Grain statistics induced size effect in the expansion of metallic micro rings

• A 3D crystal plasticity based grain level investigation on statistical size effect in the expansion of metallic micro-rings.
• Parametric investigations on the influence of grain statistics (number and orientation distribution) on final geometry.
• Influence of grain statistics on the deformation mode.
• The results could be used in material selection for stretching dominated micro-forming operations.

This study focuses on the expansion of metallic micro rings under internal pressure using a grain level three dimensional finite element analysis in combination with a rate dependent crystal plasticity constitutive model. The size effect due to grain statistics such as grain orientations and number of grains through the thickness is investigated to a certain depth, in terms of final geometries and the scatter involved. The findings of the study could be used as the preliminary guidelines for suitable material selection in stretching dominated microforming operations.