Determination of Yield Stress in a Duplex Steel with plus Lamellar Structure

Abstract

Yield stress sigma(y) is evaluated in a duplex steel with + lamellar structure by calculating the stress for the propagation of pile-up dislocations in one phase into another phase. Effective grain size of a lamella is determined to calculate the contribution of each boundary of a lamella to dislocation pile-up. Comparison of stresses required to drive -to- and -to- propagations of pile-up dislocations suggests that + lamellar structure yields by propagation of pile-up dislocations in lamella to lamella. sigma(y) of + lamellar structure is calculated as the sum of friction stress sigma(o) of and the stress component sigma for yielding of lamella at the effective grain size d(,eff) of lamella. The calculated results explain better to the experimental sigma(y) than do results calculated using rule of mixture.