Mechanical characterization of a novel nanocrystalline coating: First-principles calculations and nanoindentation

A nanostructured MoSi2 coating with the average grain size of 5 nm and a strong (111) preferred orientation, was synthesized potentially for jet engine hot-zone components against volcanic ash damage. The high hardness of the resulting coating was predicted using first-principles calculations and found to agree well with the experimental data determined by nanoindentation. We also found that the softening and subsequent breaking of the Mo―Si bonds were responsible for the failure of this nanostructured coating under tensile loading.

► A nanostructured MoSi2 coating with a strong (111) preferred orientation, was synthesized. ► The experimental data determined by nanoindentation agree well with the theoretical prediction. ► The breaking of the Mo―Si bond are responsible for the failure of C40 MoSi2.