Abstract The interaction of microstructural evolution, precipitation and mechanical properties of cold rolled 27Cr–4Mo–2Ni steels stabilised by Nb/Ti during annealing are investigated. Prior deformations provide an acceleration effect on bulk sigma precipitation and increase the starting precipitation temperature to ~1000 °C, which can induce a brittle fracture mode for annealed specimens. The precipitation temperature of Fe2Nb-type Laves phase is observed to be as high as 1050 °C, and these nanoscale Laves phases are intertwined with Nb2C particles, which are located at sub-grain boundaries. The abnormal relationship between the grain size and the annealing temperature, which is also related to the formation of Nb-containing particles, is determined. The transformation from Nb2C to Laves phase below 1050 °C release C atoms into the matrix around the Nb2C particles. This further leads to Luders deformation during tensile test because of Cottrell atmosphere formation. The γ-fibre texture development during the annealing process is explained based on orientated nucleation and orientation growth theory. Super ferritic stainless steels exhibit a good combination of strength and ductility via Laves phase precipitation control during annealing at approximately 1050 °C for 5–60 min; these properties are advantageous for their application with strong γ-fibre texture.

中文翻译：

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高温 Laves 析出及其对超铁素体不锈钢再结晶行为和 Lüders 变形的影响

摘要 研究了Nb/Ti 稳定化冷轧27Cr-4Mo-2Ni 钢在退火过程中的显微组织演变、析出和力学性能之间的相互作用。先前的变形对大块 sigma 沉淀产生加速作用，并将起始沉淀温度提高到 ~1000 °C，这会导致退火试样的脆性断裂模式。观察到 Fe2Nb 型 Laves 相的析出温度高达 1050 °C，这些纳米级 Laves 相与位于亚晶界的 Nb2C 颗粒交织在一起。确定晶粒尺寸与退火温度之间的异常关系，这也与含Nb颗粒的形成有关。在 1050 °C 以下从 Nb2C 到 Laves 相的转变将 C 原子释放到 Nb2C 颗粒周围的基质中。由于形成 Cottrell 气氛，这进一步导致拉伸试验期间 Luders 变形。基于取向成核和取向生长理论解释了退火过程中γ-纤维织构的发展。超级铁素体不锈钢在大约 1050 °C 下退火 5-60 分钟时通过 Laves 相析出控制表现出强度和延展性的良好组合；这些特性有利于它们具有强烈的 γ 纤维质地的应用。基于取向成核和取向生长理论解释了退火过程中γ-纤维织构的发展。超级铁素体不锈钢在大约 1050 °C 下退火 5-60 分钟时通过 Laves 相析出控制表现出强度和延展性的良好组合；这些特性有利于它们具有强烈的 γ 纤维质地的应用。基于取向成核和取向生长理论解释了退火过程中γ-纤维织构的发展。超级铁素体不锈钢在大约 1050 °C 下退火 5-60 分钟时通过 Laves 相析出控制表现出强度和延展性的良好组合；这些特性有利于它们具有强烈的 γ 纤维质地的应用。