Performance characterization on a novel intermetallic layer produced by interdiffusion between Ti film and 5083 Al alloy

• The Al18Ti2Mg3 layer was successfully produced by thermo-diffusion method.
• The mechanical properties of Al18Ti2Mg3 were studied by nanoindentation tests.
• The corrosive behavior of Al18Ti2Mg3 was firstly investigated.
• The Al18Ti2Mg3 layer showed good plasticity ability and high corrosion potential.

By means of magnetron sputtering method, pure Ti film with thickness of 1.25 μm was deposited on the surface of 5083 Al alloy specimens. The specimens were heated by ion bombardment in a plasma nitriding unit employing a mixed gas of N2 and H2 at 460 °C for 16 h. The treated surface layers of specimens were characterized by using SEM equipped with EDS, TEM, XRD analysis and nanoindentation as well as potentiodynamic polarization tests. The results show that the Al18Ti2Mg3 layer with a thickness of 6.3 μm can be formed on the surface of the specimens during interdiffusing of Ti, Mg and Al across the interface between Ti film and the substrate alloy. The interdiffusion layer possesses much higher Young's modulus (131 GPa), the nanohardness (8.97 GPa) and corrosion potential (−0.75VSCE) than those of 5083 Al–Mg alloy. Additionally, the Al18Ti2Mg3 phase layer has an excellent plastic deformation ability resulting mainly from its plasticity deformation power dissipation ratio (ηp) up to 87%.