Additively manufactured stainless steel exhibits different oxidation and corrosion properties compared with traditional counterparts.Molecular dynamics simulations were performed to systematically investigate Cr diffu...Additively manufactured stainless steel exhibits different oxidation and corrosion properties compared with traditional counterparts.Molecular dynamics simulations were performed to systematically investigate Cr diffusion near nanopores,in order to elucidate the fast formation of dense oxidation layers in laser powder bed fusion processed 304L stainless steel after ion irradiation.The influence of pore diameter and temperature on Cr diffusion was studied in Fe simulation boxes with 1 at.%Cr and random nanometric pores.The results show that the existence of nanopores significantly accelerates Cr diffusion,facilitating the formation of oxide layers.While increasing with temperature,the diffusion coefficient does not increase uniformly with pore diameter.Regarding the nanopores with diameters of 4.82-13.25Å,the diffusion coefficient of Cr in their vicinity is maximized at diameter of about 6Å.The specific fast diffusion paths near the nanopores were exposed and discussed.展开更多
A microscopic understanding of the complex solute-defect interaction is pivotal for optimizing the alloy’s macroscopic mechanical properties.Simulating solute segregation in a plastically deformed crystalline system ...A microscopic understanding of the complex solute-defect interaction is pivotal for optimizing the alloy’s macroscopic mechanical properties.Simulating solute segregation in a plastically deformed crystalline system at atomic resolution remains challenging.The objective is to efficiently model and predict a phys-ically informed segregated solute distribution rather than simulating a series of diffusion kinetics.To ad-dress this objective,we coupled molecular dynamics(MD)and Monte Carlo(MC)methods using a novel method based on virtual atoms technique.We applied our MD-MC coupling approach to model off-lattice carbon(C)solute segregation in nanoindented Fe-C samples containing complex dislocation networks.Our coupling framework yielded the final configuration through efficient parallelization and localized en-ergy computations,showing C Cottrell atmospheres near dislocations.Different initial C concentrations resulted in a consistent trend of C atoms migrating from less crystalline distortion to high crystalline distortion regions.Besides unraveling the strong spatial correlation between local C concentration and defect regions,our results revealed two crucial aspects of solute segregation preferences:(1)defect ener-getics hierarchy and(2)tensile strain fields near dislocations.The proposed approach is generic and can be applied to other material systems as well.展开更多
In this work,the GW63K(Mg-6.54Gd-3.93Y-0.41Zr,wt.%)alloy wire was utilized as the feedstock material and the thin-walled component was fabricated using wire-arc additive manufacturing technology(WAAM).The microstructu...In this work,the GW63K(Mg-6.54Gd-3.93Y-0.41Zr,wt.%)alloy wire was utilized as the feedstock material and the thin-walled component was fabricated using wire-arc additive manufacturing technology(WAAM).The microstructural evolution during deposition and subsequent heat treatment was explained through multi-scale microstructural characterization techniques,and the impact of heat treatment on the strengthductility synergy of the deposited alloy was systematically compared.The results showed that the microstructure of the deposited sample was mainly composed of fine equiaxedα-Mg grains and Mg_(24)(Gd,Y)_(5) phase.The optimized solution heat treatment(450℃×2 h)had little effect on the grain size,but can effectively reduce the Mg_(24)(Gd,Y)_(5) eutectic phase on the grain boundary,resulting in a significant increase in elongation from 13.7% to 26.6%.After peak-aging treatment,the strength of the GW63K alloy increased to 370 MPa,which was significantly higher than the as-built state(267 MPa).The superior strength in this study is attributed to the refinement strengthening imparted by the fine microstructure inherited in the as-built GW63K alloy,as well as the precipitation strengthening due to the formation of dense β’precipitates with a pronounced plate-like aspect ratio.展开更多
The buckling-guided three-dimensional(3D)assembly method has arisen increasing attention for its advantages in forming complex 3D architectures with a rich diversity of geometric shapes in a broad spectrum of inorgani...The buckling-guided three-dimensional(3D)assembly method has arisen increasing attention for its advantages in forming complex 3D architectures with a rich diversity of geometric shapes in a broad spectrum of inorganic functional materials.Such an assembly method relies on the controlled lateral bucking of a 2D precursor structure integrated with a pre-stretched substrate at selective regions.In the assembly process,the preservation or break-ing of rotational symmetry is crucial for understanding the mechanism of 2D-to-3D geometric transformation.Here,we present a fundamental study on the rotational symmetry of 3D spoke double-ring structures formed through buckling-guided assembly.An energetic method is introduced to analyze the rotational symmetry and to understand the symmetry-breaking mechanism.Such symmetry-breaking phenomenon is validated by experi-ments and finite element analyses(FEA).Phase diagrams of the deformation mode are established to shed light on the influences of various geometric parameters(e.g.,initial rotational symmetry order,radius ratio,and lo-cation of bonding sites).This work offers new insights into the underlying mechanism of 2D-to-3D geometric transformation in ribbon-type structures formed by compressive buckling.展开更多
