Thermomechanical deformation is one of the most efficient and facile routes to tailor microstructure in structural materials for mechanical property enhancement. Herein, the Ce‐modified SAF2507 super duplex stainless steel (Ce‐SAF2507) is deformed at different levels from 30% to 90% at a cryogenic temperature (–196 °C) to achieve superior mechanical performances. Cryogenic rolling increase fiber texture and induce ultra‐fine grain refinement which brings grains to ≈10 nm in the selected steel. The high‐density dislocations and deformation twins in the cryogenically rolled Ce‐SAF2507 lead to the nucleation and growth of martensite. Increases in the martensite volume fraction and nanoscale grain refinement occur at higher deformation levels. Cryogenically rolled deformation results in the overall increase in the Ce‐SAF2507 hardness. A higher hardness increment of austenite–martensite dual‐phase compared to that of ferrite is attributed to the austenite–martensite's higher work hardening ability. Furthermore, the ultimate tensile strength and yield strength increase with the deformation level, but the elongation decrease. Observed microstructural evolutions induced by cryogenic rolling enunciate the superiority of the present method over conventional ones to promote steel’ mechanical properties.

中文翻译：

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深冷轧Ce改性SAF2507超级双相不锈钢的微观组织演变诱导的机械性能增强

热机械变形是定制结构材料中的微结构以提高机械性能的最有效且最容易的途径之一。本文中，Ce改性的SAF2507超级双相不锈钢（Ce-SAF2507）在低温（–196°C）下以30％至90％的不同水平变形，以实现出色的机械性能。低温轧制可提高纤维的质构并诱导超细晶粒细化，从而使所选钢种的晶粒达到约10 nm。低温轧制的Ce-SAF2507中的高密度位错和变形孪晶导致马氏体的形核和生长。马氏体体积分数的增加和纳米级晶粒细化在较高的变形水平下发生。低温轧制变形会导致Ce-SAF2507硬度整体增加。与铁素体相比，奥氏体－马氏体双相的硬度增量更高，这归因于奥氏体－马氏体的较高的加工硬化能力。此外，极限抗拉强度和屈服强度随着变形水平而增加，但是伸长率降低。观察到的由深冷轧制引起的微观结构演变表明，本方法优于传统方法以提高钢的机械性能。