Iranian Journal of Materials Science and Engineering

• The proposed model provides an efficient tool for predicting extrusion force, deformation geometry, and strain localization in the backward extrusion of ultra-thin-walled tubes.
• The analytically predicted extrusion force shows acceptable agreement with experimental measurements, while the analytically determined deformation depth T exhibits consistent agreement with both metallographic observations and FEM-based strain-field analysis.
• The generality of the analytical framework is demonstrated through extensive parametric analyses covering a range of wall thicknesses, billet radii, and reduction ratios for thin and ultra-thin-walled tubes.

• WC, WC-Co, and WC-Cr specimens were fabricated using spark plasma sintering.
• The influence of the process parameters on final properties of the WC was studied.
• The effect of binders’ content on final performance of the cermets is discussed.     
• The cermets showed higher tribomechanical performance compared to pure WC.   

50.  rGO@Ag₂O composite were synthesized in order to examine their antibacterial activity.
50. The presence of diffraction peaks of rGO as well as Ag/Ag₂O in the XRD pattern of rGO@Ag₂O composite corroborated its successful preparation.
50. The composite revealed higher antibacterial activity against both of gram-negative and gram-positive bacteria, which was attributed to higher number of released Ag⁺ ions and reactive oxygen species by composite, compared to each of rGO and Ag₂O.

• Optimal La doping (0.5 mol%) drastically enhances piezoelectric performance, achieving a high piezoelectric coefficient (d₃₃) of 635 pC/N and an electromechanical coupling factor (k_p) of 0.67.

• Lanthanum acts as a powerful sintering aid, increasing the bulk density to a maximum of 7.34 g.cm^-3 for the 1.0 mol% La-doped sample sintered at 1280°C.
• Significant improvement in dielectric properties is observed, with the relative permittivity (ε_r) reaching 3000 and the dielectric loss (tan δ) remaining low at 0.018 for the 0.5 mol% La composition.
• La substitution effectively refines the microstructure, reducing the average grain size and its standard deviation, which is linked to improved mechanical reliability.
• The developed La-doped PSZTS ceramics demonstrate a superior property combination, making them highly promising for advanced piezoelectric applications such as high-sensitivity transducers, receivers, and large-displacement actuators.

Highlights

• Improvement of surface mechanical properties of the coated materials
• Apply mechanical treatment by impacts on the coated surface
• Examination of the effect of the single shot impacts on the coated surface
• Crystal Grain refinement of the coating layer by mechanical treatments on the coating surface
• Obtain a relationship between impact speed with average grain size

• Rod-like CuO NPs was prepared by a facile sol-gel method.
• CuO NPs has monoclinic crystal structure with Cu²⁺ oxidation state.
• Optical band gap is determined from Tauc plot.
• The synthesized NPs possess enhanced visible PL emission.
• The efficiency and scattering factors were calculated using Mie theory.

• High strength conductive geopolymer for smart building applications.
• Effect of adding carbon black on mechanical and electrical properties.
• Equivalent electrical circuit of pure and conductive geopolymer.
• Conductive geopolymer with stable electrothermal performance.
• The reason for deterioration of electrothermal performance.

• The structural, electronic, optical, and mechanical properties of Ce_0.75Mo_0.25O₂ under hydrostatic pressures have been reported.
•  DFT with Hubbard parameter (U) was adopted to perform the modeled systems.
• The generalized gradient approximation (GGA) supported by the PBE functional has been utilized.
• Incorporating 25% of Mo element into the host CeO₂ lattice leads in dropping the bandgap to 2.045 eV.
• Applying pressures would further reduce the bandgap up to 1.808 eV at 100 GPa.
• Ce_0.75Mo_0.25O₂ under pressures exhibits thermodynamic stability.
• The investigated crystals show potential applications in optoelectronic devices.

• A multiphase Fe₃O₄/ZnTiO₃/MWCNT nanocomposite was successfully engineered as an X‑band impedance‑matching thin film.

• Optimized composition (C4) achieved enhanced filler dispersion and superior electromagnetic matching performance.

• WR‑90 waveguide measurements (8.2–12.4 GHz) confirmed a reflection coefficient of −17.85 dB for a 1 mm thick sample.

• ZnTiO₃ significantly improved impedance matching, while Fe₃O₄ governed magnetic loss and MWCNTs enhanced electrical conductivity.

• Experimental results were validated by CST frequency‑domain simulations with accetable agreement.

• Galvanostatic iron powder deposition was investigated using additive-free sulfate electrolytes at two Fe²⁺ concentrations.
• SEM, XRD, and EDX analyses revealed a strong current-density-driven transition from dendritic α-Fe to fragmented Fe/Fe₃O₄ morphologies.
• Powder yield increased linearly with current density, with empirical models showing excellent agreement with experiments (R² > 0.96).
• High current densities induced intense hydrogen evolution, reduced current efficiency, and promoted multiscale fragmentation of the deposits.
• The environmentally benign electrolyte system provides a robust platform for controlled, high-purity iron powder production relevant to advanced materials processing.

1. A 3D orthogonal woven C/C-SiC- HfC composite was fabricated using I-CVI, SI, and LSI.
2. The composite showed superior ablation resistance compared to C/C and C/C-SiC.
3. HfC incorporation reduced ablation rates by forming a protective HfO2 layer.
4. Residual Si melted at high temperatures, creating a protective SiO2 layer.
5. The HfO2 layer blocked oxygen penetration and improved oxidation resistance.