Abstract A serrated flow, which occurs in a material undergoing mechanical deformation, is a complex process of great engineering significance. Here statistical, dynamical, and multifractal modeling and analyses were performed on the stress-time series to characterize and model the stress-drop behavior of an Al0.5CoCrCuFeNi high-entropy alloy (HEA). Results indicate that the spatiotemporal dynamics of the serrated flow is affected by changes in the strain rate and test temperature. The sample entropy, in general, was found to be the highest in the samples tested at 500 °C. The higher complexity in the serrated flow at this temperature appeared to be associated with the stress-drop behavior that had intermediate values in terms of the maximum stress drop, the multifractality of the data set, and the histogram distributions. Moreover, the sample entropy was the lowest for the samples tested at 600 °C. The lower complexity values were associated with a wider multifractal spectrum and a less uniform and sparser distribution of the stress-drop magnitudes. In terms of the serration types, Type-C serrations were related to the lowest complexity values, widest multifractal spectra, and higher probability of exhibiting larger stress drops. Conversely, Type-A and B serrations were associated with the higher complexity, narrower spectra, and lower probability of higher stress drops. Furthermore, the body-centered-cubic (BCC) structure and the fully-ordered L12 nano-particles were found to emerge in the samples at 600 °C and are thought to be linked to the decreased spatiotemporal correlations in the stress-drop behavior.

中文翻译：

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更深入地了解含铝高熵基合金中的锯齿状流动

摘要 材料发生机械变形时会产生锯齿状流动，是一个具有重大工程意义的复杂过程。在这里，对应力-时间序列进行了统计、动力学和多重分形建模和分析，以表征和建模 Al0.5CoCrCuFeNi 高熵合金 (HEA) 的应力降行为。结果表明，锯齿状流的时空动力学受应变速率和试验温度变化的影响。通常，发现样品熵在 500 °C 下测试的样品中最高。在此温度下锯齿状流的更高复杂性似乎与应力降行为有关，应力降行为在最大应力降、数据集的多重分形和直方图分布方面具有中间值。而且，在 600 °C 下测试的样品的样品熵最低。较低的复杂度值与较宽的多重分形谱和应力降幅度的较不均匀和较稀疏的分布相关。在锯齿类型方面，Type-C 锯齿与最低的复杂度值、最宽的多重分形谱和更高的应力降概率有关。相反，A 型和 B 型锯齿与更高的复杂性、更窄的光谱和更高应力下降的概率更低有关。此外，发现体心立方 (BCC) 结构和完全有序的 L12 纳米粒子在 600 °C 下出现在样品中，并被认为与应力降行为的时空相关性降低有关。较低的复杂度值与较宽的多重分形谱和应力降幅度的较不均匀和较稀疏的分布相关。在锯齿类型方面，Type-C 锯齿与最低的复杂度值、最宽的多重分形谱和更高的应力降概率有关。相反，A 型和 B 型锯齿与更高的复杂性、更窄的光谱和更高应力下降的概率更低有关。此外，发现体心立方 (BCC) 结构和完全有序的 L12 纳米粒子在 600 °C 下出现在样品中，并被认为与应力降行为的时空相关性降低有关。较低的复杂度值与较宽的多重分形谱和应力降幅度的较不均匀和较稀疏的分布相关。在锯齿类型方面，Type-C 锯齿与最低的复杂度值、最宽的多重分形谱和更高的应力降概率有关。相反，A 型和 B 型锯齿与更高的复杂性、更窄的光谱和更高应力下降的概率更低有关。此外，发现体心立方 (BCC) 结构和完全有序的 L12 纳米粒子在 600 °C 下出现在样品中，并被认为与应力降行为的时空相关性降低有关。