Stress–Strain Relations and Deformation Mechanisms of ZrN and HfN Superconductors

Abstract

Zirconium and hafnium nitrides are charmingly hard superconductors [X. J. Chen et al. Proc. Natl. Acad. Sci. U.S.A., 2005, 102, 3198] with specific application under extreme conditions. Understanding the intrinsic hardness, especially under Vickers indentation deformation, in these superconductors is very important. Here, we perform first-principles studies of the stress–strain relations and deformation mechanisms of ZrN and HfN under compressive, tensile, pure shear, and indentation strains. The results offer a comprehensive description of their versatile stress responses, and the calculated indentation shear strengths for ZrN and HfN agree well with experimental results. The superior performance characteristics of HfN, compared to the isostructural ZrN, is attributed to the higher valence electron concentration that strengthens the Hf–N bonds. These results reveal the atomistic mechanisms for the mechanical properties of ZrN and HfN, providing insights for further exploration of hard and ultrahard transition-metal compounds.

Origin of the superior oxygen reduction activity of zirconium nitride in alkaline media

“…This work is signicant given the low-cost and versatile nature (i.e., ∼zero bandgap and considerable electrical conductivity) of ZrN, 22,23 which offers promising potential for its widespread application in energy conversion technology. [24][25][26][27][28][29] Similar ORR performance of ZrN was also found by some subsequent studies (e.g., ref. 15).…”