ERC NanoHighSpeed

The aim of the project is to understand the changes in mechanical properties at high strain rates, considering the influence of the microstructure. In addition to the determination of yield curves and strain rate sensitivity / activation volumes at different strain rates, the project will focus on the mechanical behavior of grain boundaries at high strain rates, whereby mechanisms such as dislocation transmission, shear migration and fracture will be considered. The transition in deformation mechanisms is likely explained by the suppression of thermal activation at high loading rates. The gained knowledge will pave the way for developing new materials that can better withstand loads at high deformation speeds. In the long term, the outcomes of the project will result in safety, environmental and economic benefits.

Due to experimental challenges, it is currently only possible to investigate bulk, homogeneous samples at high loading rates. However small-scale components are also exposed to high loading speeds, such as hard coatings on drilling tooling, or smartphone displays upon impact with the ground to name a few. This highlights the need for developing a new experimental technique.

Nanoindentation testing, which already allows the depth-dependent mechanical characterization at low loading speeds, is an obvious candidate. While the maximum strain rate of conventional nanoindenters is limited both by the electronic components (e.g. low sampling rate) and the dynamics of the device (e.g. low resonant frequency), a nanoindenter prototype based on a system from Alemnis AG is developed in the action with a sampling rate of up to 10⁶ s^-1, which will enable a strain rate of approximately 10⁵ s^-1 .

Publications

1. J. Wang, E. Kang, U. Sultan, B. Merle, A. Inayat, B. Graczykowski, G. Fytas, N. Vogel. Influence of Surfactant-Mediated Interparticle Contacts on the Mechanical Stability of Supraparticles (2021) Journal of Physical Chemistry C, 125, pp. 23445-23456. https://doi.org/10.1021/acs.jpcc.1c06839

2. S. Gabel, B. Merle, E. Bitzek, M. Göken. A new method for microscale cyclic crack growth characterization from notched microcantilevers and application to single crystalline tungsten and a metallic glass (2022) Journal of Materials Research, 37(12), pp. 2061-2072. https://doi.org/10.1557/s43578-022-00618-x

3. S. Gabel, S. Giese, R.U. Webler, S. Neumeier, M. Göken. Microcantilever Fracture Tests of α‐Cr Containing NiAl Bond Coats (2022) Advanced Engineering Materials, 24(7), pp. 2101429. https://doi.org/10.1002/adem.202101429 

4. J. Winczewski, M. Herrera, C. Cabriel, I. Izeddin, S. Gabel, B. Merle, A. Susarrey Arce, H. Gardeniers. Additive Manufacturing of 3D Luminescent ZrO2: Eu3+ Architectures (2022) Advanced Optical Materials, 10(12), pp. 2102758. https://doi.org/10.1002/adom.202102758 

5. E. Bykova, E. Johansson, M. Bykov, S. Chariton, H. Fei, S.V. Ovsyannikov, A. Aslandukova, S. Gabel, H. Holz, B. Merle, B. Alling, I.A. Abrikosov, J.S. Smith, V.B. Prakapenka, T. Katsura, N. Dubrovinskaia, A.F. Goncharov, L. Dubrovinsky. Novel Class of Rhenium Borides Based on Hexagonal Boron Networks Interconnected by Short B2 Dumbbells (2022) Chemistry of Materials, 34(18), 8138-8152. https://doi.org/10.1039/D2TA02268K 

6. L. A. Morales, A. Bezold, A. Foerner, H. Holz, B. Merle, S. Neumeier, C. Koerner, C.H. Zenk. Influence of Cu Addition and Microstructural Configuration on the Creep Resistance and Mechanical Properties of an Fe-Based α/α’/α’’ Superalloy (2023) Advanced Engineering Materials, 25(9), 202201652. https://doi.org/10.1002/adem.202201652 

7. N. Sommer, A. Bauer, M. Kahlmeyer, T. Wegener, S. Degener, A. Liehr, A. Bolender, M. Vollmer, H. Holz, S. Zeiler, B. Merle, T. Niendorf, S. Böhm. High-Throughput Alloy Development Using Advanced Characterization Techniques During Directed Energy Deposition Additive Manufacturing (2023) Advanced Engineering Materials, 25,  pp. 202300030. https://doi.org/10.1002/adem.202300030

8. H. Khanchandani, S. Zeiler, L. Strobel, M. Göken, P. Felfer. A Carbon-Stabilized Austenitic Steel with Lower Hydrogen Embrittlement Susceptibility (2023) Steel research international, pp. 202300372, https://doi.org/10.1002/srin.202300372

9. J.P. Winczewski, S. Zeiler, S. Gabel, A. Susarrey-Arce, J.G.E. Gardeniers, B. Merle. Exploring the mechanical properties of additively manufactured carbon-rich zirconia 3D microarchitectures (2023) Materials & Design, 232, 112142. https://doi.org/10.1016/j.matdes.2023.112142 

10. H. Holz, B. Merle. Novel nanoindentation strain rate sweep method for continuously investigating the strain rate sensitivity of materials at the nanoscale (2023) Materials & Design, 236, pp. 112471. https://doi.org/10.1016/j.matdes.2023.112471

11. J. P. Winczewski, S. Zeiler, S. Gabel, D. Maestre, B. Merle, J.G.E. Gardeniers, A.S. Arce. Additive manufacturing of 3D yttria-stabilized zirconia microarchitectures (2024) Materials & Design, 238, pp. 112701. https://doi.org/10.1016/j.matdes.2024.112701

12. B. Merle, C.C. Walker, C.H. Zenk, G.M. Pharr. High strain rate persistence of the strength anomaly in the L12 intermetallic compound Ni3Si evidenced by nanoindentation testing (2025) Acta Materialia, 284, pp. 120598. https://doi.org/10.1016/j.actamat.2024.120598

13. H.C. Howard, W.S. Cunningham, A. Genc, B.E. Rhodes, B. Merle, T.J. Rupert, D.S. Gianola. Chemically ordered dislocation defect phases as a new strengthening pathway in Ni–Al alloys (2025) Acta Materialia, 289, pp. 120887. https://doi.org/10.1016/j.actamat.2025.120887

14. B. Merle, G. Tiphéne, G. Kermouche. Extending nanoindentation testing toward extreme strain rates and temperatures for probing materials evolution at the nanoscale (2025) MRS Bulletin, 50, pp. 705. https://doi.org/10.1557/s43577-025-00918-7