Oxidation behavior of GTD111 Ni-based superalloy at 900 °C in air

Oxidation Behavior of the Nickel-Based Superalloy DZ125 at 980 °C

“…6. After oxidation for 0.5 h, a thickness of 1.2 lm c 0 -free zone accompanied by alumina layer was observed in the specimens; it was generally considered that the diffusion of Al by its own concentration gradients induced the oxidation reaction resulted in the formation of c 0 -free zone on the beneath of oxide film [12,17,18,20]. As the oxidation time increased, the total oxide layer showed faster growth rate than that of c 0 -free zone.…”

“…It was apparent that the oxidefilm growth on the specimens proceeds by a rapidly increased at initial stage followed a gradually reduction stage of the oxide-film growth rate, especially after oxidation for 55 h, the oxide growth rate drastically decreased. The relationship between mass change and exposure time during oxidation usually follows an approximate power law [12,14,17], which can be described as…”

“…7a), oxygen molecules were absorbed onto the surface of alloy and decomposed into oxygen atoms. Al has a high affinity with oxygen compared other cations of the alloy [12,13,17,18] and resulting in a fast diffusion toward the metal/oxide interface to form alumina on the surface. Therefore, it concluded that the alumina growth controlled the oxidation kinetics in the initial stage, which leads to the mass rapidly to increase.…”

“…Up to now although much effort has been conducted on the oxidation kinetics and study of the oxide film of superalloy, the oxidation mechanism has not been thoroughly understand. It has been generally accepted [12][13][14] that the oxidation weight changes of superalloys follow parabolic or sub-parabolic law during whole oxidation process, but some researchers reported different kinetics differences at various oxidation periods. For example, Dryepondt and Monceau [15] found the transient stage and steady stage in the oxidation kinetic curve of MC2 single crystal superalloy during isothermal oxidation at 1150°C.…”

Preparation of Inconel 740 superalloy by electron beam smelting

“…The oxidation behavior of the EBS 740 superalloy can be explained by considering that the actual transmission species through the oxide are the electrons and the ions of metal or O 2 [17]. The metal-deficit oxides such as Cr, and Ti oxides grow outward by the outward diffusion of metal cations to react with the oxygen, therefore, they mostly concentrate on the above and within the very top portion of the surface [18].…”