Han, C. S.; Ma, A.; Roters, F.; Raabe, D.: A Finite Element approach with patch projection for strain gradient plasticity formulations. International Journal of Plasticity 23, pp. 690 - 710 (2007)
Ma, A.; Roters, F.; Raabe, D.: A dislocation density based constitutive law for BCC materials in crystal plasticity FEM. Computational Materials Science 39, pp. 91 - 95 (2007)
Ma, A.; Roters, F.; Raabe, D.: On the consideration of interactions between dislocations and grain boundaries in crystal plasticity finite element modeling – Theory, experiments, and simulations. Acta Materialia 54 (8), pp. 2181 - 2194 (2006)
Ma, A.; Roters, F.; Raabe, D.: A dislocation density based constitutive model for crystal plasticity FEM including geometrically necessary dislocations. Acta Materialia 54, pp. 2169 - 2179 (2006)
Ma, A.; Roters, F.; Raabe, D.: Studying the effect of grain boundaries in dislocation density based crystal plasticity finite element simulations. International Journal of Solids and Structures 43, pp. 7287 - 7303 (2006)
Ma, A.; Roters, F.: A constitutive model for fcc single crystals based on dislocation densities and its application to uniaxial compression of aluminium single crystals. Acta Materialia 52, pp. 3603 - 3612 (2004)
Ma, A.; Roters, F.; Raabe, D.: Numerical study of textures and Lankford values for FCC polycrystals by use of a modified Taylor model. Computational Materials Science 29, 3, pp. 259 - 395 (2004)
Nikolov, S.; Lebensohn, R. A.; Roters, F.; Raabe, D.; Ma, A.: Micromechanical modeling of large plastic deformation in semi-crystalline polymers. 12th International Symposium on Plasticity 2006, Halifax, Nova Scotia (Canada), July 17, 2006 - July 22, 2006. (2006)
Roters, F.; Ma, A.; Raabe, D.: A dislocation density based constitutive model for crystal plasticity FEM. Dislocations, Plasticity, Damage and Metal Forming: Material Response and Multiscale Modeling, pp. 445 - 447 (2005)
Ma, A.; Roters, F.; Raabe, D.: Experiments and Simulations on the micromechanics of single- and polycrystalline metals. Numiform 2004, The Ohio State University, Columbus, Ohio, U.S.A., June 13, 2004 - June 17, 2004. Materials Processing and Design: Modeling, Simulation and Applications, pp. 78 - 83 (2004)
Roters, F.; Ma, A.; Raabe, D.: Kristallplastische Simulation in der Werkstoffprüfung. In: Proceedings of the 2004- Materials-Testing Conference of DGM in Neu-Ulm. DGM-Verlag (2004)
Ma, A.; Friák, M.; Neugebauer, J.; Raabe, D.: Ab initio based design of alloys. MS&T'08, Symposium: Discovery and Optimization of Materials Through Computational Design, David Lawrence Convention Center, Pittsburgh, PA, USA (2008)
Ma, A.; Roters, F.; Raabe, D.: Introducing the Effect of Grain Boundaries into Crystal Plasticity FEM Using a Non Local Dislocation Density Based Constitutive Model. Theory and Application to FCC Bi-Crystals. Euromech Colloquium 463, MPI für Eisenforschung GmbH, Düsseldorf, Germany (2007)
Bieler, T. R.; Crimp, M. A.; Ma, A.; Roters, F.; Raabe, D.: A Slip Interaction Based Measure of Damage Nucleation in Grain Boundaries. 3rd International Conference on Multiscale Materials Modeling, Freiburg, Germany (2006)
Roters, F.; Ma, A.; Zaafarani, N.; Raabe, D.: Crystal plasticity FEM modeling at large scales and at small scales. GAMM annual meeting, Berlin, Germany (2006)
Ma, A.; Roters, F.; Raabe, D.: A dislocation density based constitutive law for BCC materials in crystal plasticity FEM. 15th International Workshop on Computational Mechanics of Materials, MPI für Eisenforschung, Düsseldorf (2005)
Hydrogen in aluminium can cause embrittlement and critical failure. However, the behaviour of hydrogen in aluminium was not yet understood. Scientists at the Max-Planck-Institut für Eisenforschung were able to locate hydrogen inside aluminium’s microstructure and designed strategies to trap the hydrogen atoms inside the microstructure. This can…
For understanding the underlying hydrogen embrittlement mechanism in transformation-induced plasticity steels, the process of damage evolution in a model austenite/martensite dual-phase microstructure following hydrogenation was investigated through multi-scale electron channelling contrast imaging and in situ optical microscopy.
We will investigate the electrothermomechanical response of individual metallic nanowires as a function of microstructural interfaces from the growth processes. This will be accomplished using in situ SEM 4-point probe-based electrical resistivity measurements and 2-point probe-based impedance measurements, as a function of mechanical strain and…
Hydrogen induced embrittlement of metals is one of the long standing unresolved problems in Materials Science. A hierarchical multiscale approach is used to investigate the underlying atomistic mechanisms.
Hydrogen embrittlement affects high-strength ferrite/martensite dual-phase (DP) steels. The associated micromechanisms which lead to failure have not been fully clarified yet. Here we present a quantitative micromechanical analysis of the microstructural damage phenomena in a model DP steel in the presence of hydrogen.
This project will aim at developing MEMS based nanoforce sensors with capacitive sensing capabilities. The nanoforce sensors will be further incorporated with in situ SEM and TEM small scale testing systems, for allowing simultaneous visualization of the deformation process during mechanical tests
The project aims to study corrosion, a detrimental process with an enormous impact on global economy, by combining denstiy-functional theory calculations with thermodynamic concepts.
Understanding hydrogen-assisted embrittlement of advanced structural materials is essential for enabling future hydrogen-based energy industries. A crucially important phenomenon in this context is the delayed fracture in high-strength structural materials. Factors affecting the hydrogen embrittlement are the hydrogen content,...
Thermo-chemo-mechanical interactions due to thermally activated and/or mechanically induced processes govern the constitutive behaviour of metallic alloys during production and in service. Understanding these mechanisms and their influence on the material behaviour is of very high relevance for designing new alloys and corresponding…