High-strength NbMoTaX refractory high-entropy alloy with low stacking fault energy eutectic phase via laser additive manufacturing
Hang Zhang, Yizhen Zhao, Jianglong Cai, Shaokun Ji, Jiale Geng, Xiaoyu Sun, Dichen Li
Abstract
The high-entropy alloys (HEAs) exhibit outstanding high-temperature properties and promise in a wide range of applications, such as aviation, nuclear energy and other fields. However, the problems of formability and defect control limit the successful realization of HEAs. Herein, we newly developed NbMoTaTi0.5Ni0.5 HEA which renders a high room-temperature compressive strength of 2297 MPa and high-temperature (1000 °C) compressive strength of 651 MPa. Meanwhile we present that the addition of both Ni and Ti can suppress the crack formation and enhance the formability of NbMoTa HEA, prepared by selective laser melting (SLM), without compromising the mechanical performance. Actually, the fracture is suppressed by the transformation of microcracks due to grain boundaries with low stacking fault energy (SFE) which can greatly improve the formability of HEAs while ensuring its high-temperature performance. The current study shall serve as a guideline for the development of refractory high-entropy alloys via additive manufacturing, such as selective laser melting.