为解决电弧增材制造TiC颗粒增强Al-Cu合金增强体颗粒团聚与孔隙缺陷等问题,本研究提出并验证了一种基于超音频脉冲(ultrasonic frequency pulse,UFP)电弧调控的熔丝增材制造工艺方法。通过调制电弧热力特性,显著增强了熔池内的对流与紊...为解决电弧增材制造TiC颗粒增强Al-Cu合金增强体颗粒团聚与孔隙缺陷等问题,本研究提出并验证了一种基于超音频脉冲(ultrasonic frequency pulse,UFP)电弧调控的熔丝增材制造工艺方法。通过调制电弧热力特性,显著增强了熔池内的对流与紊流行为,改变了传统Marangoni驱动的单环流模式,形成更加均匀的双环流结构,实现了对熔池温度场和流场的精准控制。基于构建的计算流体力学模型揭示了TiC颗粒在UFP电弧作用下的迁移及其与基体混合的机理,直接实验观测与仿真结果具有很好的一致性。结果表明,相较于常规工艺,UFP电弧有助于显著细化晶粒,提高组织均匀性,改善TiC颗粒的分布状态,降低孔洞与夹杂等典型缺陷的数量,该研究可为高性能Al-Cu合金增材制造提供新路径。展开更多
The hot compression deformation behavior of Mg-6Zn-1Mn-0.5Ca(ZM61-0.5Ca)and Mg-6Zn-1Mn-2Sn-0.5Ca(ZMT612-0.5Ca)alloys was investigated at deformation temperatures ranging from 250℃to 400℃and strain rates varying from...The hot compression deformation behavior of Mg-6Zn-1Mn-0.5Ca(ZM61-0.5Ca)and Mg-6Zn-1Mn-2Sn-0.5Ca(ZMT612-0.5Ca)alloys was investigated at deformation temperatures ranging from 250℃to 400℃and strain rates varying from 0.001 s^(-1) to 1 s^(-1).The results show that the addition of Sn promotes dynamic recrystallization(DRX),and CaMgSn phases can act as nucleation sites during the compression deformation.Flow stress increases with increasing the strain rate and decreasing the temperature.Both the ZM61-0.5Ca and ZMT612-0.5Ca alloys exhibit obvious DRX characteristics.CaMgSn phases can effectively inhibit dislocation motion with the addition of Sn,thus increasing the peak fl ow stress of the alloy.The addition of Sn increases the hot deformation activation energy of the ZM61-0.5Ca alloy from 199.654 kJ/mol to 276.649 kJ/mol,thus improving the thermal stability of the alloy.For the ZMT612-0.5Ca alloy,the optimal hot deformation parameters are determined to be a deformation temperature range of 350–400℃and a strain rate range of 0.001–0.01 s^(-1).展开更多
Received 7 August 2024;received in revised form 13 November 2024;accepted 18 November 2024 Available online 30 November 2024 Abstract The poor fracture toughness limits the widespread application of high-strength cast...Received 7 August 2024;received in revised form 13 November 2024;accepted 18 November 2024 Available online 30 November 2024 Abstract The poor fracture toughness limits the widespread application of high-strength cast Mg-Re-Zn alloys.Regulating the alloy microstructure,with phases such asα-Mg,blocky LPSO(long-period stacking order),and lamellar LPSO,offers various possibilities to enhance ductility by casting and heat treatment.This study categorizes different interface types concerning crack initiation,propagation,and ultimate fracture toughness.It distinctly presents the results of interface modulation related to alloy composition and heat treatment,elucidating the influence on crack initiation and propagation paths.Consequently,it proposes structural configurations rule and relevant heat treatment processes that can optimize and improve alloy fracture toughness.Blocky LPSO should have appropriate dispersion and size while avoiding lamellar LPSO.展开更多
Surface properties of crystals are critical in many fields,including electrochemistry and photoelectronics,the efficient prediction of which can expedite the design and optimization of catalysts,batteries,alloys etc.H...Surface properties of crystals are critical in many fields,including electrochemistry and photoelectronics,the efficient prediction of which can expedite the design and optimization of catalysts,batteries,alloys etc.However,we are still far from realizing this vision due to the rarity of surface property-related databases,especially for multicomponent compounds,due to the large sample spaces and limited computing resources.In this work,we present a surface emphasized multi-task crystal graph convolutional neural network(SEM-CGCNN)to predict multiple surface properties simultaneously from crystal structures.The model is evaluated on a dataset of 3526 surface energies and work