Investigation of equilibrium and phase stability in the liquid/solid state in nickel-based wrought superalloys

Rosen, G.I.; Dirnfeld, S. F.; Bamberger, Μ.; Prinz, B.

doi:10.1007/bf00356148

Cited by 7 publications

(5 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…13) It can be seen that the slope of the curves flatten out around 870 K and for CMSX 4 it reaches a maximum around 1 200 K which suggests that: (i) the coarsening of gЈ phase is accompanied by a decrease in R (in agreement with observations of Rosen et al 1) and (ii) the dissolution of the gЈ phase in the g matrix results in a decrease in resistivity which approaches that of the g matrix (e.g. Nimonic 901) around 1 550 K. The electrical resistivity-temperature curves for the various alloys were divided into three groups based on their Al contents, namely, (0-0.5 mass% Al), (3-4 mass% Al) and (5-5.8 mass% Al).…”

Section: Temperature Dependence Of Resistivitysupporting

confidence: 81%

“…Roebuck et al 13) found electrical resistivity data could be used to calculate the amount of gЈ phase formed in Ni-based superalloys. Rosen et al 1) followed the mechanisms for nucleation and coarsening of gЈ phase at 923 K using electrical resistivity measurements and found that the nucleation process was accompanied by an increase in resistivity and coarsening by a decrease in resistivity.…”

Section: Electrical Resistivity (R)mentioning

confidence: 99%

“…However, these dissolve in the g matrix at relatively low temperatures, 823 and 793 K, respectively. Rosen et al 1) pointed out that metal addition to Ni 3 Al is determined by the ionicity and bond order of the metal added and this is particularly favourable for 5 d metals like Ta. They also reported that Ta is more efficient than Ti in the nucleation of the gЈ phase.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Effect of Aluminium Content on Thermophysical Properties of Ni-based Superalloys

Mills

Youssef

2006

ISIJ Int.

View full text Add to dashboard Cite

Ni 3 Al is the principal component in the gЈ phase formed in Ni-based superalloys but Ni 3 Cr and Ni 3 Fe can also contribute to the gЈ phase at temperatures below 820 K. Approximate values for the gЈ phase content can be derived from a relationship based on (mass% Al). In a previous publication it was shown that the density in both the solid and liquid alloys was dependent upon the gЈ phase (or Al) contents in the alloy. Consequently, the effect of the gЈ phase on other thermophysical properties (C p , enthalpy, electrical resistivity, thermal conductivity and diffusivity) have been investigated. Linear relations were found between the property values around 300 K and the mass% Al. It was also found that property-temperature relationships were also affected by the gЈ phase (or Al) contents. Although it is known that the strong bonding between Ni and Al atoms affects the density of liquid alloys, we were unable to establish any such relationship for the other properties for liquid alloys because of the large experimental uncertainties in the measurements of these properties. This study has revealed that there is an urgent need for accurate values for C p , electrical resistivity, thermal diffusivity and conductivity for liquid, Ni-based superalloys.KEY WORDS: Ni-based superalloys; gЈ phase; heat capacity; enthalpy; electrical resistivity; thermal conductivity; thermal diffusivity. structural factors in the alloy when compared with other properties. Consequently, it would be expected that other properties may be affected by the gЈ phase content. In this paper we examine the effect of gЈ phase (via the Al content) on other thermophysical properties for solid and liquid Ni-based superalloys. Database and Treatment of DataThermophysical property data have been reported for a number of Ni-based superalloys; the chemical compositions for these alloys are given in Table 1.In this paper all temperatures are expressed as thermody- 3. Thermal Expansion Coefficient (a a ) and Density (r r )The density and the linear thermal expansion coefficient (a) were found to be functions of the gЈ phase content (or Al content).3) The difference in density, Dr 296 ϭr 298 meas Ϫ r 298 ideal , was found to increase with increasing gЈ phase and/or Al contents, (Eqs. (4) and (5), respectively). The thermal expansion coefficients for solid alloys were found to decrease with increasing gЈ phase or Al content as can be seen from Fig. 2. Thermal expansion data were collated and divided into three groups based on the Al content, namely, (0-0.5 mass%), (3-4 mass%) and (5-5.8 mass%). Vol. 46 (2006) The mean values for each group were determined and are shown in Fig. 2. It can also be seen from this figure that the slope of all three curves flatten around 870 K and that the coarsening and dissolution of the gЈ phase is accompanied by an increase in slope for the alloys with high gЈ content (CMSX 4 and Rene 80). Heat Capacity (C p ) and Enthalpy (H T ؊H 298 )The enthalpy and C p are not particularly sensitive to structure and consequently, Kopp's...

