Phase formation and thermal stability of amorphous ZrNbCrMo thin films

Abstract

We demonstrate that the atomic size mismatch, δ, can be used to predict the boundary between amorphous and crystalline phase formation ranges in ZrNbCrMo thin films. The concentrations of all alloying elements are varied systematically, which induces a change in δ. The formation of an amorphous phase is observed by x-ray diffraction for δ ≥ 6.9%, whereas crystallization is detected for δ ≤ 6.9%. The crystallization temperature increases from 575 to 625 ∘C by increasing Nb + Mo content from 10 to 34 at.%, and decreases to 475 ∘C upon further additions of Nb + Mo. Calphad calculated liquidus temperatures, Tl, increases monotonously and δ decreases monotonously with Nb and Mo additions. Consequently, δ and Tl do not serve as predictors for thermal stability of ZrNbCrMo thin films.

Keywords

• Amorphous alloys
• Thermal stability
• Refractory metal
• Calphad
• Mixing enthalpy
• ZrNbCrMo