We propose a new concept to improve functional/mechanical properties of Fe-high Mn alloys, by suppressing thermal γ → ε martensitic transformation with a proper thermo-mechanical treatment. As an experimental example to demonstrate the validity of this concept, we tried to improve the shape memory effect of a Fe-15.3Mn-5.8Si-0.24C (mass-%) alloy by hot rolling. The alloy showed a dual γ/ε phase at room temperature (M_s = 66°C) and a poor shape recovery strain of approximately 0.6% after the solution-treatment. The pre-existing thermal ε-martensite can act as obstacles against the reversible forward-reverse γ → ε martensitic transformation under loading and subsequent heating. Hot rolling at 800°C with a 70% reduction appeared to dramatically improve the shape recovery strain up to 2.9%. The rolling suppressed thermal γ → ε martensitic transformation during cooling to obtain the single γ-phase at room temperature. Further annealing of the 800°C -rolled specimen at 800 to 1000°C or rolling at 600°C deteriorated shape recovery strain to about 1%. The rolling at 400°C made the alloy brittle.

我们提出了一种新概念，通过适当的热机械处理来抑制热γ → ε马氏体转变，从而提高铁高锰合金的功能/机械性能。作为证明这一概念有效性的实验示例，我们尝试通过热轧提高 Fe-15.3Mn-5.8Si-0.24C (mass-%) 合金的形状记忆效应。该合金在室温下（M _s = 66°C）显示出双γ / ε相，固溶处理后形状恢复应变差约为 0.6%。预先存在的热ε -马氏体可以作为可逆正反转γ → ε的障碍物加载和随后加热下的马氏体转变。在 800°C 下热轧并减少 70% 似乎可以将形状恢复应变显着提高至 2.9%。轧制抑制了冷却过程中的热γ → ε马氏体相变，在室温下获得了单一的γ相。800°C 轧制试样在 800 至 1000°C 下进一步退火或在 600°C 下轧制会使形状恢复应变恶化至约 1%。400℃的轧制使合金变脆。