Local crack arrestability and deformation microstructure evolution of hydrogen-related fracture in martensitic steel
Akinobu Shibata, I. Gutiérrez‐Urrutia, Akiko Nakamura, Taku Moronaga, Kazuho Okada, Yazid Madi, Jacques Besson, Toru Hara
Abstract
Intergranular cracks in the uncharged specimen were arrested at low-angle prior austenite grain boundary (PAGB) segments of several micrometers. In contrast, even small, low-angle PAGB segments with sub-micrometer sizes impeded the propagation of hydrogen-related intergranular crack. At the hydrogen-related quasi-cleavage crack tip, the crystallographic orientation changed abruptly, and deformation microstructures developed, including the formation of low-energy dislocation structures. A certain degree of crack growth resistance (intrinsic crack growth resistance) in the hydrogen-related fractures could be attributed to the intense localized plastic works involved in the arrest of intergranular cracks and the propagation of quasi-cleavage cracks. • Low-angle boundary segments can impede hydrogen-related crack propagation. • Deformation microstructures developed remarkably around the quasi-cleavage crack. • Intense localized plastic works was involved in the hydrogen-related fracture. • A crack-growth resistance is attributed to the intense localized plastic works.