functions of binary magnesium intermetallics obtained through first-principles calculations,and obvious improvements are observed both in efficiency and accuracy over the original CGCNN model.By transferring the pre-trained model to the datasets of pure metals and other intermetallics,the fine-tuned SEM-CGCNN outperforms learning from scratch and can be further applied to other surface properties and materials systems.This study could be a paradigm for the end-to-end mapping of atomic structures to anisotropic surface properties of crystals,which provides an efficient framework to understand and screen materials with desired surface characteristics.展开更多
This study investigates the plastic deformation behaviour of the AZ31 magnesium alloy under various uniaxial loading conditions using in-situ neutron diffraction,the crystallite group method(CGM),and crystal plasticit...This study investigates the plastic deformation behaviour of the AZ31 magnesium alloy under various uniaxial loading conditions using in-situ neutron diffraction,the crystallite group method(CGM),and crystal plasticity modelling.A key novelty of this work is the direct,model independent determination of resolved shear stress(RSS)values for individual slip and twinning systems,as well as their critical values(CRSS),derived from lattice strains in grains with preferred orientations.The experiment was extended beyond the conventional loading paths along the normal direction(ND)and rolling direction(RD)to include compression at angles of 30°and 60°from the ND(referred to as NDC30 and NDC60 tests),which had not been investigated in previous studies.Notably,the NDC30 test,combined with diffraction measurements,was specifically designed to activate basal slip in the majority of grains while minimizing twinning,enabling clear identification of this slip system and accurate determination of its CRSS.For the first time,hardening parameters were determined by comparing the model predicted values of RSS with those obtained from diffraction measurements for each active system.These data,together with the results of macroscopic tests,were used to calibrate an elastic-plastic self-consistent(EPSC)model,which accurately reproduced stress partitioning under applied load,texture evolution,and twin activity.The integrated methodology enhances the reliability of CRSS input and improves the modelling of anisotropic plasticity in magnesium alloys by tuning intergranular interactions based on a modified Eshelby inclusion approach.展开更多
Understanding the temperature dependent deformation behavior of Mg alloys is crucial for their expanding use in the aerospace sector.This study investigates the deformation mechanisms of hot-rolled AZ61 Mg alloy under...Understanding the temperature dependent deformation behavior of Mg alloys is crucial for their expanding use in the aerospace sector.This study investigates the deformation mechanisms of hot-rolled AZ61 Mg alloy under uniaxial tension along rolling direction(RD)and transverse direction(TD)at-50,25,50,and 150℃.Results reveal a transition from high strength with limited elongation at-50℃ to significant softening and maximum ductility at 150℃.TD samples consistently showed 2%-6%higher strength than RD;however,this yield anisotropy diminished at 150℃ due to the shift from twinning to thermally activated slip and recovery.Fractography indicated a change from semi-brittle to fully ductile fracture with increasing temperature.Electron backscattered diffraction(EBSD)analysis confirmed twinning-driven grain refinement at low temperatures,while deformation at high temperatures involved grain elongation along shear zones,enabling greater strain accommodation before material failure.展开更多
