Detecting strain instabilities in amorphous and crystalline metals


Cynthia A. Volkert

Institute of Materials Physics, University of Göttingen

Tuesday, 26.04.2016, 17:00
Werkstoffwissenschaftliches Kolloquium in Bernhard-Ilschner-Hörsaal

We investigate the discrete plastic events that occur during deformation of both amorphous and crystalline metals using several micro-mechanical methods. The main goal of these studies is to gain understanding of the emergence of global deformation from individual plastic events. We analyze the mechanical response and the distributions of plastic events in Au single crystals and various amorphous alloys as a function of specimen size [1-2], strain rate [3,4], and stress state [5] using microcompression, spherical nanoindentation, and tensile creep methods. By combining mechanistic modeling and statistical analysis we infer certain limits on the nature of the individual events and the cooperativity of their interactions.

[1] C.A. Volkert and E.T. Lilleodden, Phil. Mag., 86, 5567 (2006).
[2] C.A. Volkert, A. Donohue and F. Spaepen, J. Appl. Phys., 103, 083539 (2008).
[3] D. Tönnies, R. Maaß and C. A. Volkert, Adv. Mat., 26, 5715 (2014).
[4] D. Tönnies, K. Samwer, P.M. Derlet, C. A. Volkert and R. Maaß, Appl. Phys. Lett., 106, 171907 (2015).
[5] J.O. Krisponeit, S. Pitikaris, K.E. Avila, S. Küchemann, A. Krüge and K. Samwer, Nat. Comm. 5, 3616 (2014).