Influence of the Size Effect on the Microstructures of the DWDS- and Bridgman-Solidified Single-Crystal CMSX-4 Superalloy

Wang, Fu; Ma, Dexin; Mao, Y.; Bogner, Samuel; Bührig–Polaczek, Andreas

doi:10.1007/s11663-015-0461-4

Cited by 10 publications

(1 citation statement)

References 25 publications

(26 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…High coherence of these phases allows classifying the structure of castings as single crystals, however with relatively low quality. [7][8][9][10] Recently, in the gas turbine industry determination of the crystal orientation in single-crystal nickel-base superalloys has been conducted using Laue X-ray diffraction. This method provides information about the crystal orientation for the area of about 1.5 mm in diameter.…”

Section: Doi: 101007/s11661-017-4305-5 ó the Author(s) 2017 This Armentioning

confidence: 99%

Determination of Crystal Orientation by Ω-Scan Method in Nickel-Based Single-Crystal Turbine Blades

Gancarczyk

Albrecht

Berger

et al. 2017

Metall Mater Trans A

View full text Add to dashboard Cite

The article presents an assessment of the crystal perfection of single-crystal turbine blades based on the crystal orientation and lattice parameter distribution on their surface. Crystal orientation analysis was conducted by the X-ray diffraction method X-scan and the X-ray diffractometer provided by the EFG Company. The X-scan method was successfully used for evaluation of the crystal orientation and lattice parameters in semiconductors. A description of the X-scan method and an example of measurement of crystal orientation compared to the Laue and EBSD methods are presented. High-pressure turbine blades (HPT) in aircraft and land-based gas turbines operate under severe conditions. These include heavy mechanical loads, high temperature and oxidizing gas environments. Turbine blades are manufactured from nickel-based superalloys in an investment casting process, which usually involves application of the lost-wax casting method. A columnar grain as well as single-crystal structure increases their high-temperature creep resistance. This kind of structure is obtained as a result of directional solidification processes. [1][2][3] Single-crystal casting is a highly advanced process in terms of maintaining proper solidification conditions, preparation of wax models and ceramic shell molds. The wax model of the turbine blade consists of a starter block and grain selector. Their specific shape makes it possible to obtain a single-crystal structure of the cast. The spiral shape of the grain selector ensures growth of only one grain at its end.[4] It has been established that during the initial stage of the solidification process, nuclei grow in a columnar manner in liquid metal toward the spiral-shaped selector. During the second stage of solidification, differences in the withdrawal rate value and the influence of the selector geometry result in elimination of the majority of disoriented columnar grains on the walls. This process enables the growth of one grain and makes obtaining a structure with a homogeneous crystallographic orientation possible. In most cases, single-crystal turbine blades are obtained with [001] direction parallel to or slightly deviating from the blade load axis, usually designated as 'z.' High deviation leads to a decrease in creep resistance due to the high anisotropy of the mechanical properties. Worldwide aircraft engine manufacturers' quality criteria require the value of the deviation angle (a) to be lower than 15 deg. [5,6] The microstructure of single-crystal nickel-based superalloys consists of two main phase components: the c phase, a solid solution of alloying elements in nickel, and c¢, an Ni 3 Al intermetallic phase. c¢ has an ordered structure-L1 2 , with a face-centered lattice-and is a main strengthening phase. The lattice parameters of the matrix (c phase) and precipitates (c¢ phase) have almost the same value: a 0 = 0.356 nm. High coherence of these phases allows classifying the structure of castings as single crystals, however with relatively low quality.

show abstract

Section: Doi: 101007/s11661-017-4305-5 ó the Author(s) 2017 This Armentioning

confidence: 99%

Determination of Crystal Orientation by Ω-Scan Method in Nickel-Based Single-Crystal Turbine Blades

Gancarczyk

Albrecht

Berger

et al. 2017

Metall Mater Trans A

View full text Add to dashboard Cite

show abstract

Evolution of Micro-Pores in a Single-Crystal Nickel-Based Superalloy During Solution Heat Treatment

Wang

Dong

et al. 2017

Metall Mater Trans A

View full text Add to dashboard Cite

Effects of a High Magnetic Field on the Microstructure of Ni-Based Single-Crystal Superalloys During Directional Solidification

Wang

Lan

Liu

et al. 2017

Metall Mater Trans A

View full text Add to dashboard Cite

Influence of the Size Effect on the Microstructures of the DWDS- and Bridgman-Solidified Single-Crystal CMSX-4 Superalloy

Cited by 10 publications

References 25 publications

Determination of Crystal Orientation by Ω-Scan Method in Nickel-Based Single-Crystal Turbine Blades

Determination of Crystal Orientation by Ω-Scan Method in Nickel-Based Single-Crystal Turbine Blades

Evolution of Micro-Pores in a Single-Crystal Nickel-Based Superalloy During Solution Heat Treatment

Effects of a High Magnetic Field on the Microstructure of Ni-Based Single-Crystal Superalloys During Directional Solidification

Contact Info

Product

Resources

About