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Pressure-induced polyamorphism in a main-group metallic glass

机译:主族金属玻璃中的压力诱导多态性

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摘要

The mechanism of pressure-induced amorphous-to-amorphous transitions (AATs) in metallic glasses (MGs) has been a subject of intense research. Most AATs in MGs were found in lanthanide-based alloys and shown to originate from 4/ orbital delocalization. Recently, evidence of an unexpected AAT in the main-group Ca-Al MGs was reported without a satisfactory explanation. Here, based on the results of first-principles molecular dynamics calculations, the suggested AAT at 12-15 GPa in the Ca_(72.7)Al_(27.3) MG is confirmed. Contrary to the common belief that the coordinate of metallic glasses with close packing cannot be increased further, the coordination around Al atoms is found to increase suddenly at the transition as a consequence of atomic migration and the aggregation of Al atoms. This transition originates from pressure-enhanced bonding between Ca 3d and Al 3p orbitals and is confirmed by the good agreement on the predicted and measured electrical conductivities. The theoretical analysis not only uncovers a mechanism of pressure-induced AAT in main-group MGs, but it can be generalized to establish a different perspective to guide the understanding of transformation phenomena in compressed MGs.
机译:金属玻璃(MGs)中压力诱导的非晶态到非晶态转变(AAT)的机理已成为研究的热点。 MG中的大多数AAT都是在镧系元素合金中发现的,并显示其起源于4 /轨道离域。最近,有报道称在主要的Ca-Al MGs中存在意外的AAT的证据,但没有令人满意的解释。在此,基于第一性原理分子动力学计算的结果,确认了Ca_(72.7)Al_(27.3)MG中建议的12-15 GPa的AAT。与通常认为不能进一步提高紧密堆积的金属玻璃的配位的观点相反,发现由于原子迁移和Al原子的聚集,Al原子周围的配位在跃迁时突然增加。这种转变源自Ca 3d和Al 3p轨道之间的压力增强键合,并通过在预测和测量的电导率上的良好一致性得到了证实。理论分析不仅揭示了主MG中压力诱导的AAT的机理,而且可以推广以建立不同的观点来指导对压缩MG的转变现象的理解。

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  • 来源
    《Physical review》 |2016年第5期|054201.1-054201.5|共5页
  • 作者单位

    College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China,International Center for New-Structured Materials, State Key Laboratory of Silicon Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China,Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2,Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2;

    International Center for New-Structured Materials, State Key Laboratory of Silicon Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China;

    Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2,State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, People's Republic of China;

    State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, People's Republic of China;

    Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2;

    KYOKUGEN, Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan;

    KYOKUGEN, Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan;

    KYOKUGEN, Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan;

    International Center for New-Structured Materials, State Key Laboratory of Silicon Materials, and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China;

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