The significance of two-phase plasticity for the crack initiation process during very high cycle fatigue of duplex steel
The present paper reviews experimental results on the fatigue damage of grade 1.4462 austenit-ic-ferritic duplex steel in the very high cycle fatigue (VHCF) regime.Electrolytically polished miniature and bulk specimens have been fatigued in an ultrasonic fatigue testing machine while the surface is observed in-situ by an optical microscope.The pre-fatigued miniature specimens are investigated by synchrotron dif-fraction contrast tomography (DCT) to reveal three-dimensional crystallographic orientation data.These data are used for finite element modeling in combination with a material model accounting for elastic anisotropy and crystal plasticity to predict crack initiation sites.The bulk specimens are carefully analyzed by means of scanning electron microscopy (SEM) in combination with electron back-scatter diffraction (EBSD).Under VHCF loading conditions,slip band formation is limited to the softer austenite grains – in particular at twin boundaries.Once being formed,the bands generate high stress concentrations where they impinge the aus-tenite-ferrite (???) phase boundaries,eventually,leading to crack initiation.The results are discussed by means of a numerical modeling approach that is based on (i) the finite element method (FEM) mentioned above and (ii) a crack initiation model proposed by Tanaka and Mura 1 and Chan 2.
Duplex steel VHCF short fatigue cracks
Alexander Giertler Marcus S(o)ker Benjamin D(o)nges Konstantin Istomin Ullrich Pietsch Claus Peter Fritzen Wolfgang Ludwig Hans-Jürgen Christ Ulrich Krupp
Faculty of Engineering and Computer Science,University of Applied Sciences Osnabrück,49009 Osnabrück Science and Technology,University of Siegen,57068 Siegen,Germany European Synchrotron Radiation Facility,38000 Grenoble,France
国际会议
北京
英文
1-8
2013-06-16（万方平台首次上网日期，不代表论文的发表时间）