Dynamic Strain Ageing in a Twin-induced Plasticity Steel

摘要

This work was to clarify the characteristics of serrated flow in an austenitic Fe-Mn-C twin-induced plasticity (TWIP) steel at room temperature using both strain- and crosshead displacement-controlled tensile tests. Three types of serrations, including type A, B and C ones, were observed in strain-controlled but not in displacement-controlled tests. The occurrence of different types of serrations depends on both strain rate and strain level. Type C serrations were identified in TWIP steels at room temperature for the first time. The critical strain for the onset of serrations exhibits a positive strain rate dependence in the high strain rate region, whereas an "inverse" critical strain behavior was observed in the low strain rate region.