Mechanical properties of AlN thin films deposited on Al 5083 substrates by magnetron sputtering under different bias voltages. Aluminum nitride (AlN) films were deposited on aluminum alloy substrates using magnetron sputtering under varying bias conditions to investigate the effect on mechanical properties and adhesion. Higher bias voltages produced finer AlN grains with higher hardness and elastic modulus due to increased residual stress, but above a threshold the film adhesive performance was reduced.