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Journal of Materials Science & Technology 2021年第36期95卷 1-9页

作者： Ruifeng Dong Hongchao Kou yuhong zhao Xiaoyang Zhang Ling Yang Hua Hou School of Materials Science and Engineering North University of ChinaTaiyuan030051China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China

Profound and comprehensive investigations on the morphology characteristics ofαprecipitates are essential for the microstructural control of metastableβtitanium *** the very beginning of aging treatment,intragranularαprecipitates with a dot-like morphology begin to generate nearby the dislocations,then those dot-likeαprecipitates with the same crystallographic orientation tend to connect with each other to develop a lath-like *** the progress of aging treatment,the orientated lath-likeαprecipitates gradually combine with each other to form the V-shaped clusters or the triangular *** dislocations of{110}_(β)βedge type are evidenced within theβgrains,and it is found that variant selection ofαprecipitates induced by the transformation strain and the interplay betweenαvariants and the dislocations are confirmed as the key factors for the formation of the V-shaped or triangular *** results of this work could provide underlying knowledge on the morphology characteristics of intraguranularαprecipitates related to the crystal defects and the strain accommodation ofαvariants in metastableβtitanium alloys.

关键词： Metastableβtitanium alloys αPrecipitates Morphology characteristics Phase transformation Strain accommodation Dislocations

Effect of Zr, Hf, and Sn Additives on Elastic Properties of α2-Ti3Al Phase by First-principles Calculations

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Journal of Wuhan University of Technology(Materials Science) 2017年第4期32卷 944-950页

作者：张超彦侯华 zhao yuhong YANG Xiaomin HAN Peide College of Materials Science and Engineering North University of China Taiyuan 030051 China College of Materials Science and Engineering Taiyuan University of Technology Taiyuan 030024 Chino

First-principles calculations within density functional theory have been carried out to investigate α2 phase in the Ti3Al based alloy with Zr, Hf, and Sn（6.25at%） elements doped. The lattice constants, total energies and elastic constants were calculated for the supercells. The formation enthalpies, bulk modulus, shear modulus, Young＇s modulus, and intrinsic hardness were investigated. The ductility of the doped α2 phases was analyzed by the Cauchy pressure, G/B and Poisson＇s ratio. The results show that the substitution of Ti（6 h） by Zr, Hf, and the substitution of Al（2n） by Sn can make the doped α2 phase more stable. The inflexibility and hardness of α2 phase can be enhanced by doping with Zr and Hf, while Sn brings the opposite effect. Sn is more powerful to improve the ductility of the doped α2 phase than Hf, but Zr can increase the brittleness. The densities of states（DOS and PDOS） and the difference charge density are obtained to reveal the underlying mechanism of the effect of alloying elements.

关键词： α2-Ti3Al neutral element ambient ductility first-principles

Crystallographic evidences for twin-assisted eutectic growth in undercooled Ni-18.7 at.%Sn eutectic melts

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Journal of Materials Science & Technology 2023年第4期135卷 65-79页

作者： Fan Zhang Jianbao Zhang Xinlei Lü Ke Hua yuhong zhao Haifeng Wang State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi’an 710072China School of Materials Science and Engineering North University of ChinaTaiyuan 030051China

Rapid solidification in undercooled Ni-18.7 at.%Sn eutectic melts was observed in-situ by a high-speed high-resolution camera and the microstructures were characterized in detail by electron backscattering *** the first time,the exact crystallographic orientation relations(ORs)between HCP-Ni_(3)Sn(α-Ni)subsets were *** HCP-Ni_(3)Sn,the{1121}and/or{1122}twin ORs(i.e.,HCP-Ni_(3)Sn twins)hold independently on undercooling,whereas forα-Ni,the{111}twin OR is the case at low undercooling and would hold initially at intermediate and high *** roles of twinning and allotropy transformation(i.e.,FCC-Ni_(3)Sn→HCP-Ni_(3)Sn)were integrated to reveal the formation mechanism of HCP-Ni_(3)Sn twins,and a reversed OR transition analysis was carried out for rep-resentative samples from low to high ***,novel twin-assisted eutectic growth was found to occur all *** this basis,we showed that the single nucleation mode of Herlach is followed,and speculated that primary and secondary coupled eutectic dendrite growth and un-coupled growth ofα-Ni and FCC-Ni_(3)Sn might all be the origins of anomalous *** work would shed some lights on the long-time controversies about the nucleation mode and the formation mechanism of anomalous eutectics in undercooled eutectic alloys.

