Experimental study and thermodynamic description of the erbium-hydrogen-zirconium ternary system

The erbium-hydrogen-zirconium (Er-H-Zr) ternary system has been investigated experimentally at 350 °C using high purity materials. The extent of the ternary homogeneity domains have been measured using two combined experimental techniques: X-ray diffraction and ion beam analysis. An isothermal section is proposed according to these measurements. The three binary systems Er-H, Er-Zr and H-Zr were already assessed using the Calphad method. After making them compatible with each other and assigning the enthalpy of formation of the new generated end-members (including in H-Zr system) to the results of DFT calculations, the ternary system has been calculated without using any ternary parameter. The calculated isothermal section at 350 °C shows a fair agreement with the experimental data and the behavior at higher temperature is predicted.