scholarly journals Numerical Investigation into the Influence of Grain Orientation Distribution on the Local and Global Elastic-Plastic Behaviour of Polycrystalline Nickel-Based Superalloy INC-738 LC

Crystals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 100
Author(s):  
Benedikt Engel ◽  
Mark Huth ◽  
Christopher Hyde
Keyword(s):  
Orientation Distribution ◽  
Cooling Process ◽  
Polycrystalline Nickel ◽  
Source Codes ◽  
Plastic Behaviour ◽  
Nickel Based Superalloy ◽  
Young’S Moduli ◽  
Schmid Factor ◽  
Orientation Distributions ◽  
Elastic Strains

Polycrystalline nickel-based superalloys tend to have large grains within component areas where high loads are dominant during operation. Due to these large grains, caused by the manufacturing and cooling process, the orientation of each grain becomes highly important, since it influences the elastic and plastic behaviour of the material. With the usage of the open source codes NEPER and FEPX, polycrystalline models of Inconel 738 LC were generated and their elastic and crystal plasticity behaviour simulated in dependence of different orientation distributions under uniaxial loading. Orientation distributions close to the [100] direction showed the lowest Young’s moduli as well as the highest elastic strains before yielding, as expected. Orientations close to the [5¯89] direction, showed the lowest elastic strains and therefore first plastic deformation under strain loading due to the highest shear stress in the slip systems caused by the interaction of Young’s modulus and the Schmid factor.

scholarly journals Strain Amount Dependent Grain Size and Orientation Developments during Hot Compression of a Polycrystalline Nickel Based Superalloy

Materials ◽  
2017 ◽  
Vol 10 (2) ◽  
pp. 161 ◽  
Author(s):  
Guoai He ◽  
Liming Tan ◽  
Feng Liu ◽  
Lan Huang ◽  
Zaiwang Huang ◽  
...  
Keyword(s):  
Grain Size ◽  
Hot Compression ◽  
Polycrystalline Nickel ◽  
Nickel Based Superalloy ◽  
Grain Size And Orientation

Growth behavior of γ′ phase in a powder metallurgy nickel-based superalloy under interrupted cooling process

2018 ◽  
Vol 54 (3) ◽  
pp. 2680-2689 ◽  
Author(s):  
X. Fan ◽  
A. Zhang ◽  
Z. Guo ◽  
X. Wang ◽  
J. Yang ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Growth Behavior ◽  
Cooling Process ◽  
Nickel Based Superalloy

scholarly journals Creep rupture properties of bare and coated polycrystalline nickel-based superalloy Rene®80

2021 ◽  
pp. 36-36
Author(s):  
M.M. Barjesteh ◽  
S.M. Abbasi ◽  
K.Z. Madar ◽  
K. Shirvani
Keyword(s):  
Elevated Temperatures ◽  
Life Time ◽  
Creep Rupture ◽  
Polycrystalline Nickel ◽  
Creep Life ◽  
Nickel Based Superalloy ◽  
Platinum Aluminide ◽  
Rupture Properties ◽  
Low Activity ◽  
Rupture Behavior

Creep deformation is one of the life time limiting reasons for gas turbine parts that are subjected to stresses at elevated temperatures. In this study, creep rupture behavior of uncoated and platinum-aluminide coated Rene?80 has been determined at 760?C/657 MPa, 871?C/343 MPa and 982?C/190 Mpa in air. For this purpose, an initial layer of platinum with a thickness of 6?m was applied on the creep specimens. Subsequently, the aluminizing were formed in the conventional pack cementation method via the Low Temperature-High Activity (LTHA) and High Temperature-Low Activity (HTLA) processes. Results of creep-rupture tests showed a decrease in resistance to creep rupture of coated specimen, compared to the uncoated ones. The reductions in rupture lives in LTHA and HTLA methods at 760?C/657 MPa, 871?C/343 MPa and 982?C/190 MPa were almost (26% and 41.8%), (27.6% and 38.5%) and (22.4% and 40.3%), respectively as compared to the uncoated ones. However, the HTLA aluminizing method showed an intense reduction in creep life. Results of fractographic studies on coated and uncoated specimens indicated a combination of ductile and brittle failure mechanisms for all samples. Although, the base failure mode in substrate was grain boundary voids, cracks initiated from coating at 760?C/657MPa and 871?C/343. No cracking in the coating was observed at 982?C/190MPa.

