Abstract The microstructure and tensile properties of thermo-mechanically processed ferritic steels alloyed with Mo, Cr, V and Nb were investigated using scanning transmission electron microscopy, atom probe tomography and uniaxial tensile loading. The microstructures consisted of predominantly polygonal ferrite (~4 ± 3 µm average grain size) and a high number density of nano-sized, disc-shaped interphase precipitates (~2-4 nm diameter and 1 ± 0.4 nm thick). Interphase fiber carbides were also present in V, Cr and Nb -alloyed steel. Cluster formation was observed both between the interphase precipitates in rows and in ferrite matrix between the rows. The individual contributions to yield strength arising from different operating strengthening mechanisms were estimated. For the first time, the operation of coherency and modulus strengthening mechanisms for nano-sized interphase precipitates in this class of steels was considered. The major contributions were due to grain boundary strengthening and nano-sized precipitation, in the order of ~280 MPa and ~395 MPa, respectively. Significant cluster strengthening (~150-170 MPa) was also evident.

中文翻译：

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应用先进的实验技术阐明相间析出微合金化铁素体钢的强化机制

摘要 使用扫描透射电子显微镜、原子探针断层扫描和单轴拉伸载荷研究了热机械加工铁素体钢的组织和拉伸性能，该钢含有 Mo、Cr、V 和 Nb 合金。显微组织主要由多边形铁素体（~4 ± 3 µm 平均晶粒尺寸）和高数量密度的纳米级圆盘状相间沉淀物（~2-4 nm 直径和 1 ± 0.4 nm 厚）组成。相间纤维碳化物也存在于 V、Cr 和 Nb 合金钢中。在行间相间析出物和行间铁素体基体中均观察到团簇形成。估计了不同操作强化机制对屈服强度的个体贡献。首次，考虑了此类钢中纳米级相间析出相的相干性和模量强化机制的作用。主要贡献是由于晶界强化和纳米尺寸的沉淀，分别约为~280 MPa 和~395 MPa。显着的簇强化（~150-170 MPa）也很明显。