关键词： Twin-assisted eutectic growth Allotropy transformation Nucleation mode Anomalous eutectics Undercooling

Machine Learning Design of Aluminum-Lithium Alloys with High Strength

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Computers, Materials & Continua 2023年第11期77卷 1393-1409页

作者： Hongxia Wang Zhiqiang Duan Qingwei Guo Yongmei Zhang yuhong zhao College of Semiconductors and Physics North University of ChinaTaiyuan030051China 2 School of Materials Science and Engineering Collaborative Innovation Center of Ministry of Education and Shanxi Province for High-Performance Al/Mg Alloy MaterialsNorth University of ChinaTaiyuan030051China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing100083China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang110004China

Due to the large unexplored compositional space,long development cycle,and high cost of traditional trial-anderror experiments,designing high strength aluminum-lithium alloys is a great *** work establishes a performance-oriented machine learning design strategy for aluminum-lithium alloys to simplify and shorten the development *** calculation results indicate that radial basis function(RBF)neural networks exhibit better predictive ability than back propagation(BP)neural *** RBF neural network predicted tensile and yield strengths with determination coefficients of 0.90 and 0.96,root mean square errors of 30.68 and 25.30,and mean absolute errors of 28.15 and 19.08,*** the validation experiment,the comparison between experimental data and predicted data demonstrated the robustness of the two neural network *** tensile and yield strengths of Al-2Li-1Cu-3Mg-0.2Zr(wt.%)alloy are 17.8 and 3.5 MPa higher than those of the Al-1Li4.5Cu-0.2Zr(wt.%)alloy,which has the best overall performance,*** demonstrates the reliability of the neural network model in designing high strength aluminum-lithium alloys,which provides a way to improve research and development efficiency.

关键词： Aluminum-lithium alloys neural network tensile strength yield strength

Microstructure and damping properties of LPSO phase dominant Mg-Ni-Y and Mg-Zn-Ni-Y alloys

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Journal of Magnesium and Alloys 2024年第3期12卷 1131-1153页

作者： Ruopeng Lu Kai Jiao Nanting Li Hua Hou Jingfeng Wang yuhong zhao College of Materials Science and Engineering North University of ChinaTaiyuan 030051China College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

This work studied the microstructure,mechanical properties and damping properties of Mg_(95.34)Ni_(2)Y_(2.66) and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys *** difference in the evolution of the long-period stacked ordered(LPSO)phase in the two alloys during heat treatment was the *** morphology of the as-cast Mg_(95.34)Ni_(2)Y_(2.66)presented a disordered *** heat treatment at 773 K for 2 hours,the eutectic phase was integrated into the matrix,and the LPSO phase maintained the 18R *** Zn partially replaced Ni,the crystal grains became rounded in the cast alloy,and lamellar LPSO phases and more solid solution atoms were contained in the matrix after heat treatment of the Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)*** Zn and the heat treatment had a significant effect on *** dislocation internal friction peaks and grain boundary internal friction peaks were found after temperature-dependent damping of the Mg_(95.34)Ni_(2)Y_(2.66)and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)*** heat treatment,the dislocation peak was significantly increased,especially in the alloy Mg_(95.34)Ni_(2)Y_(2).*** annealed Mg_(95.34)Ni_(2)Y_(2.66)alloy with a rod-shaped LPSO phase exhibited a good damping performance of 0.14 atε=10^(−3),which was due to the difference between the second phase and solid solution atom *** factors also affected the dynamic modulus of the *** results of this study will help in further development of high-damping magnesium alloys.

关键词： Mg-Ni-Y alloys Mg-Zn-Ni-Y alloys LPSO phase Heat treatment Microstructure Damping properties.

First-principles Investigation of the Structural, Electronic and Elastic Properties of Al_2Ca and Al_4Sr Phases in Mg-Al-Ca(Sr) Alloy

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Journal of Wuhan University of Technology(Materials Science) 2014年第5期29卷 1049-1056页

作者：杨晓敏侯华 zhao yuhong YANG Ling HAN Peide College of Materials Science and Engineering North University of China College of Materials Science and Engineering Taiyuan University of Technology

First-principles calculations have been carried out to investigate the structural stabilities, electronic structures and elastic properties of Mg17Al12, Al2Ca and Al4Sr phases. The optimized structural parameters are in good agreement with the experimental and other theoretical values. The calculated formation enthalpies and cohesive energies show that Al2Ca has the strongest alloying ability, and Al4Sr has the highest structural stability. The densities of states （DOS）, Mulliken electronic populations, and electronic charge density difference are obtained to reveal the underlying mechanism of structural stability. The bulk modulus, shear modulus, Young＇s modulus, and Poisson＇s ratio are estimated from the calculated elastic constants. The mechanical properties of these phases are further analyzed and discussed. The Gibbs free energy and Debye temperature are also calculated and discussed.