scholarly journals Tools for Visualizing and Analyzing Fourier Space Sampling in Cryo-EM

2020 ◽  
Author(s):  
Philip R. Baldwin ◽  
Dmitry Lyumkis
Keyword(s):  
Graphical User Interface ◽  
Signal To Noise Ratio ◽  
Orientation Distribution ◽  
Geometrical Factor ◽  
Fourier Space ◽  
Complete Understanding ◽  
Spherical Surfaces ◽  
Compensation Factor ◽  
Spectral Signal ◽  
Orientation Distributions

AbstractA complete understanding of how an orientation distribution contributes to a cryo-EM reconstruction remains lacking. It is necessary to begin critically assessing the set of views to gain an understanding of its effect on experimental reconstructions. Toward that end, we recently suggested that the type of orientation distribution may alter resolution measures in a systematic manner. We introduced the sampling compensation factor (SCF), which incorporates how the collection geometry might change the spectral signal-to-noise ratio (SSNR), irrespective of the other experimental aspects. We show here that knowledge of the sampling restricted to spherical surfaces of sufficiently large radii in Fourier space is equivalent to knowledge of the set of projection views. Moreover, the SCF geometrical factor may be calculated from one such surface. To aid cryo-EM researchers, we developed a graphical user interface (GUI) tool that evaluates experimental orientation distributions. The GUI returns plots of projection directions, sampling constrained to the surface of a sphere, the SCF value, the fraction of the empty region of Fourier space, and a histogram of the sampling values over the points on a sphere. Finally, a fixed tilt angle may be incorporated to determine how tilting the grid during collection may improve the distribution of views and Fourier space sampling. We advocate this simple conception of sampling and the use of such tools as a complement to the distribution of views to capture the different aspects of the effect of projection directions on cryo-EM reconstructions.

scholarly journals The effect of manganese and silicon additions on the corrosion resistance of a polycrystalline nickel-based superalloy

2020 ◽  
Vol 176 ◽  
pp. 109042
Author(s):  
E. Anzini ◽  
N. Glaenzer ◽  
P.M. Mignanelli ◽  
M.C. Hardy ◽  
H.J. Stone ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Polycrystalline Nickel ◽  
Nickel Based Superalloy

Interaction of Creep and High Cycle Fatigue of IN 713LC Superalloy

2016 ◽  
Vol 258 ◽  
pp. 595-598 ◽  
Author(s):  
Vít Horník ◽  
Miroslav Šmíd ◽  
Pavel Hutař ◽  
Ludvík Kunz ◽  
Karel Hrbáček
Keyword(s):  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Preliminary Evaluation ◽  
Cycle Fatigue ◽  
Polycrystalline Nickel ◽  
Nickel Based Superalloy ◽  
Wide Range ◽  
The Mean ◽  
Mean Stresses ◽  
Superimposed Vibrations

The study deals with the interaction of creep and high cycle fatigue of cast polycrystalline nickel-based superalloy IN 713LC at high temperatures. Previous works indicated that creep lifetime of superalloy structures was un-affected or even slightly increased in the cases with superimposed vibrations. The reason for this behaviour was not well described up to now. Therefore, set of fatigue tests was conducted at high mean stresses level to observe this phenomenon. The mean stress was kept constant while the stress amplitudes were selected in order to measure wide range of conditions from pure creep to pure fatigue. Fractographic analysis by scanning electron microscopy (SEM) was done with the aim to identify governing damage mechanisms for particular test conditions as a preliminary evaluation of conducted tests.

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