The work-hardening mechanisms of two novel advanced high-strength steels (Fe_67.4−xCr_15.5Ni_14.1Si_3.0B_x [x = 0 (0B), 2 (2B)] wt%) were investigated by means of field emission gun scanning electron microscopy coupled with angle-selective backscattered detection, transmission electron microscopy, and electron backscattered diffraction. The 0B and 2B specimens combined low yield stresses and high ultimate tensile strengths with good total elongation percentages, with results of 219 MPa, 568 MPa, and 83% and 357 MPa, 703 MPa, and 42%, respectively. The 0B and 2B alloys were characterized by a decreasing work hardening rate, followed by a constant and finally a steep decreasing change tendency. Detailed angle-selective backscattered and electron backscattered diffraction microscopy observations on interrupted tensile test specimens revealed that the work hardening rate in these alloys was facilitated by planar (extended stacking faults) and wavy (dislocation cell and wavy microbands) characteristics and mechanical nano-twins. The total flow stresses of the 0B and 2B specimens were calculated from the dislocation density and twin spacing. This indicated that the work hardening contribution of the microband mechanism can be estimated via a dislocation hardening formula. The rule of mixture was also used to evaluate the effect of a boron addition on the total flow stress of the 2B specimen; this illustrated that, in addition to the strengthening contribution of the second hard phase to the yield stress, the rule of mixture must also be considered. The calculated values of the contribution of the mechanical nano-twins and dislocations on the work-hardening for 0B and 2B specimens were about 62% and 18.6% and 52% and 31.8%, respectively.

两种新型先进高强度钢（Fe _67.4−x Cr _15.5 Ni _14.1 Si _3.0 B _x[x = 0（0B），2（2B）] wt％）通过场发射枪扫描电子显微镜结合角度选择性背散射检测，透射电子显微镜和电子背散射衍射进行了研究。0B和2B试样结合了低屈服应力和高极限拉伸强度，并具有良好的总伸长率，结果分别为219 MPa，568 MPa和83％和357 MPa，703 MPa和42％。0B和2B合金的特征是加工硬化率降低，然后是恒定的变化趋势，最后是急剧下降的变化趋势。在不连续的拉伸测试样品上进行的角度选择性背散射和电子背散射衍射显微镜的详细观察表明，这些合金的加工硬化速率是由平面（扩展的堆垛层错）和波浪形（位错单元和波浪微带）和机械纳米孪晶所促进的。从位错密度和孪晶间距计算出0B和2B试样的总流应力。这表明可以通过位错硬化公式来估算微带机制的工作硬化贡献。混合法则还用于评估硼添加对2B样品总流动应力的影响。这表明，除了第二硬相对屈服应力的增强作用外，还必须考虑混合规则。对于0B和2B样品，机械纳米孪晶和位错对加工硬化的贡献的计算值分别约为62％和18.6％，以及52％和31.8％。