Enhanced strength-ductility synergy in ultrafine-grained eutectic high-entropy alloys by inheriting microstructural lamellae
Enhanced strength-ductility synergy in ultrafine-grained eutectic high-entropy alloys by inheriting microstructural lamellae
复制标题
通过继承微结构片层增强超细晶共晶高熵合金的强度-延展性协同作用
DOI：
10.1038/s41467-019-08460-2
复制
发表时间：
2019-01-30
影响因子：
16.6
通讯作者：
Liaw, Peter K.
中科院分区：
文献类型：
--
作者：
Shi, Peijian;Ren, Weili;Liaw, Peter K.
在传统共晶体系中，实现共晶合金作为原位复合材料的增强强度-塑性协同作用仍然是一个挑战，这就是为什么共晶高熵合金（EHEAs）作为一种新兴的多主元共晶合金，可能提供更广泛的原位复合可能性。在这里，我们使用AlCoCrFeNi2.1 EHEA来设计一种超细晶粒的双相微观结构，通过定制的热机械加工，故意继承其复合片层性质，以实现先前报道的增强方法无法实现的性能组合。由于相分解，制备的样品表现出层次结构的非均质性，变形过程中力学响应的改善归因于双层次约束效应和自产生的微裂纹止裂机制。这项工作为增强共晶合金提供了一条途径，并扩大了基于EHEAs的高性能材料的设计工具箱。
Realizing improved strength-ductility synergy in eutectic alloys acting as in situ composite materials remains a challenge in conventional eutectic systems, which is why eutectic high-entropy alloys (EHEAs), a newly-emerging multi-principal-element eutectic category, may offer wider in situ composite possibilities. Here, we use an AlCoCrFeNi2.1 EHEA to engineer an ultrafine-grained duplex microstructure that deliberately inherits its composite lamellar nature by tailored thermo-mechanical processing to achieve property combinations which are not accessible to previously-reported reinforcement methodologies. The as-prepared samples exhibit hierarchically-structural heterogeneity due to phase decomposition, and the improved mechanical response during deformation is attributed to both a two-hierarchical constraint effect and a self-generated microcrack-arresting mechanism. This work provides a pathway for strengthening eutectic alloys and widens the design toolbox for high-performance materials based upon EHEAs.