This comprehensive study investigates the formation and evolution of intermetallic compounds during the solidification process of magnesium alloys using advanced micro X-ray computed tomography.By analyzing both commo...This comprehensive study investigates the formation and evolution of intermetallic compounds during the solidification process of magnesium alloys using advanced micro X-ray computed tomography.By analyzing both common industrial Mg-Al-Zn alloys and a novel rare earth-containing Mg-Ni-Gd-Y alloy,we aim to characterize the nucleation,growth,and distribution of Al-Mn and eutectic intermetallics across various stages of solidification.The non destructive imaging technique employed in this research provides high-resolution,three-dimensional insights into the microstructural development,allowing for a detailed examination of the morphology,spatial arrangement,and interconnectivity of intermetallic phases.This approach overcomes limitations of traditional two-dimensional metallographic methods,offering a more comprehensive understanding of the complex three-dimensional structures formed during solidification.展开更多
The strength-ductility trade-off in magnesium alloys remains a critical challenge urgently requiring resolution in their engineering applications.In this study,both mechanical and corrosion properties are enhanced in ...The strength-ductility trade-off in magnesium alloys remains a critical challenge urgently requiring resolution in their engineering applications.In this study,both mechanical and corrosion properties are enhanced in extruded Mg-Y-Nd-Zr alloys by Sm addition.Sm promotes dynamic recrystallization,activates non-basal slip systems and weakens basal texture intensity,leading to the sub-grain lamellar structure and rare earth texture.The EWS2 alloy exhibits an outstanding combination of high yield strength(328 MPa)and ductility(15.1%).Furthermore,the fragmented second phases in the Sm-containing alloy are uniformly distributed,reducing the subsequent corrosion driving force after micro-galvanic corrosion and facilitating the growth of a more passivating and compact corrosion film.These combined effects contribute to the lowest degradation rate in the EWS2 alloy.This study demonstrates the correlation between microstructure and properties in Sm-containing WE series alloys,providing insights for the design of other high performance magnesium alloys.展开更多
文摘为解决电弧增材制造TiC颗粒增强Al-Cu合金增强体颗粒团聚与孔隙缺陷等问题,本研究提出并验证了一种基于超音频脉冲(ultrasonic frequency pulse,UFP)电弧调控的熔丝增材制造工艺方法。通过调制电弧热力特性,显著增强了熔池内的对流与紊流行为,改变了传统Marangoni驱动的单环流模式,形成更加均匀的双环流结构,实现了对熔池温度场和流场的精准控制。基于构建的计算流体力学模型揭示了TiC颗粒在UFP电弧作用下的迁移及其与基体混合的机理,直接实验观测与仿真结果具有很好的一致性。结果表明,相较于常规工艺,UFP电弧有助于显著细化晶粒,提高组织均匀性,改善TiC颗粒的分布状态,降低孔洞与夹杂等典型缺陷的数量,该研究可为高性能Al-Cu合金增材制造提供新路径。
基金Sichuan Science and Technology Program(2025ZNSFSC1341)Fundamental Research Funds for the Central Universities(J2022-090,25CAFUC04087)。
文摘The hot compression deformation behavior of Mg-6Zn-1Mn-0.5Ca(ZM61-0.5Ca)and Mg-6Zn-1Mn-2Sn-0.5Ca(ZMT612-0.5Ca)alloys was investigated at deformation temperatures ranging from 250℃to 400℃and strain rates varying from 0.001 s^(-1) to 1 s^(-1).The results show that the addition of Sn promotes dynamic recrystallization(DRX),and CaMgSn phases can act as nucleation sites during the compression deformation.Flow stress increases with increasing the strain rate and decreasing the temperature.Both the ZM61-0.5Ca and ZMT612-0.5Ca alloys exhibit obvious DRX characteristics.CaMgSn phases can effectively inhibit dislocation motion with the addition of Sn,thus increasing the peak fl ow stress of the alloy.The addition of Sn increases the hot deformation activation energy of the ZM61-0.5Ca alloy from 199.654 kJ/mol to 276.649 kJ/mol,thus improving the thermal stability of the alloy.For the ZMT612-0.5Ca alloy,the optimal hot deformation parameters are determined to be a deformation temperature range of 350–400℃and a strain rate range of 0.001–0.01 s^(-1).
