The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform
T. Mori - One of the best experts on this subject based on the ideXlab platform.
-
Plastic strain-induced rafting of Gamma Prime precipitates in Ni superalloys: Elasticity analysis
Acta Materialia, 2006Co-Authors: Nicolas Ratel-ramond, G. Bruno, P. Bastie, T. MoriAbstract:Rafting in Ni-based superalloys is investigated by examining the dependence of elastic energy on the shape and orientation of Gamma Prime particles. The precipitation misfit strain and the plastic strain occurring in the matrix are taken into account. The elastic energies associated with spherical or disc-shaped particles with different orientations are evaluated for some combinations of transformation strain and matrix plastic strain. The anisotropy in elastic constants as well as the difference in elastic constant between the particles and matrix are taken into account. It is found that the elastic energy becomes minimum when Gamma Prime particles adopt a certain shape and direction with respect to the elongation axis [001]. These results are in agreement with the rafted morphologies observed in crept superalloys. The onset of the shearing of rafted Gamma Prime particles, leading to accelerated creep of the alloy, is also discussed by examining the stress state of rafted Gamma Prime particles particles.
D. Gonzalez - One of the best experts on this subject based on the ideXlab platform.
-
Particle Size of Gamma Prime as a Result of Vacuum Heat Treatment of INCONEL 738 Super Alloy
Journal of Materials Engineering and Performance, 2012Co-Authors: I. Guzmán, J. Acevedo, R. Méndez, E. Granda, G. Lopez, D. GonzalezAbstract:In this paper, the influence of the cooling rate and cooling media after a standard solution heat treatment on the size and distribution of the Gamma Prime phase (γ′) in the nickel-based super alloy INCONEL 738 in over-aged conditions is described. The volume fraction of the Gamma Prime depends on the chemical composition of the alloy, the solution treatment temperature and the cooling rate; in over-aged alloys (i.e., with more than 25,000 h of service) the volume fraction of γ′ is about 78.8%. However, it has been demonstrated that in order to maintain excellent creep strength a volume fraction of at least 60% or lower is required. In this work the volume fraction was optimized between 40 and 55% by means of a standard solution heat treatment at 1120 °C using different cooling gases. A γ′ volume fraction of 54.8% was obtained by using argon as the cooling medium at a cooling rate of 87 °C/min, producing a precipitate of partial distribution of primary and secondary γ′. Better results were obtained in a nitrogen atmosphere at a cooling rate of 287 °C/min, leading to a volume fraction of 40% and obtaining a total re-precipitation of primary and secondary γ′.
I. Guzmán - One of the best experts on this subject based on the ideXlab platform.
-
Particle Size of Gamma Prime as a Result of Vacuum Heat Treatment of INCONEL 738 Super Alloy
Journal of Materials Engineering and Performance, 2012Co-Authors: I. Guzmán, J. Acevedo, R. Méndez, E. Granda, G. Lopez, D. GonzalezAbstract:In this paper, the influence of the cooling rate and cooling media after a standard solution heat treatment on the size and distribution of the Gamma Prime phase (γ′) in the nickel-based super alloy INCONEL 738 in over-aged conditions is described. The volume fraction of the Gamma Prime depends on the chemical composition of the alloy, the solution treatment temperature and the cooling rate; in over-aged alloys (i.e., with more than 25,000 h of service) the volume fraction of γ′ is about 78.8%. However, it has been demonstrated that in order to maintain excellent creep strength a volume fraction of at least 60% or lower is required. In this work the volume fraction was optimized between 40 and 55% by means of a standard solution heat treatment at 1120 °C using different cooling gases. A γ′ volume fraction of 54.8% was obtained by using argon as the cooling medium at a cooling rate of 87 °C/min, producing a precipitate of partial distribution of primary and secondary γ′. Better results were obtained in a nitrogen atmosphere at a cooling rate of 287 °C/min, leading to a volume fraction of 40% and obtaining a total re-precipitation of primary and secondary γ′.
