First-Principles Theoretical Studies and Nanocalorimetry Experiments on Solid-State Alloying of Zr–B

摘要: The thermodynamics and kinetics of the solid-state alloying Zr-B, underlying a variety synthesis processes ultrahigh-temperature ceramic ZrB2, are widely unknown. We investigate energetics, diffusion kinetics, structural evolution this system using first-principles computational methods. identify pathways in interpenetrating network interstitial sites for single B atom demonstrate dominant rate-controlling step from octahedral to crowdion site that is distinct conventional mechanism octahedral-tetrahedral transition hexagonal close-packed structures. In intermediate compounds ZrBx, 0 < x ≤ 2, diffusivity highly dependent on composition while reaching minimum ZrB. activation barrier ZrB2 good agreement with nanocalorimetry measurements performed Zr/B reactive nanolaminates.