Mechanical properties of quasicrystalline Al–Cu–Fe coatings with submicron-sized grains

Quasicrystalline Al–Cu–Fe coatings with submicron-sized grains (∼ 400 nm) were produced by electron beam PVD. Mechanical properties of the Al–Cu–Fe quasicrystalline coating and a bulk Al–Cu–Fe quasicrystalline specimen with an average grain size of about 50 μm were examined using a set of micro- and nanoindentation techniques (with plotting stress–strain curves). It has been found that the length of the hardening stage in the stress–strain curve at room temperature for the coating is essentially greater, and the softening is weaker as compared with those for the bulk specimen. Possible reasons for such mechanical behavior of the coatings are discussed. Nanoindentation tests have shown that stepwise plastic flow is observed in both bulk sample and coating.