Studies on the Effect of Laser Shock Peening Intensity on the Mechanical Properties of Wire Arc Additive Manufactured SS316L

This study examines the impact of laser shock peening (LSP) on the mechanical properties, microstructural features, and elemental distribution of stainless steel 316L (SS316L) produced using wire arc additive manufacturing (WAAM). The investigation focuses on significant changes in mechanical behavior, surface topography, and porosity following LSP treatment, comparing these results to the untreated condition. LSP treatment significantly enhanced the ultimate tensile strength (UTS) and yield strength (YS) of WAAM-fabricated SS316L samples. The UTS of the as-manufactured WAAM specimen was 548 MPa, which progressively increased with higher LSP intensities to 595 MPa for LSP-1, 613 MPa for LSP-2, and 634.5 MPa for LSP-3, representing a maximum improvement of 15.8%. The YS showed a similar trend, increasing from 289 MPa in the as-manufactured specimen to 311 MPa (LSP-1) and 332 MPa (LSP-2), but decreasing to 259 MPa for LSP-3, indicating over-peening effects. Microstructural analysis revealed that LSP induced severe plastic deformation and reduced porosity from 14.02% to 4.18%, contributing to the improved mechanical properties. Energy dispersive spectroscopy (EDS) analysis confirmed the formation of an oxide layer post-LSP, with an increase in carbon (C) and oxygen (O) elements and a decrease in chromium (Cr) and nickel (Ni) elements on the surface, attributed to localized pressure and heat impacts. LSP-treated samples exhibited enhanced mechanical performance, with higher tensile strengths and improved ductility at higher laser intensities. This is due to LSP effectively enhancing the mechanical properties and structural integrity of WAAM-fabricated SS316L, reducing porosity, and refining the microstructure. These improvements make the material suitable for critical applications in the aerospace, automotive, and biomedical fields

A La-doped ZnO ultra-flexible flutter-piezoelectric nanogenerator for energy harvesting and sensing applications: a novel renewable source of energy

Doped zinc oxide nanorods synthesized via a wet chemical approach were used to fabricate an ultra-flexible flutter-piezoelectric nanogenerator (UF-PENG) for superior energy harvesting and self-powered sensing applications.</p

Design and development of Cu‐Al‐Mn‐Ni shape memory alloy coated optical fibre sensor for condition‐based monitoring of physical systems

Abstract Online fault detection, isolation and recovery using smart sensors play an important role in intelligent manufacturing system. Fibre optic sensors are very interesting for condition monitoring applications due to the advantage of this technology. Here, the experimental demonstration of Cu‐based shape memory alloy (SMA) coated optical fibre for temperature‐based sensing applications is reported. The benefit of Cu‐based SMA coated optical fibre over conventional metallic coating has been evaluated in the study. For consistent coating, an in situ fixture with a rotary drive setup has been designed and developed. Thermo optic test bench has been developed to study the actuation characteristics of the SMA coated optical fibre for varying current and voltage. Experiments were performed to investigate the light intensity in the SMA coated optical fibre at different actuation conditions. The displacement that takes place in the optical fibre due to the external temperature stimuli will create proportional intensity and wavelength shifts. The maximum average displacement of 4.9 mm has been achieved for Cu‐Al‐Mn‐Ni coated optical fibre. Results show variation in the optical fibre signal due to heating and cooling of the fibre from the applied electrical stimulus on Cu‐based SMA coating in the form of austenite to martensite transformation

Investigating the various properties of cold sprayed CuAlNi shape memory alloys developed by post annealing process

CuAlNi shape memory alloy (SMA) has wide scope in vibration damping applications for machine tools. A bespoke cold spray based additive manufacturing system was used to fabricate CuAlNi SMA precursor structures of two different compositions with optimized deposition parameters, which were subsequently alloyed via annealing. The two compositions of CuAlNi chosen for the study were Cu rich in wt% (Cu-82%, Al-14%, Ni-4%) and the Ni rich in wt% (Cu-12%, Al-2%, Ni-80%) shape memory alloy material. The various properties of developed samples were compared with commercially available CuAlNi structure. The properties compared include surface morphology, crystal structure, phase transformation temperature, and mechanical properties were studied with scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) compression testing respectively. The shape memory characteristics were also analyzed using dynamic mechanical analyzer (DMA). Among the two samples, Cu rich sample exhibited better SMA qualities than Ni rich sample as reported in the literature. The micro-hardness of Cu rich sample was to be 356 ± 3 VHN comparatively lower than Ni rich sample. The DSC results revealed the phase transformation hysteresis for Cu rich sample to be very low at 5 ± 3°C. The Cu rich CuAlNi SMA showed very good shape memory characteristics in the DMA results in the range of 50°C to 100°C. </jats:p

Effect of Addition of KI on the Hydrothermal Growth of ZnO Nanostructures Towards Hybrid Optoelectronic Device Applications

We report the structural and optoelectronic properties of Zinc oxide (ZnO) nanostructures prepared by hydrothermal method. The morphological, structural and optical properties of the grown ZnO nanostructures were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence spectroscopy (PL) respectively. Upon addition of relatively small amount of KI during the in-situ hydrothermal growth the nanorods were formed, further increasing the concentration led to increased diameter of these nanorods and finally at relatively higher concentration of KI, ZnO nanosheets were formed. Later these structures were used to fabricate bi-layer ZnO/P3HT based hybrid photodiode. Subsequent hybrid photodiode measurement with ZnO nanorods and ZnO nanosheets indicated that the nanosheets exhibited improved photodiode response. Compared to the ZnO nanorod/P3HT devices, the optimized photodiode with the dense ZnO nanosheets/P3HT have shown significant increase in the rectification ratio and the photosenstivity from 3.21 to 1420 and from 5.85 to 1330 respectively. The enhanced photodiode response of bi-layered devices consisting of ZnO nanosheets indicated that optimizing the shape and size of ZnO nanostructures had a significant influence on the overall photocurrent and the observed results have been explained on the basis of reduction in the defect density with pronounced absorption in the UV region, thus leading to improved transmission of light in the visible range through these layers.</jats:p