Neutron-diffraction study of hydrogenated and deuterated CuTi amorphous alloys

Neutron-diffraction experiments have been performed on amorphous Cu x Ti 1-x (x=0.67,0.50,0.35) alloys charged either with hydrogen or deuterium. The variation of the interference functions and pair-correlation functions have been studied as a function of copper and hydrogen or deuterium concentration. The results obtained of non-hydrogenated alloys confirm the existence of chemical order. First-neighbour distances are determined and can be well compared with those in corresponding crystalline phases. The good contrast between copper and titanium on the one hand and between hydrogen and deuterium on the other allows one to identify individual metal-hydrogen correlations. Their positions in the total pair-correlation functions are very close to those found in crystalline hydrides and show that Ti 3 tetrahedra are preferred hydrogenation sites in the concentration range studied.