Orientation controlled microstructure and mechanical properties of TiN-Cu nanocomposite films

Adding soft metal phases into transition metal nitrides to generate nanocomposite structures can considerably tune the mechanical properties of films. We prepared TiN-Cu nanocomposite films with different orientations on MgO (100) and (110) substrates; the hardness of the film with 〈110〉 orientation was 40.4 GPa, while the 〈111〉-oriented film hardness was 28.1 GPa. This significant difference in hardness was attributed to orientation affecting Cu segregation at grain boundaries (GBs) to form different thicknesses of amorphous layers. This study opens a new avenue for tuning the mechanical properties of ceramic thin films.