L1_(2)precipitates are known to significantly enhance the strength and ductility of single-phase face-centered cubic(FCC)medium-or high-entropy alloys(M/HEAs).However,further improvements in mechanical properties rema...L1_(2)precipitates are known to significantly enhance the strength and ductility of single-phase face-centered cubic(FCC)medium-or high-entropy alloys(M/HEAs).However,further improvements in mechanical properties remain untapped,as alloy design has historically focused on systems with specific CrCoNi-or FeCoCrNi-based FCC matrix and Ni_(3)Al L1_(2)phase compositions.This study introduces novel Co-Ni-Mo-Al alloys with L1_(2)precipitates by systematically altering Al content,aiming to bridge this research gap by revealing the strengthening mechanisms.The(CoNi)_(81)Mo_(12)Al_(7)alloy achieves yield strength of 1086 MPa,tensile strength of 1520 MPa,and ductility of 35%,demonstrating an impressive synergy of strength,ductility,and strain-hardening capacity.Dislocation analysis via transmission electron microscopy,supported by generalized stacking fault energy(GSFE)calculations using density functional theory(DFT),demonstrates that Mo substitution for Al in the L1_(2)phase alters dislocation behavior,promoting the formation of multiple deformation modes,including stacking faults,super-dislocation pairs,Lomer-Cottrell locks,and unusual nano-twin formation even at low strains.These behaviors are facilitated by the low stacking fault energy(SFE)of the FCC matrix,overlapping of SFs,and dislocation dissociation across anti-phase boundaries(APBs).The increased energy barrier for superlattice intrinsic stacking fault(SISF)formation compared to APBs,due to Mo substitution,further influences dislocation activity.This work demonstrates a novel strategy for designing high-performance M/HEAs by expanding the range of FCC matrix and L1_(2)compositions through precipitation hardening.展开更多
This paper investigates the application of Direct Current Atmospheric Plasma Spraying(DC-APS)as a versatile thermal spray technique for the application of coatings with tailored properties to various substrates.The pr...This paper investigates the application of Direct Current Atmospheric Plasma Spraying(DC-APS)as a versatile thermal spray technique for the application of coatings with tailored properties to various substrates.The process uses a high-speed,high-temperature plasma jet to melt and propel the feedstock powder particles,making it particularly useful for improving the performance and durability of components in renewable energy systems such as solar cells,wind turbines,and fuel cells.The integration of nanostructured alumina(Al_(2)O_(3))thin films into multilayer coatings is considered a promising advancement that improves mechanical strength,thermal stability,and environmental resistance.The study highlights the importance of understanding injection parameters and their impact on coating properties and uses simulation tools such as the Jets&Poudres(JP)code for in-depth analysis.Furthermore,the paper discusses the implementation of Artificial Neural Networks(ANN)to optimize the coating process by predicting flight characteristics and improving operating conditions.The results show that ANN models are effective in achieving highly accurate prediction values,highlighting the potential of AI in improving thermal spray technology.展开更多
To develop Ce based permanent magnets with high performance/cost ratio, Ta doping is was employed to enhance the magnetic performance of Ce-Fe-B alloys. For melt spun Cei7Fe78-xTaxB6 (x = 0-1) alloys, the coercivity H...To develop Ce based permanent magnets with high performance/cost ratio, Ta doping is was employed to enhance the magnetic performance of Ce-Fe-B alloys. For melt spun Cei7Fe78-xTaxB6 (x = 0-1) alloys, the coercivity Hc increases from 439 to 553 kA/m with increasing x value from 0 to 0.75. Microstructure characterizations indicate that Ta doping is helpful for grain refinement. A second phase of TaB2 is observed in Ce17Fe77.25Tao.75B6 alloy, which acts as the pinning center of the magnetic domains, resulting in the change of coercivity mechanism from nucleation type to nucleation +pinning type. The micromagnetic simulation confirms that non-magnetic particles within hard magnetic phase can increase the demagnetization field around them and it is crucial for preventing the further magnetization reverse by pinning effect. Take the advantage of Ta doping for enhancing the coercivity, Ce content of Ce-Fe-B alloy can be further cut down to increase the remanence Jr due to the reduced volume fraction of CeFe2 phase and increased Fe/Ce ratio. As a result, a good combination of magnetic properties with Hc = 514 kA/m, Jr = 0.49 T, and the maximum energy product (BH)max = 36 kJ/m^3 have been obtained in Ce15Fe79.25Tao.75B6 alloy. It is expected that the present work can serve as a useful reference for designing new permanent magnetic materials with low-cost.展开更多
