Effects of grain boundary density and dislocation density on formation of adiabatic shear bands in high-strength steel

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发表日期：

2026年3月31日

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Yong-Zheng Yu,
Yang Zhang,
Xing-Hao Li,
Jun-Peng Li,
Wei-Guo Jiang,
Zhong-Wu Zhang

摘要

The coupling effect of grain boundary density and dislocation density on the formation mechanism of adiabatic shear band (ASB) during the dynamic failure of high-strength steel was investigated. Though thermomechanical treatment, samples with different grain boundary densities (SS: 0.67 μm^–1, 1093-SS: 0.57 μm^–1, and 1273-SS: 0.24 μm^–1) and initial dislocation densities (SS: 1.3 × 10¹⁵ m^–2, 1093-SS: 8.1 × 10¹⁴ m^–2, and 1273-SS: 5.5 × 10¹⁴ m^–2) were prepared to elucidate the role of grain boundary density and dislocation density on ASB evolution. Experimental results showed that at a strain rate of 3300 s^–1, the high grain boundary density samples (SS and 1093-SS) exhibited higher dynamic flow stresses of 1580 and 1491 MPa, respectively, compared to the low grain boundary density sample of 1273-SS with a stress of 1411 MPa. Under lower dislocation density, the high-density grain boundary network exhibited unique inhibitory effects by preventing dislocation aggregation and entanglement and effectively hindering shear localization, thus significantly delaying dynamic recrystallization. ASB composed of recrystallized grains failed to form due to the significant reduction in the recrystallization ratio. In contrast, low grain boundary density samples exhibited shear localization, leading to the formation of an ASB of approximately 24 μm in width. Further studies revealed that at a higher initial dislocation density, dislocation density has a more significant influence on ASB formation compared to grain boundary density. By contrast, the SS sample with high grain boundary density presented an ASB width of 18 μm. As a result, findings demonstrate that precise regulation of grain boundary density and dislocation densities enhances the material’s resistance to dynamic recrystallization and effectively suppresses ASB formation while maintaining high flow stress, offering a promising strategy to mitigate dynamic failure in high-strength steels.