Electron beam welding (EBW) offers significant production efficiency advantages for Ti alloys in aerospace applications. However, the formation of martensitic α' in the weld joint reduces toughness and fatigue properties, posing safety challenges. To address these issues, this study investigates the effects of annealing below the β transus temperature (mill annealing, MA) and above the β transus temperature (beta annealing, BA) on the microstructure and mechanical properties of EBWed Ti-6Al-4V (Ti64). EBW produced α' in both the fusion zone (FZ) and heat-affected zone due to rapid heating and cooling. MA transformed α' into an α+β basketweave structure, but did not eliminate microstructural gradients. Conversely, BA produced a homogenized microstructure across all regions, characterized by a transformed β phase with a coarse α+β basketweave structure dominantly oriented with prismatic plane. Both annealing processes reduced the amount of low-angle grain boundaries in the FZ compared to the EBWed condition. BA achieved superior mechanical improvements, including a 20 % increase in tensile toughness, a 56 % improvement in fatigue life, and a 100 % improvement in impact toughness. These enhancements are attributed to uniform strain distribution and enhanced fracture resistance facilitated by the basketweave structure. Therefore, this study suggests that BA is the obtimal heat treatment for Ti64 weld joint, significantly improving fatigue cycle and impact toughness, and is refommened for aerospace structural applications.

A cryogenic-temperature–non-circular drawing sequence (CT-NCD) at 123 K was designed to investigate the effects of the deformation stress mode on the twin activation of a commercial pure titanium (CP-Ti) for manufacturing a high-strength CP-Ti wire. A cryogenic tensile test was conducted using a digital image correlation camera in a cryogenic chamber. The cryogenic-tensile strength of CP-Ti was improved by 58.5% and strain was improved by 52.1% when compared with the tensile-test results at room temperature. The CT-NCD was conducted in the cryogenic chamber and the results were compared with those of the room-temperature wire drawing (RT-WD). The numerical and experimental results confirmed that the CT-NCD sequence continued to produce faultless CP-Ti wires. The mechanical properties of the CT-NCD wire showed that the strength increased by 12.6% with comparable ductility, and micro-Vickers hardness increased by 17.4% when compared with that of the RT-WD. The twin map obtained through electron-backscattering diffraction showed that the twinning of the CT-NCD wire significantly increased when compared with that of the RT-WD due to temperature and process effects. From the numerical analysis results, the NCD sequence generated more tensile twin than WD owing to the deformation stress mode change by a die shape. It was concluded that the proposed CT-NCD sequence affects twin activation by deformation stress mode from the die design and temperature changes, compared to the conventional RT-WD, resulting in grain refinement and mechanical property enhancement. Based on the results, CT-NCD is considered useful for manufacturing the high-strength CP-Ti wire for industrial applications.

• A protic ionic liquid, [DBU][H 2 SO 4 ], was incorporated into catalyst layers as a proton-conductive additive to partially replace the perfluorinated ionomers Nafion. • Electrodes with a Nafion:[DBU][H 2 SO 4 ] ratio of 0.5:0.5 showed superior electrochemical performance in both toluene hydrogenation and aqueous hydrogen evolution reaction. • The high ionic conductivity of [DBU][H 2 SO 4 ], combined with Nafion’s mechanical integrity and interfacial robustness, produced a clear synergistic effect. • Thermogravimetric analysis confirmed that [DBU][H 2 SO 4 ] exhibits superior thermal stability compared to Nafion. • This strategy offers a sustainable approach to ionomer design, reducing reliance on perfluorinated compounds while improving overall performance and thermal stability. This study explores the use of a [DBU][H 2 SO 4 ], protic ionic liquid (PIL), as a proton-conductive additive in catalyst layers for proton-coupled electrochemical reactions, aiming to complement or partially replace conventional polymeric ionomers such as Nafion, which has raised increasing concern regarding per- and polyfluoroalkyl substances (PFAS). Electrochemical performance was evaluated using a Pt/C catalyst for two representative electrochemical reactions—the toluene hydrogenation and the hydrogen evolution reaction (HER). Three proton-conducting compositions were compared: Nafion only (1:0), a mixture of Nafion and [DBU][H 2 SO 4 ] (0.5:0.5), and [DBU][H 2 SO 4 ] only (0:1). In both reaction systems, electrodes incorporating the mixed ionomer demonstrated reduced overpotentials, attributed to the higher ionic conductivity of [DBU][H 2 SO 4 ] compared to Nafion. Beyond overpotential reduction, the Nafion–[DBU][H 2 SO 4 ] blend also improved faradaic efficiency and operational stability, outperforming the Nafion-only and [DBU][H 2 SO 4 ]-only configurations. These synergistic improvements arise from the combination of the [DBU][H 2 SO 4 ]’s efficient proton transport with Nafion’s mechanical integrity and interfacial adhesion. Importantly, the partial substitution of fluorinated ionomers with non-fluorinated PILs offers a more sustainable approach to ionomer design. The findings highlight the potential of PILs as co-functional additives that simultaneously enhance electrochemical performance and reduce environmental impact in both organic and aqueous systems.

