Oxidation behavior of Ni‐based superalloy GH4738 under tensile stress

Abstract

Abstract Revealing the oxidation behavior of superalloys is crucial for optimizing material properties and extending service life. This study investigated the oxidation behavior of superalloy GH4738 under stress states at 850 °C. High‐throughput specimens were fabricated to withstand different stresses at the same time. Isothermal oxidation samples were analyzed using the mass gain method to obtain oxidation kinetic curves. The results show that the external stress below 200 MPa could improve the oxidation resistance of the GH4738. With tensile stress increasing, the oxide layer becomes thinner, denser and more complete, while internal oxidation decreases. The tensile stress alters the structure of the external oxide layer from a two‐layer to a three‐layer configuration. The Cr 2 O 3 oxide layer inhibits the outward diffusion of Ti, leading to Ti enrichment at the oxide–matrix interface and altering the oxidation mechanism of GH4738.