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1. Mitigation of copper corrosion in the presence of an organic oxyanion through microstructural optimization

   Acharjee, A; Ghiara, G; Beech, IB; Fields, MW; Amendola, R (December 2025, Corrosion science)

   The investigation aimed to determine whether altering metal microstructure by introducing special grain boundaries through annealing could reduce the corrosion damage observed in the presence of pyruvate. Oxygen-free pure copper coupons were annealed at 325°C, 475°C and 950°C for varying durations to optimize the formation of ∑3 special boundaries. Samples annealed at 475°C for 30 min had the highest yield of such boundaries, thus, were selected for testing. Annealed and as-received, untreated, copper specimens were exposed under stagnant conditions to an aqueous oxic solution of sodium pyruvate for 30 days. Microscopy, spectroscopy, and electrochemical methods were employed to characterize the specimens prior to and following pyruvate exposure. Pyruvate caused localized corrosion of copper seen as micro pitting, irrespective of the specimen treatment. Reduced pitting severity and a decrease in the corrosion rate by 32 % were recorded for annealed coupons when compared to as-received ones. It is proposed that the difference in thickness and morphology of the oxide layer between annealed and as-received coupons, evidenced through electrochemical techniques, is the likely contributor to the improved corrosion resistance of annealed coupons. 

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2. Compressive-tensile yield asymmetry and aging-induced embrittlement in a selective laser melted 17-4 PH stainless steel

   https://doi.org/10.1016/j.msea.2025.149537  

   Wang, William; Farkoosh, Amir R; Raturi, Abheepsit; Eliaz, Noam; Seidman, David N (January 2026, Materials Science and Engineering: A)

   We studied the compressive-tensile yield asymmetry (CTYA) and its sensitivity to standard post-processing treatments for a 17-4 PH stainless steel processed with selective laser melting (SLM). Quasistatic tensile and compression tests at ambient temperatures reveal a consistent CTYA for all tested conditions, with compressive yield strengths exceeding tensile values. In the as-printed state, yield asymmetry (Δσ) is ∼113 MPa. Stress-relieving at 300 °C results in only a marginal decrease in asymmetry (Δσ ∼109 MPa), suggesting that the residual stresses generated during SLM have a negligible effect on the observed CTYA. Our analyses indicate that “dynamic softening” due to a stress-assisted austenite-to-martensite transformation governs the yield behavior similar to that observed in transformation-induced plasticity (TRIP)-assisted steels containing mechanically unstable retained austenite. This interpretation is further supported by the increased asymmetry, Δσ ∼127 MPa, observed in a solution-treated and aged specimen, which has a slightly higher retained austenite volume fraction (24 % vs. 21 %). Direct aging at 482 °C of the as-printed steel with a ferritic microstructure causes severe embrittlement. Brittle fracture occurs under tensile stresses well below the yield strength. This pronounced loss of ductility most likely arises from a strong <001> fiber texture along the build direction developed during SLM, which is known to promote cleavage-type fracture on {001} planes. A solution treatment at 1000 °C for 1 h, austenitizes the microstructure completely, and subsequent quenching produces a predominantly martensitic structure with a much weaker crystallographic texture, which restores a favorable strength-ductility balance after aging. 

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3. Nanostructuring of Additively Manufactured 316L Stainless Steel Using High-Pressure Torsion Technique: An X-ray Line Profile Analysis Study

   https://doi.org/10.3390/ma17020454  

   Gubicza, Jenő; Mukhtarova, Kamilla; Kawasaki, Megumi (January 2024, Materials)

