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Nickel and titanium (NiTi) based shape memory alloys (SMAs) are novel materials endowed with exceptional super-elasticity, corrosion resistance, and shape memory capabilities, making them well-suited for biomedical and industrial applications. The current study explores the impact of process parameters in powder mixed micro-electrical discharge milling (µ-EDM) on NiTi SMA, focusing on pulse on time (TON), voltage, pulse off time (TOFF), and RPM individually, employing a one factor at a time (OFAT) methodology to analyze surface characteristics, surface roughness (Ra), and material removal rate (MRR). The impact of black phosphorus powder combined with sesame oil (dielectric) on the surface of fabricated channels in commonly used biomaterials was investigated. The cytotoxicity test for biocompatibility was carried out to enhance the cell viability up to 79.89% after machining, which showed enhanced cell viability. The highest MRR the lowest Ra were obtained at the best input factors combination of 24 µs (TON), 6 µs (TOFF), 240 V, and 50 RPM tool rotation. Improved micro-channel quality was observed with lower TON, voltage, and RPM. [ABSTRACT FROM AUTHOR]

In the present work, 304L-austenitic stainless steel has been successfully processed till two passes of constrained groove pressing (CGP). The processed steel has been characterized using X-ray diffraction and a vibrating sample magnetometer. The XRD patterns and vibrating sample magnetometer confirms phase transformation (austenitic phase to martensitic phase). CGP of 304L austenitic steel improves mechanical properties such as tensile strength, yield strength and micro-hardness. The ultimate tensile strength value improves from 775 MPa to 1156 MPa, the value of yield strength improves from 332 MPa to 639 MPa and the microhardness improves from 244 VHN to 476 VHN for solution-treated, and two pass CGP processed specimens, respectively. The influence of CGP has also been reflected in electron backscatter diffraction (EBSD) results in terms of more substructure formation. The corrosion behavior has been estimated via linear polarization and electrochemical impedance spectroscopy tests. The CGPed 304L steel shows poor resistance to corrosion in comparison to parent steel. Polarization resistance values decrease from 27.88 to 12.63 kO/cm2 which represents loose and less protective passivating film after CGP. [ABSTRACT FROM AUTHOR]

Microwave absorption performance of graphene nanoplatelets based SiC composites have been studied in the present work. Graphene nanoplatelets were dispersed with varying weight fractions viz. 0.5, 1, 2, 2.5 and 3 wt.% in SiC using ultrasonication and ball milling methods. Microwave attenuation behaviour of the prepared composites have been observed in the 2-18 GHz range. The results reflect that dispersion of graphene in SiC proves to be very instrumental in attenuating the incident microwave signals translating into enhanced absorption. The enhancement in the microwave absorption performance is due to the presence of conductive graphene nanoplatelets which is very instrumental in promoting conduction and polarisation losses in the composite translating into enhanced absorption. For 3 wt.% graphene nanoplatelets dispersion in SiC, the value of reflection loss (RL) was obtained as -38.67 dB at 14.67 GHz frequency for 2.2 mm thickness with the corresponding bandwidth of 5 GHz. [ABSTRACT FROM AUTHOR]

Electromagnetic (EM) wave has become an integral part of this electronics dominated era with extensive application in wireless communication, health care, and military applications. This has led to the development of EM wave absorbers for camouflaging the military warheads from the enemy radar tracking systems. The development of these absorbers requires considerable resources viz. time, energy, raw materials and cost. This creates a need for selection of a better absorber from the existing ones rather than the development of a new one to save the valuable resources. The judicious selection of an efficient microwave absorber requires ranking the existing absorbers based on selection criteria. For the first time, an attempt has been made to apply the concept of multi-criteria decisionmaking methods viz. VIKOR and TOPSIS in ranking the microwave absorbers. Core-shell materials provides enhanced EM wave attenuation owing to their hierarchical composite structure which provides a better approach to tune the dielectric and magnetic properties of the composite for obtaining good impedance matching resulting into enhanced absorption. In the present work, magnitude of minimum reflection co-efficient value, absorber thickness, deviation from the central frequency (i.e. 10 GHz) and -10 dB bandwidth have been selected as the criteria for judiciously selecting suitable core-shell based EM wave absorbers in 2-18 GHz. The selected criterion has been assigned distinct weights using Analytic Hierarchy Process (AHP). The AHP derived weights have been employed in TOPSIS and VIKOR analysis for the absorbers ranking and selection. [ABSTRACT FROM AUTHOR]