This study reports the transition from via-hole to cross-point architectures in Al2O3-based resistive switching memories to achieve high-density integration and advanced biosensing capabilities. The fabricated IrOx/Al2O3/W cross-points demonstrate robust non-volatile memory characteristics, including a high endurance of over 1010 cycles, stable data retention, and low-power operation with currents below 100 μA as compared to via-hole memristive devices. Beyond data storage function, the cross-point structure is utilized as a label-free electrochemical biosensor for Sarcosine, a critical biomarker for prostate cancer. Experimental results show an exceptional detection limit down to 1 fM, attributed to the reduction–oxidation (redox) reactions at the electrode/dielectric interface. To further enhance sensor reliability, Artificial Intelligence (AI) algorithms have been implemented to process complex current–time (I-t) signals, effectively filtering environmental noise. The AI model successfully classifies the transient responses into a 3-tier diagnostic system (Healthy, Early Stage, and High Risk), achieving an outstanding predictive accuracy of 93.8%. Notably, the model demonstrates robust early-stage detection at the critical threshold while retaining ultra-high sensitivity down to 1 fM, perfectly aligning with the hardware’s intrinsic limits. These studies suggest that the integration of cross-point memristive devices with AI analytics provides a promising platform for next-generation smart healthcare diagnostics and high-density memory applications.
The Zr-Cr brittle intermetallic compounds usually form at the heterogeneous interface between zirconium alloy and conventional alloy coatings containing Cr element, which influence the mechanical properties. To solve the problem, this study designed and fabricated a novel TiNbMoCrx (x = 0, 0.2, 0.4, 0.6) coatings on Zr-4 substrate by laser cladding. Through microstructure, mechanical properties, and deformation mechanisms investigation at the Zr/TiNbMoCrx heterogeneous interface, the result revealed a transition zone composed of α-Zr, Zr-Nb solid solution, and Nb(Mo, Cr)2 Laves phase at the interface. Microhardness exhibits a continuous gradient transition from the TiNbMoCrx layer to the Zr-4 substrate. The shear strength of the Zr/TiNbMoCrx heterogeneous interface reached up to 263 MPa, achieving excellent combination between the substrate and coatings. The wear resistance and electrochemical properties significantly improved by TiNbMoCrx coatings, among which the TiNbMoCr0.4 coating exhibited favorable trade-off between wear and corrosion resistance.In-situ EBSD test revealed deformation is initiated preferentially on the Zr-4 side near the interface, which serves as the primary site for interfacial cracks initiation. This study provided novel research insights and experimental evidence for the design of alloy coatings on zirconium alloy surface.
The oxidation behaviour of non-equilibrium, heterogeneous microstructure in spray-deposited superalloys remain insufficiently understood. This study assesses the thermal stability and short-term high-temperature oxidation of thick IN718 deposit processed by high-velocity air fuel (HVAF) spraying. Emphasis was given to the chromia scale formation during oxidation, in relation to the process-induced heterogeneity of splat microstructure. The as-deposited IN718 microstructure exhibits dense splats with a refined cellular substructure and low-angle grain boundary coverage due to rapid solidification and severe plastic deformation. In-situ high temperature X-ray diffraction (HTXRD) revealed excellent thermal stability, low and controlled thermal expansion, and the formation of a stable Cr-rich (Cr,Fe)2O3 above 600 oC along with evolution of γ′′ and δ precipitates. Transmission Electron Microscopy (TEM-EDS) analysis confirms the development of thin (∼205 nm) continuous, and adherent Cr-rich protective oxide layer at the surface after 25h of air exposure at 700 oC. Atom Probe Tomography (APT) revealed process-induced chemical heterogeneity and solute segregation at nanoscale. The inherent microstructure contributed to excellent thermal stability and created short-circuit pathways for chromium diffusion, promoting rapid formation of chromia scale with compositional heterogeneity. These findings provide new insights into the role of non-equilibrium microstructures in governing thermal stability and oxidation resistance in HVAF-deposited IN718.
