The influence of a carbide dispersion on the recrystallization behaviour of chromium

Abstract Finely dispersed particles of tantalum carbide in a chromium-2% tantalum-0.1% carbon alloy retard recovery and recrystallization in chromium. Using transmission electron microscopy, observations were made of the structural changes that occur during the annealing of warm-worked strip. The variation in structure during the early stages of tensile deformation was also studied. The electron micrographs indicated that a similar broad sequence of events was followed in the alloy as in the pure metal. This sequence involved the formation of a sub-grain structure, gradual coalescence of sub-grains to create new high-angle boundaries, and migration of boundaries to form recrystallized grains. Retardation of recrystallization is attributed, in part, to the absence of any marked lattice misorientation within the grains of the wrought dispersion-strengthened alloy. A complex distribution of dislocations is produced in this material by the initiation of slip on many independent systems and by an increase in the frequency of cross slip. In addition, the carbide particles interfere with the rearrangement of dislocations throughout and restrict the movement of sub-grain and grain boundaries.