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solidification, A-Al Morphologies, Tensile properties and plc of Low-sc Modified Al-Mg Alloys

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ssRN 2023年

作者： Nunes, Anderson Thadeu Lisboa de Gouveia, Guilherme spinelli, José Eduardo Federal University of São Carlos Graduate Program in Materials Science and Engineering SP São Carlos13565905 Brazil Department of Materials Engineering Federal University of São Carlos – UFSCar SP São Carlos13565905 Brazil

Al alloys are very attractive in engineering applications that require a combination of low density and mechanical strength, such as in aeronautical and aerospace industry devices. Therefore, the search for alloys with higher specific strength is justified from environmental and economic points of view. This work aims to study the influence of cooling rates on the phase morphology and tensile properties of ternary Al-Mg-sc alloys, whose composition covers the spectrum of low-sc Al-Mg-sc alloys. The ternary Al-3, -5, and -10wt.% Mg-0.1wt.% sc alloys were processed by transient directional solidification. This process induces a wide range of cooling rates which causes the formation of a microstructural variety along the longitudinal cooling direction and, consequently, different tensile properties. several characterization methods were employed, including: thermal analysis, x-ray diffraction (XRD) structural analysis, sEM-EDs, optical microscopy, CALpHAD, tensile tests, and fractography. Two major findings should be noted after fully characterizing the microstructures, the formed phases, and the tensile properties. solidification evolution revealed that more Mg added resulted in higher solidification rates due to higher fluidity with more Mg. Furthermore, cell growth was mapped in the three alloy compositions while competing with dendrites. second, although the Al-10 wt.% Mg-sc alloy had more Mg in solid solution and slightly higher portevin–Le Chatelier (pLC) severity, the Al-5 wt.% Mg-sc alloy showed superior tensile strength due to the predominance of cells and thinner primary dendrites trunks forming its microstructure. © 2023, The Authors. All rights reserved.

关键词： Aluminum alloys

Layer-by-Layer Assembly of Chitosan and Quince seed Gum polyelectrolytes as a ph-Responsive, On-Off switchable Multilayer Film for Controlled Release of Ibuprofen

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ssRN 2024年

作者： Kaviani, Alireza pircheraghi, Gholamreza Bagheri, Reza Azizi saadatlou, Ghazaleh Demirel, A. Levent Department of Materials Science and Engineering Sharif University of Technology P.O. Box: 11365‐9466 Tehran Iran Materials Science & Engineering Graduate Program Koç University Sarıyer Istanbul34450 Turkey Chemistry Department Koç University Sarıyer Istanbul34450 Turkey

polysaccharide-based multilayer films have shown substantial potential for drug delivery application. Herein, polyelectrolyte multilayers using Chitosan (Cs) and Quince seed gum (QsG) are constructed and the effects of assembly pH, salt concentration, and post-assembly pH are systematically investigated. It was evident that both mass per unit area (10000 ng/cm2) and the wet thickness (107.8 nm) after the deposition of 5 bilayers were accurately estimated by viscoelastic model due to the highly swollen state of films. Atomic Force Microscopy (AFM) could feasibly demonstrate the development of globular structures during the layer-by-layer assembly. Ellipsometry analysis showed that the variation assembly pH resulted in conformational changes from extended to coiled. Consequently, different optical thicknesses as well as transitions from exponential to linear growth were observed. Moreover, extrinsic charge compensation was responsible for coiling or extensive counterion screening of polyelectrolyte chains depending on the NaCl concentration. Cs/QsG films displayed pH-stimulus on–off switching behavior in pH 2 and 7.4 for 3 cycles. The constructed film could absorb 1200 ng/cm2 within 60 min at pH 7.4. The in vitro release kinetic from IBF-loaded samples showed pH dependency. The Cs/QsG multilayer film can be considered as a smart and tunable pH stimuli system for drug loading/release applications. © 2024, The Authors. All rights reserved.

