Dresden 2011 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 31: Postersitzung II

MM 31.51: Poster

Wednesday, March 16, 2011, 17:15–18:45, P5

Tailoring the mechanical properties of nanocrystalline fcc metals: A Molecular Dynamics study on the effects of twins and miscible solutes on deformation processes — •Jonathan Schäfer, Alexander Stukowski, and Karsten Albe — TU Darmstadt, Darmstadt, Germany

For the presence of twins, a strengthening effect of nanocrystalline metals has been reported in experiment and simulation. For the case of miscible solutes, little is known about their effect on the structure and properties of nanocrystalline metals.

We present a comparative atomistic study on the effect of twins on the deformation behavior of nanocrystalline Cu and Pd. A new analysis method based on an automated Burgers circuit is applied, which allows us to analyze the dislocation interactions with twin planes and grain boundaries, and to directly measure dislocation, stacking fault, and twin boundary densities as functions of strain. We show, how a strengthening or softening effect of twins depends on the properties of a given fcc material i.e. its generalized planar fault energies.

For the case of Pd, we additionally show, how miscible solutes (Au) influence the behavior of our nanocrystalline structures in the elastic and plastic regime and why this depends on the distribution of the solutes. Here, samples are alloyed using a hybrid MD-MC method sampling the semi-grandcanonical ensemble. The automated Burgers search is applied as well and allows us to quantitatively compare the slip processes and planar faults as a function of composition and relaxation state.