Abstract The paper concentrates on the prediction of damage behavior in BCC HEAs and its subsequent dependence on intrinsic length scales. Size dependent plastic response is investigated using correlative nanomechanical testing, high resolution microscopy and phase analysis. Hot forged multiphase Al0.7CoCrFeNi HEA, comprising both face centered cubic (FCC) and body centered cubic (BCC) structured phases were used. Phase characterization inside the BCC grains indicated spinodal decomposition leading to a periodic arrangement of ordered B2 and disordered A2 phases. Room temperature nanoindentation response in the BCC grain revealed appearance of repeated strain bursts occurring in a random and stochastic manner. The observed plastic behavior was correlated to dislocation hardening mechanisms arising from a combination of the spinodally modulated microstructure and order hardening effects. Interestingly, in contrast to the commonly observed FCC to BCC transformations, certain indents revealed a structural transition from BCC to FCC. The stress induced microstructural evolution is discussed in terms of inherent compositional gradients and relevant defect-interphase interactions.

中文翻译：

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多相体心立方高熵合金的尺寸相关塑性和损伤响应

摘要 本文专注于 BCC HEAs 损伤行为的预测及其对固有长度尺度的后续依赖。使用相关纳米力学测试、高分辨率显微镜和相分析来研究尺寸相关的塑性响应。使用热锻多相 Al0.7CoCrFeNi HEA，包括面心立方 (FCC) 和体心立方 (BCC) 结构相。BCC 晶粒内的相表征表明，旋节线分解导致有序 B2 和无序 A2 相的周期性排列。BCC 晶粒中的室温纳米压痕响应揭示了以随机和随机方式发生的重复应变爆发的出现。观察到的塑性行为与位错硬化机制相关，这是由旋节线调制的微观结构和有序硬化效应的组合引起的。有趣的是，与通常观察到的 FCC 到 BCC 的转换相反，某些缩进揭示了从 BCC 到 FCC 的结构转变。应力引起的微观结构演变是根据固有的成分梯度和相关的缺陷-界面相互作用来讨论的。