关键词： Chitosan

Optimizing Lpbf-parameters by Box-Behnken Design Allows to print Crack-Free and Dense High-Boron Alloyed stainless steels

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ssRN 2024年

作者： Freitas, Brenda Juliet Martins Koga, Guilherme Yuuki Arneitz, siegfried Bolfarini, Claudemiro de Traglia Amancio-Filho, sergio Federal University of São Carlos Graduate Program in Materials Science and Engineering São Carlos13.565-905 Brazil Graz University of Technology Institute of Materials Science Joining and Forming Graz8010 Austria Federal University of São Carlos Department of Materials Engineering São Carlos13.565-905 Brazil Rod. Washington Luis São Carlos13565-905 Brazil

Boron has almost null solubility in iron, and its addition to stainless steels leads to the formation of hard borides, beneficial for increasing the wear resistance. However, these boron-containing steels have poor printability, with the occurrence of pronounced cracking, high porosity and risk of delamination. In this work Box-Behnken design coupled to analysis of variance (ANOVA) were used to optimize the LpBF (Laser powder Bed Fusion) processing parameters of a highly boron-alloyed stainless steel reinforced with a boride network. The proposed models demonstrated to be accurate to determine the porosity percentage for the studied alloys, in which the laser power and scanning speed play the main role on the alloys’ densification, and absence of extensive defects. These results indicate that the use of design of experiments tools are essential to produce defect-free boron-modified stainless steel specimens with a relatively low number of experiments, identifying a narrow optimized processing window to build bulk composite materials. © 2024, The Authors. All rights reserved.

关键词： Design of experiments

Ultrafine-Grained stainless steel with Wear-Resistant Nanoborides Decorating Grain Boundaries produced by Laser powder Bed Fusion

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ssRN 2024年

作者： Martins Freitas, Brenda Juliet Koga, Guilherme Yuuki Miguel Rodrigues, Luana Cristina Botta Filho, Walter José Amancio-Filho, sergio de Traglia Bolfarini, Claudemiro Federal University of São Carlos Graduate Program in Materials Science and Engineering São Carlos13.565-905 Brazil Graz University of Technology Institute of Materials Science Joining and Forming Graz8010 Austria Federal University of São Carlos Department of Materials Engineering São Carlos13.565-905 Brazil Rod. Washington Luis São Carlos13565-905 Brazil

stainless steel composites combine corrosion resistance and toughness of the metallic matrix with wear resistance granted by hard reinforcing nanoparticles. Given their near-net-shape manufacturing characteristics, additive manufacturing techniques are attractive to produce these hard and wear-resistant classes of materials with low machinability. In this work, from a sAF 2205 duplex stainless steel with boron addition, laser powder bed fusion (LBpF) was employed to produce an ultrafine-grained (~1 µm), dense (porosity ~0.1%), and crack-free ferritic-induced matrix composite with Cr2B-nanoborides reinforcing the grain boundaries (GBs) without formation of Cr-depleted regions. The composite showed significant higher hardness (up to 456 HV0.5) and wear resistance (4.4 x 10-5 mm3 N-1m-1) in sliding condition compared to a hot-rolled (225 HV0.5 and 2.9 x 10-3 mm3 N-1m-1) and a LpBF-produced sAF 2205 (314 HV0.5 and 3.3 x 10-4 mm3 N-1m-1). © 2024, The Authors. All rights reserved.

关键词： Wear of materials

Multi‑Functional Fibrous Dressings for Burn Injury Treatment with pain and swelling Relief and scarless Wound Healing

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Advanced Fiber materials 2023年第6期5卷 1963-1985页

作者： Zhengchao Yuan Yue Zhao Muhammad shafiq Jiahui song Jing Hou Yuqing Liang Xiao Yu Yujie Chen Fan Yu Mohamed EL‑Newehy Hany EL‑Hamshary Yosry Morsi shichao Jiang Hui Zheng Xiumei Mo State Key Laboratory for Modification of Chemical Fibers and Polymer Materials Shanghai Engineering Research Center of Nano‑Biomaterials and Regenerative MedicineCollege of Biological Science and Medical EngineeringDonghua UniversityShanghai 201620People’s Republic of China Department of Chemical Engineering Faculty of EngineeringGraduate SchoolKyushu UniversityFukuoka 819‑0395Japan United Graduate School of Drug Discovery and Medical Information Sciences Gifu University1‑1 YanagidoGifu 501‑1193Japan Department of Orthopedics Shandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinan 250021People’s Republic of China Department of Chemistry College of ScienceKing Saud UniversityP.O.Box 245511451 RiyadhSaudi Arabia Faculty of Engineering and Industrial Sciences Swinburne University of TechnologyBoroondaraVIC 3122Australia Medical Science and Technology Innovation Center Shandong First Medical University&Shandong Academy of Medical SciencesJinan 250117People’s Republic of China Department of Thoracic Surgery Shanghai Pulmonary HospitalTongji University School of MedicineShanghai 200443People’s Republic of China