16 Mg-Al-Zn-Bi quaternary alloys were utilized to measure the phase equilibria and transformation temperatures in the Mg-rich Mg-Al-Zn-Bi quaternary system by means of the X-ray diffraction,electron probe micro-analys...16 Mg-Al-Zn-Bi quaternary alloys were utilized to measure the phase equilibria and transformation temperatures in the Mg-rich Mg-Al-Zn-Bi quaternary system by means of the X-ray diffraction,electron probe micro-analysis and differential scanning calorimetry techniques.The isothermal section at 400℃and three vertical sections along Mg-8 wt%Al-0.75 wt%Zn-vBi,Mg-3.4 wt%Al-0.5 wt%Zn-ABi and Mg-6.9 wt%Al-2.3 wt%Zn-xBi in the Mg-Al-Zn-Bi quaternary system were constructed.Based on the literature data,the ternary Mg-Al-Bi and Mg-Bi-Zn systems were re-assessed using the CALculaiton of PHAse Diagram(CALPHAD)approach.The calculated phase equilibria agree well with the measured data.By directly extrapolating the constituent sub-ternary systems,the thermodynamic database for the Mg-Al-Zn-Bi quaternary system was developed.The remarkable consistency between the predicted phase equilibria and the presently measured data in Mg-Al-Zn-Bi quaternary system further demonstrated the accuracy and reliability of the established thermodynamic database.After that,by using the newly developed thermodynamic database,the growth restrict factors and the solidification curves in Bi-containing AZ series magnesium alloys were calculated and analyzed.It was confirmed that the grain size of AZ alloys can be refined with the addition of Bi,and the comp on ent Al had larger grain refinement effect than Bi.Besides,the amount of Bi had also no ticeable effect on the solidification sequence of the AZ alloys.展开更多
<span style="font-family:Verdana;">The covid pandemic points out inconsistencies and points to improve in the organization of healthcare logistics. Indeed, the dangerousness and the propagation process...<span style="font-family:Verdana;">The covid pandemic points out inconsistencies and points to improve in the organization of healthcare logistics. Indeed, the dangerousness and the propagation process of the virus imply to increase health security (patient and personal health). In this context, healthcare logistics flows require a new and safety organization improving the hospital performance. The purpose of this paper consists in optimizing healthcare logistics flows by solving problems associated to the internal logistics such as reduction of the personal health wasting time and the protection of both patients and personal health. Then, the methodology corresponds to the use of the hospital sustainable digital transformation as a response to healthcare flows and safety problems. Indeed, social, societal and environmental aspects have to be considered in addition to new technologies such as artificial intelligence (AI), Internet of Things (IoTs), Big data and analytics. These parameters could be used in the healthcare for increasing doctor, nurse, caregiver performance during their daily operations, and patient satisfaction. Indeed, this hospital digital transformation requires the use of large data associated to patients and personal health, algorithms, a performance measurement tool (actual and future state) and a general approach for transforming digitally the hospital flows. The paper findings show that the healthcare logistics performance could be improved with a sustainable digital transformation methodology and an intelligent software tool. This paper aims to develop this healthcare logistics 4.0 methodology and to elaborate the intelligent support system. After an introduction presenting the common hospital flows and their main problems, a literature review will be detailed for showing how existing concepts could contribute to the elaboration of a structured methodology. The structure of the intelligent software tool for the healthcare digital transformation and the tool development processes will be presented. An example will be given for illustrating the development of the tool.</span>展开更多
Industry 4.0 concepts have brought about a wind of renewal in the organization of companies and their production methods. However, this integration is subject to obstacles when it comes to Small and Medium sized Enter...Industry 4.0 concepts have brought about a wind of renewal in the organization of companies and their production methods. However, this integration is subject to obstacles when it comes to Small and Medium sized Enterprises—SMEs: the costs of new technologies to be acquired, the level of maturity of the company regarding its level of digitization and automation, human aspects such as training employees to master new technologies, reluctance to change, etc. This article provides a new framework and presents an intelligent support system to facilitate the digital transformation of SMEs. The digitalization is realized through physical, informational, and decisional points of view. To achieve the complete transformation of the company, the framework combines the triptych of performance criteria (cost, quality, time) with the notions of sustainability (with respect to social, societal, and environmental aspects) and digitization through tools to be integrated into the company’s processes. The new framework encompasses the formalisms developed in the literature on Industry 4.0 concepts, information systems and organizational methods as well as a global structure to support and assist operators in managing their operations. In the form of a web application, it will exploit reliable data obtained through information systems such as Enterprise Resources Planning—ERP, Manufacturing Execution System—MES, or Warehouse Management System—WMS and new technologies such as artificial intelligence (deep learning, multi-agent systems, expert systems), big data, Internet of things (IoT) that communicate with each other to assist operators during production processes. To illustrate and validate the concepts and developed tools, use cases of an electronic manufacturing SME have been solved with these concepts and tools, in order to succeed in this company’s digital transformation. Thus, a reference model of the electronics manufacturing companies is being developed for facilitating the future digital transformation of these domain companies. The realization of these use cases and the new reference model are growing up and their future exploitation will be presented as soon as possible.展开更多
