Deformation behavior and the Portevin-Le Chatelier effect in a modified 18Cr–8Ni stainless steel

Abstract

Mechanical behavior and microstructural evolution of a 2.5%W+0.4%Nb+0.3%V+0.17%N modified 18Cr–8Ni austenitic steel was studied in the temperature interval 410–740°C at initial strain rates ranging from 6.7×10−6 to 1.3×10−2s−1. The Portevin-Le Chatelier (PLC) effect attributed to dynamic strain aging (DSA) was found to occur in the temperature range 530–680°C. The PLC effect is manifested in the form of serrated (jerky) flow and planar slip. DSA increases yield strength, σ0.2, and ultimate tensile strength, σUTS, in comparison with conventional SUS304 steel due to the additional alloying that provides the formations of the clouds of solutes around the dislocations that exert the solute drag force.