Slip plane dilation and disorder in a copper—aluminium alloy

The observation of faint fringe patterns between 1/2 〈110〉 dislocations in electron micrographs of a lightly deformed Cu-15.6 at% Al alloy is attributed to the destruction of short-range order giving AlAl nearest neighbours across the slip plane with consequent expansive dilation. The expansive dilation is estimated from a comparison of experimental and computed images to be in the range 1/150 〈111〉 to 1/200 〈111〉.