Duplex high-carbon steel is widely used in ball mills in the form of grinding balls and thus subjected to impact loads during the normal operation of the mill. The influence of impact loading at different impact energies is investigated in this paper. Impact tests using a drop tower were performed in the regime of 100–150 J, and the mechanical response of the material was recorded. The deformation behaviour of the material was classified into two groups: (a) low-impact-energy regime (100–120 J) where the material bulged without fracture and (b) high-impact-energy regime (130–150 J) where the material faced catastrophic failure. An overall increase in the load-bearing capacity of the material was found with an increase in the impact energy. The energy–time curves exhibited both linear and nonlinear regions which were attributed to the nucleation and propagation of cracks. Shear bands were observed in the specimens which underwent catastrophic fracture (i.e. 130 J and above); however, significant changes in the features of shear bands were noticed with increase in the impact energy. Fracture surfaces displayed the presence of microvoids, dimples, knobby fracture and river pattern, thus indicating ductile as well as a brittle mode of failure. Transmission electron microscopy results revealed the presence of much finer nano-grains inside the shear bands as compared to the surrounding regions. Finite element simulations exhibited an increase in the shear stress with the propagation of shear bands during the ongoing deformation process.

中文翻译：

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高碳低合金钢抗冲击性能的实验与数值研究

双相高碳钢以磨球的形式广泛用于球磨机中，因此在磨机的正常运行过程中会承受冲击载荷。研究了冲击载荷在不同冲击能量下的影响。使用吊塔在100–150 J的范围内进行了冲击试验，并记录了材料的机械响应。材料的变形行为分为两类：（a）低冲击能状态（100–120 J），其中材料鼓胀而没有破裂；（b）高冲击能状态（130–150 J），其中材料面临灾难性的失败。随着冲击能量的增加，发现材料的整体承载能力增加。能量-时间曲线显示出线性和非线性区域，这归因于裂纹的形核和扩展。在经历了灾难性断裂（即130 J及以上）的样品中观察到了剪切带。然而，随着冲击能量的增加，剪切带的特征发生了显着变化。断裂表面显示出微孔，酒窝，多节形断裂和河纹，因此表明韧性和脆性破坏模式。透射电子显微镜结果表明，与周围区域相比，剪切带内部存在更细的纳米颗粒。有限元模拟显示，在正在进行的变形过程中，剪切应力随着剪切带的传播而增加。在经历了灾难性断裂（即130 J及以上）的样品中观察到了剪切带。然而，随着冲击能量的增加，剪切带的特征发生了显着变化。断裂表面显示出微孔，酒窝，多节形断裂和河纹，因此表明韧性和脆性破坏模式。透射电子显微镜结果表明，与周围区域相比，剪切带内部存在更细的纳米颗粒。有限元模拟显示，在正在进行的变形过程中，剪切应力随着剪切带的传播而增加。在经历了灾难性断裂（即130 J及以上）的样品中观察到了剪切带。然而，随着冲击能量的增加，剪切带的特征发生了显着变化。断裂表面显示出微孔，酒窝，多节形断裂和河纹，因此表明韧性和脆性破坏模式。透射电子显微镜结果表明，与周围区域相比，剪切带内部存在更细的纳米颗粒。有限元模拟显示，在正在进行的变形过程中，剪切应力随着剪切带的传播而增加。断裂表面显示出微孔，酒窝，多节形断裂和河纹，因此表明韧性和脆性破坏模式。透射电子显微镜结果表明，与周围区域相比，剪切带内部存在更细的纳米颗粒。有限元模拟显示，在正在进行的变形过程中，剪切应力随着剪切带的传播而增加。断裂表面显示出微孔，酒窝，多节形断裂和河纹，因此表明韧性和脆性破坏模式。透射电子显微镜结果表明，与周围区域相比，剪切带内部存在更细的纳米颗粒。有限元模拟显示，在正在进行的变形过程中，剪切应力随着剪切带的传播而增加。