On the compression behavior of Cr2GeC and V2GeC up to quasi-hydrostatic pressures of 50 GPa

Using a synchrotron x-ray radiation source and a diamond anvil cell we measured the functional dependences of the lattice parameters of Cr 2 GeC and V 2 GeC to quasi-hydrostatic pressures of the order of 50 GPa. Like other solids in this family of layered ternary carbides and nitrides, the bulk moduli are high and no phase transformations were observed. The bulk modulus of V 2 GeC (165 ± 2 GPa) is lower than that of Cr 2 GeC (182 ± 2 GPa). Replacing Ge by Al in V 2 GeC to form V 2 AlC leads to a 22% increase in bulk modulus. In contradistinction, the same substitution in Cr 2 GeC results in a 10% decrease in bulk modulus.