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Correlation between the glass-forming ability and activation energy of crystallization for Zr_(75-x)Ni_(25)Al_x metallic glasses

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International Journal of Minerals,Metallurgy and Materials 2013年第5期20卷 445-449页

作者： Yan-hui Li Wei Zhang Chuang Dong Jian-bing Qiang Akihiro Makino School of Materials Science and Engineering Dalian University of Technology Institute for Materials Research Tohoku University

The thermal stability and the kinetics of glass transition and crystallization for Zr75-xNi25Alx （x = 8-15） metallic glasses were investigated using differential scanning calorimetry （DSC） under continuous heating conditions. The apparent activation energy of glass transition rises monotonously with the A1 content increasing; the activation energy of crystallization increases with A1 changing from 8at% to 15at%, and then decreases with A1 further up to 24at%, which exhibits a good correlation to the thermal stability and the glass-forming ability （GFA）. The Zr60Ni25A115 metallic glass with the largest supercooled liquid region and GFA possesses the highest activation energy of crystallization. The relation between the thermal stability, GFA and activation energy of crystallization was discussed in terms of the primary precipitated phases.

关键词： metallic glass thermal stability glass-forming ability crystallization kinetics activation energy

A Diagram for glass Transition and Plastic Deformation in Model metallic glasses

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Journal of Materials Science & Technology 2014年第6期30卷 546-550页

作者： X.Q.Gao W.H.Wang H.Y.Bai Institute of Physics Chinese Academy of Sciences

In this paper, we report a strain rate related glass transition in model SrCaYbMg（Li）Zn（Cu） metallic glasses at room temperature. A critical strain rate, equivalent to glass transition temperature, is found for the strain rate induced glassy state to liquid-like viscoplastic state translation. The results show that the observation time, equivalent to temperature and stress, is a key parameter for the transition between the glass and supercooled liquid states. A three-dimension glass transition diagram involved in time, temperature and stress in metallic glasses is established.

关键词： Homogeneous plastic flow glass transition metallic glass

Near-perfect replication on amorphous alloys through active force modulation based on machine learning/neural network parameter prediction

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 181-191页

作者： Senkuan Meng Zheng Wang Ruisong Zhu Ruijie Liu Jiang Ma Lina Hu Weihua Wang Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education) School of Materials Science and Engineering Shandong University College of Mechatronics and Control Engineering Shenzhen University Songshan Lake Materials Laboratory Institute of Physics Chinese Academy of Sciences

As a microforming technique, micro/nano-structural replication possesses advantages of high precision and efficiency. With the remarkable superplasticity in the supercooled liquid region, amorphous alloys or metallic glasses(MGs) are regarded as ideal materials for miniature fabrication. However, due to the intrinsic metastable nature of supercooled liquids, the design of imprinting processes for MGs poses a challenge. In the past, process parameters have largely relied on trial-and-error *** this work, a low-frequency active force modulation system is employed to apply a stable, precise, and real-time feedback stress field for imprinting of MG samples. Low-frequency vibrations can facilitate the filling of microstructures on the template surface by reducing the effective viscosity of the supercooled liquid. With the dataset composed of orthogonal experiments, a machine learning strategy based on back-propagation(BP) neural networks was utilized to construct a 3D parameter space for temperature, stress, and time, and to predict the corresponding filling ratio. Furthermore, the optimal combination of imprinting process parameters was identified, and its filling ratio was experimentally validated to reach as high as 0.94. The near-perfect replication of microstructures confirms the superiority of the active force modulation system and the data-driven strategy of machine learning-assisted parameter design. At the same time, this one-step microforming process provides a new approach to addressing the accuracy-cost trade-off dilemma in precision manufacturing.

关键词： metallic glass amorphous alloy microforming imprinting machine learning

Processing soft ferromagnetic metallic glasses:on novel cooling strategies in gas atomization,hydrogen enhancement,and consolidation

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Journal of Materials Science & Technology 2020年第24期59卷 26-36页

作者： N.Ciftci N.Yodoshi S.Armstrong L.Madler V.Uhlenwinkel Leibniz Institute for Materials Engineering IWT Badgasteiner Straße 328359BremenGermany Cooperative Research and Development Center for Advanced Materials Institute for Materials ResearchTohoku University2-2-1 KatahiraAoba-kuSendai980-8577Japan University of Bremen Faculty of Production EngineeringBadgasteiner Straße 128359BremenGermany

