The strength-ductility trade-off has been the long-standing barrier in the pursuit of high-performance structural materials. Here, by exploiting the merit of interstitial nitrogen, a novel additive manufacture-based approach is proposed to process the hierarchically heterogeneous structured FeCoNiCrN high-entropy alloy (HEA). Compared to the undoped alloy, the 1.8 at. % nitrogen-doped HEA shows a simultaneous increase in both strength and ductility, thereby producing exceptional combination of tensile strength (853 MPa) and elongation (34 %) that outperforms many other single phase FCC HEAs. The unusual inverse strength-ductility relationship is ascribed to the strong strengthening effect and progressive strain hardening arising from the hierarchically heterogeneous structure, the latter of which is highly beneficial to the ductility. The present approach creates heterogeneous structure avoiding surface-mechanical or thermo-mechanical treatments, and thus, enables to produce readily available components with complex geometry.

强度-延展性的折衷一直是追求高性能结构材料的长期障碍。在这里，通过利用间隙氮的优点，提出了一种新的基于增材制造的方法来处理分层非均质结构化的FeCoNiCrN高熵合金（HEA）。与未掺杂的合金相比，为1.8 at。掺氮的HEA的百分比显示出强度和延性的同时增加，从而产生了优于许多其他单相FCC HEA的抗张强度（853 MPa）和伸长率（34％）的出色组合。异常的反强度-延性关系归因于分层异质结构产生的强强化效果和渐进应变硬化，后者对延展性非常有利。