved by controlling the temperature of the electrolyte. Compared with the result at 95 °C, the maximum dimensional variation in each region on the sample at 75 °C was reduced by 36% because a VGE with more uniform thickness was formed, and a properly oxidized sparse layer helped protect the substrate from ablation and over-polishing. In addition, the removal rate of elements on the surface of stainless steel is affected by its activity due to the oxidation reaction. The high removal amount in the bottom region caused a trend of increasing Cr and decreasing Fe content percentages from the top to the bottom on the stainless-steel surface. However, the oxidation removal rate of elements is extremely fast due to the high temperature of the ionization center and strong electric field; therefore, the content percentage of each element on the surface is little changed after polishing. Full article

Piezoelectric pressure sensors for dynamic monitoring face a trade-off between charge output and measurement range, and existing high-sensitivity designs are largely confined to narrow ranges. This study presents a composite layered piezoelectric pressure sensor in which a 316L stainless-steel diaphragm drives a centrally suspended PZT-5H wafer supported by a perforated alumina gasket, with the wafer thickness and cavity radius optimized under a 10 MPa full-scale stress constraint. Over 0–10 MPa, quasi-static calibration gave a highly repeatable quadratic pressure–charge relationship ($R^2=0.99995$) with a maximum residual below 1% FS. The sensitivity is pressure-dependent: the secant sensitivity increased monotonically from 3.16 pC/kPa at 1 MPa to 5.36 pC/kPa at 10 MPa, reflecting a stress-stiffening response rather than a measurement tolerance band. The output deviation remained within 3% from 25 °C to 150 °C. Shock-tube testing yielded a resonance of ∼50 kHz and a mutually consistent 10–90% leading-edge interval of 10.12 $\mathsf{\mu }$s. Combining high charge sensitivity over a wide 0–10 MPa range with a fast transient response and stable operation up to 150 °C, the proposed sensor is suited to dynamic pressure-pulsation monitoring in fluid-power and thermal and power-plant fluid systems. Full article

Pitting corrosion is particularly dangerous due to its localised nature, which can render materials unusable and cause catastrophic failures. It is important to characterise the material in regard to pitting corrosion resistance in order to improve material selection according to the conditions of the exposed environment. Electrochemical tests were carried out to assess pitting corrosion in austenitic stainless steel EN 1.4301. This study identifies the optimal experimental conditions to ensure reliability and reproducibility in electrochemical tests. The results demonstrate the influence of these parameters in evaluating the resistance of stainless steels to pitting corrosion. To ensure the reproducibility of the breakdown potential (Eb), deaeration was standardised using an N₂ flow rate of 0.6–0.8 L/min for 20 min. Furthermore, mechanical agitation at 280 rpm was established as a necessary condition to homogenise the electrolyte and effectively renew the metal/solution interface. Finally, the water flow rate was set at a critical value of 7 mL/h, statistically identified as the most decisive parameter (p < 0.05). This optimisation mitigates crevice corrosion, ensuring that damage nucleation occurs exclusively via a pitting mechanism. Full article

Although hydrogen embrittlement mechanisms focus predominantly on the plastic deformation regime, the fundamental effect of interstitial hydrogen on the elastic regime remains elusive. The elastic behavior due to hydrogen is critical because lattice alterations drive microstructural instabilities and macro-failure. This work aims to determine the hydrogen-affected single-crystal elastic constants and anisotropy of 304L stainless steel and link them to dislocation-mediated embrittlement mechanisms. Using in situ neutron diffraction and the Kröner model, this study derived, for the first time, the single-crystal elastic constants ($C_{\mathrm{i}\mathrm{j}}$) of 304L austenitic stainless steel. Hydrogen charging expanded the lattice constant by ~0.7% (from 3.558 $\mathrm{\AA }$ to 3.583 $\mathrm{\AA }$) and selectively increased $C_{11}$ and $C_{12}$ while leaving $C_{44}$ nearly unchanged. Consequently, while bulk polycrystalline Young’s and shear moduli remained invariant, Zener’s anisotropy and Poisson’s ratios increased. Hydrogen reduced the shear modulus of the {111}<110> slip system by ~8.3% and the Peierls–Nabarro stress by approximately 38%. The experimental derivation of single-crystal elastic moduli proved that lattice-scale modifications selectively enhanced volumetric stiffness while lowering the slip-direction shear modulus. Coupled with hydrogen-induced lattice expansion, these findings validate the theoretical volumetric and modulus components of the hydrogen-enhanced localized plasticity mechanism, thereby elucidating its fundamental origin. Full article

