Microstructural evolution of aged heat-resistant cast steel following strain controlled fatigue

作者：Golanski Grzegorz^*; Zielinska Lipiec Anna; Mrozinski Stanislaw; Kolan Cezary

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2015, 627: 106-110.

DOI：10.1016/j.msea.2014.12.120

• 9%Cr cast steel
• Microstructure
• Fatigue test
• Ageing

The paper presents the results of research on the microstructure of high-chromium martensitic GX12CrMoVNbN9-1 (GP91) cast steel after the isothermal ageing process and fatigue process. The fatigue process was performed at room temperature and elevated temperature (600 degrees C), with the value of total strain amplitude epsilon(ac) amounting to 0.25% and 0.60%. Microstructural tests of GP91 cast steel were carried out by means of high-resolution transmission electron microscope. Quantitative study performed by means of TEM included the characteristics of changes in the dislocation substructure and morphology of M23C6 carbides. Performed research has shown that the microstructure of the examined cast steel after ageing is characterized by partly remaining lath microstructure with numerous precipitations of the MX and M23C6 type, as well as the Laves phase. It has been shown that the fatigue test at room temperature contributes to the process of dislocation strengthening of the examined cast steel. The increase of fatigue test temperature influences the degree of increase in the matrix softening. The degree of softening of the cast steel microstructure at elevated temperature depends also on the value of strain amplitude epsilon(ac). The softening process of the examined cast steel was connected with the decrease of dislocation density and increase of subgrains.

• 出版日期2015-3-11