基于实验和元胞自动机模拟的TiNb合金非连续动态再结晶研究

Discontinuous dynamic recrystallization of TiNb alloys:Experiment and cellular automaton simulation

TiNb合金因其良好的塑性、机械加工性能和超导电性而被广泛应用于低温超导领域。动态再结晶作为材料加工过程中常见的软化行为,对材料的组织和性能有重要的影响。将实验与元胞自动机模拟相结合,研究了TiNb合金在热压缩过程中的非连续动态再结晶行为。元胞自动机模拟可以较为准确地预测TiNb合金的非连续动态再结晶行为。再结晶晶粒的平均尺寸和体积分数随着变形温度的升高而增大,随着应变速率的升高而减小。TiNb合金变形试样中的锯齿状晶界和再结晶晶粒形核位置符合晶界弓出机制特征。此外,非连续动态再结晶晶粒的随机取向效应有助于减弱TiNb合金中变形织构的强度。

TiNb alloys are widely used in the field of cryogenic superconductivity because of their excellent plasticity,machinability and superconductivity.As a common softening behavior in the process of material processing,dynamic recrystallization(DRX)has a considerable effect on the microstructure and the properties of material.The discontinuous dynamic recrystallization(DDRX)behavior of TiNb alloys during hot compression has been studied by combining experiment with cellular automaton(CA)simulation in this paper.It can be found that CA model can effectively predict DDRX behavior of TiNb alloy.The mean grain size and the volume fraction for DDRX of TiNb alloys increase with increasing deformation temperature,but they decrease with increasing strain rate.Furthermore,the serrated grain boundaries and the nucleation points of recrystallized grains in the deformed TiNb samples are in accordance with the characteristics of grain boundary bulging mechanism.In addition,the random orientation effect of DDRX grains is helpful to weaken the intensity of deformation texture in TiNb alloys.