Processing soft ferromagnetic glass-forming alloys through gas atomization and consolidation is the most effective technique to produce bulk *** commercial viability of these materials depends on commercial purity ***,crystallization in commercial purity feedstock is several orders of magnitude faster than in high purity *** production of amorphous powders with commercial purity requires high cooling rates,which can only be achieved by extending the common process window in conventional gas *** development of novel cooling strategies during molten metal gas atomization on two model alloys({(Fe0.6Co0.4)0.75B0.2Si0.05}96Nb4 and Fe76B10Si9P5)is *** inducement during liquid quenching significantly improved the glass-forming ability and soft magnetic properties of{(Fe0.6Co0.4)0.75B0.2Si0.05}96Nb4 *** plasma sintering experiments verified that amorphous rings could be produced regardless of the cooling strategies *** the saturation magnetization was almost unaffected by consolidation,the coercivity increased slightly and permeability decreased *** magnetic properties of the final bulk samples were independent of feedstock *** developed cooling strategies provide a great opportunity for the commercialization of soft ferromagnetic glass-forming alloys with commercial purity.

关键词： Gas atomization Amorphous powders metallic glass Cooling Quenching Heat transfer Hydrogen

Effect of energy density on defect evolution in 3D printed Zr-based metallic glasses by selective laser melting

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Science China(Physics,Mechanics & Astronomy) 2020年第2期63卷 104-110页

作者： Wei Xing Di Ouyang Zhen Chen Lin Liu School of Materials Science and Engineering and State Key Lab for Materials Processing and Die&Mould TechnologyHuazhong University of Science and TechnologyWuhan 430074China State Key Lab for Manufacturing Systems Engineering Xi’an Jiaotong UniversityXi’an 710049China

In this study, the defects in 3D printed Zr-based bulk metallic glasses(BMGs) fabricated by selective laser melting(SLM) under different energy densities have been investigated via both experimental and simulation approaches. Different defects, including balling, interlayer pores, open pores and metallurgical pores, are detected in the 3D-printed Zr-based MGs depending on the energy inputs. Balling mainly occurs at a relatively low energy density(E<8.33 J/mm^3) due to the incomplete melting of particles, while interlayer pores and open pores are formed at modest energy densities(E=13.89-16.67 J/mm^3) because of incomplete welding and insufficient filling of molten liquid between layers. Fine metallurgical pores appear on the upper surface at relatively high energy densities(E=20.83-27.78 J/mm^3), which originate from gas escaping from molten pools during rapid solidification of the melt. Computational fluid dynamics(CFD) simulations are carried out to verify the experimental observations. The CFD simulations reveal that the various defects formed in the 3D-printed Zr-based BMG are related to the melt flow behaviours in the molten pools under different energy densities. The present work provides in-depth understandings of defect formation in the SLM process and provides methods for eliminating these defects in order to enhance the mechanical performance of 3D printed BMGs.

关键词： metallic glass selective laser melting defect formation mesoscopic simulation

Preparation of hydroxyapatite layer on Ti-based bulk metallic glasses by acid and alkali pre-treatment

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Rare Metals 2015年第1期34卷 22-27页

作者： Hao Hu Zhen-Duo Cui Sheng-Li Zhu Zhao-Yang Li Yan-Qin Liang Xian-Jin Yang School of Materials Science and Engineering Tianjin University Tianjin Key Laboratory of Composite and Functional Materials

In this paper, a thin calcium phosphate layer was prepared on the surface of Ti4oZr10Cu36Pd14 bulk metallic glasses （BMGs）. All samples were dipped in HNO3 aqueous solution and boiled in 1.2 mol-L-I NaOH aqueous solution. After the two preliminary treatment steps, they were soaked in simulated body fluid （SBF） to form an apatite layer on the surface. After immersion for 12 days, a coating composed mainly of Ca-P particles was rapidly deposited on the surface of Ti40Zr10Cu36Pd14 bulk metallic glasses. The surfaces of chemically treated sam- ples and the samples after immersion in SBF were char- acterized by X-ray diffraction （XRD）, X-ray photoemission spectroscopy （XPS）, field emission scanning electron microscopy （FESEM）, and energy dispersive spectroscopy （EDS）. Analysis results indicate that this apatite coating consists of Ca-P particles with different diameters. In addition, the Ca/P ratio of the apatite coatings immersed for 14 days is 1.62, which is close to that of hydroxyapatite （HA）.

