Real-time observations of TRIP-induced ultrahigh strain hardening in a dual-phase CrMnFeCoNi high-entropy alloy
Real-time observations of TRIP-induced ultrahigh strain hardening in a dual-phase CrMnFeCoNi high-entropy alloy
复制标题
双相 CrMnFeCoNi 高熵合金中 TRIP 诱导的超高应变硬化的实时观察
DOI：
10.1038/s41467-020-14641-1
复制
发表时间：
2020-02-11
影响因子：
16.6
通讯作者：
Yu, Qian
中科院分区：
文献类型：
--
作者：
Chen, Sijing;Oh, Hyun Seok;Yu, Qian
涉及亚稳相的策略一直是许多合金设计的基础，但对亚稳高熵合金的研究仍处于起步阶段。在双相高熵合金中，局部化学环境和负载引起的晶体结构变化的组合表明变形机制和化学原子分布之间的关系，我们在这里研究的康托状Cr20 Mn 6 Fe 34 Co 34 Ni 6合金，包括面心立方（fcc）和六方密堆积（hcp）相。我们观察到，部分位错活动导致稳定的三维堆垛层错网络。此外，在塑性变形过程中，通过在fcc相中的层错网络边界处形成，更强的hcp相的分数逐渐增加，作为应变硬化的主要来源。在这种情况下，局部化学成分的变化促进了高密度的Lomer-Cottrell锁，这有利于堆叠断层网络的构建，为hcp相变提供成核位点。
Strategies involving metastable phases have been the basis of the design of numerous alloys, yet research on metastable high-entropy alloys is still in its infancy. In dual-phase high-entropy alloys, the combination of local chemical environments and loading-induced crystal structure changes suggests a relationship between deformation mechanisms and chemical atomic distribution, which we examine in here in a Cantor-like Cr20Mn6Fe34Co34Ni6 alloy, comprising both face-centered cubic (fcc) and hexagonal closed packed (hcp) phases. We observe that partial dislocation activities result in stable three-dimensional stacking-fault networks. Additionally, the fraction of the stronger hcp phase progressively increases during plastic deformation by forming at the stacking-fault network boundaries in the fcc phase, serving as the major source of strain hardening. In this context, variations in local chemical composition promote a high density of Lomer-Cottrell locks, which facilitate the construction of the stacking-fault networks to provide nucleation sites for the hcp phase transformation.