Håkan Hallberg

Dr. Håkan Hallberg

Division of Solid Mechanics, Lund University, P.O. Box 118, SE-221 00 Lund, Sweden
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Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 October 2011 in Metals
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Håkan HallbergHåkan Hallberg
Håkan Hallberg
Control of the material microstructure in terms of the grain size is a key component in tailoring material properties of metals and alloys and in creating functionally graded materials. To exert this control, reliable and efficient modeling and simulation of the recrystallization process whereby the grain size evolves is vital. The present contribution is a review paper, summarizing the current status of various approaches to modeling grain refinement due to recrystallization. The underlying mechanisms of recrystallization are briefly recollected and different simulation methods are discussed. Analytical and empirical models, continuum mechanical models and discrete methods as well as phase field, vertex and level set models of recrystallization will be considered. Such numerical methods have been reviewed previously, but with the present focus on recrystallization modeling and with a rapidly increasing amount of related publications, an updated review is called for. Advantages and disadvantages of the different methods are discussed in terms of applicability, underlying assumptions, physical relevance, implementation issues and computational efficiency.

1 June 2010 in Computational Materials Science
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Håkan HallbergHåkan Hallberg
Håkan Hallberg
MWMathias Wallin
Mathias Wallin
MRMatti Ristinmaa
Matti Ristinmaa

1 February 2010 in Materials Science and Engineering: A
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Håkan HallbergHåkan Hallberg
Håkan Hallberg
MWMathias Wallin
Mathias Wallin
MRMatti Ristinmaa
Matti Ristinmaa

1 July 2007 in International Journal of Plasticity
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Journal Article
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Håkan HallbergHåkan Hallberg
Håkan Hallberg
PHP Hakansson
P Hakansson
MRMatti Ristinmaa
Matti Ristinmaa

8 November 2013 in Modelling and Simulation in Materials Science and Engineering
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Håkan HallbergHåkan Hallberg
Håkan Hallberg

2 April 2019 in Modelling and Simulation in Materials Science and Engineering
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Journal Article
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Håkan HallbergHåkan Hallberg
Håkan Hallberg
VBVasily V Bulatov
Vasily V Bulatov
A level set formulation is proposed that can accurately trace the evolution of grain boundary networks in a polycrystalline aggregate while respecting grain boundary energy anisotropy. Commonly adopted simplifying assumptions related to the grain boundary energy variation with local microstructure conditions are avoided and the grain boundary energy dependence on both crystallographic misorientation and boundary plane inclination is respected. Key components in the formulation are discussed, such as an efficient and simple scheme for unequivocal identification of crystal neighbors at grain boundary junctions where an arbitrary number of crystals intersect. The method works without modifications in both two and three dimensions and is shown to provide grain boundary junction configurations that comply with classical equilibrium conditions as well as topological transforms of the grain boundary network that agree with theoretical predictions. Full grain boundary energy anisotropy is considered by adopting a parametrization of the five-parameter grain boundary energy space, as previously proposed by Bulatov et al 2014 Acta Mater. 65 161–75. Examples are provided to illustrate the relevance of the level set framework for simulations of microstructure evolution in polycrystalline solids. For example, it is clearly shown that the proposed modeling framework provides a grain boundary inclination dependence of the grain boundary energy that cannot be neglected in mesoscale simulations of grain growth.