基于CPFEM探究M_(23)C_(6)对P92耐热钢高温塑性变形的影响

Study on the Effect of M_(23)C_(6) on High Temperature Plastic Deformation of P92 Heat Resistant Steel Based on CPFEM

本文基于晶体塑性理论,耦合Orowan位错动力学方程和泰勒硬化模型,建立了考虑位错密度的P92钢力学模型。采用晶体塑性有限元方法探究了M_(23)C_(6)的析出数量和取向关系对于P92耐热钢局部高温塑性变形的影响。结果表明,M_(23)C_(6)承担较高的应力而发生较小的塑性变形,应变集中现象主要出现在M_(23)C_(6)与基体交界处,M_(23)C_(6)数量的增加引起了明显应变梯度,加剧了局部塑性变形的不均匀性。M_(23)C_(6)与基体的三种取向关系中,Pitsch取向更有利于降低局部应变集中,缓解位错塞积,减少P92钢服役过程中损伤开裂的可能性。

A P92 steel mechanical model considering dislocation density is established based on the crystal plasticity theory coupled with Orowan dislocation dynamic equation and Taylor hardening model. The effect of precipitation amount and orientation of M_(23)C_(6) on local high temperature plastic deformation of P92 heat resistant steel was studied by crystal plastic finite element method. The results show that M_(23)C_(6) suffers higher stress and smaller plastic deformation. The strain concentration mainly occurs at the junction of M_(23)C_(6) and matrix. The increase of the number of M_(23)C_(6) causes an obvious strain gradient and intensifies the non-uniformity of local plastic deformation. Among the three orientations between M_(23)C_(6) and matrix, pitsch orientation is more conducive to reduce local strain concentration, alleviate dislocation stacking and reduce the possibility of damage and cracking of P92 steel during service.