基金supports from the National Key Research and Development Plan(Grant No.2021YFB3701100)the National Natural Science Foundation of China(Grant No.U2241231,No.52071206).
文摘Received 7 August 2024;received in revised form 13 November 2024;accepted 18 November 2024 Available online 30 November 2024 Abstract The poor fracture toughness limits the widespread application of high-strength cast Mg-Re-Zn alloys.Regulating the alloy microstructure,with phases such asα-Mg,blocky LPSO(long-period stacking order),and lamellar LPSO,offers various possibilities to enhance ductility by casting and heat treatment.This study categorizes different interface types concerning crack initiation,propagation,and ultimate fracture toughness.It distinctly presents the results of interface modulation related to alloy composition and heat treatment,elucidating the influence on crack initiation and propagation paths.Consequently,it proposes structural configurations rule and relevant heat treatment processes that can optimize and improve alloy fracture toughness.Blocky LPSO should have appropriate dispersion and size while avoiding lamellar LPSO.
基金supported by the National Key R&D Program(No.2021YFB3501002)supported by the Ministry of Science and Technology of China,National Natural Science Foundation of China(No.51825101,52127801).
文摘Surface properties of crystals are critical in many fields,including electrochemistry and photoelectronics,the efficient prediction of which can expedite the design and optimization of catalysts,batteries,alloys etc.However,we are still far from realizing this vision due to the rarity of surface property-related databases,especially for multicomponent compounds,due to the large sample spaces and limited computing resources.In this work,we present a surface emphasized multi-task crystal graph convolutional neural network(SEM-CGCNN)to predict multiple surface properties simultaneously from crystal structures.The model is evaluated on a dataset of 3526 surface energies and work functions of binary magnesium intermetallics obtained through first-principles calculations,and obvious improvements are observed both in efficiency and accuracy over the original CGCNN model.By transferring the pre-trained model to the datasets of pure metals and other intermetallics,the fine-tuned SEM-CGCNN outperforms learning from scratch and can be further applied to other surface properties and materials systems.This study could be a paradigm for the end-to-end mapping of atomic structures to anisotropic surface properties of crystals,which provides an efficient framework to understand and screen materials with desired surface characteristics.
基金founded by the National Science Centre,Poland(NCN),under grant no.UMO-2023/49/B/ST11/00774The research(neutron diffraction experiments)leading to this result has been co-funded by the project NEPHEWS under grant agreement no.101131414 from the EU Framework Programme for Research and Innovation Horizon Europe+6 种基金Views and opinions expressed are however those of the author(s)only and do not necessarily reflect those of the European Union.Neither the European Union nor the granting authorities can be held responsible for them.Measurements were carried out at the CANAM infrastructure of the NPI CAS Rez.The employment of the CICRR infrastructure supported by MEYS project LM2023041 is acknowledgedThe Ministry of Education,Youth and Sports of the Czech Republic(MEYS),support of large research infrastructures LM2023057K.M.acknowledges support of the Czech Grant Agency under project no.25-16210SP.K.acknowledges support from the European Union's Horizon 2020 research and innovation program under the NOMATEN teaming grant agreement no.857470the European Regional Development Fund via the Foundation for Polish Science International Research Agenda Plus Program grant no.MAB PLUS/2018/8the Ministry of Science and Higher Education's initiative“Support for the Activities of Centers of Excellence Established in Poland under the Horizon 2020 Program”under agreement no.MEiN/2023/DIR/3795K.W.was partly supported by the program“Excellence initiative-research university”for the AGH University of Krakow.
