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A First-principles Study on the Adhesion Strength,Interfacial Stability,and Electronic Properties of Mg/Mg_(2)Y Interface

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 537-550页

作者： Yunxuan Zhou Wenjun Tian Quan Dong Hailian Wang Jun Tan Xianhua Chen kaihong zheng Fusheng Pan College of Materials Science and Engineering National Engineering Research Center for Magnesium AlloysChongqing UniversityChongqing 400044China State Key Laboratory of Mechanical Transmission Chongqing UniversityChongqing 400044China Institute of New Materials Guangdong Academy of SciencesGuangzhou 510650China

The interfacial microstructures and configurations directly affect the comprehensive properties of the composites,but their interfacial adhesion mechanism is complicated to expound by experimental methods.In this work,based on the stacking sequence of the Mg/Mg_(2)Y interface models,nine different Mg/Mg_(2)Y interface configurations with top site,bridge site,and hollow site(HCP)under Mg1,Mg_(2),and Y terminations were successfully constructed and systematically explored by first-principles calculations.The results showed that the Mg_(2)Y(0001)surface with Y termination is the most stable when the yttrium chemical potential()is less than-1.09 eV;otherwise,Mg_(2)Y(0001)surface with Mg1 termination is the most stable.The seven-layer Mg(0001)and eleven-layer Mg_(2)Y(0001)slabs are employed to reflect the bulk-like interior properties.Additionally,the Mg(0001)/Mg_(2)Y(0001)with the Y-HCP stacking has the largest interface thermodynamic stability with the value of 2.383 J/m^(2) in all interface configurations owing to its largest work of adhesion.In addition,the interfacial energy of Y-HCP stacking is significantly smaller than those of Mg1-HCP when is approximately less than-0.55 eV,showing that it is more stable.The thermodynamic stability of Mg/Mg_(2)Y with Y-HCP is due to Mg-Y chemical bonds formed between Mg and Y atoms.Lastly,the Mg/Mg_(2)Y interfaces are strong interfaces based on the Griffith fracture theory.

关键词： Mg/Mg_(2)Y interface Interface stability Work of adhesion Electronic structure First-principles calculations

Interfacial Reaction of Ti6Al4V Lattice Structure-Reinforced VW92 Alloy Matrix Composites

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 570-576页

作者： Haijun Wang Renju Cheng Xianhua Chen Mingbo Yang Daiyi Deng Lirui Liu Yongfeng Zhou Yanlong Ma kaihong zheng Fusheng Pan College of Materials Science and Engineering Chongqing University of TechnologyChongqing 400054China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Institute of New Materials Guangdong Academy of SciencesGuangzhou 510650China

A novel melting infiltration by ultrasonic vibration was investigated and applied to fabricate Ti6Al4V(TC4)lattice structure-reinforced Mg-10Gd-2Y-1Zn-xZr(refer to VW92 hereafter,x=0,0.5 wt%)alloy matrix composites.The edge-to-edge matching model indicates that the well-matching and possible orientation relationships(ORs)between theα-Mg andα-Ti,[10-10]_(α-Mg)//[11-23]_(α-Ti) in(0002)_(α-Mg)//(10-10)_(α-Ti) possesses the smallest misfit of 0.4%(f_(r)),and thus theα-Mg grains can nucleate on the TC4 lattice structure.Interfacial reaction occurred in the TC4/VW92+0.5 wt%Zr composites,and the reaction product was confirmed to be Al_(2)Zr_(3),AlZr_(2) andα-Ti(Zr)particles formed by continuous solution of Zr-Ti.Among the interfacial products,the AlZr_(2) phase is a brittle phase with high-volume fraction,which is not conducive to the load transfer.But generally speaking,theα-Ti(Zr)and theα-Mg tend to form a coherent interface,which is beneficial for improving the interfacial bonding strength of composites.

