Thick films of supersaturated solid solution nanocrystalline Co-Cu (28 at.% Cu) were synthesized through the pulsed electrodeposition technique. Microstructural changes of nanocrystalline Co-Cu were intensively studied at various annealing temperatures. Annealing at 300 °C results in a spinodal decomposition within the individual grains, with no grain coarsening. On the other hand, distinct phase separation of Co-Cu is detected at annealing temperatures beyond 400 °C. Static micro-bending tests show that the nanocrystalline Co-Cu alloy exhibits a very high yield strength and ductile behavior, with no crack formation. Static micro-bending tests also reported that a large plastic deformation is observed, but no microstructure change is detected. On the other hand, observation on the fatigue resistance of nanocrystalline Co-Cu shows that grain coarsening is observed after conducting the cyclic micro-bending test.

This study systematically compares the surface polishing performance and finishing results of the following two different electrolytic plasma polishing technologies on stainless steel AISI 316L: (i) plasma electrolytic polishing (PEP) and (ii) plasma electrolytic polishing jet (PEP-Jet). The two techniques are compared against an industrial standard polishing method, electropolishing (EP). For comparable energy density consumption, the samples treated with the PEP-Jet technique showed the highest removal rate, up to three times less than the initial roughness, resulting in the highest surface roughness reduction from Sa = 249 nm to Sa = 81 nm. Microstructure characterization of samples treated using PEP-Jet also showed well-defined crystalline grain boundaries with a distinct appearance of predominantly inter-crystalline structures within individual grains, which is uncommon with EP techniques. The surfaces treated using PEP-Jet exhibited the lowest corrosion rate of $6.79\times {10}^{-5}$ mm/year, and no signs of areal corrosion were detected in the performed corrosion tests in contrast with the other samples and their respective treatments. The comparative analysis revealed that the high ionic current delivered by the electrolyte jet flow in the PEP-Jet process effectively stabilizes the plasma at the contact zone, thereby enhancing the plasma polishing of austenitic stainless steel samples. The efficacy of this method has been demonstrated in terms of reducing energy consumption and enhancing corrosion resistance in comparison with (PEP) and (EP) as state-of-the-art processes in corrosive environments of high-alloyed steel.

Strategies to improve tensile strength and ductility of pulsed electrodeposited nanocrystalline Co-Cu were investigated. Parameters of deposition, which are pulse current density, duty cycle, and pulse-on time were adjusted to produce nanocrystalline Co-Cu deposits with different microstructures and morphologies. The most significant improvement of strength and ductility was observed at nanocrystalline Co-Cu deposited, at a low duty cycle (10%) and a low pulse-on time (0.3 ms), with a high pulse current density (1000 A/m²). Enhancement of ductility of nanocrystalline Co-Cu was also obtained through annealing at 200 °C, while annealing at 300 °C leads to strengthening of materials with reduction of ductility. In the as deposited state, tensile strength and ductility of nanocrystalline Co-Cu is strongly influenced by several factors such as concentration of Cu, grain size, and processing flaws (e.g., crystal growth border, porosity, and internal stresses), which can be controlled by adjusting the parameters of deposition. In addition, the presence of various microstructural features (e.g., spinodal and phase decomposition), as well as recovery processes induced by annealing treatments, also have a significant contribution to the tensile strength and ductility.

Objective: Urinary stone-related diseases affect approximately 6% of the global population, with nearly half of the patients experiencing recurrence. The diagnosis and management of the disease depend on the stone type and composition. Yet, current clinical imaging modalities (ultrasound, computed tomography, and radiography) lack the sensitivity and specificity required for accurate classification. Speckle-based darkfield X-ray imaging offers a potential non-invasive method for classifying urinary stones with the required hardware simplicity and robustness for potential in vivo, clinical applicability. However, the influence of diffuser masks and state-of-the-art speckle X-ray image retrievals on classification remains underexplored.Approach: This ex vivo study systematically compared the efficacy of custom diffuser masks and state-of-the-art speckle X-ray retrieval algorithms, using both grid and custom speckle masks, for single-shot dark-field imaging in urinary stone classification at high X-ray energy (80 kVp).Main Results: Among the various types of urinary stones examined in this study, canine ammonium urate showed the most distinct visibility contrast difference, deviating by 32% from the z-standardized reference transmission. Overall, the results indicate a potential to differentiate between three main groups of urinary stones based on their attenuation-to-scattering coefficients: ammonium urate, calcium-based stones, and a third group comprising cystine and struvite. Comparisons of Unified Modulated Pattern Analysis, Fokker-Planck, and classical retrieval methods showed that Fokker-Planck was the most noise-sensitive, while Unified Modulated Pattern Analysis was the most robust.Significance: The findings in this study establish a technical foundation for advancing speckle-based dark-field X-ray imaging toward clinical translation for noninvasive urinary stone classification.