Twins formation and their role in nanostructuring of zirconium

Twins formation and their role in nanostructuring of zirconium by surface mechanical attrition treatment were investigated. Twins nucleate via successive emission of partial dislocations from grain boundaries or overlapping of stacking faults and partial dislocations in grain interiors. As strain increases, twin nuclei grow up by adding more partial dislocations pairs into either side of the twin boundaries. The interaction between the formed twins and dislocations refines coarse grains into smaller ones, resulting in nanocrystallization of zirconium.