Solidification Characteristics of Advanced Nickel-Base Single Crystal Superalloys

Hobbs, R.A.; Tin, Sammy; Rae, C.M.F.; Broomfield, Robert W.; Humphreys, C. J.

doi:10.7449/2004/superalloys_2004_819_825

Cited by 27 publications

(15 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the more complex Co-based superalloy ERBOCo-0, the considered elements show a very similar behaviour as in the Ni-based superalloys ERBO-1 and Astra2-W: Cr, Co, and W (as well as Mo and Re for ERBO-1) segregate preferably to the DC, whereas Ta, Ti, Al, and Ni segregate to the IR. The computed microsegregation coefficients in ERBO-1 are in good agreement with previous studies [33][34][35], except for W and Re, for which much larger k values (up to 1.6) have been reported. This difference can result from the different casting conditions of the samples.…”

Section: Microsegregation Sem and Epma Experimentssupporting

confidence: 88%

Microsegregation and precipitates of an as-cast Co-based superalloy—microstructural characterization and phase stability modelling

et al. 2015

View full text Add to dashboard Cite

The demand for increased efficiency of industrial gas turbines and aero engines drives the search for the next generation of materials. Promising candidates for such new materials are Co-based superalloys. We characterize the microsegregation and solidification of a multi-component Co-based superalloy and compare it to a ternary CoAl-W compound and to two exemplary Ni-based superalloys by combining the experimental characterization of the as-cast microstructures with complementary modelling of phase stability. On the experimental side, we characterize the microstructure and precipitates by electron microscopy and energy-dispersive X-ray spectroscopy and determine the element distributions and microsegregation coefficients by electron probe microanalysis (EPMA). On the modelling side, we carry out solidification simulations and a structure map analysis in order to relate the local chemical composition with phase stability. We find that the microsegregation coefficients for the individual elements are very similar in the investigated Co-based and Ni-based superalloys. By interpreting the local chemical composition from EPMA with the structure map, we effectively unite the set of element distribution maps to compound maps with very good contrast of the dendritic microstructure. The resulting compound maps of the microstructure in terms of average band filling and atomic-size difference explain the formation of topologically close-packed phases in the interdendritic regions. We identify B2, C14, and D0 24 precipitates with chemical compositions that are in line with the structure map.

show abstract

Section: Microsegregation Sem and Epma Experimentssupporting

confidence: 88%

Microsegregation and precipitates of an as-cast Co-based superalloy—microstructural characterization and phase stability modelling

et al. 2015

View full text Add to dashboard Cite

show abstract

“…This maximum volume fraction of γ/γ′ eutectic is comparable to that of reported elsewhere [13] for the alloy RR3010, which has a similar chemical composition to the alloy CMSX-10.…”

supporting

confidence: 86%

“…Of the techniques available, random sampling approach, which is commonly known as point matrix scan technique, is widely used for characterizing microsegregation in Ni-base superalloys [3,4,7,[11][12][13][14]. This technique has become prevalent because it allows characterizing microsegregation with no dependence on the plane of examination and simply provides a continuous profile with respect to the fraction of solid ( s ).…”

Section: Introductionmentioning

confidence: 99%

Solute Redistribution during Planar and Dendritic Growth of Directionally Solidified Ni-Base Superalloy CMSX-10

Seo

Lee

Yoo

et al. 2008

Superalloys 2008 (Eleventh International Symposium)

View full text Add to dashboard Cite

The solute redistribution behavior during directional solidification of the alloy CMSX-10 with planar and dendritic solid/liquid (S/L) interfaces has been investigated by directional solidification and quenching (DSQ) technique. In particular, the elemental partitioning coefficient during the solidification of primary γ and γ/γ′ eutectic was quantitatively estimated by electron probe microanalysis (EPMA) on the sample quenched during planar growth of primary γ and γ/γ′ eutectic, respectively. The EPMA compositional profiles clearly revealed that Scheil solidification occurs during the solidification of primary γ with planar S/L interface. Based on this result, the evolution of γ/γ′ eutectic volume fraction with respect to the solidification rate in dendritic solidification regimes could be rationalized by considering the back-diffusion effect on decreasing the extent of microsegregation. The comparison of the compositional profiles of Cr in the planar grown DSQ sample and the local distribution of Cr in dendritically solidified sample indicated that the solidification of the alloy CMSX-10 completes with the formation of supersaturated γ phase after the γ/γ′ eutectic reaction.

show abstract

“…The originally equiaxed materials have been replaced progressively by more complex structures, namely directionally solidified (DS) and single-crystal (SX) materials, thus improving the mechanical and oxidation properties at temperatures up to about 1,000°C [1][2][3][4][5]. In particular, DS columnar materials are still in use in e.g., highpressure turbine blades because of their appropriate compromise between creep and oxidation properties.…”

Section: Introductionmentioning

confidence: 99%

Cyclic and Isothermal Oxidation at 1,100 °C of a CVD Aluminised Directionally Solidified Ni Superalloy

2008

View full text Add to dashboard Cite

CVD aluminide coatings deposited on a Directionally Solidified (DS) substrate were oxidized at 1,100°C up to 240 h under isothermal and cyclic oxidation conditions to study the growth mechanisms of the oxide scales and the possible degradation of the coatings. The specimens were investigated using light and scanning electron (SEM) microscopy, energy-dispersive spectrometry (EDS) and X-Ray Diffraction (XRD). The results indicate that the coatings provide a much greater beneficial effect under isothermal conditions than upon cycling. The cycled specimens undergo oxide-scale spallation and increased roughening, which can derive from growth and thermal stresses as well as from the NiAl ? Ni 3 Al phase transformation associated with Al depletion. Under isothermal conditions, typical oxide scales formed with the appearance of some rumples. However, the origin of rumpling is uncertain from these experimental results.

show abstract

Solidification Characteristics of Advanced Nickel-Base Single Crystal Superalloys

Cited by 27 publications

References 14 publications

Microsegregation and precipitates of an as-cast Co-based superalloy—microstructural characterization and phase stability modelling

Microsegregation and precipitates of an as-cast Co-based superalloy—microstructural characterization and phase stability modelling

Solute Redistribution during Planar and Dendritic Growth of Directionally Solidified Ni-Base Superalloy CMSX-10

Cyclic and Isothermal Oxidation at 1,100 °C of a CVD Aluminised Directionally Solidified Ni Superalloy

Contact Info

Product

Resources

About