Mechanisms of deformation in an age-hardenable Ni-Mo-Cr alloy containing
large precipitates of the coherent ordered phase were investigated.
The dominant deformation mechanism in the examined alloy depended on
the applied amount of strain: for low strains micro-twinning within the ordered
precipitates and dislocation slip in the matrix prevailed; at higher strains
the f.c.c. twinning became the major deformation mechanism. Micro-twinning within
the ordered phase was size related - micro-twins occur in large precipitates at
relatively small strains. Twinning within the ordered precipitates may occur
in all possible twin systems. Ten out of twelve possible twinning systems lead
to the formation of true twins, and the long range order is preserved in the
twinned regions. Formation of shear bands at high strains destroys the long
range order.