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.

中文翻译：

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利用差热分析揭示Fe–30Mn–5Al–0.5C孪生诱导塑性钢中的奥氏体稳定性

通过差热分析（​​DTA）研究了铸态高合金Fe – 30Mn – 5Al – 0.5C孪晶诱导塑性（TWIP）钢中奥氏体的热稳定性。TWIP钢在800至1200ºC的温度范围内进行了奥氏体化处理，保持时间为3至100分钟。应用了不同的加热和冷却速率条件，包括在0.1和1.0 K s ^-1之间的冷却速率以及三个加热速率0.08、0.33和0.83 K s ^-1。DTA结果表明，奥氏体对所有热处理均稳定。显微组织分析显示，由于TWIP钢中Mn和Al的含量较高，因此存在强烈的树枝状偏析。最后，奥氏体化温度显着影响奥氏体晶粒尺寸，这与冷却和加热速率的影响无关紧要。DTA结果通过X射线衍射分析得到证实，揭示了单相γ奥氏体晶体结构。