Two distinct regimes of strain rate sensitivity on yield strength are found in a high-strength nantwinned steel. The yield strength increases from 1410 to 1776 MPa when the strain rate increases from 10^–3 to 1400 s⁻¹. It is proposed from the measured small activation volume that the yielding of the nanotwinned steel at higher strain rates is governed by the dislocation bowing out from the carbon atmosphere. At lower strain rates, however, the yielding is controlled by the continuous re-pinning of dislocations due to the fast diffused carbon atoms, which leads to the relative insensitivity of yield strength to the strain rate.

中文翻译：

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1.5 GPa纳米孪晶钢的应变率敏感性

在高强度纳米缠绕钢中发现了两种不同的应变速率敏感性对屈服强度的机制。当应变率从10 ^–3增加到1400 s ^-1时，屈服强度从1410 MPa增加到1776 MPa 。从测得的小的活化体积中提出，在较高的应变速率下纳米孪晶钢的屈服由碳气氛中的位错弯曲决定​​。然而，在较低的应变速率下，由于碳原子快速扩散，位错的连续重新钉扎控制了屈服，这导致了屈服强度对应变速率的相对不敏感性。