1. Institute for Materials Testing, Materials Science and Strength of Materials University of Stuttgart Pfaffenwaldring 32 70569 Stuttgart Germany
2. Institute of Strength Physics and Materials Science Siberian Branch of Russian Academy of Sciences Tomsk 2/4 Akademicheskii Av. 634055 Tomsk Russian Federation
3. Donetsk Institute of Physics and Engineering National Academy of Sciences Kiev, Nauki Ave. 46 03680 Donetsk Ukraine