Mechanical and Electrochemical Behavior of Dual-Phase Steels Having Varying Ferrite–Martensite Volume Fractions

Abstract

Dual-phase (DP) steels behave differently under corrosive environment depending upon the volume fractions of phases, mainly martensite, ferrite and bainite. The mechanical behavior and corrosion resistance of DP steels with varying martensite (from 32 to 100%) are investigated. The increase in martensite volume fraction of DP steel results in significant improvement in tensile strength and hardness with a subsequent reduction in elongation. Unlike the mechanical behavior, the increase in martensite volume fraction in steel does not exhibit a direct relationship with their corrosion resistance behavior. The corrosion mechanism in DP steels having different martensite and ferrite volume fractions depends on the self-corrosion resistance behavior of both the phases as well as the occurrence of galvanic corrosion between them.