Microstructural strain localization and crack evolution in ductile iron

Autor: Kasvayee, Keivan Amiri, Ehsan, Ghassemali, Salomonsson, Kent, Jarfors, Anders E. W.
Jazyk: angličtina
Rok vydání: 2015
Předmět:
Popis: This paper focuses on the deformation and crack evolution in ductile iron under tension, investigated by coupled in-situ tensile test and finite element simulation. Micro-crack initiation and development were tracked at the microstructure level. The local strain around micro-cracks were measured by using Digital Image Correlation (DIC). The results obtained from the experiments were compared to a finite element model including cohesive elements to enable crack propagation. The resulting local strains were analyzed in connection to the observed micro-crack incidents in both DIC and simulation. The predictions of the finite element model showed good agreement with those obtained from the experiment, in the case of early decohesion, the amplitude of the strain localization and macroscopic stress-strain behavior. The results revealed that decohesion was commonly initiated early around graphite surrounded by ferrite which was identified as high strain regions. By increasing the global deformation, micro-cracks initiated in these areas and propagated but were arrested within the ferrite zone due to strain hardening and stress shielding of pearlite. Both the DIC and the simulation revealed that irregular shaped graphite were more susceptible to strain localization and micro-crack initiation. It could be observed that the cohesive model was able to capture the main trends of localized plastic deformation and crack initiation
Databáze: OpenAIRE