|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Deformation and Transitions at Interfaces
||Investigations on the Origin of Crack Initiation and Propagation Susceptibility of Prior Austenite Grain Boundaries in DP and Martensitic Steels
||Fady Archie, Stefan Zaefferer
|On-Site Speaker (Planned)
Prior austenite grain boundaries (PAGbs) in martensite are highly favored locations for initiation and propagation of cracks. A comprehensive statistical analysis of crystallography and crack susceptibility illustrates the underlying mechanisms of damage initiation at PAGbs under monotonic and cyclic deformation modes. The study is based on coupled high resolution SEM-based diffraction techniques, namely, electron channeling contrast imaging, and electron backscatter diffraction. Results from local micro-cantilever bending experiments have been employed to study the influence of martensite variant selection on crack initiation at the prior austenite boundaries. The low fracture strength of PAGbs is analyzed with respect to two contributing factors, namely, solute element segregation, and localized residual elastic stresses. The first is studied by atom probe tomography, the latter by full field elastic strain analysis using focused ion beam milling and digital image correlation. Possible tracks for grain boundary engineering of DP-steels are revealed through varying heat treatment parameters.