Temperature dependence of strengthening mechanisms in a twinning-induced plasticity steel

The temperature dependence of strengthening mechanisms in twinning-induced plasticity (TWIP) steels is of fundamental importance because of the broad range of environmental temperatures during manufacturing and applications. In this study, the temperature dependence of dislocation, twin and dynamic strain aging strengthenings, was investigated over a wide range of temperatures ranging from 298 to 973 K. Uniaxial tensile tests and microstructural characterization via electron backscatter diffraction and electron channelling contrast imaging were carried out. In addition, synchrotron X-ray diffraction was used to measure the dislocation density at various temperatures. Based on the experimental observations, the strengthening mechanisms at various temperatures are elucidated with the quantification of the respective strengthening contributions from dislocations, twins and dynamic strain aging. These experimental results shed light on the temperature-dependent plasticity of TWIP steels and provide guidance for developing temperature-sensitive constitutive models.