ICAMS / Interdisciplinary Centre for Advanced Materials Simulation

Deformation and fracture mechanisms in TiAl alloys

In the present project, we investigate deformation and fracture mechanisms of g-TiAl alloys. In particular, modern 3rd generation high-Nb containing TNB alloys are under investigation, one with a fine-grained duplex (TNB-V5) and one with a nearly lamellar (TNB-V2) microstructure.

TiAl-based materials are attractive for structural high temperature applications due to their low density and high mechanical strength as well as high creep and corrosion resistance.

Secondary electron SEM micrographs of fracture surfaces after tensile testing: (a) The duplex alloy reveals mainly intergranular fracture in regions of globular g grains and (b) cleavage-like fracture at lamellar interfaces.

The first objective is the characterization of tensile and creep behavior with focus on the influence of microstructural features on observed properties. The microstructural deformation mechanisms and the fracture characteristics will be studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in combination with quantitative metallographic methods.

The second objective is the modeling of the microstructural mechanisms of deformation and fracture. The experimental microstructural and mechanical data will be used as a basis for the development of a multiscale model for deformation, crack initiation and crack growth in lamellar structures.

Furthermore, the role of different types of interfaces and grain boundaries with respect to initiation and crack propagation will be investigated.

Project Files:

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Poster from the ICAMS Advisory Board meeting 2009.

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