Fracture Toughness and Fracture Mechanism of EH47 High-Strength Steel Subjected to Different Temperatures

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2022-10, Vol.53 (10), p.3588-3603
• Main Authors: Xue, Chunyang, Yang, Mengmeng, Liu, Peng, Cheng, Yuan, Shang, Xinchun, Ren, Xuechong
• Format: Article
• Language: English
• Subjects: Boltzmann distribution; Brittle fracture; Characterization and Evaluation of Materials; Chemistry and Materials Science; Crack initiation; Crack opening displacement; Crack tips; Distribution functions; Ductile fracture; Ductile-brittle transition; Fracture mechanics; Fracture surfaces; Fracture toughness; Heat treating; High strength steel; High strength steels; Materials Science; Metallic Materials; Nanotechnology; Original Research Article; Prediction models; Structural Materials; Surface analysis (chemical); Surfaces and Interfaces; Temperature; Temperature effects; Thin Films; Transition temperature
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-022-06763-6

The objective of this work was to investigate the effect of temperature on the fracture behavior of EH47 high-strength steel, which is one of the materials used for large ocean freighter decks. The fracture toughness and mechanism were studied using compact tensile (CT) specimens at different temperatures. The results showed that the fracture toughness (characterized by the crack tip opening displacement, CTOD) δ of the EH47 high-strength steel decreased with decreasing temperature and that the average values of the fracture toughness tested at different temperatures followed a Boltzmann distribution. The fracture surface analysis showed that the fracture mechanism changed from ductile fracture (above 0 °C) to ductile–brittle mixed fracture (− 20 °C to − 60 °C) and then to complete brittle fracture (below − 80 °C). In particular, the extension of fibrous cracks was the main factor affecting the fracture toughness in the transition temperature region (− 20 °C to − 60 °C). The distance from the cleavage initiation site to the fibrous crack tip increased with the fibrous crack width. Moreover, the Weibull and Boltzmann distribution functions were combined, a prediction model of the fracture toughness with different temperatures and failure probabilities was proposed, and the predicted results were in good agreement with the test results.