Abstract The high temperature compressive characteristics of relatively light weight AlCoCrFeNi HEA were investigated via compression tests in a wide deformation temperature (T) range of 1073–1373 K and strain rate ( e ˙ ) range of 10−3–1 s−1. Hot deformation led to the phase constitution transformation from the disorder BCC (A2) + order BCC (B2) at the room temperature to FCC + A2+ B2 +σ at 1073 K and 1173 K, and then to FCC + A2+B2 phase at 1273 K and 1373 K. The kinetic analysis was performed based on the flow stress data by using the hyperbolic sine law constitutive models with a higher the correlation coefficient (R2). Using combination of kinetics analysis and microstructure evolution results, it can be concluded that there was a gradual transformation of the dominant deformation mechanism from the symbiosis effects of grain boundary sliding (GBS) in fine grains and local dislocation gliding in coarse grains at 1073 K to the dislocation climbing mechanisms at 1373 K. The flow stress decreased with the decreasing strain rate and/or increasing true strain, as well as the deformation temperature. At 1073 K and 1173 K, the flow softening was primarily associated with the GBS of ultrafine dynamic recrystallization (DRX) grains in the local phase transformation regions, as well as the dynamic precipitation of FCC phases. While, the softening effect was primarily controlled by the dynamic precipitation of FCC phases and dynamic recovery (DRV) at 1273 K. When the deformation temperature rose to 1373 K, the main softening mechanisms were the continuous DRX (CDRX) and DRV, as well as the coarsening and dissolution of A2 phases. Moreover, the clear serration behaviors at 1373 K/1s−1 and 1373 K/10−3s−1 were induced by the interaction effect between the dislocation and cluster.

中文翻译：

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相对轻质AlCoCrFeNi高熵合金的高温变形机制及组织演变

摘要 通过在 1073-1373 K 的变形温度 (T) 范围和 10-3-1 s-1 的应变率 (e·) 范围内进行压缩试验，研究了相对较轻的 AlCoCrFeNi HEA 的高温压缩特性。热变形导致相组成从室温下的无序 BCC (A2) + 有序 BCC (B2) 转变为 1073 K 和 1173 K 的 FCC + A2+ B2 +σ，然后到 1273 的 FCC + A2+B2 相K 和 1373 K。通过使用具有较高相关系数 (R2) 的双曲正弦定律本构模型，基于流动应力数据进行动力学分析。结合动力学分析和微观结构演化结果，可以得出结论，在 1073 K 时，主要变形机制从细晶粒中的晶界滑动 (GBS) 和粗晶粒中的局部位错滑动的共生效应逐渐转变为 1373 K 时的位错爬升机制。应力随着应变速率的降低和/或真实应变的增加以及变形温度的增加而降低。在 1073 K 和 1173 K 处，流动软化主要与局部相变区域中超细动态再结晶 (DRX) 晶粒的 GBS 以及 FCC 相的动态析出有关。而软化效应主要受 FCC 相的动态析出和 1273 K 的动态回复 (DRV) 控制。当变形温度升至 1373 K 时，主要的软化机制是连续 DRX（CDRX）和 DRV，以及 A2 相的粗化和溶解。此外，在 1373 K/1s-1 和 1373 K/10-3s-1 处的明显锯齿行为是由位错和簇之间的相互作用引起的。