The possible role of stacking faults is discussed in some problems of glide and twinning of cubic metals, especially at low temperatures.The first part analyzes a model for the thermal variation of macroyield in b.c.c. metals. If one assumes that the dislocations of such metals split along either the (110) or the (112) planes, the screw dislocations will be sessile. The strong temperature variation of macroyield could be due to the thermally activated slip of such screws, previously developed at lower stresses during the less temperature-dependent microyield. Reasonably high stacking-fault energies are required for satisfactory numerical fits.The second part studies the influence of a dense dislocation network on the propagation of a stacking fault. The friction force acting on the partial that propagates the fault must be taken into account when deducing a stacking-fault energy from the stress at which stacking faults develop in a strongly work-hardened (f.c.c.) metal. The trails of dipoles left at each tree crossed should prevent any creation of point defects; they should lead, after the faults have propagated some length, to its multiplication into a twin or martensitic lamella. The analogies with problems of slip bauds and dipole formation in easy glide are stressed.
Role of Point Defects and Defect Complexes in Silicon Device Processing: Summary Report and Papers of the Second Workshop, 24-26 August 1992, Breckenridge, Colorado