关键词： Mg-Al alloys electronic structure elastic properties thermodynamics properties first- principles

Phase-Field Simulation of δ Hydride Precipitation with Interfacial Anisotropy

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Computers, Materials & Continua 2023年第11期77卷 1425-1443页

作者： Hailong Nie Xincheng Shi Wenkui Yang Kaile Wang yuhong zhao School of Materials Science and Engineering Collaborative Innovation Center of Ministry of Education and Shanxi Province for High-Performance Al/Mg Alloy MaterialsNorth University of ChinaTaiyuan030051China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing100083China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang110004China

Previous studies ofδhydride in zirconium alloys have mainly assumed an isotropic *** practice,the difference in crystal structure at the interface between the matrix phase and the precipitate phase results in an anisotropic *** the purpose of probing the real evolution ofδhydrides,this paper couples an anisotropy function in the interfacial energy and interfacial *** influence of anisotropic interfacial energy and interfacial mobility on the morphology ofδhydride precipitation was investigated using the phase-field *** results show that the isotropy hydride precipitates a slate-like morphology,and the anisotropicδhydride precipitates at the semi-coherent and non-coherent interfaces exhibited parallelogram-like and needle-like,which is consistent with the actual experimental *** with the coherent interface,the semi-coherent or non-coherent interface adjusts the lattice mismatch,resulting in lower gradient energy that is more consistent with the true interfacial ***,an important chain of relationships is proposed,in the range of I_(x)1.5I_(x)),with the increase of the anisotropic mobility I_(y) in the y-axis,the gradient energy increases(decreases),the tendency of the non-coherent(semi-coherent)relationship at the interface,and the precipitation rate of hydride decreases(increases).Furthermore,the inhomogeneous stress distribution around the hydride leads to a localized enrichment of the hydrogen concentration,producing a hydride *** study of interfacial anisotropy is informative for future studies ofδhydride precipitation orientation and properties.

关键词： Zirconium δhydride phase-field method interfacial anisotropy interfacial mobility

Dissolution and reprecipitation of 14H-LPSO structure accompanied by dynamic recrystallization in hot-extruded Mg_(89)Y_(4)Zn_(2)Li_(5) alloy

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Journal of Magnesium and Alloys 2023年第4期11卷 1408-1421页

作者： Wei Liu Yu Su Yuntao Zhang Liwen Chen Hua Hou yuhong zhao College of Materials Science and Engineering North University of ChinaTaiyuan 030051China

We investigate the variation induced in long-period stacking ordered(LPSO)structures,dynamic recrystallization(DRX),and mechanical performance of hot-extruded Mg89Y4Zn2Li5 alloys fabricated at different extrusion speeds(Ve=0.4,0.8,1.0,1.2 mm/s)and die angles(α=30°,60°,90°)under 400℃,the dissolution and reprecipitation of 14H LPSO structure accompanied by DRX process are then clarified in *** all extrusion conditions,the block 18R LPSO structures elongate in the extrusion direction,while the lamellar 14H LPSO structures dissolve under the deformation *** addition,due to discontinuous and continuous DRX mechanisms,all hot-extruded alloys have a full DRX microstructure consisting of equiaxed recrystallized grains,but the DRX grain size reduces when both extrusion speed and die angle *** that,in the interior of DRX grains,thin LPSO lamellae mixing 14H,18R and 24R structures nucleate and dynamically precipitate due to the dissolution of the original lamellar 14H LPSO ***,the hot-extruded Mg_(89)Y_(4)Zn_(2)Li_(5)alloy becomes stronger as decreasing of the extrusion speed and die angle,whereas the ductility remains nearly ***,the hotextruded Mg_(89)Y_(4)Zn_(2)Li_(5)alloy achieves an excellent strength-ductility balance at a relatively low extrusion speed(0.4 mm/s)and small die angle(30°)mainly due to the elongated 18R LPSO structure,fine and full DRX microstructure,thin mixed LPSO precipitates in the DRX grains,twins and dislocations.

