复杂 concentrated 合金中的雪崩类塑性：跨尺度综述
Avalanche-like Plasticity in Complex Concentrated Alloys: A Review Across Scales
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中文总结 AI 辅助
本综述跨尺度探讨复杂 concentrated 合金的雪崩类与锯齿状塑性，指出其锯齿状流动非单一现象，源于多种机制，未确立独特普适类，该类合金是可调控系统。
中文摘要 AI 辅助
复杂 concentrated 合金（CCAs），包括高熵合金和中熵合金，在化学不均匀的能量景观中发生变形，其中位错滑移、溶质时效、孪生、相变和微观结构障碍均可能发挥作用。本综述讨论了CCAs中跨尺度的雪崩类塑性和锯齿状塑性。第一部分划分了相关的长度尺度及用于观测这些尺度的方法：在微观和介观尺度，声发射（AE）和微压缩研究揭示了离散位错雪崩和应变爆发，这些现象可能隐藏在常规宏观曲线中；在试样尺度，对Portevin-Le Chatelier效应的局部引伸计和数字图像相关（DIC）研究表明，集体缺陷动力学可如何组织成变形带和宏观应力锯齿。这些方法共同显示，塑性流动仅作为平均响应看似平滑，而在更精细的尺度上仍呈间歇性。第二部分综述了CCAs的直接证据，重点关注AE、应力锯齿统计、微塑性、DIC、纳米压痕和小尺度变形。核心结论是，CCAs中的锯齿状流动不应被视为单一现象，其起源取决于化学成分、温度、应变速率和微观结构，可能来自动态应变时效、孪生、马氏体相变、滑移局部化或这些机制的组合。报道的类幂律分布及其指数与 simpler 晶体和合金的结果部分重叠，现有证据未确立独特的CCA特定普适类，因此CCAs最佳被视为可调控系统，其中化学无序、短程有序、相稳定性和微观结构可修改集体塑性事件的形核、阻滞和同步。
英文摘要
Complex concentrated alloys (CCAs), including high- and medium-entropy alloys, deform in chemically heterogeneous energy landscapes where dislocation glide, solute aging, twinning, phase transformation and microstructural barriers may all contribute. This review discusses avalanche-like and serrated plasticity in CCAs across scales. The first part separates the relevant length scales and methods used to access them. At microscopic and mesoscopic scales, acoustic emission (AE) and microcompression studies reveal discrete dislocation avalanches and strain bursts that may be hidden in conventional macroscopic curves. At the specimen scale, local extensometry and digital image correlation (DIC) studies of the Portevin-Le Chatelier effect show how collective defect dynamics can organize into deformation bands and macroscopic stress serrations. Together, these approaches show that plastic flow may appear smooth only as an average response, while remaining intermittent at finer scales. The second part reviews direct CCA evidence, with emphasis on AE, stress-serration statistics, microplasticity, DIC, nanoindentation and small-scale deformation. A central conclusion is that serrated flow in CCAs should not be treated as a single phenomenon. Depending on chemistry, temperature, strain rate and microstructure, it may originate from dynamic strain aging, twinning, martensitic transformation, slip localization, or a combination of these mechanisms. Reported power-law-like distributions and exponents partly overlap with those known from simpler crystals and alloys, and the present evidence does not establish a distinct CCA-specific universality class. CCAs are therefore best viewed as tunable systems in which chemical disorder, short range order, phase stability and microstructure can modify the nucleation, arrest and synchronization of collective plastic events.
