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Science China(Technological Sciences) 2011年第3期54卷 676-681页

作者： ZHAO Man DAI Ye LI JiaHao LIU BaiXin Advanced Materials Laboratory Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

For the Pd-Ta system characterized by a negative heat of formation of -78 kJ/mol, 200 keV xenon ion beam mixing with nano-sized Pd-Ta multilayered films was conducted to study the non-equilibrium phase formation. The results showed that uniform amorphous alloys can be formed within a composition range of 25 at%-78 at% Ta, which falls in the maximum possible amorphization range of 22 at%-80 at% Ta predicted by the empirical model. Moreover, two metastable crystalline phases both of FCC structure, yet with different lattice constants were obtained. Interestingly, a self-assembled fractal pattern was observed in the Pd52Ta48 multilayered films after irradiation to a dose of 1×1015 Xe+/cm2 and its dimension was determined to be 1.75±0.05. The possible mechanisms for the formation of amorphous and metastable crystalline phases as well as for the growth of the fractal pattern were discussed.

关键词： amorphous phase Pd-Ta alloy ion beam mixing metastable crystalline phase fractal

Non-equilibrium alloy phase formation and transformation driven by ion beam mixing in the Fe-Hf-Nb multilayers

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Science China(Technological Sciences) 2012年第3期55卷 640-645页

作者： LI Nan WANG TongLe DING Ning DAI Ye BAI Xue LIU BaiXin Advanced Materials Laboratory Department of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

In the ion beam mixing experiments,eight Fe-Hf-Nb multilayered films,with overall compositions of Fe67Hf22Nb11,Fe67Hf11Nb22,Fe54Hf38Nb8,Fe54Hf30Nb16,Fe54Hf11Nb35,Fe25Hf67Nb8,Fe25Hf50Nb25 and Fe25Hf11Nb64,were irradiated by 200 keV xenon ions to doses ranging from 3×1014 Xe+/cm2 to 7×1015 Xe+/*** results showed that unique amorphous phases were obtained at designed alloy compositions,falling in the favored glass-forming region deduced from three binary metal ***,at some alloy compositions,the crystal-amorphous-crystal transformations were observed back and forth while varying the irradiation *** addition,at the alloy composition of Fe25Hf67Nb8,a metastable FCC phase was formed through an HCP-FCC structural phase transformation and it had a large lattice constant identified to be a=4.51 .Besides,the formation mechanism of non-equilibrium alloy phases was also discussed in terms of thermodynamics of solids and atomic collision theory.

关键词： phase transformation ion beam mixing amorphous phase Fe-Hf-Nb system shearing mechanism

Effect of Cu content on the glass forming ability of Cu-Zr-Ti system studied by ion beam mixing

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Science China(Technological Sciences) 2015年第4期58卷 750-752页

作者： WANG Yuan Yu WANG Qi LIU Bai Xin Key Laboratory of Advanced Materials (MOE) School of Materials Science and Engineering Tsinghua University

Based on the Cu-Zr-Ti ternary phase diagram,four sets of Cu-Zr-Ti multilayered films with various compositions of Cu20Zr36Ti44,Cu36Zr31Ti33,Cu49Zr24Ti27,and Cu67Zr16Ti17 were prepared and then the ion beam mixing was carried *** turned out that the increase of Cu content doesn't always have a positive effect on the glass forming *** glass forming ability of Cu49Zr24Ti27 was degraded due to the appearance of a Cs Cl-type B2 structure Cu Zr phase in the eutectic *** experimental observations justify the existence of the Cu Zr phase under the non-equilibrium *** formation mechanisms for the crystalline phase were also discussed in terms of the atomic collision theory.

关键词： glass forming ability ion beam mixing films

Metallic glass formation in the ternary Ni-Nb-Mo system by ion beam mixing

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Science China(Technological Sciences) 2012年第8期55卷 2206-2211页

作者： LI Yang WANG TongLe DING Ning LIU JianBo LIU BaiXin Advanced Materials Laboratory Department of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Glass forming ability of the ternary Ni-Nb-Mo system was studied by ion beam mixing of the Ni-Nb-Mo multilayered *** the experiment,metallic glasses *** alloys were formed in the Ni51Nb19Mo30,Ni52Nb35Mo13,Ni61Nb15Mo24 and Ni72Nb20Mo8 multilayered films,while only solid solutions were obtained in the Ni24Nb29Mo47 and Ni26Nb53Mo21 multilayered *** turned out that the Ni concentration played a dominating role in affecting the glass-forming ability of the ***,thermodynamic calculations predicted a favored composition region for metallic glass formation,matching well with the observations from ion beam mixing.

