1. Institute of Metallurgy (IMET), Clausthal University of Technology, Robert-Koch-Strasse 42, 38678 Clausthal-Zellerfeld, Germany
2. Department of Applied Mechanics, Saarland University, Campus A4 2, 66123 Saarbruecken, Germany
3. CNRS UMR 7504, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg, 23 rue du Lœss BP 43, 67034 Strasbourg, France