show abstract

Section: Temperature Dependence Of Resistivitysupporting

confidence: 81%

Section: Electrical Resistivity (R)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Effect of Aluminium Content on Thermophysical Properties of Ni-based Superalloys

Mills

Youssef

2006

ISIJ Int.

View full text Add to dashboard Cite

show abstract

“…It should be noted, however, that the microstructural characterizations in the current work have been conducted with a field emission gun-scanning electron microscope (FEG-SEM); thus, all the microstructural observations have been obtained within the limits of the FEG-SEM with 2-nm resolution. Additionally, research conducted by Rosen et al [28] provides concrete support of this idea. They have used a four-point probe arrangement to determine resistivity changes during aging of an already solution-treated, c¢ precipitate forming alloy.…”

Section: A Solution Treatmentsmentioning

confidence: 80%

Multimodal Precipitation in the Superalloy IN738LC

Balikci

Erdeniz

2010

Metall Mater Trans A

View full text Add to dashboard Cite

ERCAN BALIKCI and DINC ERDENIZIN738LC is a polycrystalline, nickel-base superalloy, which is used in aggressive environments at high temperatures. The required strength is provided by precipitate strengthening. Both unimodal and multimodal precipitate distributions are observed in IN738LC. After reaching a critical size, a unimodal precipitate microstructure transforms to a bimodal one. This transformation is controlled by the precipitate-matrix interface, which is under compression in IN738LC. As the unimodal precipitates grow, the strained interface, due to differential lattice parameter of the matrix and the precipitate phase, stops solute diffusion into the growing precipitates. Hence, the solute atoms, entrapped in the matrix, saturate the matrix and form new, fine precipitates. Dissolution of some large precipitates also supplies solute to supersaturate the matrix. On the other hand, a multimodal precipitate distribution tends to become unimodal at low aging temperatures and bimodal at high aging temperatures. Interestingly, the activation energy is calculated for the coarsening of large precipitates in multimodal distribution and is found to vary with aging time.

show abstract

“…The second phase was formed by the γ solid solution based on nickel. It possessed the FCC lattice and short range atomic order [4,5].…”

Section: Results Of Investigationmentioning

confidence: 99%

Influence of the High-Temperature Creep on the Phase Composition and Morphology of the γ' Phase of a Nickel Alloy

et al. 2015

View full text Add to dashboard Cite

Results of electron microscopic study of Ni-Cr-Al based superalloy are presented. The superalloy prepared by the method of directed crystallization is investigated in the initial state and after creep for 10 h at Т = 1100°С and σ = 100 MPa. It is established that the alloy in both states is formed by γ and γ′ phases based on the FCC crystal lattice; the γ′ phase has ordered arrangement of atoms (the L1 2 superstructure) and is the main phase in all states. The phase composition and morphology are studied. The change in the phase composition and particle sizes of phases as a result of creep is analyzed. The influence of the high-temperature creep on the superalloy structure is established.

show abstract

Investigation of equilibrium and phase stability in the liquid/solid state in nickel-based wrought superalloys

Cited by 7 publications

References 8 publications

The Effect of Aluminium Content on Thermophysical Properties of Ni-based Superalloys

The Effect of Aluminium Content on Thermophysical Properties of Ni-based Superalloys

Multimodal Precipitation in the Superalloy IN738LC

Influence of the High-Temperature Creep on the Phase Composition and Morphology of the γ' Phase of a Nickel Alloy

Contact Info

Product

Resources

About