skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Formation of β-NiAl Phase During Casting of a Ni-Based Superalloy

Publication Date:
Research Org.:
National Energy Technology Lab. (NETL), Pittsburgh, PA, and Morgantown, WV (United States). In-house Research
Sponsoring Org.:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1073-5615; PII: 1202
Resource Type:
Journal Article
Resource Relation:
Journal Name: Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science; Journal Volume: 49; Journal Issue: 2
Country of Publication:
United States
36 MATERIALS SCIENCE; Ni-based superalloy, casting, phase formation

Citation Formats

Detrois, Martin, and Jablonski, Paul D. Formation of β-NiAl Phase During Casting of a Ni-Based Superalloy. United States: N. p., 2018. Web. doi:10.1007/s11663-018-1202-2.
Detrois, Martin, & Jablonski, Paul D. Formation of β-NiAl Phase During Casting of a Ni-Based Superalloy. United States. doi:10.1007/s11663-018-1202-2.
Detrois, Martin, and Jablonski, Paul D. 2018. "Formation of β-NiAl Phase During Casting of a Ni-Based Superalloy". United States. doi:10.1007/s11663-018-1202-2.
title = {Formation of β-NiAl Phase During Casting of a Ni-Based Superalloy},
author = {Detrois, Martin and Jablonski, Paul D.},
abstractNote = {},
doi = {10.1007/s11663-018-1202-2},
journal = {Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science},
number = 2,
volume = 49,
place = {United States},
year = 2018,
month = 2
  • The cutting of {gamma}{prime}-particles by dislocations during shear creep deformation of CMSX 6 superalloy single crystals loaded on the macroscopic crystallographic shear system {l_angle}110{r_angle}{l_brace}111{r_brace} at T = 1,025 C and {tau} = 85 MPa is analyzed using transmission electron microscopy (TEM). The formation of a {l_angle}010{r_angle}-dislocation in the {gamma}{prime}-phase was observed and investigated by means of stereo microscopy, line trace and g{center_dot}b-analysis. Two {gamma}-matrix channel dislocations with different Burgers vectors (b) of type a{sub 0}/2<110> jointly shear the {gamma}{prime}-particle where they form a superdislocation with a total Burgers vector of a{sub 0}{l_angle}010{r_angle}. The present paper provides microstructural evidence for thismore » high temperature cutting process. The results are discussed in relation to the evolution of the dislocation structure in the {gamma}-channels during primary creep. Peach-Koehler forces were calculated to explain the formation of the {l_angle}010{r_angle}-dislocation.« less
  • The low-cycle fatigue behavior of a cobalt-based superalloy was studied in situ using neutron-diffraction experiments. The alloy exhibited stress-induced formation of a hexagonal-close-packed (hcp) phase within its parent face-centered-cubic (fcc) phase at ambient temperature under strain-controlled fatigue conditions with a total strain range, {Delta}{var_epsilon} = 2.5%. The (101) hcp peak was first observed during the 12th fatigue cycle under the given conditions following a period during which no hcp phase was detected. Subsequently, the intensity of the hcp peaks increased as fatigue progressed. Furthermore, within a single fatigue cycle, the intensity of the (101) hcp peak decreased during the compressionmore » half-cycle and increased again when the specimen was subjected to a subsequent tensile strain. The result suggests that the fcc to hcp transformation is partially reversible within one fatigue cycle.« less
  • The mechanism by which iron causes casting defects in the AA309 (Al-5 pct Si-1.2 pct Cu-0.5 pct Mg) may be related to the solidification sequence of the alloy. Superimposing calculated segregation lines on the liquidus projection of the ternary Al-Si-Fe phase diagram suggests that porosity is minimized at a critical iron content when solidification proceeds directly from the primary field to the ternary Al-Si-{beta}Al{sub 5}FeSi eutectic point. Solidification via the binary Al-{beta}Al{sub 5}FeSi eutectic is detrimental to casting integrity. This hypothesis was tested by comparing the critical iron content observed in the standard AA309 alloy to that of a high-siliconmore » (10 pct Si) variant of this alloy.« less
  • Oxidation of a NiAl(111) single crystal surface was investigated using high resolution soft X-ray photoelectron spectroscopy (HRSXPS), high resolution scanning electron microscopy (HRSEM), energy dispersive X-ray spectroscopy (EDS), X-ray mapping, and atomic force microscopy (AFM). After repeated oxygen exposure, annealing, and cleaning cycles under ultrahigh vacuum conditions, a new oxide phase in the form of tiny 3-dimensional surface structures was detected. These features are several micrometers long and {approx}300 nm high and oriented along low index {l_angle}{bar 1}01{r_angle} directions in the plane of the substrate; they have nickel aluminate spinel (NiAl{sub 2}O{sub 4}) stoichiometry. We propose that repeated cycles ofmore » oxygen dosing and annealing of the NiAl(111) surface leads to oxygen diffusion into the bulk and nucleation of spinel below the surface.« less