Background： Lung cancer ranks as the fifth largest of all cancer cases in Thailand. However, it is the first leading cancer in the northern part of Thailand （data from 2003-2007）. There are several predisposing cau...Background： Lung cancer ranks as the fifth largest of all cancer cases in Thailand. However, it is the first leading cancer in the northern part of Thailand （data from 2003-2007）. There are several predisposing causes that lead to lung cancer and one important inducement is particulate matters （PMs）. Lampang Province in Thailand is famous for the ceramic industry, where there are over 200 ceramic industrial factories. PMs are produced during the ceramic manufacturing process and spread throughout all of the working areas. It is very possible that workers could directly inhale PM-contaminated air during working hours. Objective： This study focuses on the toxic effects of PMs collected from ceramic factories on genes and lungs of rats. Methods： PMs collected from six ceramic factories in Lampang Province were extracted using dimethyl sulfoxide （DMSO）. The inductively coupled plasma mass spec- trometry （ICP-MS） and inductively coupled plasma optical emission spectrometry （ICP-OES） were used to analyze the chemical elements at lower and higher concentrations, respectively. Then, the toxicity of PMs on the genes was ex- amined by the Ames test, and subsequently, the effect of PMs on DNA was examined by quantifying the amount of 8-hydroxy-2＇-deoxyguanosine （8-OHdG）. Finally, the toxicity of the PMs on rat＇s lungs was examined by histology. Results： As chemical elements of lower concentrations, cadmium, chromium, nickel, copper, and lead were detected by ICP-MS. As chemical elements of higher concentrations, manganese, magnesium, zinc, iron, potassium, calcium, and sodium were detected by ICP-OES. No mutagenicity in Salmone/la typhimurium was found in the PM extracts from all six factories by utilizing the Ames test. In the histological study, the reduction in spaces of alveolar ducts and sacs, and terminal bronchioles, the thickening of interstitial connective tissues were noted by PM extracts in high amounts （100 and 350 pg）. Female rats were more sensitive to PM extracts than males in terms of their pulmonary damages. Conclusions： PMs were not mutagenic to S. typhimurium but can damage the lung tissue of rats.展开更多
The interaction between{112}<111>deformation twinning and grain boundary in coaxial polycrystalline tantalum under shock compression was studied with molecular dynamics simulation under different grain pair miso...The interaction between{112}<111>deformation twinning and grain boundary in coaxial polycrystalline tantalum under shock compression was studied with molecular dynamics simulation under different grain pair misorientation angles(MA)and geometric compatibility factor(m’).Generally,in the coaxial polycrystal,the value of MA determines the occurrence of twin transfer(TT)or twin blockage(TB),i.e.,twin transfer occurs at MA≤29°with twin blockage otherwise.Under TT,the value of m’affects the selection of twin variants.,i.e.,the twin system with a larger m’is easier to active.The morphology of twin pairs is ruler-shaped and lenticular under TT and TB,respectively,with different thickening mechanisms,including grain boundary dislocation emission.展开更多
Additive manufacturing features rapid production of complicated shapes and has been widely employed in biomedical,aeronautical and aerospace applications.However,additive manufactured parts generally exhibit deteriora...Additive manufacturing features rapid production of complicated shapes and has been widely employed in biomedical,aeronautical and aerospace applications.However,additive manufactured parts generally exhibit deteriorated fatigue resistance due to the presence of random defects and anisotropy,and the prediction of fatigue properties remains challenging.In this paper,recent advances in fatigue life prediction of additive manufactured metallic alloys via machine learning models are reviewed.Based on artificial neural network,support vector machine,random forest,etc.,a number of models on various systems were proposed to reveal the relationships between fatigue life/strength and defect/microstructure/parameters.Despite the success,the predictability of the models is limited by the amount and quality of data.Moreover,the supervision of physical models is pivotal,and machine learning models can be well enhanced with appropriate physical knowledge.Lastly,future challenges and directions for the fatigue property prediction of additive manufactured parts are discussed.展开更多
基金financial support of National Natural Science Foundation of China(Nos.U2241245,52073176 and U22B2067)Natural Science Foundation of Shenyang(No.23-503-6-05)Shanghai Engineering Research Center of High-Performance Medical Device Materials(No.20DZ2255500).
