Nanostructured NbMoTaW high entropy alloy thin films: High strength and enhanced fracture toughness

Y. Xiao; Y. Zou; H. Ma; A. S. Sologubenko; X. Maeder; R. Spolenak; J. M. Wheeler

Scripta Materialia 168 (2019) 51-55

Nanocrystalline NbMoTaW high entropy alloys (HEAs) have attracted significant attention due to their superior mechanical properties at elevated temperatures. However, the fracture behavior of nanocrystalline HEAs is still unknown. In this study, the fracture behavior of thin HEA films was investigated using micro-cantilever bending. The nanocrystalline films demonstrated critical stress intensities of ~3 MPa√m, which is significantly higher than previous single- and bi-crystalline values. This work demonstrates the capability of ion beam assisted deposition to strengthen nanocrystalline thin films with only minor losses in toughness.