Twin-twin interaction behavior in tensile-deformed austenitic manganese steel

Electron back scatter diffraction instrument and high-resolution transmission electron microscope were used to observe and characterize the twin-twin interaction behavior in tensile-deformed 120Mn13 steel at the atomic scale. Here the whole twin-twin interaction behavior was divided into three processes and the deformation mechanisms of each process were revealed, including the interaction between the incident twin and the coherent twin boundary of the barrier twin, which can lead to a twinning or detwinning process of the barrier twin, the trigger formation of secondary twins and the formation of second order twins in the intersection region. Based on the Thomson tetrahedron, the dislocation movements in different twin-twin interaction processes were systematically described, and the possibility of dislocation reactions were discussed in energy. The interaction mechanism of the microscopic zero-stain twin (MZST) was proposed for the first time, and its differences from the classical twin-twin interaction mechanism were expounded. Present work further enriches the twin-twin interaction behavior in face centered cubic metallic materials. It can also guide the in-depth understanding of the classical twin-twin interaction behaviors and be used to explain the formation of classical secondary and second order twins.