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Influence of oscillation strain on the dynamic mechanical relaxation of a La-based metallic glass

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Science China(Technological Sciences) 2023年第11期66卷 3309-3316页

作者： LIANG ShuYi ZHANG LangTing WANG YunJiang PINEDA E QIAO JiChao School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an 710072China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China Department of Physics Institute of Energy TechnologiesUniversitat Politècnica de Catalunya–BarcelonaTechBarcelona 08019Spain Innovation Center NPU-ChongqingChongqing 401135China

Dynamic mechanical relaxation processes,particularly secondary relaxation processes,are closely related to the mechanical and physical properties of metallic *** the effect of oscillation strain amplitude on the secondary relaxation of a typical Labased metallic glass was studied using the dynamic mechanical analysis *** apparent activation energy of theβrelaxation is shown to increase with the oscillation strain *** it changes from 0.02%to 0.16%,the activation energy increases from 0.73 to 0.96 ***,the intensity of theβrelaxation shifts toward high ***,the apparentβrelaxation is found to be sensitive to the physical aging below the glass transition *** findings suggest a correlation between the inelastic deformation and the relaxation behavior of amorphous metals.

关键词： metallic glass dynamic mechanical analysis internal friction βrelaxation oscillation amplitude

Structural rejuvenation and toughening of bulk metallic glass via ultrasound excitation technique

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Science China(Technological Sciences) 2020年第11期63卷 2395-2402页

作者： ZHAI Wei HUI XiDong XIAO Ying QIAO JiChao WEI ShaoLou WANG Tuo NIE LiHui WEI BingBo School of Physical Science and Technology Northwestern Polytechnical UniversityXi’an 710072China State Key Laboratory for Advanced Metals and Materials University of Science&TechnologyBeijing 100083China School of Materials Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an 710072China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Bulk metallic glasses(BMGs)represent a class of solid materials which have randomly packed atomic structure in long range but exhibit unique ***,the macroscopic brittleness at ambient temperature is the fundamental and intriguing issue to impede the engineering application of *** this article,we report a breakthrough in solving the strength-ductility tradeoff dilemma of BMGs by introducing strong forced vibration of atoms named ultrasonic vibration(USV)*** find that not only the ambient temperature compressive plasticity is remarkably increased but also yield strength is augmented by kHZ level USV *** toughening of BMGs has also been evidenced by the pronounced increase in the first pop-in event,which represents by the critical stress to stimulate the initial yield with the formation of shear *** has also been confirmed that the free volume in USV treated BMGs is strikingly ***,the intrinsic mechanism of USV induced toughening can be interpreted in the frame of structural heterogeneities and energy landscape theory,i.e.,the USV induced structural rejuvenation by increasing the loosely packed soft regions and decreasing the closely packed hard *** basins that possess larger potential energies are overwhelmingly increased after USV *** findings provide a new approach for surmounting strength-ductility trade-off dilemma of single atom glassy matter such as BMGs.

关键词： metallic glass microstructure mechanical property nanoindentation ultrasound

The anelastic origin of mechanical cycling induced rejuvenation in the metallic glass

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Science China(Physics,Mechanics & Astronomy) 2023年第8期66卷 93-100页

作者： Langting Zhang Yunjiang Wang Yong Yang Jichao Qiao School of Mechanics CivilEngineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 70072China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China Department of Mechanical Engineering College of EngineeringCity University of Hong KongHong Kong 999077China Department of Materials Science and Engineering College of EngineeringCity University of Hong KongHong Kong 999077China Innovation Center NPU-ChongqingChongqing 401135China

Mechanical cycling is one of the effective methods to rejuvenate metallic glasses(MGs)and improve their mechanical *** anelastic origin of the rejuvenation by mechanical cycling in a La_(30)Ce_(30)Ni_(10)Al_(20)Co_(10) MG was investigated via differential scanning calorimetry(DSC)and dynamic mechanical analysis(DMA).We demonstrate that mechanical cycling promotes the activation of flow defects with short relaxation times,leading to anelastic strains and therefore considerable energy storage,which manifests itself as larger relaxation enthalpy on the DSC curves of ***,the MGs release the excess relaxation enthalpy caused by anelastic strain with time,thus suppressing atomic mobility and elevating β relaxation activation *** strategy of mechanical cycling at small strains,as demonstrated in the current work,can expand the energy states of MGs over a wide range of relaxation enthalpies.