Reduced-oxide titanium (Ti) protective coatings were fabricated on 316L stainless-steel substrates to improve the corrosion resistance of low-cost metallic components for proton exchange membrane water electrolysis (PEMWE). A low-temperature atmospheric plasma spraying process assisted by a self-designed extended protective nozzle was employed to suppress the oxidation of Ti particles during deposition. The nozzle provided auxiliary argon shielding and reduced the thermal exposure of in-flight particles, thereby limiting their interaction with ambient air. The deposited coatings exhibited a continuous lamellar structure with average thicknesses of approximately 78–98 μm. Phase and elemental analyses indicated that α-Ti(O) was the dominant phase, with limited oxide formation in the coating. ONH analysis further showed that the oxygen and nitrogen contents of the coatings were 0.95–1.69 wt.% and 0.049–0.087 wt.%, respectively. During the 6 h potentiostatic test, all Ti-coated samples showed lower and more stable current densities than bare stainless steel, with the 500 A 55 V coating maintaining the lowest final current density of approximately 0.4–0.5 mA/cm². These results demonstrate that low-temperature atmospheric plasma spraying is a feasible and cost-effective approach for preparing reduced-oxide Ti coatings for PEMWE components. Full article

In some Generation IV reactor configurations, embrittlement of the liquid metal can manifest in various forms, and this behaviour strongly depends on the specific solid–liquid couple. For the ALFRED demonstrator, which will be built at the RATEN ICN site in Romania, the study of embrittlement induced by molten lead in 316L stainless steel at temperatures of 350–450 °C is of interest. The purpose of the paper is to evaluate the effect of liquid metal embrittlement on the fracture mechanics properties of 316L tested in liquid lead. To do this, the “Normalisation Data Reduction Technique” (ASTM E1820) is used to obtain the J-R resistance curve for 316L steel in molten lead. In this way, the fracture mechanics parameters were obtained, indicating the fracture toughness of 316L steel in liquid lead with a saturated oxygen concentration at 350 °C. Optical and SEM examinations complement the analyses. Full article

To improve the efficiency of TIG (Tungsten Inert Gas) welding, our team developed a novel fast-frequency pulsed twin-TIG welding power source and matched welding procedures to overcome the drawbacks of conventional high-efficiency TIG welding. After parameter optimization, stable, high-efficiency and high-quality welding of 316L stainless steel can be realized. Compared with traditional DC TIG welding, the mechanical properties of joints are greatly improved: the weld grain size is refined by 38% under moderate current, while tensile strength, elongation and microhardness rise by 13.6%, 26% and 10% respectively, which achieves simultaneous improvement in strength and ductility. Numerical simulations were carried out to analyze the evolution of molten pool temperature field and velocity vector flow field. The simulation results are highly consistent with experimental data, which verifies the reliability of the model and lays a foundation for the study of molten pool behavior. Combined with molten pool flow characteristics and weld microstructure, the evolution mechanism of microstructure and texture as well as grain refinement in this welding process is revealed. Full article

Additive manufacturing has emerged as a transformative technology for fabricating complex drug-eluting medical devices, offering unprecedented design freedom and functional integration capabilities. This comprehensive review systematically analyzes 3D printing technologies applied to pharmaceutical device manufacturing, focusing on drug-eluting vascular stents as a representative application. This review covers six primary additive manufacturing techniques, ranging from high-resolution vat photopolymerization (25 μm resolution) to direct energy deposition, with a focus on their capabilities for produce pharmaceutical devices with controlled drug release properties. Novel 4D/5D/6D printing technologies introduce stimuli-responsive behaviors enabling programmable drug release profiles and adaptive device functionality. Manufacturing process optimization reveals superior design flexibility compared to conventional methods, with 85–95% reduction in design iteration time and elimination of tooling costs for complex geometries. The material landscape encompasses traditional metals (316L stainless steel, cobalt–chromium), biodegradable polymers (polylactic acid, PLA; polycaprolactone, PCL; poly(lactic-co-glycolic acid), PLGA), shape-memory materials (i.e., polymers and alloys capable of recovering a pre-programmed shape upon exposure to a specific stimulus such as body temperature, moisture, or light), and advanced nanocomposites, each offering distinct drug-loading capacities (100–500 μg/cm²) and release kinetics. Critical challenges include standardization requirements (International Organization for Standardization (ISO) 5840 and American Society for Testing and Materials (ASTM) F2606), pharmaceutical-grade manufacturing protocols, and regulatory pathways for novel drug-device combinations. This review identifies key research priorities including development of biocompatible printing materials, accelerated drug release testing protocols, and scalable manufacturing processes suitable for medical device production. This analysis demonstrates that 3D printing enables integration of multiple pharmaceutical functions within single devices, controlled spatiotemporal drug delivery, and elimination of secondary manufacturing steps for drug coating processes, advancing the development of next-generation therapeutic medical devices. Full article