Antagonism in Fracture and Notch Toughness of UHSLA Steels

článek ve sborníku ve WoS nebo Scopus

angličtina

Values of initial fracture toughness KIc and impact absorbed energy of ultra-high strength low alloy steel were determined for 6 different heat treatments leading to 3 different mean prior austenite grain sizes dm. Fracture surfaces of all specimens, except of the standard one, exhibited intergranular morphology. The fracture toughness values increased with increasing dm whereas the absorbed energy decreased. The increase in KIc values is explained in terms of the crack driving force reduction caused by the intergranularly induced crack tip shielding. The inverse behavior of impact test specimens is associated with a low resistance of coarse grained structures against crack nucleation. Separation of the extrinsic shielding effect from the measured KIc values by using a 3D model of the intergranular crack front resulted in a comparable intrinsic fracture toughness of all investigated steel grades.

fracture toughness, impact absorbed energy, ultra-high strength low alloy steel, shielding effect

POKLUDA, J., VLACH, B., ŠANDERA, P., JURÁŠEK, L.

2001

1. 1. 2001

SF2M Les Fontelles

Les Fontelles

465

472

8