Influence of sample size, strain rate and temperature on deformation of an Fe-2.4 wt.% Si Bi-crystal and its paired single crystals

Acta Materialia, vol. 316, pp. 122498

Abstract

Grain boundaries play an important role in determining mechanical properties of materials. To investigate the behavior of a single grain boundary, micropillar compression on bi-crystals has been widely applied, which however, mainly focuses on face-centered cubic metals. In this work, we investigate the influence of micropillar size, strain rate and temperature on deformation behavior of an Fe-2.4 wt.% Si bi-crystal with a high angle grain boundary and its paired single crystals. Tests were carried out at room temperature and -80°C, nominal micropillar sizes were 1 µm, 2 µm and 4 µm, while strain rates were 0.001 s -1 , 0.01 s -1 and 0.1 s -1 . Slip trace analysis reveals slip transmission across the grain boundary in bi-crystalline pillars. The transmitted slip systems can be different from those activated in single crystals depending on orientation. The identified transmission pair has a high transmission factor and is insensitive to strain rate and temperature, but dependent on pillar size. In contrast, the difference in yield strength between bi-crystals and single crystals is more closely related to testing parameters. For single crystals, smaller pillars can activate slip systems with a lower Schmid factor and slip traces become wavy due to cross-slip at a sub-ambient temperature.

Authors 10

1. Chunhua Tian corresponding Aachen Institute for Physical Metallurgy and Materials Physics

   RWTH Aachen University

   Affiliation as printed

   Institute for Physical Metallurgy and Materials Physics, RWTH Aachen University, 52074 Aachen, Germany

2. Hexin Wang Aachen Institute for Physical Metallurgy and Materials Physics

   RWTH Aachen University

   Affiliation as printed

   Institute for Physical Metallurgy and Materials Physics, RWTH Aachen University, 52074 Aachen, Germany

3. Pei‐Ling Sun Aachen Institute for Physical Metallurgy and Materials Physics

   RWTH Aachen University

   Affiliation as printed

   Institute for Physical Metallurgy and Materials Physics, RWTH Aachen University, 52074 Aachen, Germany

4. Martina Freund Aachen Institute for Physical Metallurgy and Materials Physics

   RWTH Aachen University

   Affiliation as printed

   Institute for Physical Metallurgy and Materials Physics, RWTH Aachen University, 52074 Aachen, Germany

5. Marcus Hans Aachen Materials Chemistry

   RWTH Aachen University

   Affiliation as printed

   Materials Chemistry, RWTH Aachen University, 52074 Aachen, Germany

6. Maral Sarebanzadeh

   Karlsruhe Institute of Technology

   Affiliation as printed

   Institute for Applied Materials Mechanics of Materials and Interfaces, KIT, Karlsruhe 76131, Germany

7. Zhuocheng Xie Aachen Institute for Physical Metallurgy and Materials Physics

   RWTH Aachen University

   Affiliation as printed

   Institute for Physical Metallurgy and Materials Physics, RWTH Aachen University, 52074 Aachen, Germany

8. Gaurav Mohanty

   Tampere University · University of Tampere

   Affiliation as printed

   Materials Science and Environmental Engineering, Tampere University, 33014 Tampere, Finland

9. Jakob Schwiedrzik

   Swiss Federal Laboratories for Materials Science and Technology

   Affiliation as printed

   Empa Swiss Federal Laboratory for Material Science and Technology, Laboratory of Mechanics of Materials and Nanostructures, Feuerwerkerstrasse 39, 3603 Thun, Switzerland

10. Sandra Korte‐Kerzel Aachen Institute for Physical Metallurgy and Materials Physics

    RWTH Aachen University

    Affiliation as printed

    Institute for Physical Metallurgy and Materials Physics, RWTH Aachen University, 52074 Aachen, Germany