文摘Additively manufactured stainless steel exhibits different oxidation and corrosion properties compared with traditional counterparts.Molecular dynamics simulations were performed to systematically investigate Cr diffusion near nanopores,in order to elucidate the fast formation of dense oxidation layers in laser powder bed fusion processed 304L stainless steel after ion irradiation.The influence of pore diameter and temperature on Cr diffusion was studied in Fe simulation boxes with 1 at.%Cr and random nanometric pores.The results show that the existence of nanopores significantly accelerates Cr diffusion,facilitating the formation of oxide layers.While increasing with temperature,the diffusion coefficient does not increase uniformly with pore diameter.Regarding the nanopores with diameters of 4.82-13.25Å,the diffusion coefficient of Cr in their vicinity is maximized at diameter of about 6Å.The specific fast diffusion paths near the nanopores were exposed and discussed.
基金the funding from the Ger-man Research Foundation(DFG)-BE 5360/1-1 and ThyssenKrupp Europe.
文摘A microscopic understanding of the complex solute-defect interaction is pivotal for optimizing the alloy’s macroscopic mechanical properties.Simulating solute segregation in a plastically deformed crystalline system at atomic resolution remains challenging.The objective is to efficiently model and predict a phys-ically informed segregated solute distribution rather than simulating a series of diffusion kinetics.To ad-dress this objective,we coupled molecular dynamics(MD)and Monte Carlo(MC)methods using a novel method based on virtual atoms technique.We applied our MD-MC coupling approach to model off-lattice carbon(C)solute segregation in nanoindented Fe-C samples containing complex dislocation networks.Our coupling framework yielded the final configuration through efficient parallelization and localized en-ergy computations,showing C Cottrell atmospheres near dislocations.Different initial C concentrations resulted in a consistent trend of C atoms migrating from less crystalline distortion to high crystalline distortion regions.Besides unraveling the strong spatial correlation between local C concentration and defect regions,our results revealed two crucial aspects of solute segregation preferences:(1)defect ener-getics hierarchy and(2)tensile strain fields near dislocations.The proposed approach is generic and can be applied to other material systems as well.
基金Supported by the Industrial Collaborative Innovation Project of Shanghai(Grant No XTCX-KJ-2022-2-11)the National Natural Science Foundation of China(Grant No52073176)。
文摘In this work,the GW63K(Mg-6.54Gd-3.93Y-0.41Zr,wt.%)alloy wire was utilized as the feedstock material and the thin-walled component was fabricated using wire-arc additive manufacturing technology(WAAM).The microstructural evolution during deposition and subsequent heat treatment was explained through multi-scale microstructural characterization techniques,and the impact of heat treatment on the strengthductility synergy of the deposited alloy was systematically compared.The results showed that the microstructure of the deposited sample was mainly composed of fine equiaxedα-Mg grains and Mg_(24)(Gd,Y)_(5) phase.The optimized solution heat treatment(450℃×2 h)had little effect on the grain size,but can effectively reduce the Mg_(24)(Gd,Y)_(5) eutectic phase on the grain boundary,resulting in a significant increase in elongation from 13.7% to 26.6%.After peak-aging treatment,the strength of the GW63K alloy increased to 370 MPa,which was significantly higher than the as-built state(267 MPa).The superior strength in this study is attributed to the refinement strengthening imparted by the fine microstructure inherited in the as-built GW63K alloy,as well as the precipitation strengthening due to the formation of dense β’precipitates with a pronounced plate-like aspect ratio.
基金supported by the National Natural Science Foundation of China(Grant Nos.12225206,11921002,and 12202233)the New Cornerstone Science Foundation through the XPLORER PRIZE,the Tsinghua National Laboratory for Information Science and Technology,a grant from the Institute for Guo Qiang,Tsinghua University(Grant No.2021GQG1009)。
文摘The buckling-guided three-dimensional(3D)assembly method has arisen increasing attention for its advantages in forming complex 3D architectures with a rich diversity of geometric shapes in a broad spectrum of inorganic functional materials.Such an assembly method relies on the controlled lateral bucking of a 2D precursor structure integrated with a pre-stretched substrate at selective regions.In the assembly process,the preservation or break-ing of rotational symmetry is crucial for understanding the mechanism of 2D-to-3D geometric transformation.Here,we present a fundamental study on the rotational symmetry of 3D spoke double-ring structures formed through buckling-guided assembly.An energetic method is introduced to analyze the rotational symmetry and to understand the symmetry-breaking mechanism.Such symmetry-breaking phenomenon is validated by experi-ments and finite element analyses(FEA).Phase diagrams of the deformation mode are established to shed light on the influences of various geometric parameters(e.g.,initial rotational symmetry order,radius ratio,and lo-cation of bonding sites).This work offers new insights into the underlying mechanism of 2D-to-3D geometric transformation in ribbon-type structures formed by compressive buckling.
