Key Engineering Materials Vol. 1061

Abstract: Several group 13 elements-based materials offer excellent performance in alkali metal ion batteries due to their high capacity and self-repairing capabilities, providing a good balance between energy and power density. Germanium carbide (GeC) has been developed and studied as an anode material for lithium (Li), boron (B), aluminum (Al), and gallium (Ga) ion batteries. This is because it forms nanoclusters such as Ge(Li₂)C, Ge(B₂)C, Ge(A_l2)C, and Ge(Ga₂)C, which have been identified using density functional theory (DFT) calculations. Extensive research has been conducted on these complexes using computational methods, including the analysis of charge density differences (CDD), total density of states (TDOS), and electron localization function (ELF) to understand the behavior of these hybrid clusters. When a small amount of Li, B, Al, or Ga enters the Ge-C layer, it helps maintain electrode stability even in the presence of numerous ions, improving the battery's capacity retention. Increasing the amount of Ge and C can enhance battery capacity through these nanoclusters, as well as improve conductivity for faster battery operation. Additionally, using GeC as an anode may prolong battery life by preventing electrode degradation and increasing capacity due to improved surface effects. This research article discusses recent advancements in anodes made from boron, aluminum, or gallium, as well as their energy storage capabilities. It also explores how DFT studies can address upcoming scientific challenges and provides insights into future research directions.

Abstract: The Pb₁₀₋ₓYₓ(PO₄)₆(OH)₂ compounds were synthesized by solid-state reaction at 825 °C across a broad composition range (0 ≤ x ≤ 2.0) to examine the extent of yttrium substitution in the lead hydroxyapatite structure. Through high-resolution X-ray diffraction (XRD), the compositions are shown to crystallize in a hexagonal apatite structure (space group P6₃/m) up to x ≈ 1.0 with single-phase purity. The Pb²⁺ ions are found to be promptly substituted by Y³⁺ ions resulting in a linear contraction of the lattice parameters a and c in accordance to Vegard’s law, suggesting the involvement of yttrium ions into the apatite lattice. At high substitution levels (x ≥ 1.2), the appearance and increase of typical YPO₄ reflections, mainly the (120) peak indicates the beginning of the secondary phase development caused by the solubility limit of Y³ in the structure. Lattice parameters, atomic positions, high-quality fit (Rwp = 8.45%, χ² = 1.24) during Rietveld refinement of representative samples indicates a high order crystal structure. The main phosphate vibrational modes are retained according to Fourier-transform infrared spectroscopy with small spectral shifts and band broadening suggesting Y³⁺ incorporation causes lattice distortions. SEM analyses indicates that the microstructure is made up of relatively even, solid, polyhedral, highly crystalline grains. The evidences show the definite correlation of yttrium substitution with the structure evolution and phase stability of lead phosphate apatite, and as a result, guidance on how to rationally design ceramic components of advanced functional ceramics for environmental and other technical applications.

Abstract: This work presents ANSYS Workbench simulations analyzing fatigue crack propagation in high-performance aluminum alloys 2524-T3, 2024-T42, and 2024-T351 under stress ratios R = 0.1, 0.3, and 0.5 using pre-meshed crack tools and SMART Fracture automation. Key simulation outputs include crack length evolution, cycle count, equivalent stress intensity factor ranges (ΔK), and crack resistance curves (Kr). At R = 0.1, 2524-T3 exhibited the highest crack growth rate (da/dN = 3.20×10⁻⁸ mm/cycle, ΔK = 7.28 MPa√m, Nf ≈ 459×10⁶ cycles), while 2024-T351 showed the lowest rate (da/dN = 2.76×10⁻⁹ mm/cycle, ΔK = 1.65 MPa√m, Nf ≈ 5.27×10⁹ cycles) — a 10.4-fold reduction in da/dN and 11.5-fold increase in fatigue life. At R = 0.5, 2024-T351 achieved da/dN < 1.0×10⁻⁸ mm/cycle with Nf > 6×10⁹ cycles, outperforming 2024-T42 (da/dN = 3.82×10⁻⁹ mm/cycle, Nf ≈ 2.92×10⁹) and 2524-T3 (da/dN = 2.76×10⁻⁹ mm/cycle, Nf ≈ 5.27×10⁹). Kr curve analysis revealed steep resistance decay for 2524-T3 (R = 0.1), stable plateau behavior for 2024-T42 (R = 0.3–0.5), and rising Kr trends for 2024-T351 across all R-ratios, indicating active crack-tip shielding mechanisms. SEM fractography validated simulation trends: 2524-T3 showed brittle trans granular features with secondary crack density of 12.3 ± 2.1 cracks/mm²; 2024-T42 exhibited mixed-mode fracture with moderate dimple density (8.7 ± 1.4 μm⁻²); 2024-T351 displayed ductile dimple morphology with the highest dimple density (18.4 ± 2.6 μm⁻²) and minimal secondary cracking (2.1 ± 0.8 cracks/mm²). These microstructural metrics confirm 2024-T351 as the optimal candidate for fatigue-critical aerospace and automotive applications.