Multicomponent γ’-strengthened Co-based superalloys with increased solvus temperatures and reduced mass densities

Eric A. Lass*, Daniel J. Sauza, David C Dunand, David N Seidman

*Corresponding author for this work

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Several Co-Al-(W)-based γ-(FCC)/γ’-(L12) alloys are investigated to combine recent results indicating significant increases in the γ′-solvus temperature with additions of Ni, Ta, and Ti, and reduced mass density with the substitution of Mo and Nb for W. A maximum solvus temperature of 1167 ± 6 °C is achieved for an alloy with the composition Co-30Ni-7Al-4Ti-7W-1Ta (mole fraction × 100); while the composition Co-30Ni-7Al-4Ti-3Mo-2W-1Nb-1Ta (L19) exhibits a promising combination of high γ′ volume fraction and solvus temperature, low mass density, and excellent two-phase γ-γ′microstructural stability. Atom probe tomographic measurement of L19 aged for 4 h at 900 °C indicates that Ni, Al, Ti, W, Nb, and Ta partition preferentially to the γ′-precipitates while Co partitions strongly to the γ-matrix. Molybdenum segregates at the γ/γ′ interface, resulting in a reduction in the interfacial free energy of 1.63 ± 0.85 mJ m−2. Decreasing the mole fraction of Ni from 30% to 10% decreases the partitioning of Al and Ti to the γ′-phase and increases partitioning of Co, Mo, W, Nb, and Ta to the γ′-phase. From an analysis of coarsening kinetics (Ostwald ripening) at 900 °C in Co-xNi-7Al-4Ti-3Mo-2W-1Nb-1Ta (x = 10 and 30) interfacial free energies of 35.0 ± 18.6 mJ m−2 and 29.2 ± 15.5 mJ m−2 are calculated for mole fractions of Ni of 10% and 30%, respectively. This decrease in interfacial free energy with increasing Ni-concentration is attributed partially to both Mo-segregation at the γ-γ′ interface and a decrease in the lattice parameter misfit between the γ′-precipitate and γ-matrix, and concomitantly the misfit strain energy.

Original languageEnglish (US)
Pages (from-to)284-295
Number of pages12
JournalActa Materialia
Volume147
DOIs
StatePublished - Apr 1 2018

Fingerprint

Superalloys
Free energy
Precipitates
Ostwald ripening
Molybdenum
Coarsening
Strain energy
Chemical analysis
Temperature
Lattice constants
Volume fraction
Substitution reactions
Atoms
Kinetics

Keywords

  • Alloy development
  • Co-based
  • Microstructural evolution
  • Superalloy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

Cite this

@article{1378fbc1121e4f09aad7eac235b816ec,
title = "Multicomponent γ’-strengthened Co-based superalloys with increased solvus temperatures and reduced mass densities",
abstract = "Several Co-Al-(W)-based γ-(FCC)/γ’-(L12) alloys are investigated to combine recent results indicating significant increases in the γ′-solvus temperature with additions of Ni, Ta, and Ti, and reduced mass density with the substitution of Mo and Nb for W. A maximum solvus temperature of 1167 ± 6 °C is achieved for an alloy with the composition Co-30Ni-7Al-4Ti-7W-1Ta (mole fraction × 100); while the composition Co-30Ni-7Al-4Ti-3Mo-2W-1Nb-1Ta (L19) exhibits a promising combination of high γ′ volume fraction and solvus temperature, low mass density, and excellent two-phase γ-γ′microstructural stability. Atom probe tomographic measurement of L19 aged for 4 h at 900 °C indicates that Ni, Al, Ti, W, Nb, and Ta partition preferentially to the γ′-precipitates while Co partitions strongly to the γ-matrix. Molybdenum segregates at the γ/γ′ interface, resulting in a reduction in the interfacial free energy of 1.63 ± 0.85 mJ m−2. Decreasing the mole fraction of Ni from 30{\%} to 10{\%} decreases the partitioning of Al and Ti to the γ′-phase and increases partitioning of Co, Mo, W, Nb, and Ta to the γ′-phase. From an analysis of coarsening kinetics (Ostwald ripening) at 900 °C in Co-xNi-7Al-4Ti-3Mo-2W-1Nb-1Ta (x = 10 and 30) interfacial free energies of 35.0 ± 18.6 mJ m−2 and 29.2 ± 15.5 mJ m−2 are calculated for mole fractions of Ni of 10{\%} and 30{\%}, respectively. This decrease in interfacial free energy with increasing Ni-concentration is attributed partially to both Mo-segregation at the γ-γ′ interface and a decrease in the lattice parameter misfit between the γ′-precipitate and γ-matrix, and concomitantly the misfit strain energy.",
keywords = "Alloy development, Co-based, Microstructural evolution, Superalloy",
author = "Lass, {Eric A.} and Sauza, {Daniel J.} and Dunand, {David C} and Seidman, {David N}",
year = "2018",
month = "4",
day = "1",
doi = "10.1016/j.actamat.2018.01.034",
language = "English (US)",
volume = "147",
pages = "284--295",
journal = "Acta Materialia",
issn = "1359-6454",
publisher = "Elsevier Limited",

}

Multicomponent γ’-strengthened Co-based superalloys with increased solvus temperatures and reduced mass densities. / Lass, Eric A.; Sauza, Daniel J.; Dunand, David C; Seidman, David N.

