Abstract This paper presents the results of an experimental study aimed to obtain an ultrafine equiaxed grain distribution in 18Cr oxide dispersion strengthened (ODS) ferritic steel through cold working and annealing starting with an initial columnar grain structure with a predominant α-fibre texture in a product consolidated from the alloy powders during extrusion at high temperatures. Deformation along the extruded direction (ED) resulted in the retention of α-fibre texture, while deformation in the transverse direction (TD) showed a shear banded structure with a reduced percentage of α-fibre texture. Differential Scanning Calorimetry (DSC) analysis of the deformed steel established the occurrence of two significant events during heating namely recovery and recrystallization, whose temperatures were influenced by the heating rate. The recovery and recrystallization domains have been distinctly observed at 1350 K and 1420 K respectively at a low heating rate of 7 K min−1. The resultant microstructure showed very coarse elongated grains interspersed with regions of ultrafine ( //ED α-fibre texture, which improved further with repeated deformation and two step heat treatment cycles. A gradual increase in hardness during the above cycles was observed reflecting the increase in dislocation density which offers the propensity to achieve an ultrafine grained microstructure.

中文翻译：

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氧化物弥散强化18Cr铁素体钢变形和再结晶行为评价

摘要 本文介绍了一项实验研究的结果，旨在通过冷加工和退火在 18Cr 氧化物弥散强化 (ODS) 铁素体钢中获得超细等轴晶粒分布，从初始柱状晶粒结构开始，在产品中具有主要的 α 纤维织构。在高温挤压过程中由合金粉末固结。沿挤压方向 (ED) 的变形导致 α-纤维织构的保留，而横向 (TD) 的变形显示剪切带状结构，α-纤维织构的百分比降低。变形钢的差示扫描量热法 (DSC) 分析确定了加热过程中发生的两个重要事件，即恢复和再结晶，其温度受加热速率的影响。在 7 K min-1 的低加热速率下，分别在 1350 K 和 1420 K 处明显观察到恢复和再结晶域。所得显微组织显示出非常粗大的细长晶粒，其中散布着超细（//ED α-纤维织构，随着反复变形和两步热处理循环进一步改善。观察到在上述循环期间硬度逐渐增加，反映了位错密度提供了实现超细晶粒微观结构的倾向。随着反复变形和两步热处理循环进一步改善。观察到在上述循环期间硬度逐渐增加，这反映了位错密度的增加，这提供了实现超细晶粒显微组织的倾向。随着反复变形和两步热处理循环进一步改善。观察到在上述循环期间硬度逐渐增加，这反映了位错密度的增加，这提供了实现超细晶粒显微组织的倾向。