文摘This study investigates the plastic deformation behaviour of the AZ31 magnesium alloy under various uniaxial loading conditions using in-situ neutron diffraction,the crystallite group method(CGM),and crystal plasticity modelling.A key novelty of this work is the direct,model independent determination of resolved shear stress(RSS)values for individual slip and twinning systems,as well as their critical values(CRSS),derived from lattice strains in grains with preferred orientations.The experiment was extended beyond the conventional loading paths along the normal direction(ND)and rolling direction(RD)to include compression at angles of 30°and 60°from the ND(referred to as NDC30 and NDC60 tests),which had not been investigated in previous studies.Notably,the NDC30 test,combined with diffraction measurements,was specifically designed to activate basal slip in the majority of grains while minimizing twinning,enabling clear identification of this slip system and accurate determination of its CRSS.For the first time,hardening parameters were determined by comparing the model predicted values of RSS with those obtained from diffraction measurements for each active system.These data,together with the results of macroscopic tests,were used to calibrate an elastic-plastic self-consistent(EPSC)model,which accurately reproduced stress partitioning under applied load,texture evolution,and twin activity.The integrated methodology enhances the reliability of CRSS input and improves the modelling of anisotropic plasticity in magnesium alloys by tuning intergranular interactions based on a modified Eshelby inclusion approach.
基金supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Korea Program(No.RS-2025-02603127,Innovation Research Center for Zero-carbon Fuel Gas Turbine Design,Manufacture,and Safety)。
文摘Understanding the temperature dependent deformation behavior of Mg alloys is crucial for their expanding use in the aerospace sector.This study investigates the deformation mechanisms of hot-rolled AZ61 Mg alloy under uniaxial tension along rolling direction(RD)and transverse direction(TD)at-50,25,50,and 150℃.Results reveal a transition from high strength with limited elongation at-50℃ to significant softening and maximum ductility at 150℃.TD samples consistently showed 2%-6%higher strength than RD;however,this yield anisotropy diminished at 150℃ due to the shift from twinning to thermally activated slip and recovery.Fractography indicated a change from semi-brittle to fully ductile fracture with increasing temperature.Electron backscattered diffraction(EBSD)analysis confirmed twinning-driven grain refinement at low temperatures,while deformation at high temperatures involved grain elongation along shear zones,enabling greater strain accommodation before material failure.
基金Project(2023YFB4606200)supported by the National Key Research and Development Program of ChinaProject(2023-SSRF-HZ-503114-2)supported by Shanghai Synchrotron Radiation Facility,Instrument BL16U2,China。
文摘This comprehensive study investigates the formation and evolution of intermetallic compounds during the solidification process of magnesium alloys using advanced micro X-ray computed tomography.By analyzing both common industrial Mg-Al-Zn alloys and a novel rare earth-containing Mg-Ni-Gd-Y alloy,we aim to characterize the nucleation,growth,and distribution of Al-Mn and eutectic intermetallics across various stages of solidification.The non destructive imaging technique employed in this research provides high-resolution,three-dimensional insights into the microstructural development,allowing for a detailed examination of the morphology,spatial arrangement,and interconnectivity of intermetallic phases.This approach overcomes limitations of traditional two-dimensional metallographic methods,offering a more comprehensive understanding of the complex three-dimensional structures formed during solidification.
基金supported by the National Natural Science Foundation of China(Nos.52201119,52371108)Frontier Exploration Project of Longmen Laboratory,China(No.LMQYTSKT014)The Joint Fund of Henan Science and Technology R&D Plan of China(No.242103810056).
文摘The strength-ductility trade-off in magnesium alloys remains a critical challenge urgently requiring resolution in their engineering applications.In this study,both mechanical and corrosion properties are enhanced in extruded Mg-Y-Nd-Zr alloys by Sm addition.Sm promotes dynamic recrystallization,activates non-basal slip systems and weakens basal texture intensity,leading to the sub-grain lamellar structure and rare earth texture.The EWS2 alloy exhibits an outstanding combination of high yield strength(328 MPa)and ductility(15.1%).Furthermore,the fragmented second phases in the Sm-containing alloy are uniformly distributed,reducing the subsequent corrosion driving force after micro-galvanic corrosion and facilitating the growth of a more passivating and compact corrosion film.These combined effects contribute to the lowest degradation rate in the EWS2 alloy.This study demonstrates the correlation between microstructure and properties in Sm-containing WE series alloys,providing insights for the design of other high performance magnesium alloys.
