Mechanical properties of MAX phase thin films: The effect of band filling on the elastic properties of M2AlC thin Films (M=Ti, V, Cr)

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Mn+1AXn phases (where M is an early transition metal, A an A group element and X is either C or N, n=1-3) possess an unusual combination of mechanical, chemical, thermal and electrical properties. The origin of this rather unique set of properties, i.e. a previously unforeseen combination of metallic and ceramic Attributes is due to their nanolaminated atomic Arrangement. While the properties of Ti3SiC2 are comparatively well described by Barsoum and coworkers 1 and others, many basic materials science questions with respect to the synthesis and properties of structurally related compounds remain unanswered: One such experimentally unexplored question is the dependence of the elastic and plastic properties on the valence electron configuration of the carbide forming metal M in 211 MAX phases. The M2AlC system was selected based on our recently published ab initio calculations. Our strategy is, once suitable growth conditions for these materials are identified and optimized, to correlate the mechanical properties measured by nanoindentation with the information gained through structure, chemistry and bonding characterization for the systematically varied valence electron configuration of the carbide forming metal M in M2AlC. Through correlation with already published ab initio data we expect to contribute towards a better basic understanding of this fascinating class of solids.