The effect of crack propagation mechanism on the fractal dimension of fracture surfaces in steels

• Published in: Engineering fracture mechanics Vol. 75; no. 3; pp. 726 - 738
• Main Authors: Dlouhý, I., Strnadel, B.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Tarrytown, NY Elsevier Ltd 01-02-2008; Oxford Elsevier
• Subjects: Brittle fracture; Ductile fracture; Exact sciences and technology; Fractal dimension; Fractography; Fracture mechanics (crack, fatigue, damage...); Fracture surface; Fracture toughness; Fundamental areas of phenomenology (including applications); Intergranular fracture; Low-alloyed steel; Physics; Solid mechanics; Structural and continuum mechanics; Fractal dimension; Brittle fracture; Low-alloyed steel; Fracture surface; Ductile fracture; Fractography; Intergranular fracture; Fracture toughness; Heat treatment; Embrittlement; Roughness; Metal; Rough surface; Surface analysis; Low alloy steel; Crack propagation; Alloy steel; Fractal; Wavy surface; Corrugated surface; Microstructure; Crack
• ISSN: 0013-7944; 1873-7315
• DOI: 10.1016/j.engfracmech.2007.03.038

The paper reports on the results of a fractal analysis of fracture surfaces of Ni–Cr steel in two different states of heat treatment simulating embrittlement. The change in the fractal dimension of the fracture surface demonstrates a wavy character and dispersion depending on the microstructural state of the tested steel. The results of the fractal analysis in the crack growth direction and across the entire crack front were used as the basis for a reconstruction of the geometry of the fracture surface, providing a new geometric tool for fractographic analysis. The competing effects of transgranular and intergranular brittle fracture may lead to increased roughness of the fracture surface and its fractal dimension. The threshold value of the fractal dimension of the sections perpendicular to the fracture surface, indicating the transition from transgranular to intergranular fracture, is 1.12.