Inconel 718, a Ni–Fe-based alloy, is applied in aerospace and gas turbine applications owing to its excellent resistance to high temperatures and extreme environments, leading to an increasing demand for improved workability. Delta processing (DP) influences the microstructural characteristics of Inconel 718 via controlled heat treatment to precipitate the δ phase. This study investigated the effect of DP on the microstructure and high-temperature workability of Inconel 718. Homogenization and DP after homogenization were applied to control the initial microstructure. High-temperature compression tests were conducted at 900–1150 °C with strain rates of 0.01–10 s -1 and true strain of 1.0. An Arrhenius-based constitutive model was derived and processing maps were established to evaluate workability. Electron backscatter diffraction analyzed microstructure evolution and relationships among workability, mechanical properties, and microstructure. Surface cracks were observed in specimens homogenized at 1150 °C due to NbC precipitation along grain boundaries. Generally, the δ phase and NbC exhibit competitive precipitation behavior for Nb consumption, and DP can effectively suppress NbC formation by preferentially precipitating the δ phase, preventing grain boundary weakening and crack initiation. Furthermore, the δ phase provides preferential nucleation sites for dynamic recrystallization, promoting grain refinement during deformation. The DP-treated specimens exhibited improved hot workability with enhanced microstructural stability and crack prevention. This study confirmed that DP can improve the hot workability of Inconel 718 by suppressing NbC precipitation, which promotes crack formation, and promoting dynamic recrystallization through recrystallization nucleation, thereby offering insights into microstructure control with guidelines for process design and optimization. • δ phase precipitation increased peak stress and work hardening during hot deformation. • DPed specimen showed lower activation energy and enhanced DRX sensitivity. • Processing maps showed wider high-efficiency domains and better workability in DPed. • δ phase precipitation prevented NbC-induced cracking and improved hot workability. • DPed specimens showed greater DRX and grain refinement with homogeneous structure.

This study aimed to evaluate the effects of dietary protein levels and the use of a probiotic cocktail (Bacillus subtilis and Bacillus licheniformis) on growth performance, apparent digestibility, fecal microbiota, blood profile, and fecal gas emissions in broiler chickens. A total of 225 one-day-old Ross 308 broiler chicks, weighing 48.10 ± 0.86 g, were used in a completely randomized design. Birds were randomly assigned to three dietary treatments, with five replicates per treatment and 15 birds per replicate. Experimental diets were formulated with two protein levels at each feeding phase: a low-protein (LP) diet and a high-protein (HP) diet. The three treatment groups included: (1) HP group (high-protein basal diet), (2) LP group (low-protein basal diet), and (3) LP-P group (low-protein diet supplemented with a probiotic mixture). The HP diet improved body weight and growth metrics compared to the LP diet. However, the LP-P group achieved similar or superior growth performance (ADG, BWG) and feed conversion ratio (FCR) to the HP diet, particularly during the 14-35 day period, indicating that probiotics compensated for the reduced protein content. Probiotics enhanced nitrogen digestibility and reduced ammonia and nitrous oxide emissions compared to the HP diet. Additionally, the LP-P group exhibited lower blood urea nitrogen levels, suggesting improved nitrogen metabolism. Probiotics also showed potential benefits in alleviating metabolic stress and modulating gut microbiota. These findings demonstrate that probiotic supplementation in low-protein diets can sustain broiler growth efficiency while reducing environmental impacts, offering a viable strategy for sustainable poultry production.

Electron beam welding (EBW) offers significant production efficiency advantages for Ti alloys in aerospace applications. However, the formation of martensitic α' in the weld joint reduces toughness and fatigue properties, posing safety challenges. To address these issues, this study investigates the effects of annealing below the β transus temperature (mill annealing, MA) and above the β transus temperature (beta annealing, BA) on the microstructure and mechanical properties of EBWed Ti-6Al-4V (Ti64). EBW produced α' in both the fusion zone (FZ) and heat-affected zone due to rapid heating and cooling. MA transformed α' into an α+β basketweave structure, but did not eliminate microstructural gradients. Conversely, BA produced a homogenized microstructure across all regions, characterized by a transformed β phase with a coarse α+β basketweave structure dominantly oriented with prismatic plane. Both annealing processes reduced the amount of low-angle grain boundaries in the FZ compared to the EBWed condition. BA achieved superior mechanical improvements, including a 20 % increase in tensile toughness, a 56 % improvement in fatigue life, and a 100 % improvement in impact toughness. These enhancements are attributed to uniform strain distribution and enhanced fracture resistance facilitated by the basketweave structure. Therefore, this study suggests that BA is the obtimal heat treatment for Ti64 weld joint, significantly improving fatigue cycle and impact toughness, and is refommened for aerospace structural applications.

A cryogenic-temperature–non-circular drawing sequence (CT-NCD) at 123 K was designed to investigate the effects of the deformation stress mode on the twin activation of a commercial pure titanium (CP-Ti) for manufacturing a high-strength CP-Ti wire. A cryogenic tensile test was conducted using a digital image correlation camera in a cryogenic chamber. The cryogenic-tensile strength of CP-Ti was improved by 58.5% and strain was improved by 52.1% when compared with the tensile-test results at room temperature. The CT-NCD was conducted in the cryogenic chamber and the results were compared with those of the room-temperature wire drawing (RT-WD). The numerical and experimental results confirmed that the CT-NCD sequence continued to produce faultless CP-Ti wires. The mechanical properties of the CT-NCD wire showed that the strength increased by 12.6% with comparable ductility, and micro-Vickers hardness increased by 17.4% when compared with that of the RT-WD. The twin map obtained through electron-backscattering diffraction showed that the twinning of the CT-NCD wire significantly increased when compared with that of the RT-WD due to temperature and process effects. From the numerical analysis results, the NCD sequence generated more tensile twin than WD owing to the deformation stress mode change by a die shape. It was concluded that the proposed CT-NCD sequence affects twin activation by deformation stress mode from the die design and temperature changes, compared to the conventional RT-WD, resulting in grain refinement and mechanical property enhancement. Based on the results, CT-NCD is considered useful for manufacturing the high-strength CP-Ti wire for industrial applications.