Fatigue Investigations and Numerical Modeling of Forged Ti6A14V in Different Microstructural Conditions
Two types of bi-modal microstructures were investigated with respect to fatigue crack initiation and short crack growth characteristics. SN-type experiments,followed by interrupted fatigue tests were carried out using a servohydraulic test facility. SEM together with the EBSD technique was applied for crack observation as well as for the determination of local crystallographic orientations,in order to link crack paths and propagation rates to microstructural features. FIB technique was applied to selected cracks to provide detailed information of crack paths into the depth. It was found that most of the cracks initiated on boundaries between two lamellae or between primary alpha grains and lamellae. FIB analysis revealed the influence of the phase boundaries,i, e. the remaining beta phase. Cracks are dominated by following favourably oriented boundaries in terms of the Burgers relation and using basal and prismatic slip planes. Crack deflection is a common feature,and is related to high tilt and twist angles between the grains involved. Based on these experimental investigations a two-dimensional model for stage I crack propagation was developed, which accounts for crack propagation on these slip planes as well as on grain boundaries. The model considers the barrier effect of grain boundaries and is solved numerically by dislocation dipole boundary elements.
Short cracks boundary elements numerical modelling microstructure optimization
Helge Knobbe Philipp Koster Hans-Jiirgen Christ Claus-Peter Fritzen Martin Riedler
Institut fur Werkstofftechnik ,Universitdt Siegen,Paul-Bonatz-Strafie 9-11 ,57068 Siegen ,Germany Institut fiir Mechanik und Regelungstechnik-Mechatronik ,Paul-Bonatz-Straβe 9-11 ,57068 Siegen ,Germ Bohler Schmiedetechnik GmbH & Co KG Mariazeller Strafe 25,8605 Kapfenberg,Austria
国际会议
The 12th World Conference Titanium(第十二届世界钛会 Ti-2011)
北京
英文
853-857
2011-06-19（万方平台首次上网日期，不代表论文的发表时间）