Fracture toughness of heat-treated SA508 steels predicted by instrumented spherical indentation test

Abstract

This paper presents a comprehensive analysis of the tensile properties and fracture toughness of five heat-treated SA508 steels, utilizing the instrumented spherical indentation test (ISIT). It critically examines the impact of microstructural variations induced by various heat treatment methodologies on these mechanical properties. A novel ISIT computational framework, IITv1.0, has been developed through enhancements to existing predictive algorithms, facilitating more accurate predictions of yield stress, strain hardening, tensile strength and fracture toughness. The IITv1.0 integrates an advanced critical fracture stress criterion alongside an enhanced energy release rate model, effectively differentiating between cleavage and ductile fracture modes resulting in SA508 steels from the five heat treatment processes. The study underscores the establishment of an automated selection criterion for differentiating the cleavage and ductile fracture modes of metallic materials. The predictive outcomes for tensile properties and fracture toughness by this IITv1.0 demonstrate strong concordance with experimental data obtained from the corresponding standard testing methods.