The creep behavior of Fe–17Cr–1.2Cu–0.5Nb–0.01C ferritic heat-resistant stainless steel was investigated at temperatures ranging from 973 to 1123 K and stresses from 15 to 90 MPa. The evolution of precipitates after creep deformation was analyzed by scanning electron microscopy, energy dispersion spectrum, and transmission electron microscopy. The minimum creep rate decreased with the decrease in the applied load and temperature, thereby extending the rupture life. Cu-rich phase and Nb-rich Laves particles were generated in dominant quantities during the creep process, and the co-growth relationship between them could be detected. Creep rupture was featured by ductile fracture with considerable necking. As increasing the temperature and decreasing the stress, the softening of the metal matrix was accelerated, showing more obvious plastic flow. The true stress exponent and activation energy were 4.9 and 375.5 kJ/mol, respectively, indicating that the creep deformation was dominated by the diffusion-controlled dislocation creep mechanism involving precipitate-dislocation interactions. Based on the creep rupture data obtained, the Monkman–Grant relation and Larson-Miller parameter were established, which described the creep rupture life for the studied steel well.

研究了Fe–17Cr–1.2Cu–0.5Nb–0.01C铁素体耐热不锈钢在973至1123 K的温度和15至90 MPa的应力下的蠕变行为。通过扫描电子显微镜，能量分散谱和透射电子显微镜分析蠕变变形后沉淀物的演变。随着施加的载荷和温度的降低，最小蠕变速率降低，从而延长了断裂寿命。蠕变过程中产生了大量的富Cu相和富Nb Laves颗粒，并且可以检测它们之间的共生长关系。蠕变断裂的特点是韧性断裂，颈缩明显。随着温度的升高和应力的降低，金属基体的软化加速，显示出更明显的塑性流动。真实的应力指数和活化能分别为4.9和375.5 kJ / mol，这表明蠕变变形主要由涉及沉淀-位错相互作用的扩散控制的位错蠕变机理决定。根据获得的蠕变断裂数据，建立了Monkman-Grant关系和Larson-Miller参数，该参数描述了所研究钢井的蠕变断裂寿命。