Dense mechanical twins and phase transformation are the most attractive athermal transformation processes since they can endow alloys with significant strength enhancement as well as maintain a high-level total elongation. The initiation of the two effects are highly dependent on alloys’ stacking fault energy (SFE), which is sensitive to change in composition and deformation temperature. Most studies focus on obtaining desirable SFE by tuning composition and mechanical behaviors at room to high temperatures. Strengthening effects at a wider temperature range, especially cryogenic temperatures, however, have scarcely been investigated. Herein, we propose to perform in situ tensile tests using neutron diffraction on TWIP steels at a wide temperature range (from 15K to 393K), providing a well-rounded understanding of the relationship among composition, strengthening mechanisms, SFE and corr