关键词： TC4 VW92 composites TC4 lattice structure Interfacial reaction Mismatch

Aging Behavior of As-Extruded Ti Particles Reinforced VW94 Composites

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 401-406页

作者： Dongmei Pu Xianhua Chen Jingfeng Wang Jun Tan Jianbo Li Hong Yang Bo Feng kaihong zheng Fusheng Pan College of Materials Science and Engineering Chongqing UniversityChongqing 400045China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400045China Institute of New Materials Guangdong Academy of SciencesGuangzhou 510650China

The ageing behavior of as-extruded Ti_(P)/VW94 composites was investigated.The peak hardness of the composites increases compared to the matrix alloy and the 5%Ti_(P)/VW94 composite presents the highest peak hardness of 148.7 HV after aging for about 50 h.However,the hardness increments first decrease and then slightly increase with increasing Ti particle content due to the introduction of high-density dislocations by Ti particles.

关键词： Magnesium matrix composites Ti particles Ageing behavior Hardness

In Situ Investigation of Si-Poisoning Effect in Al-Cu-Si Alloys Inoculated by Al-5Ti-1B

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Acta Metallurgica Sinica(English Letters) 2022年第1期35卷 146-156页

作者： Yiwang Jia Dongfu Song Nan Zhou kaihong zheng Yanan Fu Da Shu Guangdong Provincial Key Laboratory of Metal Toughening Technology and Application Institute of New MaterialsGuangdong Academy of SciencesGuangzhou510650China Shanghai Synchrotron Radiation Facility Shanghai Institute of Applied PhysicsChinese Academy of SciencesShanghai201204China Shanghai Key Lab of Advanced High-Temperature Materials and Precision Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200240China

In situ synchrotron X-radiography was carried out on Al-13 Cu and Al-13 Cu-7 Si alloys with and without addition of Al-5 Ti-1 B master alloy.The effects of Si content on grain growth and the solute-suppressed nucleation zone(SSNZ)were quantitatively studied.The average grain size can be refined to 164μm of Al-13 Cu alloy inoculated by Al-5 Ti-1B.After addition of 7%Si content,a large number of TiB 2 sites in the melt lost the inoculating ability due to"Si poisoning."The radius of the dendrite tip curvature of Al-13 Cu is more than two times as large as that of Al-13 Cu-7 Si.The sharper tip is able to disperse the solute more effectively and thus grains can grow more rapidly.This causes that the dendrite arm growth rate with addition of 7%Si solute is about 2.6 times that of no Si addition.In addition,the solute enrichment in the SSNZ of Al-13 Cu is faster,and the area change of SSNZ is slower than that of Al-13 Cu-7 Si.Thus more nucleation sites in the SSNZ cannot be activated with addition of Si.This study will shed light on the understanding of Si poisoning in casting Al-Cu-Si alloys.

关键词： Al-Si alloy Dendrite tip Si poisoning X-ray radiography Al-5Ti-1B

Tailoring microstructure and texture of Mg-3Al-1Zn alloy sheets through curve extrusion process for achieving low planar anisotropy

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Journal of Materials Science & Technology 2022年第18期113卷 48-60页

作者： Jun Xu Bin Jiang Yuehua Kang Jun Zhao Weiwen Zhang kaihong zheng Fusheng Pan Institute of New Materials Guangdong Academy of SciencesGuangzhou 510650China National Engineering Research Centre of Near-net-shape Forming for Metallic Materials South China University of TechnologyGuangzhou510641China State Key Laboratory of Mechanical Transmissions College of Materials Science and EngineeringChongqing UniversityChongqing 400044China School of Mechanical and Electrical Engineering Hunan City UniversityYiyang413002China

Curve extrusion processes,including symmetric curve extrusion(SCE)and asymmetric curve extrusion(ACE)processes,were proposed to fabricate Mg-3Al-1Zn(AZ31)alloy sheets with the aim of improving planar anisotropy.For comparison,traditional extrusion(TE)was conducted on producing AZ31 sheets.The dynamic recrystallization and flow behavior of AZ31 Mg alloy during extrusion were examined and analyzed,and the final microstructures and mechanical properties of AZ31 sheets were investigated.In comparison with the TE sheet,finer grain size,more uniform microstructure and weaker tilted basal tex-ture were achieved in the SCE and ACE sheets.Both the SCE and ACE sheets exhibited unique textures which basal poles tilted to extrusion direction(ED)and new transverse direction(TD)-tilted texture com-ponent was developed.The reasons were mainly ascribed to the introduction of additional flow velocity difference along TD during extrusion.Furthermore,the ACE sheet exhibited the lowest basal pole inten-sity,which was attributed to the introduction of extra asymmetric shear deformation during extrusion process.As a result,the ACE sheet showed the lowest yield strength and r-value,but highest elongation and n-value.Improving the planar anisotropy of AZ31 sheet was achieved by the ACE process.

