Effect of the Al2O3 + Ni–Al multilayer on the mechanical properties of Inconel 600 alloy

Al2O3 + Ni–Al multilayer coatings have been produced on Inconel 600 by glow discharge assisted oxidizing of substrates pre-coated with aluminum by magnetron sputtering. These layers have a diffusive structure and can be produced on parts of complicated shapes. The presence of the Al2O3 layer on intermetallic Al–Ni imparts high hardness (7.2 GPa) and good wear resistance.In this paper, the influence of the multilayered coatings on the mechanical properties of Inconel 600 was investigated. The structure of layers was examined on a scanning electron microscope with energy dispersive spectrometer and the surface topography using a profilometer. The coated and uncoated samples were subjected to a tensile tests at room temperature and 500 °C with the two strain rates: 8.3 · 10− 3 s− 1 and 8.3 · 10− 4 s− 1. Low-cycle fatigue resistance was also determined at room temperature.It has been found that the coatings slightly decrease the strength of Inconel 600. The quantitative analysis of the serrations observed on the stress–strain curves showed also that they decrease the intensity of the Portevin-Le Chatelier effect. The measurements of dynamic mechanical properties showed that they do not influence on the fatigue strength.