关键词： metallic glasses ion beam mixing the Ni-Nb-Mo system

Synthesis of metallic glasses and metallic glass based composites in the Cu-Mo-Hf system by ion beam mixing

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Science China(Technological Sciences) 2012年第5期55卷 1353-1358页

作者： BAI Xue WANG TongLe CUI YuanYuan DING Ning LI JiaHao LIU BaiXin Advanced Materials Laboratory Department of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Single-phase and dual-phase metallic glasses as well as metallic glass based composites were synthesized in the Cu-Mo-Hf ternary metal system by 200 keV xenon ion beam mixing of far-from-equilibrium. It was found that Mo-Hf-based and Cu-Mo-based single-phase metallic glasses could be obtained at compositions around CulTMo20Hf63 and Cu34Mo57Hf9, respectively. Interestingly, at the nearly equal-atomic stoichiometry of Cu38Mo31Hf3i, a dual-phase Cu-Mo-Hf metallic glass, consisting both of the Mo-Hf-based and Cu-Mo-based phases, was first obtained at relatively low irradiation doses ranging from （1-5）×10^15 Xe＋/cm2, and a single-phase metallic glass was eventually obtained at a dose of 7×10^15 Xe＋/cm2. In addition, two glass-based composites were obtained at the compositions of Cu14Mo62Hf24 and Cu77Mo14Hf9, and they consisted of the Mo-Hf based and Cu-Mo based metallic glasses, dissolved with some uniformly distributed BCC Mo-based and FCC Cu-based crystalline solid solutions, respectively. The formation mechanism of the above described non-equilibrium alloy phases was also discussed in terms of the atomic collision theory.

关键词： Cu-Mo-Hf system ion beam mixing metallic glass dual-phase metallic glass glass-based composite

Different atomic structures observed from ternary Ni-Nb-Ta metallic glasses obtained by ion beam mixing

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Science China(Technological Sciences) 2013年第8期56卷 1842-1846页

作者： WANG YuanYu LIU JianBo DAI Ye LIU BaiXin Advanced Materials Laboratory School of Materials Science and EngineeringTsinghua University

Four sets of ternary Ni-Nb-Ta multilayered samples with overall compositions of Ni69Nb8Ta23,Ni55Nb13Ta32,Ni42Nb16Ta42 and Ni29Nb18Ta53,respectively were prepared and subjected to 185 keV xenon ion beam *** experimental results showed that in the four Ni-Nb-Ta multilayered samples,metallic glasses could all be obtained at appropriate doses,supporting the prediction directly from a proven realistic Ni-Nb-Ta interatomic potential through molecular dynamics simulations,and that two different atomic structures were observed,as in the corresponding selected area diffraction patterns,the locations of the diffused bands reflected from the metallic glass phases were observed at different angles for the Ni69Nb8Ta23 and Ni29Nb18Ta53 metallic ***,Voronoi tellessation analysis indicated that the observed difference in atomic structures could be attributed to the distinct coordinate number spectra,i.e.,the spectrum of the Ni69Nb8Ta23 metallic glass has its coordinate number(CN) equal to 13 as dominating atomic configuration(with a weight of about 27%),whereas for the Ni29Nb18Ta53 metallic glass,CN=14 is the dominating atomic configuration(also about 27%).Moreover,the distinct atomic configurations of the obtained Ni-Nb-Ta metallic glasses could be correlated to the structures of the constituent metals of the ternary Ni-Nb-Ta system,as the first neighbor of fcc is 12 and the sum of the first and second neighbors of bcc is 14,implying the structural heredity did play a role in metallic glass formation.

关键词： ion beam mixing molecular dynamics coordinate number structural heredity

The Cu-Zr-Nb Crystalline-amorphous Composites Investigated by Thermodynamic Calculation and ion beam mixing Experiments

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The Cu-Zr-Nb Crystalline-amorphous Composites Investigated b...

Metallic Glass Formation and Calculation of Glass-Forming-Ability From Inter-Atomic Potential in the Binary Metal Systems

中国材料大会2012

作者： S.H.Liang T.L.Wang X.Bai J.H.Li State Nuclear Electric Power P D&R Institute Direct Digital Imaging Technology Inc. Department of Materials Science and Engineering Tsinghua University

The formation of Cu-Zr-Nb metallic glass was predicted by thermodynamic calculation and then five Cu-Zr-Nb ternary metallic multilayered films were designed and prepared by electron depositing. The metastable supersaturated solid solutions, amorphous phase as well as their composites were able to be obtained in these Cu-Zr-Nb metallic multilayered films upon ion beam mixing. The observations provided a clew to improve the ductibility of the metallic glasses. Some possible interpretations were presented concerning the formation of the crystalline-amorphous composites.

关键词： Cu-Zr-Nb system Metallic multilayered films ion beam mixing Crystalline-amorphous Composites

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Metallic Glass Formation and Calculation of Glass-Forming-Ab...