关键词： metallic glass Titanium alloy Hydroxyapatite Thin film

Influence of Cu content on the mechanical properties and corrosion resistance of Mg-Zn-Ca bulk metallic glasses

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International Journal of Minerals,Metallurgy and Materials 2014年第5期21卷 487-493页

作者： Yan-feng Zhao Jian Zhu Li Chang Jing-guo Song Xiao-hua Chen Xi-dong Hui State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing

（***28.8Cas）10o-xCux （at%, x = 0, 1, 3, and 5） bulk metallic glasses （BMGs） of 2 mm in diameter were prepared by the conventional copper mold injection casting method. Besides, the influence of Cu content on the microstructure, thermal stability, mechanical properties, and corrosion behavior of Mg-Zn--Ca BMGs was investigated. It is found that the addition of Cu decreases the glass-forming ability of Mg-Zn-Ca BMGs. Crystalline phases are precipitated at a higher Cu content, larger than 3at%. The compressive fracture strength of Mg-Zn-Ca BMGs is enhanced by the addition of Cu. With the formation of in-situ composites, the compressive strength of the Mg-Zn-Ca alloy with 3at% Cu reaches 979 MPa, which is the highest strength among the Mg-Zn-Ca alloys. Furthermore, the addition of Cu also results in the increase of corrosion potential and the decrease of corrosion current density in Mg-Zn-Ca BMGs, thereby delaying their biodegradability.

关键词： metallic glass glass-forming ability compressive strength corrosion thermal stability

Correlation Between Dynamic Compressive Strength and Fracture Behaviors of Bulk metallic glasses

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Acta Metallurgica Sinica(English Letters) 2020年第10期33卷 1407-1415页

作者： Wenqing Li Zhengwang Zhu Guojie Li Long Zhang Zhengkun Li Huameng Fu Hongwei Zhang Hong Li Aimin Wang Haifeng Zhang 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 Beijing Institute of Space Long March Vehicle Beijing 10076China

The mechanical behaviors of Zr43.5Cu43.5Ni4Al8Nb1,Zr55.4Cu31.6Ni4Al8Nb1,Ti32.8Zr30.2Ni5.3Cu9Be22.7(at.%)metallic glass at different strain rates were *** all the present alloys,the dispersion over 700 MPa was observed on the strength in the repeated dynamic compressions,which was much stronger than that of the quasi-static compressive *** the dispersion of the dynamic compressive strength was well correlated with the corresponding fracture *** area of fracture surface was calculated and also showed a strong dispersion for all the fractured specimens tested at the strain rate of 500 s^-1 and 1000 s^-*** the specimens showed a linear relationship between the square of dynamic compressive strength and the area of fracture surface in the dynamic compression *** phenomenon was mainly thought to be related to the difference of mean initial free volume concentration of different samples,stress concentration caused by the split Hopkinson pressure bar experimental setup and high sensitivity of defects under dynamic *** findings were beneficial to deeply understand the effect of strain rate on the mechanical properties of the metallic glass.

关键词： metallic glass Dynamic compression Weibull statistics Shear bands

Second phase effect on corrosion of nanostructured Mg-Zn-Ca dual-phase metallic glasses

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Journal of Magnesium and Alloys 2021年第5期9卷 1561-1570页

作者： Chang Liu Qing Wang Bin Han Junhua Luan Ji-Jung Kai Chain-Tsuan Liu Ge Wu Jian Lu Department of Mechanical Engineering City University of Hong KongHong KongChina Max-Planck-Institut für Eisenforschung Max-Planck-Straße 1Düsseldorf40237Germany Laboratory for Microstructures Institute of Materials ScienceShanghai UniversityShanghai 200072China Hong Kong Branch of National Precious Metals Material Engineering Research Centre Department of Material Science and EngineeringCity University of Hong KongHong KongChina Centre for Advanced Structural Materials City University of Hong Kong Shenzhen Research InstituteGreater Bay Joint DivisionShenyang National Laboratory for Materials ScienceShenzhen 518057China CityU-Shenzhen Futian Research Institute Shenzhen 518045China

Dual-phase metallic glasses(DP-MGs),a special member of the MGs family,often reveal unusual strength and ductility,yet,their corrosion behaviors are not ***,we developed a nanostructured Mg_(57)Zn_(36)Ca_(7)(at.%)DP-MG and uncovered its corrosion mechanism in simulated body fluid(SBF)at the near-atomic scale utilizing transmission electron microscope(TEM)and atom probe tomography(APT).The 10-nm-wide Ca-rich amorphous phases allow oxygen propagation into the DP-MG,resulting in a micrometer thick hydroxides/oxides *** dense corrosion layer protects the DP-MG from further corrosion,enabling a corrosion rate that is 77%lower than that of Mg(99.99%purity).

关键词： Magnesium alloys metallic glass Corrosion Sputtered films TEM APT