A simple principle about how to get the corresponding BF and DF images for the Al3Li precipitates in Al-Li alloy (shown here), in which the Al3Li precipitates are in
bright contrast in the DF image since the DF image is formed by using AL3Li (001) diffracted spot, meanwhile the precipitates are in dark contrast in the BF image. The composite
SAED pattern is with the orientations of Al [110] and Al3Li [110] .