Influence of volume fraction of martensite on the work hardening behaviour of two dual-phase steels with high and low silicon contents

Abstract

Abstract Two low carbon steels with the same manganese content (approximately 1.6 wt.%) but different silicon contents (0.34 and 2.26 wt.%) with the initial microstructures consisting of ferrite and pearlite were intercritically annealed at five different temperatures followed by water quenching to obtain dual-phase microstructures. The modified Crussard–Jaoul analysis was employed to describe the work hardening behaviour of the dual-phase steels. Both steels exhibited two stages of work hardening in the range of plastic deformation. It is shown that for each stage the work hardening exponent is not constant and varies with volume fraction of martensite and silicon content. The dependence of the transition stress σk and strain ∊k of dual-phase steels on the annealing temperature is discussed for both steels. It is concluded that ∊k increases with increasing silicon content and decreases with annealing temperature, while the reverse is true for σk.