Early stages of scale formation during oxidation of γ / γ ′ strengthened single crystal ternary Co-base superalloy at 900 °C

Initial oxidation behavior of a single crystal superalloy during stress at 1150 °C

“…Figure 6 After the oxidation experiment, the element distribution of air-cooling specimen was mapped in Fig. 7(a-f) by EDS, Al and O elements show almost the same distribution, it indicates the precipitate are mainly Al 2 O 3 , which is also found in γ channel reported by Weiser 20 . In this paper, more precisely, nucleation on the original interface of the two phases or called the side surface of γ phase was clearly observed.…”

Thermogravimetric investigations of new γ-γ′ cobalt-based superalloys

“…Afterward, the rate of oxidation slowed down, what may be observable as an visible threshold on the mass change profile and is implied by the DTG peak. In this case, it may be also explained by the formation of an another type of oxide, namely by transition of Co 3 O 4 to CoO oxide, which is more stable over 900°C [22][23][24][25][26][27][28][29][30][31]. The TG plot shot up after exceedance of 920°C at which increase in mass reached 0.21%.…”

“…The deleterious effect of Cr and Si on the c-c 0 microstructure may be neutralized by Ni addition, whose occurrence in the alloy improves the c 0 stability [21]. The newest data show detailed analysis of Co-Al-W alloys oxidation, including role of c and c 0 phases in initial stage of oxidation [22]. Despite the oxidation properties, alloys based on Co-Al-W system have other limitations, resulting from W occurrence, i.e.…”

Correlative Nano‐Computed Tomography and Focused Ion‐Beam Sectioning: A Case Study on a Co‐Base Superalloy Oxide Scale

“…In recent years, the applicability of Co-base superalloys as high-temperature material has been a research topic of high interest. [1][2][3][4][5] This new class of superalloys was first reported by Lee [6] and rediscovered in 2006 by Sato et al [7] So far, the mechanical properties of Co-base alloys have been studied extensively [8][9][10][11][12][13] and they are deemed promising for applications in the intermediate-temperature regime. [14][15][16] Phase stability and high-temperature mechanical properties were significantly improved in the last years by addition of a wide range of alloying elements.…”

“…Recently, research on oxidation of Co-base superalloys has attracted a lot of interest and considerable progress has been achieved by dedicated alloy design. [21][22][23][24][25] Since pores and phases of these complex multilayered oxide scales extend into 3D with both nanometer-and micrometersized features, a site-specific, scale-bridging, and 3D characterization approach is required. One commonly used technique is focused ion beam/scanning electron microscopy tomography (FIB/SEM tomography or, shortly, FIB tomography).…”