关键词： metallic glass mechanical cycling rejuvenation anelastic strain structural heterogeneity

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Tensile and compressive behavior of Ti-based bulk metallic glass composites

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International Journal of Minerals,Metallurgy and Materials 2013年第6期20卷 582-588页

作者： Yong-sheng Wang Guo-jian Hao Jun-pin Lin State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing

This article focuses on the tensile and compressive characteristics of a Ti-based bulk metallic glass composite （BMGC）. It is found that the yield stress, maximum strength, and fracture strain are 1380 MPa, 1516 MPa, and 4.3% for uniaxial tension, but 1580 MPa, 4010 MPa, and 29% for uniaxial compression, respectively. The composite displays a linear ＂work hardening＂ capacity under compression; however, the ＂work softening＂ behavior is observed in the true engineering stress-strain curve upon tensile loading. The fracture surfaces of specimens also exhibit dissimilar properties under the different loadings.

关键词： metallic glass composite materials tensile testing compression testing fracture

Enhancing strength and plasticity by pre-introduced indent-notches in Zr36Cu64 metallic glass:A molecular dynamics simulation study

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Journal of Materials Science & Technology 2020年第8期36卷 119-125页

作者： Shidong Feng Lin Li K.C.Chan Lei Zhao Limin Wang Riping Liu State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao066004China Advanced Manufacturing Technology Research Centre Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic University999077Hong KongChina Department of Metallurgical and Materials Engineering The University of AlabamaTuscaloosaAL35487USA

The deformation behavior in Zr36 Cu64 metallic glasses with pre-introduced indent-notches has been studied by molecular dynamics simulation at the atomic *** indent-notches can trigger the formation of densely-packed clusters composed of solid-like atoms in the indent-notch affected *** denselypacked clusters are highly resistant to the nucleation of shear ***,there is more tendency for the shear bands to nucleate outside the indent-notch affected zone,which enlarges the deformation region and enhances both the strengthening effect and the plastic deformation *** indent-notched MGs,when determining the initial yielding level,there is a competition process occurring between the densely-packed clusters leading to the shear band formation outside the indent-notch affected zone and the stress-concentration localizing deformation around the notch *** the indent-notch depth is small,the stress-concentration around the notch root plays a dominant role,leading to the shear bands initiating from the notch root,reminiscence of the *** the indent-notch depth increases,there are many densely-packed clusters with high resistance to deformation in the indent-notch affected zone,leading to the shear band formation from the interface between the indent-notch affected zone and the *** research findings provide a feasible means for improving the strength and the plasticity of metallic glasses at room temperature.

关键词： metallic glass Notch Shear band Microstructure Molecular dynamics simulation

Effect of Aspect Ratio on the Evolution of Shear Bands in Zr_(61.7)Al_8Ni_(13)Cu_(17)Sn_(0.3)Bulk metallic glass

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Journal of Materials Science & Technology 2017年第1期33卷 99-104页

作者： Wenli Ma Yuanli Xu Bo Shi Jiangong Li Institute of Materials Science and Engineering and MOE Key Laboratory for Magnetism and Magnetic Materials Lanzhou UniversityLanzhou 730000China

Zr61.7A18Ni13Cu17Sn0.3 bulk metallic glass samples with different aspect ratios in the range of 0.25-2.25 were deformed by compression, and the effect of aspect ratio on the evolution of shear bands was investigated. It is found that for the deformed Zr61.7AlaNi13CulTSno3 bulk metallic glass, the average shear band spacing decreases and the shear band density increases monotonically as the aspect ratio increases from 0.25 to 2.25. A minimal average shear band spacing of 0.478μm is achieved for the sample with an aspect ratio of 2.25. In addition, the fractions of shear bands with spacings below 100 and 50 nm are about 12.84% and 6.76%, respectively, for the sample with an aspect ratio of 2.25. The reason for the formation of a higher density of shear bands can probably be attributed to the increase of the driving force for the samole with a larger aspect ratio.

