CHARACTERISTICS OF SHEAR BANDING IN DUAL-PHASE STEEL

The evolution process of shear banding in a ferrite-martensite dual ph ase steel has been investigated via in situ tensile testing in a scann ing electron microscope. Shear band type deformation localisation occu rs at the maximum loading point of uniaxial tension. Necking occurs si multaneously and locally. Voids nucleate in ferrite domains and on the interfaces between the two component phases or grain boundaries. The void volume fraction is greater within the shear band than away from t he band and is greater in the interior than at the specimen surface. T he results also show that void damage promotes the initiation of shear bands and the development of shear banding stimulates further void da mage. (C) 1993 The Institute of Materials.