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张剑, 郝奇, 邢光辉, 乔吉超. 基于应力松弛变形探索La基金属玻璃微观非均匀性[J]. 力学学报.
引用本文: 张剑, 郝奇, 邢光辉, 乔吉超. 基于应力松弛变形探索La基金属玻璃微观非均匀性[J]. 力学学报.
Probing on microstructural heterogeneity of La-based metallic glass: Based on the stress relaxation[J]. Chinese Journal of Theoretical and Applied Mechanics.
Citation: Probing on microstructural heterogeneity of La-based metallic glass: Based on the stress relaxation[J]. Chinese Journal of Theoretical and Applied Mechanics.

基于应力松弛变形探索La基金属玻璃微观非均匀性

Probing on microstructural heterogeneity of La-based metallic glass: Based on the stress relaxation

  • 摘要: 金属玻璃由于独特微观结构而表现出优异的物理和力学性能,大量研究表明其微观结构表现为显著非均匀性,并且采用传统分析方法难以充分表征. 如何建立宏观力学性能与微观结构非均匀性之间的内禀性关联是金属玻璃在固体力学领域尚未很好解决的重要科学问题之一. 本文以La62Cu12Ni12Al14金属玻璃为研究载体,研究了宽温度窗口应力松弛行为,尝试探索金属玻璃在力学激励下微观结构非均匀性的演化规律. 借助于经典扩展指数方程和激活能谱模型,研究了温度以及退火对金属玻璃应力松弛行为的影响规律. 基于自由体积理论,明晰了金属玻璃应力松弛过程应力及缺陷演化规律,揭示了应力松弛变形过程老化与变形的竞争机理. 借助于流变单元模型,厘清了金属玻璃在应力松弛变形老化与变形竞争过程可能存在的物理机制. 本研究以应力松弛作为力学激励切入口,实验研究结合理论分析,从力学响应角度尝试揭示金属玻璃在变形过程微观结构非均匀性演化规律.

     

    Abstract: Metallic glass exhibits outstanding physical and mechanical properties owing to its unique microstructure. Many investigations demonstrated that the microstructural heterogeneity of metallic glasses is a challenging issue in the field of metallic glasses. The microstructural heterogeneity of metallic glasses is difficult to characterize with the help of the traditional techniques/methods. How to establish the intrinsic correlation between the macroscopic mechanical properties and microstructural heterogeneity of metallic glass is a crucial scientific challenging issue of solid mechanics. In the current work, La62Cu12Ni12Al14 metallic glass was selected as the model alloy. The stress relaxation behavior over a wide temperature window was investigated. One attempt to explore the evolutionary patterns of microstructural heterogeneity in metallic glasses under mechanical stimuli. With the help of stretched exponential equation and activation energy spectrum model, effect of thephysical aging below the glass transition temperature on the stress relaxation behavior was investigated. In parallel, in the framework of the free volume theory, the evolution of stress and defect in metallic glass during stress relaxation process was analyzed. In addition, the competition between aging and deformation during the stress relaxation behavior was discussed, and a potential physical mechanism was clarified based on the flow units model. This current work employs stress relaxation as a mechanical excitation approach, on the basis of experimental investigations and theoretical analysis, one tries to reveal the evolution of the microstructural heterogeneity in metallic glasses during deformation from the perspective of mechanical response.

     

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