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Modelling and Simulation of deformation and fracture of Titaniumaluminide alloys

Kabir, M. Rizviul and Chernova, Liudmila and Bartsch, Bartsch (2011) Modelling and Simulation of deformation and fracture of Titaniumaluminide alloys. Institutsseminar, Institut für Werkstoff-Forschung, DLR, Köln.

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Abstract

The two-phase Titaniumaluminide alloys show poor ductility and brittle fracture at room tempera-ture. The overall ductility and fracture behaviour depends on the intrinsic properties of the phases as well as on the morphology of grains and colony structures. During fracture mostly inter-granular fracture occurs at globular grains (consists of g-TiAl phases). However, fracture in lamellar colonies (consists of lamellar plates of a2-Ti3Al and g-TiAl phases) is much more complicated and often occurs by a single/combined action of inter-lamellar and trans-lamellar fracture, which is again highly dependent on the orientation of the lamellar interfaces with respect to the loading axis. Still today no numerical tool is available that can predict the microstructure dependent crack initiation and crack propagation, correlating them to the global failure of the material. Motivated by such issues we are developing numerical models to predict the generation of local and global plasticity at dif-ferent structural length scale as well as to predict the component failure based on micro-meso damages of the structure. In this presentation I will show a multiscale modelling approach that incorporates micro and meso scale structural description of a fully-lamellar TiAl alloy. The most important structural details, i.e., the vol.% of the phases, morphology of lamellar structure and orientation of the phases has been considered. The constitutive behaviour of the a2-Ti3Al -and g-TiAl-phases has been described in a crystal plasticity model where the mechanisms of crystallographic deformation (slip planes, slip di-rection and critical resolved shear stress) have been incorporated. Thus the model allows to predict the evolution of local plasticity in a realistic manner. In this work we also introduce fracture in the phases and colonies, which have been realized via “local-approach of damage mechanics” incorpo-rating decohesion at phase-boundaries (for inter-lamellar fracture) and splitting of phases (for trans-lamellar fracture). Development of this fracture model is in preliminary stage; therefore, only some fundamental results will be shown that may explain the quasi-brittle fracture of TiAl alloy at room temperature.

Item URL in elib:https://elib.dlr.de/71564/
Document Type:Conference or Workshop Item (Speech)
Title:Modelling and Simulation of deformation and fracture of Titaniumaluminide alloys
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Kabir, M. RizviulInstitut für Werkstoff-ForschungUNSPECIFIED
Chernova, LiudmilaInstitut für Werkstoff-ForschungUNSPECIFIED
Bartsch, BartschInstitut für Werkstoff-ForschungUNSPECIFIED
Date:7 July 2011
Open Access:No
In DOAJ:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:TiAl alloy, Lamellar fracture, Modeling
Event Title:Institutsseminar
Event Location:Institut für Werkstoff-Forschung, DLR, Köln
Event Type:Other
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Propulsion Systems (old)
DLR - Research area:Aeronautics
DLR - Program:L ER - Engine Research
DLR - Research theme (Project):L - Virtual Engine and Validation Methods (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Research > Experimental and Numerical Methods
Deposited By: Kabir, Dr. -Ing Mohammad Rizviul
Deposited On:14 Nov 2011 10:09
Last Modified:14 Nov 2011 10:09

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