摘要
应用不可逆热力学方法，本文建立了一个新的动态再结晶过程的分析模型。在这个模型中根据动态再结晶重复形核有限长大机理，分别考虑原始晶粒和再结晶晶粒分布的变化。由于模型不考虑再结晶晶粒形成细节，所以本模型也适用于由亚晶直接转变成新晶粒的情况。这种情况中只有晶界能增加并无明显晶粒长大。由此模型导出了再结晶体积分数及有关晶粒尺寸的演化方程。将这些演化方程插人到作者给出的考虑不同变形机制的热塑性本构关系中，便得到了有动态再结晶过程伴随的热塑性本构关系。这一本构关系不仅适用于一般的热加工变形，还适用于动态再结晶引起晶粒细化所造成的变形机理改变的热变形过程。最后给出一些算例并对一些有关问题进行了讨论。
A new analytical model of dynamoic recystallization is developed by means of thermodynamics,where the distribution variation of both initial grains and recrystallized grains with deformation are considered on the basis of the dynamic recrystallization mechanism, which is characterized by the repeated nucleation and limited growth of new grains. The model does not treat the details of forming new grain so that it can be also used for new recrystallized grains formed from subgrains where the increase in subgrain boundary energy and no growth in subgrain size are observed. The evolution equations of the volume fraction of dynamic recreastallization and varieties of grain size are derived from this model. A constitutive relation of thermo-plastic deformation accompanied by dynamic recrystallization is obtained through adding the evolution equations into a constitutive relation of thermo-plastic deformation including three deformation mechanisms, namely diffusion creep, grain boundary sliding and dislocation creep. The constitutive relation can be used for not only general heat working problems but also the deformation process where dynamic recrystallization results grain refinement so that the grain boundary sliding becomes the predominant deformation mechanism. Finally, some numerical examples and discussion about the model are presented.
出处
《塑性工程学报》
CAS
CSCD
1994年第1期3-13,共11页
Journal of Plasticity Engineering
关键词
动态再结晶
热塑性变形
本构关系
热加工
再结晶
dynamic recrystallization, thermo-plastic deformation, constitutive relation
