Dresden 2014 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 13: Topical Session: Nanomechanics of nanostructured materials and systems III - Small scale plasticity
MM 13.4: Vortrag
Montag, 31. März 2014, 17:00–17:15, BAR 205
Influence of microalloying on the mechanical properties of molybdenum disilicide — •Carolin Puscholt1, Steffen Neumeier1, Mathias Göken1, and Sandra Korte-Kerzel2 — 1FAU Erlangen-Nürnberg, Germany — 2RWTH Aachen, Germany
Molybdenum disilicide (MoSi2) is a very promising candidate material for high temperature structural applications due to its high melting point (2030°C), low density and good oxidation resistance. However, the use of the pure material is limited by its low fracture toughness below 900°C which is associated with the plastic anisotropy and the high critical resolved shear stress on particular slip systems.
Microalloying of MoSi2 clearly enhances the room temperature ductility. For example, Ta, Al and Nb increase the ductility due to the activation of an additional slip system. However, the underlying mechanisms by which ductility is improved remain poorly understood, predominantly due to the difficulties encountered in low temperature experiments along the most brittle crystal orientation [001].
Here, this problem is overcome by using characterization methods at the microscale. A combination of uniaxial testing, where cracking is suppressed and hence the critical resolved shear stresses in specific crystal orientations can be determined individually, and nanoindentation in conjunction with EBSD and TEM was used. Results on pure and microalloyed MoSi2 with Tantalum will be presented, focusing on the influence of microalloying on the critical resolved shear stresses of particular slip systems.