The microstructure and mechanical properties of a 4130-grade steel processed by L-PBF using a feedstock of low-cost water atomized powder have been investigated considering the effects of powder recycling. Chemical analysis of the recycled powder showed a constant amount of alloying elements with a slight reduction in oxygen content. The as-built microstructure was mainly composed of a martensitic structure separated by a high fraction of low-angle grain boundaries, suggesting the application of a direct tempering treatment starting from the as-built condition as a cost-effective post-process thermal treatment rather than the conventional quench and tempering treatment. Moreover, the degree of anisotropy generated by L-PBF in as-built specimens could be reduced after performing either the direct tempering or the quench and tempering treatments. The possible degradation of powder properties on the steel performance was also investigated. After various powder recycling events, no significant deterioration in tensile properties was measured, indicating that the water atomized powder could be a sustainable feedstock candidate for L-PBF.
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http://dx.doi.org/10.3390/ma15010336 | DOI Listing |
J Am Chem Soc
January 2025
Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, Kowloon 999077, China.
Heterogeneous ice nucleation is a widespread phenomenon in nature. Despite extensive research on ice nucleation near biological antifreeze proteins, a probe for ice nucleation and growth processes at the atomic level is still lacking. Herein, we present simulation evidence of the heterogeneous ice nucleation process on the ice-binding surface (IBS) of the antifreeze protein (TmAFP).
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Beijing Institute of Technology, Research Center of Materials Science, School of Materials Science and Engineering, No.5 South Street of Zhongguancun, Haidian District, 100081, Beijing, CHINA.
Copper (Cu)-based catalysts exhibit distinctive performance in the electrochemical CO2 reduction reaction (CO2RR) with complex mechanism and sophisticated types of products. The management of key intermediates *CO and *H is a necessary factor for achieving high product selectivity, but lack of efficient and versatile strategies. Herein, we designed Pt modified Cu catalysts to effectively modulate the competitive coverage of those intermediates.
View Article and Find Full Text PDFAdv Mater
January 2025
State Key Laboratory of Organic-Inorganic Composites and College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China.
The confining effect is essential to regulate the activity and stability of single-atom catalysts (SACs), but the universal fabrication of confined SACs is still a great challenge. Here, various lattice-confined Pt SACs supported by different carriers are constructed by a universal co-reduction approach. Notably, Pt single atoms confined in the lattice of Ni(OH) (Pt/Ni(OH)) with a high electron-deficient state exhibit excellent activity for basic hydrogen evolution reaction (HER).
View Article and Find Full Text PDFFront Vet Sci
January 2025
Jiangsu Agri-animal Husbandry Vocational College, Taizhou, Jiangsu, China.
Introduction: The H9N2 avian influenza virus is widely disseminated in poultry and poses a zoonotic threat, despite vaccination efforts. Mutations at residue 198 of hemagglutinin (HA) are critical for antigenic variation and receptor-binding specificity, but the underlying molecular mechanisms remain unclear. This study explores the molecular mechanisms by which mutations at the HA 198 site affect the antigenicity, receptor specificity, and binding affinity of the H9N2 virus.
View Article and Find Full Text PDFNat Phys
November 2024
Laboratory of Physical Chemistry, ETH Zürich, Zurich, Switzerland.
A dynamical rearrangement in the electronic structure of a molecule can be driven by different phenomena, including nuclear motion, electronic coherence or electron correlation. Recording such electronic dynamics and identifying its fate in an aqueous solution has remained a challenge. Here, we reveal the electronic dynamics induced by electronic relaxation through conical intersections in both isolated and solvated pyrazine molecules using X-ray spectroscopy.
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