Effects of heat treatment and high-temperature oxidation on 3D-printed Inconel718 alloy
In the present paper, Inconel 718 alloy was prepared by direct metal laser sintering. The bare alloy was post-processed through different heat-treatment routes, and the changes in its metallurgical and microstructural properties were investigated. In comparison to the bare alloy, grains in the overlapping region of the heat-treated alloys became refined. The strengthening phase of γ’ and γ” precipitations was high in the heat-treated alloys. Furthermore, cyclic oxidation studies were conducted on the bare and heat-treated samples at 1000°C. The variation in mass change per unit area and the corresponding corrosion mechanism were explored. Moreover, the formation mechanism of surface oxides under the influence of each alloying element was discussed. Chromium oxides were mainly formed during oxidation, and the mass change of the heat-treated alloys increased with these oxides. Therefore, an appropriate heat-treatment plan is highly recommended to prevent an alloy from continuous degradation and oxide formation.