Effect of silicon content on microstructure and mechanical properties of AlSi alloy coating obtained by physical vapour deposition

Several contents of silicon in AlSi coatings, and substrate nature, were investigated in this present research. For this purpose, thin films were deposited by Physical Vapour Deposition onto three substrates: The effect of silicon content on the microstructure and mechanical properties of the coatings was studied. The microstructural observations showed that the coating carried out with 7 wt-%. silicon reduced the porosities by making the microstructures more homogeneous and denser. Also, the influence of substrate characteristics on the evolution and distribution of the microstructure formed during coating is important. Content of 13 wt-% eutectic enhanced the mechanical properties. The crystallite size evolves in a completely opposite way to that of the dislocation density and micro-deformation, with a minimum for the same values of silicon content (10–12 wt-%). The microstructural analysis allowed us to highlight the importance of silicon in the formation of intermetallic compounds.