Dislocation Clusters and Microcracks in Thin Films of LCF -Tested Austen itic Steel

摘要

Austenitic chromium-nickel stainless steel CrNiNb 18-10 was studied using TEM technique. Characterizations of thin films prepared from bulk cylindrical samples after low-cycle fatigue (LCF) tests were conducted. Focus was made on the dislocation clusters, slip bands, defects and microstructure changes taking place in the steel during LCF. It is shown that microcracks occur in slip bands. Stereographic and trace analyses revealed the microcrack propagation directions. Two types of microcracks were observed: wedge-shaped and with parallel sides. The obtained results on possible reasons and mechanisms of microcrack formation in the above places are discussed in line with the theoretical assumptions and the existing literature.