COMPARISON OF SMALL-ANGLE NEUTRON-SCATTERING OF DELTA' PRECIPITATION IN AN AL-LI ALLOY AT A HIGH-FLUX REACTOR AND AT A PULSED-NEUTRON SOURCE

Two different small-angle neutron scattering (SANS) facilities, the D1 1 camera at the Institut Laue-Langevin (ILL, Grenoble, France) and the LOQ time-of-flight diffractometer at the Rutherford Appleton Laborato ry (RAL, Didcot, Oxon, England), were used in the investigations of de lta'-Al3Li precipitation at 463 K in Al-Li 3% alloy. The results obtai ned from the steady-state reactor and from the pulsed source by using two different data-acquisition techniques and two different procedures for data analysis are compared. The SANS curves for the same set of s amples investigated using the two different instruments are in good ag reement within the experimental uncertainties. A check was also made o n the metallurgically relevant quantities, namely the average size and the size-distribution function of the delta' precipitates at the vari ous stages of the ageing process, obtained from the two sets of SANS c urves by applying the same numerical method. Good agreement was found between the results from the two data sets.