关键词： Magnesium alloy Curve extrusion Texture Mechanical properties

Preparation, structure and properties of Mg/Al laminated metal composites fabricated by roll-bonding, a review

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Journal of Magnesium and Alloys 2022年第8期10卷 2062-2093页

作者： Tingting Liu Bo Song Guangsheng Huang Xianquan Jiang Shengfeng Guo kaihong zheng Fusheng Pan School of Materials and Energy Southwest UniversityChongqing400715China School of Materials Science and Engineering Chongqing UniversityChongqing400044China Institute of New Materials Guangdong Academy of ScienceGuangzhou510650China

Laminated metal composites(LMCs) are a unique composite material and have great application prospects in automobiles, ships, aircraft,and other manufacturing industries. As lightweight materials, the Mg/Al LMCs are expected to combine the advantages of both Mg and Al alloys to broaden their application prospects. Roll-bonding is the most popular process for the fabrication of Mg/Al LMCs due to high production efficiency and good product quality stability. The roll-bonding process involves the deformation of the substrates and the formation of the interfacial diffusion layer. The latter will directly determine the interface bonding strength of Mg/Al LMCs. Bonding strength is very sensitive to the thickness of the reaction layer in the diffusion layer. When the thickness of the reaction layer exceeds 5 μm, the bonding strength decreases sharply. Therefore, controlling the thickness of the reaction layer is very important for the design of rolling parameters.The latest research also showed that the addition of intermediate layer metal and the construction of three-dimensional interfaces can further improve the interface bonding strength. How to apply these methods to roll-bonding is the focus of future research. Recently, a new rolling technique, corrugated roll/plat roll rolling+flat roll/flat roll rolling has been developed to fabricate Mg/Al LMCs. It can effectively promote the deformation of the hard layer and generate a wavy interface, resulting in the enhancement of the bonding quality and rolling quality.In the current review, the effects of rolling parameters and subsequent annealing on the interface structure of Mg/Al LMCs were elaborated in detail. The application of some special rolling techniques in the preparation of Mg/Al LMCs was also summarized. The latest research results on the relationship between interface structure and mechanical properties of Mg/Al LMCs were reviewed. Finally, further research directions in this field were proposed.

关键词： Mg/Al Laminated metal composites Roll-bonding Interface Mechanical properties

Improved suspension quality and liquid level stability in stirred tanks with Rotor-Stator agitator based on CFD simulation

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Particuology 2023年第11期82卷 64-75页

作者： Cuicui Yin Jiazhen He Yongnan Xiong Zhibo Zhang Xing Luo Yao Shu Danfeng Long kaihong zheng Institute of New Materials Guangdong Academy of SciencesNational Engineering Research Center of Powder Metallurgy of Titanium&Rare MetalsGuangdong Provincial Key Laboratory of Metal Toughening Technology and ApplicationGuangzhou510651China Institute of Intelligent Manufacturing Guangdong Academy of SciencesGuangzhou510651China

The solid-liquid mixing is an important operation unit in the preparation of composites by stirring casting.High quality composite materials need good homogeneity and stable liquid level.In this work,the performances of the Rotor-Stator agitator for solid suspension in stirred tank were investigated through CFD modeling,including the homogeneity,power consumption and liquid level stability.The Eulerian-Eulerian(E-E)multiphase model and the RNG k-εturbulence model were adopted for modeling the multiphase flow and the turbulence effects,respectively.The effect of various important parameters such as stirring speed,particle size,solid loading and the use of baffles were examined.Adding a stator structure with array holes outside the rotor can optimize the flow pattern,thereby improving the mixing uniformity and liquid level stability.The homogeneity and liquid level stability attained by the Rotor-Stator agitator were better than those for the A200(an axial-flow agitator)and the Rushton(a radial-flow agitator).