关键词： metallic glass Aspect ratio Shear band Compressive deformation

Unexpected creep behavior in a rejuvenated metallic glass

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Journal of Materials Science & Technology 2023年第32期163卷 140-149页

作者： J.P.Wu Y.Lin F.H.Duan Q.Chen H.T.Wang N.Li J.L.Wen J.Pan L.Liu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China State Key Laboratory of Material Processing and Die&Mould Technology and School of Materials Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Laboratory of Nanomaterials&Nanomechanics Department of Mechanical EngineeringCity University of Hong KongHong KongChina Wuhan National High Magnetic Field Center Huazhong University of Science and TechnologyWuhan 430074China Shenzhen Polytechnic Shenzhen 518055China

Rejuvenation,bringing metallic glasses(MGs)to the younger and higher energy states,provides an alternative avenue to explore the interplay between the property and microstructures of *** this study,the creep behavior of the Zr_(69.5)Cu_(12)Ni_(11)Al_(7.5)MGs was experimentally examined by controlling the energy state in terms of structural rejuvenation and thermal *** is found that compared to the as-cast counterpart,the annealed MG at a lower energy state exhibits a higher hardness,a smaller displacement,and a lower creep rate due to the decreased free volume and the inhibited activation of the shear transformation ***,the rejuvenated MG at a high energy state displays lower hardness and increased free volume content,yet it demonstrates superior creep resistance compared to its as-cast counterpart,which deviates from conventional *** unexpected phenomenon occurs as the initial high-content free volume annihilates during creep,and strain hardening takes precedence over strain softening as the prevailing process during creep deformation,leading to a superior creep performance in extremely rejuvenated MGs.

关键词： metallic glass Energy state Rejuvenation Creep Strain-hardening

Effect of Nb on the corrosion behavior of continuous bulk metallic glass-coated steel wire composites

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International Journal of Minerals,Metallurgy and Materials 2013年第6期20卷 589-592页

作者： Xiao-hua Chen Bao-yu Zhang Xi-dong Hui State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing

（***10Be22.5）100-~Nb~ （at%, x=0 and 8） bulk metallic glasses （BMGs） were coated on the surface of Q195 steel wires by a continuous coating process. The potentiodynamic polarization tests of these BMGs were conducted in 3.5wt% NaC1 aqueous solution. It is found that the addition of 8at% Nb into ***10Be22.5 alloy results in the improvement of corrosion resistance with the pitting potential of -52 mV, the open circuit potential of-446 mV, and the corrosion current density of 9.86x 10-6 mA/cm2. This may be attributed to that Nb is beneficial to passivate and stabilize Zr and Ti.

关键词： composite materials metallic glass coatings corrosion niobium

Structural color of metallic glass through picosecond laser

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Chinese Physics B 2024年第10期33卷 120-128页

作者： Yue’e Zhang Xing Tong Yuqiang Yan Shuo Cao Hai-Bo Ke Wei-Hua Wang College of Physics Liaoning UniversityShenyang 110036China Songshan Lake Materials Laboratory Dongguan 523808China Institute of Physics Chinese Academy of SciencesBeijing 100190China

The alteration in surface color of metallic glasses(MGs)holds great significance in the context of microstructuredesign and commercial *** is essential to accurately describe the structures that are formed during the laser and colorseparation processes in order to develop practical laser coloring *** to the high oxidation sensitivity of Labasedmetallic glass,it can broaden the color range but make it more *** coloring by laser processing on thesurface of La-based metallic glass can be conducted after thermoplastic *** is particularly important to clarify therole of structure and composition in the surface coloring *** aim is to study the relationship between amorphoussurface structural color,surface geometry,and oxide formation by laser processing in metallic *** findings revealedthat the periodic structure primarily determines the surface color at laser energy densities below 1.0 J/mm^(2).In contrast,thesurface color predominantly depends on the proportion of oxides that are formed when energy densities exceed 1.0 J/mm^(2).Consequently,this study provides a novel concept for the fundamental investigation of laser coloring and establishes a newavenue for practical application.

关键词： metallic glass picosecond laser periodic structure oxides