Institute of Physics of Materials AS CR, v. v. i. > Projects > Role of lattice defects in early stadia of fatigue damage of structural materials

Role of lattice defects in early stadia of fatigue damage of structural materials

InvestigatorIng. Jiří Man, Ph.D.
Number of Project106/06/1096
AgencyGrantová agentura České republiky
Duration2005-12-31 - 2008-12-30

Anotace
The proposed project is focused on the understanding of the role of lattice defects in the early fatigue stages in structural materials (316L austenitic stainless steel). Attention will be paid to the study of effect of temperature on the cyclic slip localization and surface relief evolution preceding fatigue crack initiation. The project is closely connected with the existing knowledge of surface relief evolution in 316L steel at room temperature. The patterns of growth of extrusions and intrusions will be studied using high resolution microscopy techniques – atomic force microscopy (AFM) and scanning electron microscopy equipped with field emission gun (SEM-FEG) – at depressed and elevated temperatures and experimental results obtained will be quantified. Dislocation structures corresponding to areas of cyclic slip localization will be studied using transmission electron microscopy (TEM). Study of localization of cyclic plastic deformation in wide temperature range will contribute to better understanding of fundamental micromechanisms in the early stages of fatigue damage and to the clarification of the role of point defects in surface relief evolution and fatigue crack initiation. Temperature dependence of surface relief evolution obtained could be a criterion of validity of theoretical models of fatigue crack initiation proposed so far and/or alternatively, can stimulate the creation of more exact models.

2010

Man J., Valtr M., Weidner A., Petrenec M., Obrtlík K., Polák J.: AFM study of surface relief evolution in 316L steel fatigued at low and high temperatures. Proc. Eng. 2 (2010) 1625-1633

Man J., Weidner A., Kuběna I., Vystavěl T., Skrotzki W., Polák J.: Application of FIB technique to study early fatigue damage in polycrystals. J. Phys.: Conf. Series 240 (2010) 012058


2009

Man J., Klapetek P., Man O., Weidner A., Obrtlík K., Polák J.: Extrusions and intrusions in fatigued metals. Part 2. AFM and EBSD study of the early growth of extrusions and intrusions in 316L steel fatigued at room temperature. Philos. Mag. 89 (2009) 1337-1372

Polák J., Man J., Vystavěl T., Petrenec M.: The shape of extrusions and intrusions and initiation of stage I fatigue cracks. Mater. Sci. Eng. A 517 (2009) 204-211

Man J., Obrtlík K., Polák J.: Extrusions and intrusions in fatigued metals. Part 1. State of the art and history. Philos. Mag. 89 (2009) 1295-1336


2008

Weidner A., Man J., Tirschler W., Klapetek P., Blochwitz C., Polák J., Skrotzki W.: Half-cycle slip activity of persistent slip bands at different stages of fatigue life of polycrystalline nickel. Mater. Sci. Eng. A 492 (2008) 118-127

Polák J., Petrenec M., Man J.: Cyclic stress in 316L austenitic stainless steel at low temperatures. Mater. Sci. Forum 567-568 (2008) 401-404


2007

Polák J., Man J., Vystavěl T., Zouhar L.: Fatigue crack initiation in crystalline materials - experimental evidence and models. Key Eng. Mater. 345-346 (2007) 379-382