A05 – Dislocations in complex intermetallic phases

PI: Prof. Sandra Korte-Kerzel (Institute for Physical Metallurgy and Materials Physics, RWTH Aachen University)

SFB researchers: Martina Freund Institute for Physical Metallurgy and Materials Physics, RWTH Aachen University)

In this project, we focus on the evaluation of plasticity in the occurring intermetallic phases of the Mg-Al-Ca system, which are the CaAl2-, the Ca(Mg,Al)2- and the CaMg2 –  Laves phases as well as the Mg17Al12 phase. We achieve plasticity by using nanomechanical testing like nanoindentation tests with constant and changing strain rates and micropillar compression tests, to analyse mechanical properties and slip planes by correlating orientation information from EBSD measurements with the alignment of the surface traces forming during the deformation and additionally calculate the critical resolved shear stress. To confirm the active slip planes and identify Burgers vectors, we use transmission electron microscopy (TEM).

We aim to observe changes in plasticity with changing stoichiometry and/or changing temperature in order to guide us to dislocation defect phase or mechanism transitions within the intermetallic. In this way, we achieve a much better understanding of deformation in these complex crystals. In this way, we not only discover dislocation defect phases and the way in which they allow deformation to occur, but also gain valuable insights into potential strategies to make these hard phases more ductile or use them in high performance alloys.

 Publications:

  • [1] C. Zehnder, K. Czerwinski, K.D. Molodov, S. Sandlöbes-Haut, J.S.K.-L. Gibson, S. Korte-Kerzel, 2019 Plastic deformation of single crystalline C14 Mg2Ca Laves phase at room temperature, Materials Science and Engineering Volume 759, pp.754-761 - doi.org/10.1016/j.msea.2019.05.092
  • [2] M. Freund, D. Andre, C. Zehnder, H. Rempel, D. Greber, M. Zubair, S. Sandlöbes-Haut, J.S.K.-L. Gibson, S. Korte-Kerzel, 2021 Plastic deformation of the CaMg2 C14-Laves phase from 50 - 250°C, Materialia Volume 20, doi.org/10.1016/j.mtla.2021.101237
  • [3] J.S.K.-L. Gibson, P. Risheng, M. Heller, S. Medghalchi, W. Luo, S. Korte-Kerzel, 2021 Finding and Characterising Active Slip Systems: A Short Review and Tutorial with Automation Tools  Materials Volume 407, DOI: doi.org/10.3390/ma14020407
  • [4] J.S.K.-L. Gibson, P. Risheng, M. Heller, S. Medghalchi, W. Luo, S. Korte-Kerzel, 2021 Software, 10.5281/ZENODO.4581088
  • [4] Z. Xie, D. Chauraud, E. Bitzek, S. Korte-Kerzel & J. Guénolé, 2021 Laves phase crystal analysis (LaCA): Atomistic identification of lattice defects in C14 and C15 topologically close-packed phases, Journal of Materials Research Volume 36
  • [5] S. Korte-Kerzel, T. Hickel, L. Huber, D. Raabe, S. Sandlöbes-Haut, M. Todorova, J. Neugebauer, 2021&2022 Defect phases – thermodynamics and impact on material properties, International materials reviews Volume 67, pp. 89-117 – DOI: 10.1080/09506608.2021.1930734
  • [6] D. Andre, M. Freund, U. Rehmann, W. Delis, M. Felten, J. Nowak, C. Tian, M. Zubair, L. Tanure, L. Abdellaoui, H. J. Springer, J. P. Best, D. B. Zander, G. Dehm, S, Sandlöbes-Haut, S. Korte-Kerzel, 2022 Metallographic preparation methods for the Mg based system Mg-Al-Ca and its Laves phases, Materials characterization Volume 192, DOI: 10.1016/j.matchar.2022.112187