  Using first-principles density functional calculations, a systematic study on
the elastic properties for all known superconducting MAX phases (Nb2SC, Nb2SnC,
Nb2AsC, Nb2InC, Mo2GaC and Ti2InC) was performed. As a result, the optimized
lattice parameters, independent elastic constants, indicators of elastic
anisotropy and brittle/ductile behavior as well as the so-called machinability
indexis were calculated. We derived also bulk and shear moduli, Young's moduli,
and Poisson's ratio for ideal polycrystalline MAX aggregates. The results
obtained were discussed in comparison with available theoretical and
experimental data and elastic parameters for other layered superconductors.
