Effects of Shear Strain on Orientation Gradients, the Instability of Austenite Diffraction Peak, and Microstructure in Twinning‐Induced Plasticity (TWIP) Steels

Abstract

As automotive steels require high safety standard for absorbing impact energy during vehicle body collision, detailed investigation of deformation behavior at shear strain state of TWIP steels is crucial. The orientation gradients, the instability of austenite diffraction peak, and microstructure of TWIP steel are investigated as a function of shear strain using transmission electron microscopy, electron back‐scatter diffraction, and X‐ray diffraction analyses of interrupted shear specimens. According to microstructural evolution results, both orientation rotation and supplementary twinning system impact the intensities of austenite diffraction peak. The decrease of γ(220) peak intensity occurs at ϵe = 0.49, since the orientations rotate mainly toward the <111> and <001> poles. The reversion of intensity of γ(220) peak happens at ϵe = 1.18, which may be caused by supplementary twinning system. Due to the kinking formed at the twin border region, orientation gradient of matrix in front of twin boundary increases significantly at ϵe = 1.18.