-
Effect of Heat Treatment Solution on the Size and Distribution of Gamma Prime (γ′) of Super-alloy INCONEL 738
MRS Online Proceedings Library, 2011Co-Authors: I. Guzmán, A. Garza, F. Garcia, J. Acevedo, R. MéndezAbstract:Nickel base superalloys, which are Gamma Prime γ′(Ni_3Al, Ti) precipitation strengthened, is largely responsible for the elevated-temperature strength of the material and the higher resistance to creep deformation. The amount of γ′ depends on the chemical composition and temperature, heat treatment, these alloy are widely used in hot sections of aero-engines, land based turbines, stator parts, nozzle guide vanes, blades and integral wheels, due to its excellent elevated temperature strength and hot corrosion resistance. The γ′ size decreases not only by the high temperature of heat treatment solution (1120 °C), the cooling environment and cooling rate are important parameter to decrease γ′ size to 0.65 μm. This paper presents the effect of heat treatment solution in base nickel IN 738 superalloy under service conditions, on the size and morphology of the Gamma phase γ′ Ni_3 (AI, Ti), main phase in the nickel base superalloys. Also shown coarse carbide and precipitates Gamma Prime size distributed and improve interdentritic spacing in the matrix after heat treatment solution.
R. Méndez - One of the best experts on this subject based on the ideXlab platform.
-
Particle Size of Gamma Prime as a Result of Vacuum Heat Treatment of INCONEL 738 Super Alloy
Journal of Materials Engineering and Performance, 2012Co-Authors: I. Guzmán, J. Acevedo, R. Méndez, E. Granda, G. Lopez, D. GonzalezAbstract:In this paper, the influence of the cooling rate and cooling media after a standard solution heat treatment on the size and distribution of the Gamma Prime phase (γ′) in the nickel-based super alloy INCONEL 738 in over-aged conditions is described. The volume fraction of the Gamma Prime depends on the chemical composition of the alloy, the solution treatment temperature and the cooling rate; in over-aged alloys (i.e., with more than 25,000 h of service) the volume fraction of γ′ is about 78.8%. However, it has been demonstrated that in order to maintain excellent creep strength a volume fraction of at least 60% or lower is required. In this work the volume fraction was optimized between 40 and 55% by means of a standard solution heat treatment at 1120 °C using different cooling gases. A γ′ volume fraction of 54.8% was obtained by using argon as the cooling medium at a cooling rate of 87 °C/min, producing a precipitate of partial distribution of primary and secondary γ′. Better results were obtained in a nitrogen atmosphere at a cooling rate of 287 °C/min, leading to a volume fraction of 40% and obtaining a total re-precipitation of primary and secondary γ′.
-
Effect of Heat Treatment Solution on the Size and Distribution of Gamma Prime (γ′) of Super-alloy INCONEL 738
MRS Online Proceedings Library, 2011Co-Authors: I. Guzmán, A. Garza, F. Garcia, J. Acevedo, R. MéndezAbstract:Nickel base superalloys, which are Gamma Prime γ′(Ni_3Al, Ti) precipitation strengthened, is largely responsible for the elevated-temperature strength of the material and the higher resistance to creep deformation. The amount of γ′ depends on the chemical composition and temperature, heat treatment, these alloy are widely used in hot sections of aero-engines, land based turbines, stator parts, nozzle guide vanes, blades and integral wheels, due to its excellent elevated temperature strength and hot corrosion resistance. The γ′ size decreases not only by the high temperature of heat treatment solution (1120 °C), the cooling environment and cooling rate are important parameter to decrease γ′ size to 0.65 μm. This paper presents the effect of heat treatment solution in base nickel IN 738 superalloy under service conditions, on the size and morphology of the Gamma phase γ′ Ni_3 (AI, Ti), main phase in the nickel base superalloys. Also shown coarse carbide and precipitates Gamma Prime size distributed and improve interdentritic spacing in the matrix after heat treatment solution.
Nicolas Ratel-ramond - One of the best experts on this subject based on the ideXlab platform.
-
Plastic strain-induced rafting of Gamma Prime precipitates in Ni superalloys: Elasticity analysis
Acta Materialia, 2006Co-Authors: Nicolas Ratel-ramond, G. Bruno, P. Bastie, T. MoriAbstract:Rafting in Ni-based superalloys is investigated by examining the dependence of elastic energy on the shape and orientation of Gamma Prime particles. The precipitation misfit strain and the plastic strain occurring in the matrix are taken into account. The elastic energies associated with spherical or disc-shaped particles with different orientations are evaluated for some combinations of transformation strain and matrix plastic strain. The anisotropy in elastic constants as well as the difference in elastic constant between the particles and matrix are taken into account. It is found that the elastic energy becomes minimum when Gamma Prime particles adopt a certain shape and direction with respect to the elongation axis [001]. These results are in agreement with the rafted morphologies observed in crept superalloys. The onset of the shearing of rafted Gamma Prime particles, leading to accelerated creep of the alloy, is also discussed by examining the stress state of rafted Gamma Prime particles particles.
