Chemical short-range order in liquid and amorphous Cu 66 Ti 34 alloys

It is demonstrated that the chemical short-range order (CSRO) which exists in the transition-metal glass Cu 66 Ti 34 originates in the liquid state, and that this CSRO appears to be enhanced on vitrification. The structure factor S(Q) of the liquid alloy Cu 66 Ti 34 has been obtained by neutron diffraction. The form of S(Q), and in particular the existence of a 'prepeak' at a Q value of approximately 1.9 AA -1 , provides direct experimental evidence of CSRO in the liquid state. A comparison of the S(Q) curves of Cu 66 Ti 34 for the liquid and glass states indicates that the CSRO is less well developed in the liquid. This qualitative analysis is supported by a rough estimate of the value of the CSRO parameter, alpha , which appears to be reduced by a factor of about two in the liquid state.