Bending ductility of heavily cold-rolled Ni3Al thin foils

Our recent studies revealed that heavily cold-rolled Ni3Al foils have a good bending ductility in spite of almost no elongation in tensile test. In this paper, bending characteristics of 95% cold-rolled foils around transverse and rolling directions (TD and RD, respectively) were examined to understand the bending mechanism. Fracture elongation on the tension surface shows a large bending anisotropy: 5 % for the TD bending, while less than 1% for the RD bending. The bending ductility is due to {111}<110> slip deformation. In the TD bending, slip occurs on the slip systems operated during cold rolling, and cracks initiate along the shear bands. In the RD bending, slip occurs on the other {111} planes besides the slip planes operated during cold rolling, and fracture occurs as a result of the dislocation interaction in the both planes.