Microstructure and fracture mode of unalloyed dual-phase austempered ductile iron

Dual-phase ADI material microstructure consists of different amounts and morphologies ausferrite free ferrite, obtained by subjecting ductile iron to specific heat treatment. Its strength is lower compared comparable materials but exhibits a higher ductility, the major disadvantage ADI. In current study, an unalloyed was intercritical austenitized in two-phase regions (?+?) at four temperatures from 840 780 ?C for 2 h austempered 400 1 obtain dual-phase with percentages ferrite ausferrite. Light scanning electron microscopy performed metallographic fracture studies, respectively. Microscopy results were correlated tensile testing results. The indicated that, as amount present matrix increases, values ductility are obtained. surfaces microstructures 22.8% their have quasi-cleavage around last-to-freeze zones, related presence those areas. specimens highest 86.8% among dominant type fracture.