Effect of Al on microstructures and hydrogen storage properties of Ti26.5Cr20(V0.45Fe0.085)100-xAlxCe0.5 alloy

The effect of Al additive on microstructures and hydrogen storage characteristics of Ti26.5Cr20(V0.45Fe0.085)(100-x)AlxCe0.5 (x=0, 0.5, 1.0 and 1.5 at %) alloys have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and P-C-isotherm measurements. All of Al-added alloys consist of major BCC and secondary Al-Ce-O phases. The EDS analysis results show that aluminum is poor in the BCC phase but enriches in the secondary Al-Ce-O phase. As Al additive content increased, both the lattice parameters of the BCC phase and the hydrogen desorption equilibrium pressures increase, but the hydrogen storage capacities decrease. It is revealed that the substitution solid solution with BCC structure is formed by the substitution of Al for V atoms. It decreases the hydride stability of the BCC phase and degrades the hydrogen storage performance of the Al-added Ti26.5Cr20(V0.45Fe0.085)(100-x)AlxCe0.5 alloys. (C) 2009 Elsevier B.V. All rights reserved.