In: Acta Materialia, Vol. 147, 01.04.2018, p. 284-295.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Multicomponent γ’-strengthened Co-based superalloys with increased solvus temperatures and reduced mass densities

AU - Lass, Eric A.

AU - Sauza, Daniel J.

AU - Dunand, David C

AU - Seidman, David N

PY - 2018/4/1

Y1 - 2018/4/1

N2 - Several Co-Al-(W)-based γ-(FCC)/γ’-(L12) alloys are investigated to combine recent results indicating significant increases in the γ′-solvus temperature with additions of Ni, Ta, and Ti, and reduced mass density with the substitution of Mo and Nb for W. A maximum solvus temperature of 1167 ± 6 °C is achieved for an alloy with the composition Co-30Ni-7Al-4Ti-7W-1Ta (mole fraction × 100); while the composition Co-30Ni-7Al-4Ti-3Mo-2W-1Nb-1Ta (L19) exhibits a promising combination of high γ′ volume fraction and solvus temperature, low mass density, and excellent two-phase γ-γ′microstructural stability. Atom probe tomographic measurement of L19 aged for 4 h at 900 °C indicates that Ni, Al, Ti, W, Nb, and Ta partition preferentially to the γ′-precipitates while Co partitions strongly to the γ-matrix. Molybdenum segregates at the γ/γ′ interface, resulting in a reduction in the interfacial free energy of 1.63 ± 0.85 mJ m−2. Decreasing the mole fraction of Ni from 30% to 10% decreases the partitioning of Al and Ti to the γ′-phase and increases partitioning of Co, Mo, W, Nb, and Ta to the γ′-phase. From an analysis of coarsening kinetics (Ostwald ripening) at 900 °C in Co-xNi-7Al-4Ti-3Mo-2W-1Nb-1Ta (x = 10 and 30) interfacial free energies of 35.0 ± 18.6 mJ m−2 and 29.2 ± 15.5 mJ m−2 are calculated for mole fractions of Ni of 10% and 30%, respectively. This decrease in interfacial free energy with increasing Ni-concentration is attributed partially to both Mo-segregation at the γ-γ′ interface and a decrease in the lattice parameter misfit between the γ′-precipitate and γ-matrix, and concomitantly the misfit strain energy.

AB - Several Co-Al-(W)-based γ-(FCC)/γ’-(L12) alloys are investigated to combine recent results indicating significant increases in the γ′-solvus temperature with additions of Ni, Ta, and Ti, and reduced mass density with the substitution of Mo and Nb for W. A maximum solvus temperature of 1167 ± 6 °C is achieved for an alloy with the composition Co-30Ni-7Al-4Ti-7W-1Ta (mole fraction × 100); while the composition Co-30Ni-7Al-4Ti-3Mo-2W-1Nb-1Ta (L19) exhibits a promising combination of high γ′ volume fraction and solvus temperature, low mass density, and excellent two-phase γ-γ′microstructural stability. Atom probe tomographic measurement of L19 aged for 4 h at 900 °C indicates that Ni, Al, Ti, W, Nb, and Ta partition preferentially to the γ′-precipitates while Co partitions strongly to the γ-matrix. Molybdenum segregates at the γ/γ′ interface, resulting in a reduction in the interfacial free energy of 1.63 ± 0.85 mJ m−2. Decreasing the mole fraction of Ni from 30% to 10% decreases the partitioning of Al and Ti to the γ′-phase and increases partitioning of Co, Mo, W, Nb, and Ta to the γ′-phase. From an analysis of coarsening kinetics (Ostwald ripening) at 900 °C in Co-xNi-7Al-4Ti-3Mo-2W-1Nb-1Ta (x = 10 and 30) interfacial free energies of 35.0 ± 18.6 mJ m−2 and 29.2 ± 15.5 mJ m−2 are calculated for mole fractions of Ni of 10% and 30%, respectively. This decrease in interfacial free energy with increasing Ni-concentration is attributed partially to both Mo-segregation at the γ-γ′ interface and a decrease in the lattice parameter misfit between the γ′-precipitate and γ-matrix, and concomitantly the misfit strain energy.

KW - Alloy development

KW - Co-based

KW - Microstructural evolution

KW - Superalloy

UR - http://www.scopus.com/inward/record.url?scp=85041377329&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85041377329&partnerID=8YFLogxK

U2 - 10.1016/j.actamat.2018.01.034

DO - 10.1016/j.actamat.2018.01.034

M3 - Article

VL - 147

SP - 284

EP - 295

JO - Acta Materialia

JF - Acta Materialia

SN - 1359-6454

ER -