   Experiments were conducted to reveal the nanostructure evolution in additively manufactured (AMed) 316L stainless steel due to severe plastic deformation (SPD). SPD-processing was carried out using the high-pressure torsion (HPT) technique. HPT was performed on four different states of 316L: the as-built material and specimens heat-treated at 400, 800 and 1100 °C after AM-processing. The motivation for the extension of this research to the annealed states is that heat treatment is a usual step after 3D printing in order to reduce the internal stresses formed during AM-processing. The nanostructure was studied by X-ray line profile analysis (XLPA), which was completed by crystallographic texture measurements. It was found that the as-built 316L sample contained a considerable density of dislocations (1015 m−2), which decreased to about half the original density due to the heat treatments at 800 and 1100 °C. The hardness varied accordingly during annealing. Despite this difference caused by annealing, HPT processing led to a similar evolution of the microstructure by increasing the strain for the samples with and without annealing. The saturation values of the crystallite size, dislocation density and twin fault probability were about 20 nm, 3 × 1016 m−2 and 3%, respectively, while the maximum achievable hardness was ~6000 MPa. The initial <100> and <110> textures for the as-built and the annealed samples were changed to <111> due to HPT processing. 

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4. Synergistic Thermal and Electron Wind Force-Assisted Annealing for Extremely High-Density Defect Mitigation

   https://doi.org/10.3390/ma17133188  

   Rahman, Md Hafijur; Todaro, Sarah; Waryoba, Daudi; Haque, Aman (July 2024, Materials)

   This study investigates the effectiveness of combined thermal and athermal stimuli in mitigating the extremely high-density nature of dislocation networks in the form of low-angle grain boundaries in FeCrAl alloy. Electron wind force, generated from very low duty cycle and high current density pulses, was used as the athermal stimulus. The electron wind force stimulus alone was unable to remove the residual stress (80% low-angle grain boundaries) due to cold rolling to 25% thickness reduction. When the duty cycle was increased to allow average temperature of 100 °C, the specimen could be effectively annealed in 1 min at a current density of 3300 A/mm2. In comparison, conventional thermal annealing requires at least 750 °C and 1.5 h. For specimens with 50% thickness reduction (85% low-angle grain boundaries), the electron wind force was again unable to anneal the defects even at 3300 A/mm2 current density and average temperature of 100 °C. Intriguingly, allowing average concurrent temperature of 200 °C eliminated almost all the low-angle grain boundaries at a current density of 700 A/mm2, even lower than that required for the 25% thickness reduced specimens. Comprehensive electron and X-ray diffraction evidence show that alloys with extremely high defect density can be effectively annealed in less than a minute at approximately 200 °C, offering a substantial improvement over conventional high-temperature annealing. 

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5. Structure-Property Relationships of Differently Heat-Treated Binder Jet Printed Co-Cr-Mo Biomaterial

   https://doi.org/10.1016/j.mtcomm.2023.107716  

   Khademitab, M; Rodriguez_de_Vecchis, P; Staszel, P; Vaicik, M_K; Chmielus, M; Mostafaei, A (November 2023, Materials Today Communications)

   This investigation systematically examines the influence of sintering temperature and aging treatment on the density, microstructure evolution, phase formation, and mechanical properties of a binder jet printed Co-Cr-Mo biomedical alloy. Sintering at 1380 °C for 2 h yielded a near-fully dense part (99.1%) with favorable mechanical properties (up to 325 HV0.1 hardness and up to 693 MPa ultimate tensile strength). The grain size remained unchanged after aging at 800 °C for 24 h (89 ± 21 µm). Aging resulted in increased microhardness and tensile strength due to phase formation (Cr23C6, CrMo, and ε phase), but a significant decrease in ductility. Consequently, the sintered and aged specimen exhibited higher hardness (522 HV0.1), yield strength (641 MPa), and ultimate tensile strength (854 MPa) compared to cast Co-Cr-Mo alloy. Biocompatibility testing with fibroblasts showed a cell viability of 95 ± 2%, indicating that binder jet printing did not affect the biocompatibility of the Co-Cr-Mo alloy. Exemplary printed parts including hip-joint, partial denture, and small-scale knee joint were successfully demonstrated. This study highlights the comparable properties of binder jet Co-Cr-Mo alloy to the cast alloy, affirming its potential for biomedical applications. 

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