1,720,974 research outputs found
Interfacial characteristics of austenitic 316L and martensitic 15-5PH stainless steels joined by laser powder bed fusion
No full textLaser powder bed fusion (LPBF) is an additive manufacturing (AM) technology capable of producing complex geometry components from a range of metals and alloys. The static mechanical strength of LPBF manufactured materials can rival that of the equivalent cast and wrought materials, but are more susceptible to fatigue failures due to stress concentrating roughness and porosity defects. The ability to process and join multiple powder materials within a single LPBF build process is an emerging capability that is now becoming commercially available. This new capability offers the possibility of compositional complexity, in addition to the geometric complexity offered by AM, and can help to eliminate the need for additional processing to join different materials. This study focuses on the combination of 316 L austenitic stainless steel (SS) and precipitation hardening 15–5PH martensitic SS by LPBF. The interfacial characteristics and microhardness variation at the interface were investigated by optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, electron backscatter diffraction, and microhardness testing. Good apparent bonding was observed at the interface without any visible cracks or defects. A finer-grain region was observed at a distance of 115 μm below the interface with a grain size of about 25% of that in the surrounding 15–5PH SS. A narrow compositional transition distance of 7 μm along the building direction (less than the 30 μm LPBF layer thickness) and a wavey-morphology interface with an amplitude of about 66 μm (about twice the LPBF layer thickness) were found. A sharp change of hardness was measured within ±200 μm from the interface. Regions far from the interface exhibited similar microstructure and hardness as the corresponding single material components. The results suggest that LPBF joining between 316 L SS and 15–5PH SS can achieve each material's distinct microstructure and properties at far-interface regions, with a narrow wavey region (∼115 μm) at the interface that exhibits high densification and a sharp transition in microstructure and properties.</p
Dataset in support of the journal article 'Interfacial characteristics of austenitic 316L and martensitic 15–5PH stainless steels joined by laser powder bed fusion'
No full textOriginal data of plots in accepted manuscript submitted to Material Characterization "Interfacial characteristics of austenitic 316L and martensitic 15-5PH stainless steels joined by laser powder bed fusion" https://doi.org/10.1016/j.matchar.2023.112719</span
3D food printing: a comprehensive review and critical analysis on technologies, food materials, applications, challenges, and future prospects
No full text3D (three-dimensional) food printing has emerged as a transformative technology, offering exceptional adaptability and customization across various industries. This review explores its potential to enhance environmental sustainability by minimizing food waste, improving portion control, and promoting eco-friendly practices. Key technological foundations, such as rheological assessments for material fow optimization, colorimetric analysis for accurate color representation, and advanced material handling techniques for consistent texture and nutrition, are critically examined. Moreover, it highlights the synergy between mechanical precision, algorithmic control, and material science, illustrating how these elements collectively ensure adherence to high-quality and safety standards in food engineering. The study also reviews 3D food printing technologies, methods, materials, and applications, emphasizing the pivotal role of customization in addressing diverse dietary, cultural, medical, and aerospace needs. A SWOT (strengths, weaknesses, opportunities, and threats) analysis evaluates the current capabilities and limitations of the technology, identifying challenges and future prospects. This comprehensive analysis underscores the potential of 3D food printing to revolutionize food production, ofering valuable insights for researchers, practitioners, and policymakers
Micro-scratching behavior of heat-treated cutting chips of Inconel 718
No full textThe present work investigates the micro-scratching behavior of Inconel 718 alloy processed by machining and subsequent heat-treatment. As-machined chips were heat-treated at 700 °C, 800 °C, and 900 °C, all for a short duration of 15 min, followed by water quenching to allow the precipitation of γ
I and γ
II phases. Microstructural analysis of the processed Inconel 718 chips revealed the formation of nano-size precipitates either along the grain boundaries or at the triple junctions, which contributed to the improved mechanical property compared to the solution annealed sample. It was found that the chips heat-treated at 700 °C possessed the highest average hardness (548 Kgf/mm
2) among all the sample conditions. High hardness of as-machined chips and short heat-treatment at 700 °C led bimodal microstructure and precipitation pining resulting in maximum wear resistance compared to other heat-treatment conditions. Subsequently, to verify the outcome, worn surface analysis of as-machined and subsequently heat-treated chips was performed. Comparatively, larger size cracks in sample heat-treated at 900 °C attributed to a high cracking scratch zone in the processed material, i.e., less wear resistance, whereas no/nominal crack in as-machined chips and chips heat-treated at 700 °C attributed to no cracking scratch zone.
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Synthesis of MG-Al-Zn alloy nanoparticles via laser ablation and deposited on porous silicon for enhancement in the spectral responsivity
No full textIn this research, the nanoparticles (NPs) of magnesium alloy (Mg–Al-Zn) were prepared using a laser ablation technique in a solution and then deposited on porous silicon. The structural characterization, electrical, and spectral properties of the nanoparticles deposited on the porous silicon were investigated. Firstly, the initial alloy was made as a bulk nanostructured alloy using high-pressure torsion processing at a grain size of 100 nm and then subjected to laser ablation at different powers of 500, 600, 700, 800, and 900 mJ, to produce metallic nanoparticles at a minimum particle size of 5.6 nm. Secondly, metallic nanoparticles were deposited on the porous silicon. Porous silicon (PS) was fabricated by photo-electrochemical etching (PECE) on an n-type crystalline silicon (c-Si) wafer with (111) orientation An etching current density of 20 mA/cm2 was applied for 15 min in an etchant medium of a 20% concentration of HF in the aforementioned etching process. The resultant particles were analyzed using the X-ray diffraction (XRD) technique, scanning electron microscopy (SEM), and UV–visible spectrophotometry, as well as the electrical properties and photodetection studies were achieved here. The XRD data indicated the presence of Mg–Al-Zn NPs with a hexagonal wurtzite structure at a distinct diffraction peak at 28.5°. The morphological characteristics of Mg–Al-Zn nanoparticles deposited on the porous silicon indicated that the nanoparticle layer predominantly comprises particles with various shapes and sizes, randomly distributed on the porous silicon, with a relatively large particle size of an average of 24.15 nm when using a laser power of 500 mJ in the ablation process. The optical characteristics of the synthesized nanoparticles showed a rise in the value of the band gap with the augmentation of wavelength. Current–voltage (I-V) characterization showed there was an ohmic contact between deposited samples and electrodes. The photo-detector investigation yielded spectrum responsivity curves with three distinct zones. The initial region in the curve is ascribed to the assimilation of ultraviolet (UV) radiation by the Mg–Al-Zn NPs. The second region was attributed to the absorption of visible light by the PS layer, whereas the third peak resulted from the edge absorption of the Si substrate. The Mg–Al-Zn NPs/PS photodetector demonstrated a responsivity of 0.41 A/W when using a laser intensity of 900 mJ. The findings of this work open the way for future investigations to utilize such complex metallic systems as in Mg–Al-Zn NPs in photodetectors and optoelectronic devices utilizing complex metallic systems with advanced properties
Dataset in support of the University of Southampton Doctoral Thesis 'Microstructural engineering for enhanced fatigue performance using laser powder bed fusion' by Anqi Liang.
No full textDataset in support of the University of Southampton Doctoral Thesis 'Microstructural engineering for enhanced fatigue performance using laser powder bed fusion' by Anqi Liang.
This dataset contains the original data of plots in PhD thesis.
Related projects:
Microstructural engineering for enhanced fatigue performance using laser powder bed fusion
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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