Abstract The continuous and discontinuous yielding behaviors in ferrite-cementite steels were complementarily investigated via nano- and macro-scale deformation examinations. The continuous yielding behavior was observed in heat-treated specimens with a lamellar or cementite-spheroidal structure even after strain-aging treatment. However, the discontinuous yielding behavior accompanied by the Luders elongation appeared in ferrite-cementite steel that was recrystallized after cold rolling. The results obtained by electron microscopy, synchrotron X-ray, and neutron diffractions indicate that the ferrite-cementite interface of the heat-treated specimen is semi-coherent with a high internal stress field, whereas that of the recrystallized one is incoherent with a low internal stress field. Moreover, coherency strain, which depends on the total area of the ferrite-cementite interface, and thermal strain, which is governed by temperature, are the two factors that influence peak broadening. The nanoindentation tests revealed that the critical loads are significantly lower near the semi-coherent interface than those near the incoherent interface and the ferrite grain boundary; this suggests that dislocations are easily emitted from the semi-coherent interface.

中文翻译：

---

铁素体-渗碳钢的连续和不连续屈服行为

摘要 通过纳米尺度和宏观尺度变形检测，对铁素体-渗碳体钢的连续和不连续屈服行为进行了补充研究。即使在应变时效处理后，在具有层状或渗碳体-球状结构的热处理试样中观察到连续屈服行为。然而，冷轧后再结晶的铁素体-渗碳钢出现了伴随Luders伸长率的不连续屈服行为。电子显微镜、同步辐射X射线和中子衍射结果表明，热处理试样的铁素体-渗碳体界面是半相干的，具有高内应力场，而再结晶的则是非相干的，具有低内应力场。内应力场。此外，相干应变，取决于铁素体-渗碳体界面的总面积，而受温度控制的热应变是影响峰展宽的两个因素。纳米压痕测试表明，半相干界面附近的临界载荷明显低于非相干界面和铁素体晶界附近的临界载荷；这表明位错很容易从半相干界面发出。