Mechanical and tribological behavior of dual-phase ductile iron with different martensite amounts

Abstract

Ferrite-martensite (F/M) dual-phase ductile iron with different relative amounts of martensite was fabricated via intercritical quenching in the present study. The mechanical properties and tribological behavior were investigated. The strength of ductile iron increased linearly with the increase of martensite level, while the ductility decreased rapidly. Fracture surface morphology analysis indicated that ductile fracture was predominant when the proportion of martensite in ductile iron was less than 20%. However, the samples with more than 40% martensite exhibited brittle fractures. Wear tests indicated that F/M dual-phase ductile iron exhibited a significantly lower friction coefficient compared with directly quenched ductile iron. Additionally, the martensite amounts affected the tribological behavior of ductile iron significantly. Abrasive wear was predominant in ductile iron with small amounts of martensite, while delamination wear was the main wear mechanism in case of ductile iron with high amounts of martensite.