Microstructural evolution during friction stir-processing of pure iron

Microstructural evolution during friction stir-processing of pure iron was studied. The development of grain structure was found to be a complex process driven mainly by grain subdivision, but also involving the geometrical effect of strain and local grain-boundary migration. The evolution of deformation-induced grain boundaries was found to be linked to the global straining state and texture evolution as well as to slip patterns within the grains in which they develop.