Subproject in DFG SPP 1594: Topological Engineering of Ultra-Strong Glasses
Influence of the glass structure on the local mechanical properties of borosilicate glasses
The aim of the subproject is to extend the understanding of the deformation behaviour of borosilicate glasses. The influence of the glass structure is realised by different chemical compositions or process parameters. The mechanical properties on a local scale will be demonstrated by means of indexing tests.
Borosilicate glasses react to such external stress in three different ways: The material begins to densify structurally, to flow plastically or with the initiation of cracks. In order to illuminate all these aspects, the tested glasses are then examined by Raman spectroscopy and atomic force microscopy. This allows a determination of the material density and provides information about sink-in or pile-up formations in the peripheral area of the indentations. FEM simulations are used to map the complex elastic-plastic stress/strain
states in the material and to understand the influence of hydrostatic stresses on the flow behaviour and the subsequent deformation in the material. Plastic material behaviour is illustrated with the models of von Mises, Drucker-Prager and Mohr-Coulomb and the differences between the material models are shown. The insertion of cohesive elements along the indenter edges also allows the crack propagation during indentation to be mapped. In correlation with the experimental results, the results of the simulations will be used to determine the optimum material parameters for increasing the strength and fracture toughness of borosilicate glasses.
List of publications
2018
Benzine, O., Bruns, S., Pan, Z., Durst, K., & Wondraczek, L. (2018). Local Deformation of Glasses is Mediated by Rigidity Fluctuation on Nanometer Scale. Advanced Science.Text
Minnert, C., Kuhnt, M., Bruns, S., Marshal, A., Pradeep, K. G., Marsilius, M., . . . Durst, K. (2018). Study on the embrittlement of flash annealed Fe85.2B9.5P4Cu0.8Si0.5 metallic glass ribbons. Materials & Design, 156, 252-261. Text
2017
Bruns, S., Johanns, K.E., ur Rehman, H., Pharr, G.M., and Durst, K. (2017). Constitutive modeling of indentation cracking in fused silica. Journal of the American Ceramic Society, n/a-n/a. doi: 10.1111/jace.14734. Text
Zehnder, C., Bruns, S., Peltzer, J.-N., Durst, K., Korte-Kerzel, S., and Möncke, D. (2017). Influence of Cooling Rate on Cracking and Plastic Deformation during Impact and Indentation of Borosilicate Glasses. Frontiers in Materials 4(5). doi: 10.3389/fmats.2017.00005. Text
Konferenzen / Conferences
SPP 1594 Annual Meeting 2018, Jena, Germany
Gordon Research Conference 2018, Lewiston, USA
Glass and Optical Materials Division (GOMD) Meeting 2018, San Antonio, USA
SPP 1594 Spring School 2018, Hannover, Germany
ECI Nanomechanical Testing in Materials Research and Development VI 2017, Dubrovnik, Croatia
Summer School on Experimental Nano- and Micromechanics 2017, Düsseldorf, Germany
AK Rasterkraftmikroskopie und nanomechanische Methoden 2017, Aachen, Germany
MSE Congress 2016, Darmstadt, Germany
Gordon Research Conference 2016, Lewiston, USA
AK Rasterkraftmikroskopie und nanomechanische Methoden 2016, Saarbrücken, Germany