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Microscopic Origins of Fracture Toughness

Objective

The resistance to crack propagation is undoubtedly one of the most important properties of structural materials. However, our current mechanistic understanding of the fracture processes in typical semi-brittle materials like steels, refractory metals or semiconductors is not sufficiently advanced to predict the fracture toughness KIc and its dependence on the microstructure, temperature and strain rate. Therefore, KIc is commonly regarded as a phenomenological material parameter for fracture mechanics models that require experimental calibration.

The aim of microKIc is to study fracture in model materials in order to gain a detailed understanding of the microscopic crack-tip processes during fracture initiation, propagation and arrest, and to systematically study the interactions of cracks with constituents of the microstructure like dislocations, voids, precipitates and grain boundaries. To this end, we will perform fully 3D, large-scale atomistic simulations on cracks in bcc-based materials (W, NiAl) with varying crack orientation, crack front quality, and in the presence of dislocations and microstructural obstacles. The obtained criteria for crack advance and dislocation nucleation at crack tips will be implemented in a coupled finite element - discrete dislocation dynamics code, which will allow for the first time a fully 3D study of fracture and crack-tip plasticity at the mesoscale. The simulations will be compared to in-situ micro-mechanical tests on well-characterized fracture specimens produced by focused ion beam milling.

The ultimate goal of microKIc is to use this experimentally validated multiscale modelling framework to develop a microstructure-sensitive, physics-based micromechanical model of the fracture toughness, which will be tested against macroscopic fracture experiments. Such predictive models are crucial for the development of new failure-resistant materials and for improved design guidelines for safety-relevant structures and components.

Host institution

MAX PLANCK INSTITUT FUR EISENFORSCHUNG GMBH
Net EU contribution
€ 656 738,25
Address
Max Planck Strasse 1
40237 Dusseldorf
Germany

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Region
Nordrhein-Westfalen Düsseldorf Düsseldorf, Kreisfreie Stadt
Activity type
Research Organisations
Non-EU contribution
€ 0,00

Beneficiaries (3)

MAX PLANCK INSTITUT FUR EISENFORSCHUNG GMBH
Germany
Net EU contribution
€ 656 738,25
Address
Max Planck Strasse 1
40237 Dusseldorf

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Region
Nordrhein-Westfalen Düsseldorf Düsseldorf, Kreisfreie Stadt
Activity type
Research Organisations
Non-EU contribution
€ 0,00
CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
France
Net EU contribution
€ 297 395,00
Address
Rue Michel Ange 3
75794 Paris

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Region
Ile-de-France Ile-de-France Paris
Activity type
Research Organisations
Non-EU contribution
€ 0,00
FRIEDRICH-ALEXANDER-UNIVERSITAET ERLANGEN-NUERNBERG

Participation ended

Germany
Net EU contribution
€ 1 042 436,75
Address
Schlossplatz 4
91054 Erlangen

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Region
Bayern Mittelfranken Erlangen, Kreisfreie Stadt
Activity type
Higher or Secondary Education Establishments
Non-EU contribution
€ 0,00