Abstract The microstructure evolution and tensile properties of a newly designed Fe-21Mn-10Al-1C-5Ni (wt.%) lightweight steel subjected to two annealing conditions (inducing partial recrystallization and full recrystallization) and subsequent aging treatment have been investigated. In the as-annealed condition, the microstructure of the steel consists of polygonal B2 particles along grain boundaries of recrystallized austenite grains and plate-shape B2 particles within unrecrystallized austenite grains, with no B2 bands. In addition, there is a formation of nano-sized κ-carbide and D03 particles within austenite grains and B2 particles, respectively. Subsequent aging promotes the formation of intragranular κ-carbide and D03 nanoparticles within austenite grains and B2 particles, respectively. As a result, the present steel shows an ultrahigh yield strength of 1.6 GPa after aging, which is mainly due to the presence of fine B2 particles within austenite grains and along grain boundaries as well as the additional strengthening effect of nano-sized κ-carbide and D03 particles present in austenite grains and B2 particles, respectively. The steel possesses good ductility (total elongation of 20%) even at such an ultrahigh strength level in the as-aged condition, surpassing the tensile properties of other B2 and κ-carbide strengthened lightweight steels.

中文翻译：

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B2强化轻钢的强度提高-延展性平衡

摘要 研究了一种新设计的 Fe-21Mn-10Al-1C-5Ni (wt.%) 轻钢在两种退火条件（诱导部分再结晶和完全再结晶）和后续时效处理下的组织演变和拉伸性能。在退火状态下，钢的显微组织由沿再结晶奥氏体晶粒晶界的多边形 B2 颗粒和未再结晶奥氏体晶粒内的板状 B2 颗粒组成，没有 B2 带。此外，在奥氏体晶粒和 B2 颗粒中分别形成了纳米尺寸的 κ-碳化物和 D03 颗粒。随后的时效分别促进了奥氏体晶粒和 B2 颗粒内晶粒内 κ-碳化物和 D03 纳米颗粒的形成。因此，本钢在时效后显示出 1.6 GPa 的超高屈服强度，这主要是由于在奥氏体晶粒内和沿晶界存在细小的 B2 颗粒以及存在的纳米级 κ-碳化物和 D03 颗粒的额外强化作用分别在奥氏体晶粒和 B2 颗粒中。即使在时效条件下达到如此超高的强度，该钢仍具有良好的延展性（总伸长率为 20%），超过了其他 B2 和 κ-碳化物强化轻质钢的拉伸性能。