Thermophysical properties of Mo-Ru-Rh-Pd alloys

Mo-Ru-Rh-Pd alloys as the simulated materials for metallic inclusions precipitated in irradiated nuclear fuels were prepared by high vacuum induction melting. The compositions of the alloys evaluated by energy dispersive X-ray spectroscopy (EDX) analysis are Mo35Ru31Rh9Pd25, Mo20Ru54Rh15Pd11, Mo30Ru43Rh14Pd13 and Mo43Ru34Rh12Pd11. The thermophysical properties of the alloys, such as the elastic moduli, Debye temperature, and thermal conductivity were evaluated. The relationships between the micro-Vickers hardness and Young's modulus for the alloys show metallic characteristics. The thermal conductivities of all the alloys almost linearly increase with increasing temperature, and above about 1000 K, they are 10-fold as large or larger than that of UO2. The electronic contribution to the thermal conductivity was also evaluated from the Wiedemann-Franz-Lorenz relation by using the electrical resistivity. It is confirmed that the characteristics of the mechanical and thermal properties of the alloys differ from those of UO2. (C) 2002 Elsevier Science B.V. All rights reserved.