Abstract Effects of size and volume fraction of the B2-type NiAl precipitates on the deformation behavior of Fe–Al–Ni single crystals were investigated. In the crystals with different Ni contents, the fine NiAl phase was precipitated in the bcc matrix with small misfit strain. Strong precipitation hardening occurred due to the difference in primary slip system between the bcc matrix and the NiAl precipitates. Moreover, not only slip but also slip occurred depending on the loading axis, the precipitate morphology and the deformation temperature, though the occurrence of slip is generally impossible in bcc metals. The dependence of the critical resolved shear stress for slip on the precipitate size was consistent with the modified precipitation hardening theory. To understand the precipitation hardening, an antiphase boundary energy of the NiAl precipitates was evaluated by first-principles calculations. Moreover, higher volume fraction of the NiAl precipitates was favorable for the activation of slip. Furthermore, the activated slip system varied with deformation temperature, and therefore, the temperature dependence of the yield stress was closely related to the slip system.

中文翻译：

---

NiAl析出物显微组织、加载轴和温度对Fe-Al-Ni单晶变形行为的影响

摘要 研究了B2 型NiAl 析出物的尺寸和体积分数对Fe-Al-Ni 单晶变形行为的影响。在不同Ni含量的晶体中，细小的NiAl相以较小的错配应变在bcc基体中析出。由于 bcc 基体和 NiAl 沉淀物之间的主要滑移系统不同，发生了强烈的沉淀硬化。此外，根据加载轴、析出物形态和变形温度，不仅发生滑移，还会发生滑移，尽管在 bcc 金属中滑移的发生通常是不可能的。滑移的临界解析剪切应力对析出物尺寸的依赖性与改进的沉淀硬化理论一致。要了解沉淀硬化，NiAl 析出物的反相边界能通过第一性原理计算进行评估。此外，较高体积分数的 NiAl 沉淀有利于滑移的活化。此外，激活的滑移系统随变形温度而变化，因此屈服应力的温度依赖性与滑移系统密切相关。