-
非晶合金高温流变行为是理解其结构演化与动力学行为的重要窗口, 阐明其动力学弛豫行为与流变行为的内秉性关联是理解非晶固体变形行为的重要研究内容之一. 本文基于动态力学分析仪从激活体积和缺陷演化动力学角度系统探究了三种La基非晶合金的高温流变行为与动力学弛豫特征的耦合机理. 在自由体积理论框架下通过应变率跳跃实验结合, 揭示了非晶合金的流变应力随温度和应变率变化的双曲正弦依赖关系, 建立了高温流变激活能与α弛豫过程的关联. 参考应变率与温度正相关, 反映非晶合金结构非均匀性对原子扩散速率的调控. 此外, β弛豫激活能与高温流变平均激活能呈相反趋势, 为β弛豫作为α弛豫前驱过程提供理论依据. 缺陷湮灭与生成速率的动态竞争主导了非晶合金的高温流变行为, 以动力学参量定量描述了非晶合金热力耦合变形特征. 研究结果为非晶合金高温变形机制的微观解释提供了实验数据与理论指导, 有利于优化其高温加工与成型工艺.This study aims to establish the intrinsic link between the high-temperature rheological behavior and kinetic relaxation characteristics of La-based metallic glasses. By conducting dynamic mechanical analysis and high-temperature tensile strain-rate jump experiments on three La-based metallic glasses with significant β relaxation, and combining the findings within the free volume theory framework, their high-temperature rheological properties are investigated systematically. The results show that the steady-state flow stress and activation volume evolution trend are consistent within the normalized temperature range. The average activation energy for high-temperature rheology aligns with the activation energy range of α relaxation, confirming the strong association between rheological behavior and α relaxation. The activation energy for β relaxation shows an opposite trend, indicating that it may precede α relaxation. A dynamic competition between defect annihilation and generation governs the rheological behavior, and kinetic parameters reveal the temperature and strain-rate sensitivity of metallic glasses. This study lays a theoretical foundation for optimizing the high-temperature mechanical properties of La-based metallic glasses and also provides new insights into understanding the coupling relationship between multi-scale relaxation behavior and rheological mechanisms in metallic glasses.
-
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45] [46] [47] [48] [49] [50] [51] [52] [53] [54] [55] [56] [57] [58] [59] [60] [61] [62] [63] [64] [65] [66] [67]
下载:
计量
- 文章访问数: 361
- PDF下载量: 10
- 被引次数: 0