Concentration dependence of short-range order parameters in annealed copper-aluminum alloys

The method of diffuse X-ray scattering was used to investigate -CuAl alloys containing between 11.9 and 17.6 at.% aluminum after prolonged stepwise annealing. Analysis of the short-range order coefficients indicated uniform ordering at concentrations up to 15 at.% aluminum and possible departure from uniform ordering in alloys with higher concentrations. It was shown that the structure of the ordered alloy is consistent with the model proposed by Gehlen and Cohen [13].