Predicting Coherency Loss of $$ \gamma^{\prime\prime} $$ γ ″ Precipitates in IN718 Superalloy

2016 ◽  
Vol 47 (6) ◽  
pp. 3235-3247 ◽  
Author(s):  
Yanzhou Ji ◽  
Yucun Lou ◽  
Meng Qu ◽  
John David Rowatt ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Gamma Prime ◽  
In718 Superalloy ◽  
Coherency Loss

Coherency loss in γ' precipitates in nickel-base superalloy

1983 ◽  
Vol 41 ◽  
pp. 244-245
Author(s):  
R. A. Ricks ◽  
Angus J. Porter
Keyword(s):  
Lattice Mismatch ◽  
Lattice Parameter ◽  
Nickel Base Superalloy ◽  
Large Size ◽  
The Matrix ◽  
Nimonic 80A ◽  
Interfacial Dislocations ◽  
Nickel Base ◽  
Coherency Loss ◽  
Nimonic 115

During a recent investigation concerning the growth of γ' precipitates in nickel-base superalloys it was observed that the sign of the lattice mismatch between the coherent particles and the matrix (γ) was important in determining the ease with which matrix dislocations could be incorporated into the interface to relieve coherency strains. Thus alloys with a negative misfit (ie. the γ' lattice parameter was smaller than the matrix) could lose coherency easily and γ/γ' interfaces would exhibit regularly spaced networks of dislocations, as shown in figure 1 for the case of Nimonic 115 (misfit = -0.15%). In contrast, γ' particles in alloys with a positive misfit could grow to a large size and not show any such dislocation arrangements in the interface, thus indicating that coherency had not been lost. Figure 2 depicts a large γ' precipitate in Nimonic 80A (misfit = +0.32%) showing few interfacial dislocations.

Effect of rhenium and cobalt additions on the microstructure and gamma prime phase stability of vacuum arc melted modified nickel-based superalloys grade MGA 1400

2019 ◽  
Vol 61 (7) ◽  
pp. 609-617 ◽  
Author(s):  
Arpaporn Nararak ◽  
Panyawat Wangyao ◽  
Tanaporn Rojhirunsakool ◽  
Gobboon Lothongkum
Keyword(s):  
Phase Stability ◽  
Vacuum Arc ◽  
Gamma Prime ◽  
Prime Phase

INCONEL ALLOY 718SPF

Alloy Digest ◽  
1994 ◽  
Vol 43 (11) ◽  
Keyword(s):  
Base Alloy ◽  
Low Flow ◽  
Inconel Alloy ◽  
Gamma Prime ◽  
Size Stability ◽  
Super Plastic ◽  
Plastic Forming ◽  
Super Plastic Forming ◽  
Grain Size Stability ◽  
Prime Phase

Abstract INCONEL alloy 718SPF is an age-hardenable austenitic material whose strength is largely dependent on the precipitation of a gamma prime phase following heat treatment. The base alloy, however, possesses two-essential characteristics for super-plastic forming; grain size stability over time and temperature; and a combination of low flow stress and significant ductility. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, and tensile properties as well as creep and fatigue. It also includes information on low and high temperature performance. Filing Code: Ni-471. Producer or source: Inco Alloys International Inc.

scholarly journals Phase-field model of precipitation processes with coherency loss

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Tian-Le Cheng ◽  
You-Hai Wen
Keyword(s):  
Phase Field ◽  
Field Model ◽  
Ostwald Ripening ◽  
Phase Field Model ◽  
Energy Criterion ◽  
Field Variable ◽  
Ginzburg Landau ◽  
Underlying Mechanisms ◽  
Flood Fill ◽  
Coherency Loss

AbstractA phase-field model is proposed to simulate coherency loss coupled with microstructure evolution. A special field variable is employed to describe the degree of coherency loss of each particle and its evolution is governed by a Ginzburg-Landau type kinetic equation. For the sake of computational efficiency, a flood-fill algorithm is introduced that can drastically reduce the required number of field variables, which allows the model to efficiently simulate a large number of particles sufficient for characterizing their statistical features during Ostwald ripening. The model can incorporate size dependence of coherency loss, metastability of coherent particles, and effectively incorporate the underlying mechanisms of coherency loss by introducing a so-called differential energy criterion. The model is applied to simulate coarsening of Al3Sc precipitates in aluminum alloy and comprehensively compared with experiments. Our results clearly show how the particle size distribution is changed during coherency loss and affects the coarsening rate.

scholarly journals Microstructural Development and Coarsening Behavior of γ′ Precipitates in Co–Ni–Al–W-Base ODS Alloys

2012 ◽  
Vol 53 (11) ◽  
pp. 1922-1928 ◽  
Author(s):  
Lin Zhang ◽  
Xuanhui Qu ◽  
Mingli Qin ◽  
Rafi-ud-din ◽  
Xinbo He ◽  
...  
Keyword(s):  
Microstructural Development ◽  
Gamma Prime ◽  
Coarsening Behavior ◽  
Ods Alloys

scholarly journals Morphology of γ″ Precipitates in Ni-18Cr-16Fe-5Nb-3Mo Alloy

1994 ◽  
Vol 80 (4) ◽  
pp. 348-352 ◽  
Author(s):  
Kiyoshi KUSABIRAKI ◽  
Itaru HAYAKAWA ◽  
Shuuichi IKEUCHI ◽  
Takayuki OOKA
Keyword(s):  
Gamma Prime

Detection of Compositional Fluctuations in High Temperature Exposed Waspaloy

2001 ◽  
Vol 699 ◽  
Author(s):  
Xiaodong Zou ◽  
Tariq Makram ◽  
Rosario A. Gerhardt
Keyword(s):  
Exposure Time ◽  
Structural Integrity ◽  
Thermal Exposure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gamma Prime ◽  
Distribution Shape ◽  
The Matrix ◽  
Quantitative Stereology ◽  
Nickel Base

AbstractWaspaloy is a nickel base super-alloy used in aircraft engines. When this alloy is placed in service, it is subjected to long term exposure at high temperatures, which can cause the reinforcing gamma prime precipitate population to fluctuate and thus affect its structural integrity. The population fluctuates as a result of coarsening, dissolution or re-precipitation. Samples exposed to 1200° F for times ranging from 0 to 12626 hours were characterized using impedance spectroscopy, microhardness measurements, x-ray diffraction and quantitative stereology. Two important parameters were derived from the impedance measurements: (1) the imaginary admittance peak magnitude (Ymax) and (2) the associated relaxation frequency (fmax). As the distribution, shape and size of the precipitates change with exposure time, these parameters were also found to vary. In addition to the changes in precipitate geometry, lattice constant changes detected by analyzing x-ray diffraction data suggest that there are compositional shifts in the matrix as well as the gamma prime precipitates. Furthermore, the preferred orientation of the precipitates can also be seen to change with exposure time. These changes in composition, size and shape as a function of thermal exposure time are accompanied by changes in the volume fractions of primary and secondary gamma prime particles present. Using effective medium models, it is possible to predict that the measured properties are related to the gamma prime population. The grain boundary carbides do not appear to play any role at the conditions presented.

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