Dendritic segregation and arm spacing in directionally solidified CMSX-4 superalloy

Matache, Gheorghe; Stefanescu, Doru M.; Puşcaşu, Cristian; Alexandrescu, Elvira

doi:10.1080/13640461.2016.1166726

Cited by 49 publications

(16 citation statements)

References 38 publications

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“…The primary arm spacing (PAS) was determined both in the ring-shaped area d 4–10 around CB1 at a width of W = 1.8 mm, and in the circular area f 1–13 with a diameter of D = 9.4 mm, which includes the fragment of CE. The W and D values were chosen so that the widths of the areas d 4–10 and f 1–13 marked in Figure 7 would be equal to those marked in Figure 6 c. It has been assumed that the PAS, defined in the d 4–10 ring-shaped area, corresponds to the LPAS in the d 4–10 area shown in Figure 6 c; on the other hand, the PAS, defined in the circular area of a diameter D, was assumed to correspond to the LPAS in the area f 1–13 marked in Figure 6 c. The “dendrites array method”, based on the relationship of a square array of points [ 37 ], was chosen for PAS determination. Calculations were made using the equation: PAS = c · (A/n) 0.5 , where n is the number of dendrite cores marked in Figure 7 by red points, A is the area of the surface defined for counting the dendrites when measuring PAS, and c = 1 for a “square array” according to [ 38 ].…”

Section: Resultsmentioning

confidence: 99%

“…It has been assumed that the PAS, defined in the d 4-10 ring-shaped area, corresponds to the LPAS in the d 4-10 area shown in Figure 6c; on the other hand, the PAS, defined in the circular area of a diameter D, was assumed to correspond to the LPAS in the area f 1-13 marked in Figure 6c. The "dendrites array method", based on the relationship of a square array of points [37], was chosen for PAS determination. Calculations were made using the equation: PAS = c • (A/n) 0.5 , where n is the number of dendrite cores marked in Figure 7 by red points, A is the area of the surface defined for counting the dendrites when measuring PAS, and c = 1 for a "square array" according to [38].…”

Section: Resultsmentioning

confidence: 99%

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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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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

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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“…The primary spacing controls the maximum length scale for the microsegregation [7], the solutioning heat treatment times [8,9], and the mechanical properties of the directionally solidified material [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. In addition, the λ 1 directly influences the mushy zone convection, the formation of low melting point secondary phase eutectics, as well as incoherent precipitates and pores in the interdendritic region [25][26][27][28][29][30][31][32]. Consequently, the mechanical properties of unidirectional solidified crystals are strongly dependent on the temperature and convection within the melt, as this controls the concentration of solute at the solid-liquid interface.…”

Section: Introductionmentioning

confidence: 99%

On Directional Dendritic Growth and Primary Spacing—A Review

2020

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The primary spacing is intrinsically linked with the mechanical behavior of directionally solidified materials. Because of this relationship, a significant amount of solidification work is reported in the literature, which relates the primary spacing to the process variables. This review provides a comprehensive chronological narrative on the development of the directional dendritic growth problem over the past 85 years. A key focus within this review is detailing the relationship between key solidification parameters, the operating point of the dendrite tip, and the primary spacing. This review critiques the current state of directional dendritic growth and primary spacing modelling, briefly discusses dendritic growth computational and experimental research, and suggests areas for future investigation.

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“…[3] Typically, this class of alloys shows strong segregations during solidification resulting in pronounced dendritic microstructures. [4] Thus, great efforts with respect to the casting process as well as the successive heat treatments have been undertaken to homogenize the microstructure in order to improve high-temperature properties. [3,5] Generally, single crystalline components evolve from a starter block superimposed on a cooled copper chill plate combined with a spiral grain selector.…”

Section: Cmsx-4mentioning

confidence: 99%

Microstructure and Mechanical Properties of CMSX-4 Single Crystals Prepared by Additive Manufacturing

Körner

Ramsperger

Meid

et al. 2018

Metall Mater Trans A

133

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Currently, additive manufacturing (AM) experiences significant attention in nearly all industrial sectors. AM is already well established in fields such as medicine or spare part production. Nevertheless, processing of high-performance nickel-based superalloys and especially single crystalline alloys such as CMSX-4 Ò is challenging due to the difficulty of intense crack formation. Selective electron beam melting (SEBM) takes place at high process temperatures (~1000°C) and under vacuum conditions. Current work has demonstrated processing of CMSX-4 Ò without crack formation. In addition, by using appropriate AM scan strategies, even single crystals (SX SEBM CMSX-4 Ò ) develop directly from the powder bed. In this contribution, we investigate the mechanical properties of SX SEBM CMSX-4 Ò prepared by SEBM in the as-built condition and after heat treatment. The focus is on hardness, strength, low cycle fatigue, and creep properties. These properties are compared with conventional cast and heat-treated material.

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Dendritic segregation and arm spacing in directionally solidified CMSX-4 superalloy

Cited by 49 publications

References 38 publications

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

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

On Directional Dendritic Growth and Primary Spacing—A Review

Microstructure and Mechanical Properties of CMSX-4 Single Crystals Prepared by Additive Manufacturing

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