Aayush Gupta

This study reports the development of brass slag-reinforced LM30 Al matrix composites fabricated through the powder metallurgy route with reinforcement concentration ranging from 2.5 to 10 wt.%. Microstructural analysis confirmed a uniform dispersion of brass slag particles and faceted primary Si within the Al-Si matrix. The density of the composite samples decreased with increasing brass slag concentration owing to the lower intrinsic density of the brass slag reinforcement as compared with the LM30 matrix, while porosity remained below 2%, indicating effective consolidation of powder. Hardness has been improved gradually from 50.02 HRB for LM30 alloy to 73.10 HRB for the composite sample containing 10 wt.% reinforcement. Compressive tests revealed a significant increase in yield and ultimate compressive strength with brass slag addition. Although the ductility has been decreased with increasing concentration of reinforcement. The results demonstrated good interfacial bonding between LM30 alloy and brass slag during sintering. Also, brass slag (an industrial by-product) can serve as a cost-effective and sustainable reinforcement, significantly enhancing the mechanical performance of Al alloys while contributing to waste utilization.

Lanthanum-doped bismuth titanate (BLT) was synthesized via high-energy ball milling to improve its dielectric and ferroelectric properties. Structural analysis using X-ray diffraction confirmed the successful incorporation of La³⁺ into the Bi₄Ti₃O₁₂ lattice, resulting in reduced crystallite size (BIT 15.28 nm and BLT 16.02 nm ) and enhanced lattice distortion. Scanning electron microscopy revealed particle sizes of approximately 11–12 nm, while TEM confirmed nanoscale crystallinity with less than 20 nm particle dimensions. Raman spectroscopy further validated structural modifications, including TiO₆ octahedral distortions induced by La substitution. The dielectric performance showed a significant increase in the dielectric constant from 142 (BIT) to 176.3 (BLT) at 100 Hz, alongside reduced dielectric loss (BIT 1.89, BLT 2.18), attributed to enhanced space-charge polarization at grain boundaries. Ferroelectric hysteresis loops demonstrated improved remnant polarization, increasing from 5.19 μC cm⁻² (BIT) to 6.94 μC cm⁻² (BLT), while retaining a low coercive field. The study highlights the potential of La-doped Bi₄Ti₃O₁₂ as an efficient dielectric and ferroelectric material for high-performance applications in non-volatile memory devices and high-temperature capacitors. Quantitative results validate the effectiveness of mechanical alloying as a cost-efficient and scalable synthesis route, offering a platform for future optimization of dopant concentrations and processing conditions to maximize material performance.

This study describes the impact of single- and dual-sized Fe slag particles as reinforcement on an Al alloy composite microstructural and mechanical property. These composite samples were fabricated through a liquid metallurgy method (stir casting). Optical microscopy analysis was performed to investigate the distribution of Fe slag particles along with microstructure modifications upon adding Fe slag. The primary Si has been refined compared to the base LM30 alloy. The study combines fine (F) and coarse (C) slag particles. LM30 + 15 wt.% (F:C-4:1) Fe Slag reinforced composite shows the maximum microstructure refinement. Further, mechanical tests such as stress-strain analysis and impact testing were performed to evaluate fabricated samples strength, ductility, and impact resistance. The maximum increment in yield and ultimate tensile strength has been observed that is, ∼32% and ∼33%, (respectively) compared to base alloy. However, increased Fe slag content reduces ductility (∼62%) due to enhanced hindrance to defect mobility. Dual-range composites exhibited higher mechanical strength than single-range Fe slag reinforced composites, attributed to microstructure refinement. Surface analysis of the fractured sample indicates brittle fracture behavior with stress concentrations around Fe slag particles. Impact strength decreases (∼25%) with higher Fe slag content, reflecting increased brittleness of the composite sample compared to base alloy.

In this work, we have functionalized ZnO nanoparticles (NPs) with N-[3-(tri-methoxy-silyl)-propyl]-ethylenediamine to prepare hybrid ZnO/Ag nanostructures. A multi-technique characterization approach has been adopted to unravel structural, morphological and optical properties of the pristine ZnO and hybrid ZnO/Ag nanostructures. The presence of silver nanoparticles on ZnO is supported by XRD, SEM and EDS. SEM results show the presence of silver NPs on the surface of ZnO nanoparticles. Raman analysis reveals a significant broadening and shift of peaks towards lower energy along with reduction in E₂ mode intensity for ZnO/Ag hybrid nanostructures, specifying lower crystallinity as compared to ZnO NPs. A higher concentration of defects is supported by Nelson-Riley factor analysis for ZnO/Ag-I hybrid. Photoluminescence quenching shows the high charge-separation efficiency or low electron–hole recombination of hybrid nanostructures. An improvement in the photocatalytic activity of ZnO/Ag-I and ZnO/Ag-II hybrid nanostructures is observed for the degradation of methylene blue, nitrophenol and doxycycline dyes as compared to ZnO. Photocatalytic performance further improved with increase in Ag content due to surface phonon resonance mechanism leading to augmented charge separation.