Study of surface relief evolution in fatigued 316L austenitic stainless steel by AFM

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2003-06, Vol.351 (1), p.123-132
• Main Authors: Man, J, Obrtlı́k, K, Polák, J
• Format: Article
• Language: English
• Subjects: 316L Austenitic steel; Applied sciences; Atomic force microscopy; Elasticity. Plasticity; Exact sciences and technology; Extrusion; Fatigue; Intrusion; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Persistent slip band
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/S0921-5093(02)00846-8

Atomic force microscopy was applied to study the surface relief evolution at emerging persistent slip bands (PSBs) in individual grains of polycrystalline 316L stainless steel cycled with constant plastic strain amplitude. Quantitative data on the changes of the surface topography of persistent slip markings (PSMs) and on the kinetics of extrusion growth during the fatigue life of smooth specimens were obtained. The extrusion height can be assessed by a direct observation of the metal surface and the intrusion depth using the plastic replica technique. The first PSMs appear after the initial hardening (0.1–0.25% of N f). PSBs can be active in the whole period of fatigue life in grains in which no cracks develop. The initial rapid growth of extrusions is followed by a period of stable linear growth up to the end of the fatigue life. The width of extrusions, corresponding to the thickness of the emerging PSBs quickly stabilizes and remains constant during the whole fatigue life. The experimental results are discussed in terms of recent vacancy models of surface relief evolution.