Fabrication of a dual-phase ductile iron with an exceptional combination of strength and toughness

A dual-phase ductile iron with a good balance of strength and plasticity was successfully produced in the present study through tailoring the morphology and distribution of ferrite and martensite. The results indicated that the uniform distribution of punctate martensite in ferrite could effectively improve the strength and toughness of dual-phase ductile iron simultaneously. The punctate martensite not only strengthened dual-phase matrix obviously and hardly restricted the plastic flow of ferrite during deformation, which resulted in a tensile strength of 947 MPa and a toughness with impact energy of 127 J in a dual-phase ductile iron.