Microstructural Characterization of Ni-Base Superalloy As-Cast Single Crystal (CMSX-4)

Moreira, Marcelo Ferreira; Fantin, Luiza; Azevedo, César Roberto de Farias

doi:10.1007/s40962-020-00496-1

Cited by 20 publications

(11 citation statements)

References 52 publications

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“…The proper selection of technological parameters, such as the temperature gradient and crystallization rate, will allow for obtaining the blades with high structural perfection and good strength and mechanical properties [ 17 , 18 , 19 , 20 ]. It was stated that any deviation of [001] direction from the Z-axis defined by the α angle ( Figure 1 ) causes deterioration in blade quality [ 1 , 21 , 22 ]. Therefore, the value of the α angle and its spatial distribution in the blade significantly influence the mechanical and strength properties of blades.…”

Section: Introductionmentioning

confidence: 99%

The Influence of the Cooling Bores on Crystal Orientation and Lattice Parameter in Single-Crystalline Cored Turbine Blades

2021

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The areas located near the cooling bores of single-crystalline cored turbine blades made of nickel-based CMSX-4 superalloy were studied. The blades were solidified by the vertical Bridgman technique in the industrial ALD furnace. Longitudinal sections of the blades were studied by Scanning Electron Microscopy, X-ray diffraction topography, X-ray diffraction measurements of the γ′-phase lattice parameter a, and the α angle of the primary crystal orientation. The local changes in α were analyzed in relation to the changes of the dendrite’s growth direction near the cooling bores. It was found that in the area approximately 3 ÷ 4 mm wide around the cooling bores, changes of α and a, both in the blade root and in the airfoil occurred. The local temperature distribution near the cooling bores formed a curved macroscopic solidification front, which caused changes in the chemical composition and, consequently, changes in the a value in a range of 0.002 Å to 0.014 Å. The mechanism of alloying elements segregation by tips of the dendrites on the bent solidification front was proposed. The multi-scale analysis that allows determining a relation between processes proceed both on a millimeter-scale and a micrometric and nanometric scale, was applied in the studies.

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Section: Introductionmentioning

confidence: 99%

The Influence of the Cooling Bores on Crystal Orientation and Lattice Parameter in Single-Crystalline Cored Turbine Blades

2021

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“…It is known that any local deviation of the [001] direction from the blade axis Z, described by the α angle ( Figure 1 c), causes inhomogeneity in the dendritic structure of the blade [ 1 , 20 , 21 ]. However, full primary orientation is defined by two angles, α and β, which define the arrangement of the primary dendrite arms as a result of their growth in the direction of the unit vector

.…”

Section: Introductionmentioning

confidence: 99%

The Influence of the Cooling Bores on the Dendritic Structure and Crystal Orientation in Single-Crystalline Cored CMSX-4 Turbine Blades

Krawczyk

Bogdanowicz

2021

Materials

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Single-crystalline cored CMSX-4 blades obtained at a withdrawal rate of 3 mm/min by the vertical Bridgman method were analyzed. The dendritic structure and crystal orientation near the cooling bores of the blades were studied through Scanning Electron Microscopy, the X-ray diffraction measurements of α and β angular components of the primary crystal orientation, and the γ angular component of the secondary crystal orientation. Additionally, the primary arm spacing (PAS) was studied in areas near and far from the cooling bores. It was found that in the area approximately 3–4 mm wide around the cooling bores, changes occurred in the α, β, and γ angles, as well as in the PAS. The PAS determined for the transverse section of the root and the linear primary arm spacing (LPAS) determined for the longitudinal sections, as well as their relationship, have been defined for the areas located near the cooling bores and those at a distance from them. The vertical temperature gradient of 29.5 K/cm was estimated in the root areas located near the cooling bores based on the PAS values. The value of this gradient was significantly higher compared to the growth chamber operating gradient of 16 K/cm. The two-scale analysis applied in this study allowed for the determination of the relationship between the process of dendrite array creation proceeding on a millimeter scale, which is associated with the local changes in crystal orientation near the cooling bores, and that which proceeds on a scale of tens of millimeters, associated with the changes in crystal orientation in the whole blade cast.

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“…A key factor in the extreme durability of Ni-base superalloys is the presence of a highvolume fraction (~70%) of γ ′, which is highly resistant to creep and fatigue crack propagation. Thus, the mechanical properties of Ni-base superalloys are strongly dependent upon the 𝛾 ′ size, shape, morphology, and 𝛾/𝛾 ′ coherency throughout the solidified crystal 316 .…”

Section: Sample Descriptionmentioning

confidence: 99%

Patterns in Directionally Solidified Alloys

Strickland

2021

SSRN Journal

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Microstructural Characterization of Ni-Base Superalloy As-Cast Single Crystal (CMSX-4)

Cited by 20 publications

References 52 publications

The Influence of the Cooling Bores on Crystal Orientation and Lattice Parameter in Single-Crystalline Cored Turbine Blades

The Influence of the Cooling Bores on Crystal Orientation and Lattice Parameter in Single-Crystalline Cored Turbine Blades

The Influence of the Cooling Bores on the Dendritic Structure and Crystal Orientation in Single-Crystalline Cored CMSX-4 Turbine Blades

Patterns in Directionally Solidified Alloys

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