Regensburg 2022 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 4: Structural Materials
MM 4.5: Vortrag
Montag, 5. September 2022, 11:15–11:30, H46
Plasticity of the Ca(Al,Mg)2 phase with variable temperature and composition — •Martina Freund1, Doreen Andre1, Pei-Ling Sun1, Nicolas J. Peter2, and Sandra Kort-Kerzel1 — 1Institut für Metallkunde und Materialphysik, RWTH Aachen University — 2Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf
Magnesium is a promising lightweight material, but its application as cast alloys at elevated temperature is limited because of its low creep resistance. By alloying with Al and Ca different Laves phases form, which improve creep strength. While investigating largely unknown properties with respect to composition and temperature changes, a challenge is to physically relate and represent such results. Here, we explore - in addition to the specific findings - how this may be done in terms of defect phase diagrams. Due to their complex packing, Laves phases are brittle at low temperatures. In order to overcome this restriction and to study their mechanical properties and mechanisms of plasticity, we used nanomechanical testing. For the cubic CaAl2 phase, nanoindentation tests revealed a constant hardness of 5.9 +- 1.2 GPa and indentation modulus of 120.3 +- 17.9 GPa. Slip traces and cracks in the vicinity of indents were correlated with the crystal orientation and mostly corresponded to the {111} and {112} planes. Microcompression revealed deformation on {111} and {112} planes in <1-10> direction and the CRSS has been calculated as 0.97 +- 0.03 GPa and 0.96 +- 0.03 GPa, respectively. These planes and Burgers vectors were also confirmed by TEM using the g*b criterion.