Measurement and Discussion of Low-Temperature Hot Corrosion Damage Accumulation upon Nickel-Based Superalloy Rene 104

Abstract

This study presents quantitative information regarding the extent and morphology of hot corrosion damage evolved upon the surface of nickel-based superalloy Rene 104. Exposure times under an accelerated corrosion regime at 704°C range from 0.5 to 100 hours. Unlike oxidation, hot corrosion is observed to proceed at an alarmingly rapid rate. The evolution of high-temperature damage can be distinguished into two regimes. The first describes damage occurring at low exposure times, corresponding to what is ascribed as a phenomenon of transient oxidation, leading to a pitted surface. Following a distinguishable incubation period, hot corrosion damage proceeds such that damage depths are typically several hundreds of microns, with a generalized attack mode dominating the corrosion observed. Characteristics of the damage evolution are quantified via optical profilometry, while microscopy and XPS are used to support mechanistic interpretations.

Corrosion characteristics of high entropy alloys

“…Such a phenomenon of Al 2 O 3 being detected in conjunction with Cr 2 O 3 is common to Cr and Al containing superalloys (nominally Ni based superalloys) following high temperature oxidation. 48–51 In such instances, the oxidation occurs in air (at high temperatures) and preferential oxidation of Al occurs, somewhat akin to what occurs due to preferential Al dissolution in aqueous electrolytes. For example, in the case of AlCoCrFeNi coatings, after anodic polarisation in 3.5 wt- NaCl, both Al 2 O 3 and Cr 2 O 3 peaks are observed in XPS spectra.…”

“…The Al 2 O 3 is most likely formed due to preferential Al dissolution, then subsequent oxidation in the aqueous environment or air. Such a phenomenon of Al 2 O 3 being detected in conjunction with Cr 2 O 3 is common to Cr and Al containing superalloys (nominally Ni based superalloys) following high temperature oxidation [48][49][50][51]. In such instances, the oxidation occurs in air (at high temperatures) and preferential oxidation of Al occurs, somewhat akin to what occurs due to preferential Al dissolution in aqueous electrolytes.…”

Interfacial reactions of a MAX phase/superalloy hybrid

“…Emerging problem areas of environmental degradation in turbines are gas phase embrittlement, oxidation, and low temperature hot corrosion (LTHC) of advanced disk alloys used in the high pressure turbine stage . This issue becomes more critical at the highly stressed disk and blade attachment regions.…”

Isothermal Oxidation Behavior of FGH720Li Superalloy at Service Temperatures

“…The polycrystalline precipitate-hardened nickel-based Udimet720Li superalloy was of particular interest for modern turbine engines [1][2][3]. It was being considered for applications within aircraft engine turbine disk owing to the excellent high temperature strength、creep properties、resistance to fatigue crack growth and microstructure stability up to 680°C for extended periods of exposure [4][5].…”