关键词： Magnesium Extrusion LPSO Recrystallization Precipitation

Simultaneously improving thermal conductivity,mechanical properties and metal fluidity through Cu alloying in Mg-Zn-based alloys

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Journal of Magnesium and Alloys 2024年第9期12卷 3823-3839页

作者： Yuntao Zhang Wei Liu Weipeng Chen Zhiqiang Li Hua Hou yuhong zhao School of Materials Science and Engineering Collaborative Innovation Center of Ministry of Education and Shanxi Province for High-performance Al/Mg Alloy MaterialsNorth University of ChinaTaiyuanShanxi 030051PR China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083PR China School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuanShanxi 030024PR China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004PR China

Mg-Zn-based alloys have been widely used in computer,communication,and consumer(3C)products due to excellent thermal ***,it is still a challenge to balance their mechanical performance and thermal ***,we investigate microstructure,mechanical performance,thermal conductivity and metal fluidity of Mg-5Zn(wt.%)alloy after Cu alloying by experimental and simulation ***,Mg-5Zn alloy consist ofα-Mg matrix and interdendritic MgZn *** the Cu content increases,however,MgZn phases disappear but intragranular Mg_(2)Cu and interdendritic MgZnCu phases appear in Mg-5Zn-Cu ***,the grain size ofα-Mg phase is refined and the volume fraction of MgZnCu phase increases as the Cu content ***,Cu addition is found to improve thermal conductivity of Mg-5Zn alloy ***,Mg-5Zn-4Cu alloy exhibits the best thermal conductivity of 124 W/(m·K),which is mainly due to the significant reduction in both solid solubility of Zn in theα-Mg matrix and lattice distortion ofα-Mg ***,a stable crystal structure of MgZnCu phase also contributes to an increased thermal conductivity based on first principles and molecular dynamics ***,Cu addition simultaneously enhances strength and ductility of Mg-5Zn *** yield strength and elongation of Mg-5Zn-6Cu alloy reach 117 MPa and 18.0%,respectively,which is a combined result of refinement,solution,second phase,and dislocation ***,combined with a phase field simulation,we found that Cu addition enhances metal fluidity of Mg-5Zn *** the one hand,Cu alloying not only delays dendrite growth but also prolongs solidification *** the other hand,MgZnCu phase stabilizes the dendrite growth of theα-Mg phases by reducing energy consumption during solidification of liquid *** work demonstrates that Cu alloying is an ideal strategy for synergistically improving the thermal conductivity,mechanical performance and metal fluidi

关键词： Mg-Zn-Cu alloy Phase field Molecular dynamics Thermal conductivity Metal fluidity

Corrosion Behavior of Graphene Nanosheets Reinforced Magnesium Matrix Composites in Simulated Body Fluids

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 525-536页

作者： Liwen Chen Jianhui Jing Lulu Zhang Jing Li Weipeng Chen Limin Li Yuan zhao Hua Hou yuhong zhao School of Materials Science and Engineering Collaborative Innovation Center of Ministry of Education and Shanxi Province for High-Performance Al/Mg Alloy MaterialsNorth University of ChinaTaiyuan 030051China Shanxi Key Laboratory of Advanced Manufacturing Technology School of Mechanical EngineeringNorth University of ChinaTaiyuan 030051China School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China

Magnesium(Mg)alloy is considered as a promising biodegradable implant material but restricted to rapid ***,the new strategies based on thixomolding process had been explored to utilize the outstanding anti-permeability of graphene nanosheets(GNPs)while inhibit its galvanic corrosion with the matrix,so as to improve the corrosion resistance of *** agglomerate of GNPs with 0.9 wt%content is the main reason for the deterioration of corrosion performance due to the formation of micro-galvanic *** grain refinement of composites with 0.6 wt%content had positive effects on the better corrosion *** process adjusting,the unique distributions of GNPs along grain boundaries play a vital role in improving the corrosion *** can be ascribed to the following mechanisms:(I)The barriers can be established between the Mg matrix and corrosive medium,hence blocking the charge transfer at the interface;(II)The GNPs can effectively promote apatite deposition on the Mg matrix,leading to form dense apatite layers and prevent the further invasion of SBF;(III)The GNPs acting as reinforcements exists in the corrosion layer and apatite layer,impede the apatite layer falling off from the Mg *** findings broaden the horizon for biomedical applications in Mg matrix composites to realize desired performances.

关键词： Magnesium matrix composite Graphene nanosheets Corrosion resistance