It was noted that dislocation mechanisms could be studied in detail by performing critical pre-straining experiments. Here, the effect of pre-strain upon the flow stress of an alloy with L12 long-range order was investigated. It was found that the yield strength increased with temperatures ranging from ambient to 450C. The pre-straining of monocrystals at 800C activated the primary a[11¯0](001) cube slip system. Climb-dissociated segments interconnected superlattice dislocations of Lomer-Cottrell type. Subsequent additional deformation at room temperature introduced superlattice dislocations of the primary  a[101¯](001) glide system. This subsequent deformation resulted in almost the same flow stress as that found in single crystals which had been subjected only to room temperature deformation. Pre-straining was found to have a huge effect upon work-hardening, and this was consistent with dislocation interactions of the cube and octahedral glide systems. It was concluded that yielding was an intrinsic property of dislocation motion due to extended core configurations.

A.Korner: Materials Science and Engineering A, 1995, 192-193, 262-7