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通过Gleeble-3800热模拟试验机对V-N微合金化钢进行了热模拟压缩试验,分析了V-N微合金化钢高温下塑性变形的变化规律,并通过分析应力-应变曲线,建立形变抗力模型和应变速率本构方程。结果表明,V-N微合金化钢在较低应变速率和较高温度下,流变应力随变形程度的不断增加而增加至某一峰值,然后逐渐下降至某一稳态值;应变速率、温度和峰值应力之间的关系可用幂指数关系来描述,在较低温度(900～950℃)下,应力指数约为7.1,变形激活能为118～185 kJ/mol,变形机制属于位错芯区扩散控制的幂律蠕变;在较高温度(1000～1150℃)下,应力指数约为6.6,变形激活能为125～285 kJ/mol,变形机制属于位错芯区控制的幂律蠕变。
The thermal simulation of VN microalloyed steels was carried out by Gleeble-3800 thermal simulator. The variation of plastic deformation of VN microalloyed steels at high temperature was analyzed. Through the analysis of stress-strain curves, the deformation resistance model and strain Rate constitutive equation. The results show that the flow stress of VN microalloyed steels increases to a certain peak at a lower strain rate and a higher temperature with the increase of deformation, and then gradually decreases to a steady state value. The strain rate, temperature and The relationship between peak stress can be described by exponential relationship. At lower temperature (900-950 ℃), the stress exponent is about 7.1 and deformation activation energy is 118-185 kJ / mol. The deformation mechanism belongs to the diffusion of dislocation core The stress exponent is about 6.6 and the deformation activation energy is 125-285 kJ / mol at higher temperature (1000-1150 ℃). The deformation mechanism belongs to the power-law creep controlled by dislocation core.