基金financially supported by the National Research Foundation of Korea grant funded by the Korea government(MSIT)(Nos.NRF-2022R1A5A1030054,NRF-RS-2024-00345498,and NRFRS-2023-00281508)by Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)(HRD Program for Industrial Innovation-No P0023676)+1 种基金funded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)-No 519607530funding from the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation program(Grant Agreement No 865855).
文摘L1_(2)precipitates are known to significantly enhance the strength and ductility of single-phase face-centered cubic(FCC)medium-or high-entropy alloys(M/HEAs).However,further improvements in mechanical properties remain untapped,as alloy design has historically focused on systems with specific CrCoNi-or FeCoCrNi-based FCC matrix and Ni_(3)Al L1_(2)phase compositions.This study introduces novel Co-Ni-Mo-Al alloys with L1_(2)precipitates by systematically altering Al content,aiming to bridge this research gap by revealing the strengthening mechanisms.The(CoNi)_(81)Mo_(12)Al_(7)alloy achieves yield strength of 1086 MPa,tensile strength of 1520 MPa,and ductility of 35%,demonstrating an impressive synergy of strength,ductility,and strain-hardening capacity.Dislocation analysis via transmission electron microscopy,supported by generalized stacking fault energy(GSFE)calculations using density functional theory(DFT),demonstrates that Mo substitution for Al in the L1_(2)phase alters dislocation behavior,promoting the formation of multiple deformation modes,including stacking faults,super-dislocation pairs,Lomer-Cottrell locks,and unusual nano-twin formation even at low strains.These behaviors are facilitated by the low stacking fault energy(SFE)of the FCC matrix,overlapping of SFs,and dislocation dissociation across anti-phase boundaries(APBs).The increased energy barrier for superlattice intrinsic stacking fault(SISF)formation compared to APBs,due to Mo substitution,further influences dislocation activity.This work demonstrates a novel strategy for designing high-performance M/HEAs by expanding the range of FCC matrix and L1_(2)compositions through precipitation hardening.
文摘This paper investigates the application of Direct Current Atmospheric Plasma Spraying(DC-APS)as a versatile thermal spray technique for the application of coatings with tailored properties to various substrates.The process uses a high-speed,high-temperature plasma jet to melt and propel the feedstock powder particles,making it particularly useful for improving the performance and durability of components in renewable energy systems such as solar cells,wind turbines,and fuel cells.The integration of nanostructured alumina(Al_(2)O_(3))thin films into multilayer coatings is considered a promising advancement that improves mechanical strength,thermal stability,and environmental resistance.The study highlights the importance of understanding injection parameters and their impact on coating properties and uses simulation tools such as the Jets&Poudres(JP)code for in-depth analysis.Furthermore,the paper discusses the implementation of Artificial Neural Networks(ANN)to optimize the coating process by predicting flight characteristics and improving operating conditions.The results show that ANN models are effective in achieving highly accurate prediction values,highlighting the potential of AI in improving thermal spray technology.
基金financially supported by the National Natural Science Foundation of China (No. 51774146)the Guangzhou Municipal Science and Technology Program (No. 201605120111410)
文摘To develop Ce based permanent magnets with high performance/cost ratio, Ta doping is was employed to enhance the magnetic performance of Ce-Fe-B alloys. For melt spun Cei7Fe78-xTaxB6 (x = 0-1) alloys, the coercivity Hc increases from 439 to 553 kA/m with increasing x value from 0 to 0.75. Microstructure characterizations indicate that Ta doping is helpful for grain refinement. A second phase of TaB2 is observed in Ce17Fe77.25Tao.75B6 alloy, which acts as the pinning center of the magnetic domains, resulting in the change of coercivity mechanism from nucleation type to nucleation +pinning type. The micromagnetic simulation confirms that non-magnetic particles within hard magnetic phase can increase the demagnetization field around them and it is crucial for preventing the further magnetization reverse by pinning effect. Take the advantage of Ta doping for enhancing the coercivity, Ce content of Ce-Fe-B alloy can be further cut down to increase the remanence Jr due to the reduced volume fraction of CeFe2 phase and increased Fe/Ce ratio. As a result, a good combination of magnetic properties with Hc = 514 kA/m, Jr = 0.49 T, and the maximum energy product (BH)max = 36 kJ/m^3 have been obtained in Ce15Fe79.25Tao.75B6 alloy. It is expected that the present work can serve as a useful reference for designing new permanent magnetic materials with low-cost.