As one of the most common forms of skin injuries,skin burns are often accompanied by edema pain,suppuration of infection,slow tissue regeneration,and severe scar formation,which significantly delay wound healing as well as affect the quality of *** prepared multifunctional electrospun poly(L-lactide-co-glycolide)/gelatin(p/G)-based dressings to synergistically harness the therapeutic benefits of peppermint essential oil(T),burn ointment(B),and Oregano essential oil(O)(p/G@TBO)for skin regeneration in punch and burn injury *** p/G@TBO can afford the sustained release of bioactive cues for up to 72 h as well as remarkably promote cell migration(ca.p/G@TBO,89%*** group,51%)at 24 *** p/G@TBO membranes also showed significant angiogenic effect as well as antibacterial and anti-inflammatory properties than that of the control group in ***,p/G@TBO dressings enabled fast wound healing(ca.p/G@TBO,100%wound closure *** group,95%)in a full-thickness excisional defect model up to 14 days in *** evaluation of membranes in different animal models,including tail wagging model,facial itch model,and hot burn injury model showed significant pain relieve effect as well as itching and swelling relief functions during earlier stages of wound *** were next transplanted into a scalded wound model in rats and an ear punch wound model in rabbits,which manifested antibacterial and anti-inflammatory properties and promoted re-epithelialization to achieve scarless wound healing percentage wound closure at day 28:p/G@TBO,96%*** group 66%.Taken together our approach of simultaneously harnessing T,B,and O to enable multifunctionality to fibrous dressings may hold great promise for burn wound healing applications and other related disciplines.

关键词： Burn injury Wound healing skin regeneration pain and swelling relief Nanofiber membrane

In-situ synthesis and characterization of lightweight steel matrix composites reinforced by TiB2

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Journal of Alloys and Metallurgical Systems

Journal of Alloys and Metallurgical systems 2024年 7卷

作者： Vidilli, André L. Otani, Lucas B. Koga, Guilherme Y. Amigó, Vicente Bolfarini, Claudemiro Federal University of São Carlos Graduate Program in Materials Science and Engineering Rodovia Washington Luís km 235 SP São Carlos13565-905 Brazil Valencia Spain Rodovia Washington Luís km 235 SP São Carlos13565-905 Brazil

This study aimed to synthesize lightweight steels in situ reinforced with 5 % and 10 vol% of TiB2 and evaluate the microstructural, physical, and mechanical properties. The Fe-(15;20 wt%)Mn-3 wt%Al-0.1 wt%C with 5 and 10 vol% of TiB2 were produced by spray forming followed by hot rolling and annealing. The concept of varying the manganese content was to assess the influence of the matrix constitution on the composite properties. The findings pointed to a direct correlation between the manganese content and the size and morphology of the TiB2 particles. The presence of the ceramic particles re-established the modulus of elasticity above 200 Gpa only for composites with a predominantly ferritic matrix. The composites with a matrix composed mostly of austenite showed no gains in ductility during the tensile tests despite the activation of the TWIp effect. However, their wear behavior stands out positively. © 2024 The Authors

关键词： Tensile testing

Early and advanced crystallization stages in lithia-alumina-silica glasses nucleated by ZrO2

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Ceramics International 2025年

作者： Revelo, Raúl Julián souza, Mauricio Lima pena, Rafaella Bartz Yoshida, satoshi Zanotto, Edgar Dutra Federal University of São Carlos Graduate Program in Materials Science and Engineering SP São Carlos13565-905 Brazil São Carlos Institute of Physics University of São Paulo SP São Carlos13566-590 Brazil Materials Integration Laboratories AGC Inc 1-1 Suehiro-Cho Tsurumi-Ku Kanagawa Yokohama230-0045 Japan

