It was recalled that it was generally accepted that the mechanical behavior and dislocation sub-structures of metals and alloys were functions of the stacking fault energy. The present metal was known to have a high stacking fault energy but, although stacking faults had been observed experimentally, there was still some doubt concerning them; due to the high value of the stacking fault energy. An attempt was made here to obtain further information on stacking faults in fatigued single crystals, and to determine the relationship between stacking faults and twinning. It was suggested that the formation of stacking faults during {11•1}-type twinning could be described by:

(a/3)[11•0](1¯1•0)  (a/9)[¯1¯1•0](1¯1•0) + (2a/9)[¯1¯1•0](1¯1•0) - 2b

Stacking faults were observed within {11•1} cyclic twins in (2¯1•0) slices of fatigued single crystals of high-purity material. The results could be interpreted by supposing that <a>-type dislocations reacted with {11•1} twin interfaces during twinning. This facilitated dissociation of the dislocations.

X.L.Tan, H.C.Gu: Scripta Metallurgica et Materialia, 1995, 33[12], 1977-80