基金The financial support from Hebei Provincial Science and Technology Program of China(Grant no.E2019202234)Research Foundation from Education Department of Hebei Province(Grant no.BJ2018026)-Outstanding Young Talents Plan is acknowledged.
文摘16 Mg-Al-Zn-Bi quaternary alloys were utilized to measure the phase equilibria and transformation temperatures in the Mg-rich Mg-Al-Zn-Bi quaternary system by means of the X-ray diffraction,electron probe micro-analysis and differential scanning calorimetry techniques.The isothermal section at 400℃and three vertical sections along Mg-8 wt%Al-0.75 wt%Zn-vBi,Mg-3.4 wt%Al-0.5 wt%Zn-ABi and Mg-6.9 wt%Al-2.3 wt%Zn-xBi in the Mg-Al-Zn-Bi quaternary system were constructed.Based on the literature data,the ternary Mg-Al-Bi and Mg-Bi-Zn systems were re-assessed using the CALculaiton of PHAse Diagram(CALPHAD)approach.The calculated phase equilibria agree well with the measured data.By directly extrapolating the constituent sub-ternary systems,the thermodynamic database for the Mg-Al-Zn-Bi quaternary system was developed.The remarkable consistency between the predicted phase equilibria and the presently measured data in Mg-Al-Zn-Bi quaternary system further demonstrated the accuracy and reliability of the established thermodynamic database.After that,by using the newly developed thermodynamic database,the growth restrict factors and the solidification curves in Bi-containing AZ series magnesium alloys were calculated and analyzed.It was confirmed that the grain size of AZ alloys can be refined with the addition of Bi,and the comp on ent Al had larger grain refinement effect than Bi.Besides,the amount of Bi had also no ticeable effect on the solidification sequence of the AZ alloys.
文摘<span style="font-family:Verdana;">The covid pandemic points out inconsistencies and points to improve in the organization of healthcare logistics. Indeed, the dangerousness and the propagation process of the virus imply to increase health security (patient and personal health). In this context, healthcare logistics flows require a new and safety organization improving the hospital performance. The purpose of this paper consists in optimizing healthcare logistics flows by solving problems associated to the internal logistics such as reduction of the personal health wasting time and the protection of both patients and personal health. Then, the methodology corresponds to the use of the hospital sustainable digital transformation as a response to healthcare flows and safety problems. Indeed, social, societal and environmental aspects have to be considered in addition to new technologies such as artificial intelligence (AI), Internet of Things (IoTs), Big data and analytics. These parameters could be used in the healthcare for increasing doctor, nurse, caregiver performance during their daily operations, and patient satisfaction. Indeed, this hospital digital transformation requires the use of large data associated to patients and personal health, algorithms, a performance measurement tool (actual and future state) and a general approach for transforming digitally the hospital flows. The paper findings show that the healthcare logistics performance could be improved with a sustainable digital transformation methodology and an intelligent software tool. This paper aims to develop this healthcare logistics 4.0 methodology and to elaborate the intelligent support system. After an introduction presenting the common hospital flows and their main problems, a literature review will be detailed for showing how existing concepts could contribute to the elaboration of a structured methodology. The structure of the intelligent software tool for the healthcare digital transformation and the tool development processes will be presented. An example will be given for illustrating the development of the tool.</span>
文摘Industry 4.0 concepts have brought about a wind of renewal in the organization of companies and their production methods. However, this integration is subject to obstacles when it comes to Small and Medium sized Enterprises—SMEs: the costs of new technologies to be acquired, the level of maturity of the company regarding its level of digitization and automation, human aspects such as training employees to master new technologies, reluctance to change, etc. This article provides a new framework and presents an intelligent support system to facilitate the digital transformation of SMEs. The digitalization is realized through physical, informational, and decisional points of view. To achieve the complete transformation of the company, the framework combines the triptych of performance criteria (cost, quality, time) with the notions of sustainability (with respect to social, societal, and environmental aspects) and digitization through tools to be integrated into the company’s processes. The new framework encompasses the formalisms developed in the literature on Industry 4.0 concepts, information systems and organizational methods as well as a global structure to support and assist operators in managing their operations. In the form of a web application, it will exploit reliable data obtained through information systems such as Enterprise Resources Planning—ERP, Manufacturing Execution System—MES, or Warehouse Management System—WMS and new technologies such as artificial intelligence (deep learning, multi-agent systems, expert systems), big data, Internet of things (IoT) that communicate with each other to assist operators during production processes. To illustrate and validate the concepts and developed tools, use cases of an electronic manufacturing SME have been solved with these concepts and tools, in order to succeed in this company’s digital transformation. Thus, a reference model of the electronics manufacturing companies is being developed for facilitating the future digital transformation of these domain companies. The realization of these use cases and the new reference model are growing up and their future exploitation will be presented as soon as possible.
