The use of the Laser Metal Deposition (LMD) technology as a manufacturing and repairing technique in industrial sectors like the die and mold and aerospace is increasing within the last decades. Research carried out in the field of LMD process situates argon as the most usual inert gas, followed by nitrogen. Some leading companies have started to use helium and argon as carrier and shielding gas, respectively. There is therefore a pressing need to know how the use of different gases may affect the LMD process due there being a lack of knowledge with regard to gas mixtures. The aim of the present work is to evaluate the influence of a mixture of argon and helium on the LMD process by analyzing single tracks of deposited material. For this purpose, special attention is paid to the melt pool temperature, as well as to the characterization of the deposited clads. The increment of helium concentration in the gases of the LMD processes based on argon will have three effects. The first one is a slight reduction of the height of the clads. Second, an increase of the temperature of the melt pool. Last, smaller wet angles are obtained for higher helium concentrations.
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http://dx.doi.org/10.3390/ma11081388 | DOI Listing |
Materials (Basel)
December 2024
State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, No. 127, Youyi Road (West), Xi'an 710072, China.
This study explores the fatigue behavior and fracture mechanisms of TC11 titanium alloy formed by laser metal deposition (LMD) and subjected to double annealing. The research focuses on how the alloy's unique microstructure, consisting of alternating equiaxed and columnar crystals, influences its fatigue performance. The microstructure's basket-like α' phase, made up of both plate-shaped and needle-like structures, leads to variations in crack growth behavior, as shown in the relationship between the crack growth rate and the stress intensity.
View Article and Find Full Text PDFSci Rep
January 2025
Department of ECE, Kallam Haranadhareddy Institute of Technology, Guntur, Andhra Pradesh, India.
Cognitive load stimulates neural activity, essential for understanding the brain's response to stress-inducing stimuli or mental strain. This study examines the feasibility of evaluating cognitive load by extracting, selection, and classifying features from electroencephalogram (EEG) signals. We employed robust local mean decomposition (R-LMD) to decompose EEG data from each channel, recorded over a four-second period, into five modes.
View Article and Find Full Text PDFTransl Psychiatry
December 2024
Wellcome Centre for Integrative Neuroimaging, University of Oxford, OX3 9DU, Oxford, United Kingdom.
Depression and anxiety are associated with deficits in adjusting learning behaviour to changing outcome contingencies. This is likely to drive and maintain symptoms, for instance, by perpetuating negative biases or a sense of uncontrollability. Normalising such deficits in adaptive learning might therefore be a novel treatment target for affective disorders.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Key Laboratory of Quantum Precision Measurement of Zhejiang Province, School of Physics, Zhejiang University of Technology, Hangzhou 310023, China.
This article addresses the knowledge gap regarding the effect of Ti addition on the microstructure and corrosion behavior of the LMD-processed GH3536 alloy in a simulated solution of proton exchange membrane fuel cells (PEMFCs). The microstructural evolution, corrosion resistance, and passive film characteristics of LMD-processed GH3536 alloy with varying Ti contents were characterized through a variety of techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), electron backscatter diffraction (EBSD), X-ray photoelectron spectroscopy (XPS), and a series of electrochemical measurements. The results indicate that the corrosion resistance of the LMD-processed GH3536 alloy significantly improves with increasing Ti content.
View Article and Find Full Text PDFCarbohydr Polym
January 2025
University of Potsdam, Germany. Electronic address:
Biochemical analysis of plastidial phosphorylase (Pho1)-deficient mutants of rice strongly suggests that Pho1 plays an important role in the initiation of starch biosynthesis in the endosperm. The present study examined structures and amounts of maltodextrins, malto-oligosaccharides (MOS) as well as sugars in maturing rice endosperm and compared between a pho1-mutant line EM633 and its wild-type cultivar Taichung-65 (TC65). By using a gel permeation HPLC from developing rice endosperm of both lines, branched maltodextrins (BMD) with distinct fine structure could be isolated for the first time, a possible intermediate in the initiation process of starch biosynthesis, whereas its amount was much lower than starch content in both endosperms.
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