摘 要 借助于热模拟压缩变形实验和OM、SEM、EBSD及TEM技术，研究了低碳钢铁素体晶粒尺寸相似，渗碳体粒子尺寸不同的两种原始组织在700℃、0.01s-1条件下的组织演变过程，分析了渗碳体粒子尺寸对铁素体动态再结晶的影响作用。实验结果表明：变形过程中，尺寸较大的渗碳体粒子附近容易产生大的应变梯度，通过粒子激发形核导致动态再结晶核心的形成。在变形初期，动态再结晶核心主要在尺寸大于1m的渗碳体粒子附近形成；随着应变量的增加，动态再结晶核心也可以在尺寸在0.5-1.0m范围内的渗碳体粒子附近形成。而尺寸小于0.3m的渗碳体粒子附近无法形成大的应变梯度，同时钉扎位错和亚晶界，阻碍动态回复和动态再结晶的发展。
ABSTRACT The microstructure evolution of ferrite in a low carbon steel during hot uniaxial compression tests at 700℃ at 10-2s-1 was investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), electron back scattering diffraction (EBSD) and transmission electron microscopy (TEM). In order to understand the effect of cementite particles size on dynamic recrystallization (DRX) of ferrite, two different microstructures consisting of similar size ferrite and different size cementite particles were adopted by quenching and tempering of a low carbon steel. The results showed that large cementite particles acted as nucleation sites for dynamic recrystallization of ferrite by particle-stimulated nucleation mechanism (PSN), due to the large orientation gradient near them during hot deformation. In the earlier stage, DRX nuclei were mainly formed near cementite particles large than 1m. With increasing strain, they would also be formed near particles between 0.5 to 1m. On the contrary, because of much smaller orientation gradient and pinning effect on the movement of the dislocation and sub-boundary, the cementite particles smaller than 0.3m retarded dynamic recovery and dynamic recrystallization of ferrite.
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| [1] | |
| [2] | |
| [3] | |
| [4] | |
| [5] | |
| [6] | |
| [7] |
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