基金Project supported by the Oncological Society of Thailand under the Royal Patronage of Her Majesty the Queen(No.RE53006)
文摘Background： Lung cancer ranks as the fifth largest of all cancer cases in Thailand. However, it is the first leading cancer in the northern part of Thailand （data from 2003-2007）. There are several predisposing causes that lead to lung cancer and one important inducement is particulate matters （PMs）. Lampang Province in Thailand is famous for the ceramic industry, where there are over 200 ceramic industrial factories. PMs are produced during the ceramic manufacturing process and spread throughout all of the working areas. It is very possible that workers could directly inhale PM-contaminated air during working hours. Objective： This study focuses on the toxic effects of PMs collected from ceramic factories on genes and lungs of rats. Methods： PMs collected from six ceramic factories in Lampang Province were extracted using dimethyl sulfoxide （DMSO）. The inductively coupled plasma mass spec- trometry （ICP-MS） and inductively coupled plasma optical emission spectrometry （ICP-OES） were used to analyze the chemical elements at lower and higher concentrations, respectively. Then, the toxicity of PMs on the genes was ex- amined by the Ames test, and subsequently, the effect of PMs on DNA was examined by quantifying the amount of 8-hydroxy-2＇-deoxyguanosine （8-OHdG）. Finally, the toxicity of the PMs on rat＇s lungs was examined by histology. Results： As chemical elements of lower concentrations, cadmium, chromium, nickel, copper, and lead were detected by ICP-MS. As chemical elements of higher concentrations, manganese, magnesium, zinc, iron, potassium, calcium, and sodium were detected by ICP-OES. No mutagenicity in Salmone/la typhimurium was found in the PM extracts from all six factories by utilizing the Ames test. In the histological study, the reduction in spaces of alveolar ducts and sacs, and terminal bronchioles, the thickening of interstitial connective tissues were noted by PM extracts in high amounts （100 and 350 pg）. Female rats were more sensitive to PM extracts than males in terms of their pulmonary damages. Conclusions： PMs were not mutagenic to S. typhimurium but can damage the lung tissue of rats.
基金financially supported by the Key-Area Re-search and Development Program of GuangDong Province(No.2019B010941001)National Key Laboratory Foundation of Science and Technology on Materials under Shock and Impact(No.6142902220301)+1 种基金Shanghai Engineering Research Center of High-Performance Medical Device Materials(No.20DZ2255500)the Major Science and Technology Infrastructure Project of Material Genome Bigscience Facilities Platform supported by Municipal Development and Reform Commission of Shenzhen.
文摘The interaction between{112}<111>deformation twinning and grain boundary in coaxial polycrystalline tantalum under shock compression was studied with molecular dynamics simulation under different grain pair misorientation angles(MA)and geometric compatibility factor(m’).Generally,in the coaxial polycrystal,the value of MA determines the occurrence of twin transfer(TT)or twin blockage(TB),i.e.,twin transfer occurs at MA≤29°with twin blockage otherwise.Under TT,the value of m’affects the selection of twin variants.,i.e.,the twin system with a larger m’is easier to active.The morphology of twin pairs is ruler-shaped and lenticular under TT and TB,respectively,with different thickening mechanisms,including grain boundary dislocation emission.
基金support of National Natural Science Foundation of China(No.U2241245)support of National Natural Science Foundation of China(No.91960202)+4 种基金National Key Laboratory Foundation of Science and Technology on Materials under Shock and Impact(No.6142902220301)Natural Science Foundation of Shenyang(No.23-503-6-05)support of Opening Project of National Key Laboratory of Shock Wave and Detonation Physics(No.2022JCJQLB05702)Aeronautical Science Foundation of China(No.2022Z053092001)support of Shanghai Engineering Research Center of High-Performance Medical Device Materials(No.20DZ2255500).
文摘Additive manufacturing features rapid production of complicated shapes and has been widely employed in biomedical,aeronautical and aerospace applications.However,additive manufactured parts generally exhibit deteriorated fatigue resistance due to the presence of random defects and anisotropy,and the prediction of fatigue properties remains challenging.In this paper,recent advances in fatigue life prediction of additive manufactured metallic alloys via machine learning models are reviewed.Based on artificial neural network,support vector machine,random forest,etc.,a number of models on various systems were proposed to reveal the relationships between fatigue life/strength and defect/microstructure/parameters.Despite the success,the predictability of the models is limited by the amount and quality of data.Moreover,the supervision of physical models is pivotal,and machine learning models can be well enhanced with appropriate physical knowledge.Lastly,future challenges and directions for the fatigue property prediction of additive manufactured parts are discussed.
