Only few available interatomic interaction potentials implement the α ↔ γ phase transformation in iron by featuring a stable low-temperature bcc and high-temperature fcc lattice structure. Among these are the potentials by Meyer and Entel [Phys. Rev. B 57, 5140 (1998)], by Mu ller et al. [J. Phys.: Condens. Matter 19, 326220 (2007)] and by Lee et al. [J. Phys.: Condens. Matter 24, 225404 (2012)]. We study how these potentials model the phase transformation during heating and cooling; in order to help initiating the transformation, the simulation volume contains a grain boundary. For the martensitic transformation occurring on cooling an fcc structure, we additionally study two potentials that only implement a stable bcc structure of iron, by Zhou et al. [Phys. Rev. B 69, 144113 (2004)] and by Mendelev et al. [Philos. Mag. 83, 3977 (2003)]. We find that not only the transition temperature depends on the potential, but that also the height of the energy barrier between fcc and bcc phase governs whether the transformation takes place at all. In addition, details of the emerging microstructure depend on the potential, such as the fcc/hcp fraction formed in the α → γ transformation, or the twinning induced in and the lattice orientation of the bcc phase in the γ → α transformation.

中文翻译：

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铁中的α↔γ相变：原子间相互作用势影响的比较研究

通过具有稳定的低温 bcc 和高温 fcc 晶格结构，只有少数可用的原子间相互作用势能在铁中实现 α ↔ γ 相变。其中包括 Meyer 和 Entel [Phys. Rev. B 57, 5140 (1998)]，Muller 等人。[J. 物理：凝聚。Matter 19, 326220 (2007)] 和 Lee 等人。[J. 物理：凝聚。问题 24, 225404 (2012)]。我们研究了这些电位如何模拟加热和冷却过程中的相变；为了帮助启动转变，模拟体积包含一个晶界。对于冷却 fcc 结构时发生的马氏体转变，我们还研究了 Zhou 等人仅实现铁的稳定 bcc 结构的两种势能。[物理。Rev. B 69, 144113 (2004)] 和 Mendelev 等人。[菲洛斯。玛格。83, 3977 (2003)]。我们发现不仅转变温度取决于电势，而且 fcc 和 bcc 相之间的能垒高度也决定了转变是否发生。此外，新兴微观结构的细节取决于电位，例如在 α → γ 转变中形成的 fcc/hcp 分数，或在 γ → α 转变中诱导的孪晶和 bcc 相的晶格取向。