关键词： Solid-liquid mixing Rotor-Statoragitator Suspension quality Liquid level stability Powerconsumption Computational fluid dynamics(CFD)

Atomistic simulation on the generation of defects in Cu/SiC composites during cooling

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Journal of Materials Science & Technology 2022年第28期123卷 1-12页

作者： Yongnan Xiong Wangyu Hu Yao Shu Xing Luo Zhibo Zhang Jiazhen He Cuicui Yin kaihong zheng Guangdong Academy of Sciences Institute of New MaterialsGuangzhou 510651China Guangdong Provincial Key Laboratory of Metal Toughening Technology and Application Guangzhou 510561China College of Materials Science and Engineering Hunan UniversityChangsha 410082China

The coefficient of thermal expansion(CTE)mismatch between the reinforcement and the matrix results in thermal residual stresses and defects within metal-matrix composites(MMCs)upon cooling from the processing temperature to ambient temperature.The residual stresses and thermally induced defects play an important role in the mechanical properties of MMCs,it is critical to understand the mechanism of defect formation and evolution.This study provides atomistic simulations to reveal the generation of thermal residual stresses,dislocation and incomplete stacking fault tetrahedron(ISFT)during cooling in the idealized Cu/SiC composites.We found that dislocations are generated explosively in a certain temperature range during cooling,which results in a non-linear relationship between dislocation density and temperature.The combined effect of the stresses induced by CTE mismatch and the thermodynamic state of the metal leads to the rapid generation of dislocations.The Shockley partial and the highly stable stair rod are the two dominant dislocation structures.The immobile stair-rod dislocations and the highly stable ISFTs formed in the initial high temperature stage inhibit further development of plastic deformation.The present results provide new insights into the defect formation mechanism and the dislocation strengthening mechanism of MMCs caused by thermal mismatch between constituents.

关键词： Metal-matrix composite(MMC) Thermal residual stress Dislocation Incomplete stacking fault tetrahedron Molecular dynamics

Comparison on crack propagation under tension at 150℃ of Mg-2Zn-1.5Mn alloy sheets with and without crack notch

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Journal of Magnesium and Alloys 2023年第5期11卷 1536-1548页

作者： Qiang Liu Jiangfeng Song Qiuyan Shen Liangyin Wu Bin Jiang Weimin Gan kaihong zheng Fusheng Pan National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China GEMS at MLZ Helmholtz-Zentrum HereonGarching D-85748Germany Institute of New Materials Guangdong Academy of SciencesGuangzhou 510650China

Generally,edge crack of rolled magnesium alloy sheets initiates in the RD(rolling direction)-ND(normal direction)plane and then propagate in the RD-TD(transverse direction)plane.Hence,the Mg-2Zn-1.5Mn(ZM21)alloy sheets with and without crack notch were designed to carry out in-situ tensile experiments under 150℃(the same temperature of rolling),with the aim to understand their crack propagation mechanism.The scanning electron microscopy(SEM)and electron backscattered diffraction(EBSD)techniques were utilized to reveal microstructural evolution in real time at designated displacements.The results show that the prismatic slip,basal slip,and extension twining play synergistic role in coordinating strain during the tensile process in ZM21 alloy sheet at 150℃.In both tensile samples with and without crack notch,localized strain is mainly concentrated at relatively fine grain area and the grain boundaries or triple junctions of the grains with large basal Schmid factor(SF)difference,which eventually leads to severe surface roughening and subsequent crack initiation.Compared with the sample without crack notch,the pre-cracked sample exhibits severer deformation at the crack tip due to strain concentration.Strain gradient distribution is observed at the crack tip region in the pre-cracked sample.The crack propagation path of the sample with pre-crack is identified and the underlying mechanism is also discussed.

关键词： ZM21 alloy In-situ tensile test Crack propagation path Crack notch