Revealing Austenite Stability in Fe–30Mn–5Al–0.5C Twinning‐Induced Plasticity Steel Using Differential Thermal Analysis

The thermal stability of austenite in as‐cast high‐alloyed Fe – 30Mn – 5Al – 0.5C twinning‐induced plasticity (TWIP) steel has been studied by differential thermal analysis (DTA). TWIP steels are subjected to austenization treatments in the temperature range between 800 and 1200 ºC and holding times between 3 and 100 min. Different heating and cooling rate conditions are applied, including cooling rates between 0.1 and 1.0 K s −1 and three heating rates 0.08, 0.33, and 0.83 K s −1 . The DTA results show that austenite is stable for all of the heat treatments applied. Microstructural analysis reveals a strong dendritic segregation due to the high percentages of Mn and Al in the composition of the TWIP steel. Finally, the austenitization temperature significantly influences the austenite grain size, unlike the cooling and heating rates that have an insignificant effect. The DTA results are confirmed by the X‐ray diffraction analysis, revealing a single‐phase γ ‐austenite crystal structure.