基于微观组织演化的P91钢长时蠕变寿命预测

通过对P91耐热钢在高温长时蠕变过程中微观组织演化行为的综合考察,探讨了影响其长时蠕变寿命的主要因素,其中包括强化相(M_(23)C_6、MX)与析出相(Laves、Z相)的粗化现象以及和位错间的交互作用等。在此基础上,通过对蠕变幂率本构方程中耦合相应内应力参量,并结合Monkman-Grant方程,从微观组织演化的角度建立了P91耐热钢长时蠕变寿命预测模型。最后利用该模型对873K(600℃)时的P91耐热钢的相关蠕变寿命进行了预测,结果显示其计算数值与实验数据吻合较好,从而进一步表明基于微观组织演化的预测模型在P91耐热钢长时蠕变寿命的研究中具有重要意义。

Prediction of Long-term Creep Rupture Time of P91 Steel Based on Microstructure Evolution

According to the analysis of microstructure evolution of P91 heat-resistant steel during the long-term creep, main factors determining its creep rupture time were discussed in detail, such as the coarsing of precipitated phases (M₂₃C₆, MX, Laves phase and Z phase) and interactions between them and dislocations. Based on these results, a prediction model of creep rupture time for P91 heat-resistant steel was provided by introducing the internal stress to power-law creep equation and Monkman-Grant equation. Besides, the calculated creep rupture time at 873 K with the proposed model was very close to those values obtained by experiments, which further confirmed that the present method based on the microstructure evolution offers a potential tool to predict the long-term creep rupture time of P91 heat-resistant steel.