Influence of chemical composition on the room temperature plasticity of C15 Ca-Al-Mg Laves phases
Martina Freund, Zhuocheng Xie, Pei-Ling Sun, Lukas Berners, Joshua Spille, Hexin Wang, C. Thomas, M. Feuerbacher, Marta Lipińska-Chwałek, Joachim Mayer, Sandra Korte‐Kerzel
Abstract
The influence of chemical composition changes on the room temperature mechanical properties in the binary Ca33Al67 C15 CaAl2 Laves phase were investigated in two ternary alloys with off-stoichiometric compositions with 5.7 at.% Mg substitution (Ca33Al61Mg6) and 10.8 at.% Mg and 3.0 at.% Ca substitution (Ca36Al53Mg11) and compared to the stoichiometric (Ca33Al67) composition. Cubic Ca-Al-Mg Laves phases with multiple crystallographic orientations were characterised and deformed using nanoindentation. The hardness and indentation modulus were measured to be 4.1 ± 0.3 GPa and 71.3 ± 1.5 GPa for Ca36Al53Mg11, 4.6 ± 0.2 GPa and 80.4 ± 3.8 GPa for Ca33Al61Mg6 and 4.9 ± 0.3 GPa and 85.5 ± 4.0 GPa for Ca33Al67, taken from our previous study, respectively. The resulting surface traces as well as slip and crack planes, were distinguished on the indentation surfaces, revealing the activation of several different {11n} slip systems, as further confirmed by conventional transmission electron microscopic observations. Additionally, the deformation mechanisms and corresponding energy barriers of activated slip systems were evaluated by atomistic simulations.