Title

Investigation Of Interdiffusion Behavior In The Mo-Zr Binary System Via Diffusion Couple Studies

Keywords

Diffusion couples; Interdiffusion; Interdiffusion coefficients; Molybdenum; Zirconium

Abstract

Zirconium has recently garnered attention for use as a diffusion barrier between U-Mo metallic nuclear fuels and Al alloy cladding. In order to gain a fundamental understanding of the diffusional interactions, the interdiffusion behavior in the binary Mo-Zr system was investigated via solid-to-solid diffusion couples annealed in the temperature range of 750 to 1050 C. A combination of scanning electron microscopy, X-ray energy dispersive spectroscopy, and electron probe microanalysis were used to examine the microstructure and concentration profiles across the interdiffusion zone. A large β-Zr (cI2) solid solution layer and a thin (~ 1-2 μm) layer of Mo2Zr (cF24) developed in all couples. Parabolic growth constants and concentration dependent interdiffusion coefficients were calculated for the Mo2Zr and Zr solid solution phases, respectively. The pre-exponential factor and activation energy for growth of the Mo2Zr phase were determined to be approximately 6.5 × 10- 15 m2/s and 90 kJ/mol, respectively. The interdiffusion coefficient in β-Zr solid solution decreased with an increase in Mo concentration. Both the pre-exponential factors (2 × 10- 8 m2/s at 2 at.% Mo to near 5 × 10- 8 m2/s at 9 at.% Mo) and activation energies (140 kJ/mol at 2 at.% Mo to approximately 155 kJ/mol at 9 at.% Mo) of interdiffusion coefficients were determined to increase with an increase in Mo concentration. © 2014 Elsevier Ltd.

Publication Date

3-1-2014

Publication Title

International Journal of Refractory Metals and Hard Materials

Volume

43

Number of Pages

317-321

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.ijrmhm.2013.12.017

Socpus ID

84893479617 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84893479617

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