ZrO2 is one of the most effective and widely used nucleating agents in various families of glass-ceramics;however, its detailed mechanism remains a subject of debate. Understanding its nucleation mechanism requires a thorough analysis of microstructural evolution and the identification of factors influencing this process. This study investigates the effects of ZrO2 incorporation on the internal nucleation and microstructural evolution in stoichiometric LAs (Li2O·Al2O3·nsiO2) glass-ceramics of varying composition. Glasses with different siO2 molar ratios (n = 2, 4, 5, and 6) were prepared with ZrO2 additions of 3.0 and 3.5 mol%. several thermal treatments were employed, followed by characterization using XRD, sEM, sTEM, and Raman spectroscopy. The results indicate that a minimum of 3.5 mol% ZrO2 is required to induce internal nucleation in LAs glasses with n = 4, 5, and 6. In these compositions, Zr-enriched regions formed through liquid-liquid phase separation serve as preferential sites for ZrO2 crystal precipitation, which subsequently induces the nucleation of β-quartz solid solution. Upon further treatment at higher temperatures, this metastable phase transforms into β-spodumene or its solid solution. As expected, increasing siO2 content enhances glass network polymerization, as evidenced by the increased presence of Q3 species in Raman spectroscopy, leading to higher characteristic temperatures of glass transition and peak crystallization in DsC analyses. A higher siO2 content results in fewer but larger crystals, whereas a lower siO2 content promotes a higher number density of crystals within the glass matrix. © 2025 Elsevier Ltd and Techna Group s.r.l.

关键词： Glass ceramics

Corrosion-Resistant and Ultrafine-Grained Boron-Containing stainless steel produced by Laser powder Bed Fusion

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ssRN 2024年

作者： Freitas, Brenda Juliet Martins Koga, Guilherme Yuuki de Traglia Amancio-Filho, sergio Bolfarini, Claudemiro Federal University of São Carlos Graduate Program in Materials Science and Engineering São Carlos13.565-905 Brazil Graz University of Technology Institute of Materials Science Joining and Forming Graz8010 Austria Federal University of São Carlos Department of Materials Engineering São Carlos13.565-905 Brazil Rod. Washington Luis SP São CarlosCEP 13565-905 Brazil

Ultrafine-grained stainless steel armored with borides was produced by laser powder bed fusion (L-pBF). The in-situ formed composite was characterized by refined grains of high-alloyed ferritic stainless steel matrix with hard and rigid nanoborides along the grain boundaries. Besides being hard and wear resistant, the resulted material was unsensitized and resistant against pitting corrosion, with corrosion resistance comparable to a sAF 2205 duplex stainless steel. Besides unveiling the microstructural and electrochemical nexus, this work opens positive perspectives to surpass the corrosion-wear resistance trade-off upon the in-situ formation of stainless steel matrix reinforced by hard Cr-containing nanoborides using additive manufacturing technologies. © 2024, The Authors. All rights reserved.

关键词： steel corrosion

Development and Application of a Genetic Algorithm for selecting High Entropy Alloys with Good Combinations of Mechanical properties

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ssRN 2024年

作者： stoco, Caroline Binde Cassar, Daniel Roberto Kaufman, Michael Clarke, Amy Coury, Francisco Gil Federal University of São Carlos Graduate Program in Materials Science and Engineering SP São Carlos Brazil SP Campinas Brazil Center for Advanced Non-Ferrous Structural Alloys George S. Ansell Department of Metallurgical and Materials Engineering Colorado School of Mines GoldenCO United States

A genetic algorithm was developed to search for high entropy alloys (HEAs) with good combinations of mechanical properties. The algorithm was designed to solve a multi-objective problem of finding single-phase face-centered cubic HEAs with high Hall-petch constants and high critical resolved shear stresses. The goal was to obtain an alloy with good ductility and strength. The most promising alloy suggested by the genetic algorithm was an unconventional composition (Co32.73Cu15.11Fe0.72Hf0.72Mn35.97Mo3.96Ni10.43sn0.36);this alloy was experimentally produced and characterized. An advantage of the proposed method is the possibility of more systematically identifying and exploring new compositions in the complex composition space characteristic of these multicomponent alloys. However, the thermodynamic parameters used for this selection process exhibited limitations, which were further explored in the present study, as evidenced by the fact that the microstructure of the selected alloy was not single-phase. © 2024, The Authors. All rights reserved.

关键词： phase equilibria