scholarly journals Study on the Solidification Behavior of Inconel617 Electron Beam Cladding NiCoCrAlY: Numerical and Experimental Simulation

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 58
Author(s):  
Jian Chen ◽  
Hailang Liu ◽  
Zhiguo Peng ◽  
Jie Tang
Keyword(s):  
Electron Beam ◽  
Temperature Gradient ◽  
Cooling Rate ◽  
Molten Pool ◽  
Solidification Rate ◽  
Solidification Process ◽  
The Self ◽  
Cooling Effect ◽  
Tissue Structure ◽  
Solidification Behavior

To better control the Inconel617 electron beam cladding solidification process, a three-dimensional temperature field model was built to simulate the temperature gradient, cooling rate, and solidification rate in the solidification process and take a deep dive into the solidification behavior, as well as the calculation of the solidification characteristic parameters at the edge of the molten pool and then predict the solidification tissue structure. The study shows that the largest temperature gradient occurred in the material thickness direction. The self-cooling effect of the material dominated the solidification of the alloy layer; the cooling rate depended on the high-temperature thermal conductivity of the material and the self-cooling effect of the matrix, and the maximum cooling rate in the bonding zone was 1380 °C/s. The steady-state solidification rate was equal to the moving speed of the heat source; the solidification characteristics of the solidification process at the edge of the molten pool increased with the distance from the surface: the cooling rate decreased from 1421.61 to 623 °C/s, the temperature gradient increased from 0.0723 × 106 to 0.417 × 106, and the solidification rate decreased from 0.01 to 0 m/s. The prediction was made that the small and thin equiaxed crystals are on the top, a thin and short dendritic transition structure in the middle, and relatively coarse dendrites at the bottom. Experiments confirmed that the solidification tissue structure is basically consistent with the simulation law.

scholarly journals Numerical Simulation of Directional Solidification Process of Single Crystal Ni- Based Superalloy Casting

2017 ◽  
Vol 17 (2) ◽  
pp. 111-118 ◽  
Author(s):  
D. Szeliga ◽  
K. Kubiak ◽  
J. Sieniawski
Keyword(s):  
Temperature Gradient ◽  
Single Crystal ◽  
Cooling Rate ◽  
Solidification Rate ◽  
Solidification Process ◽  
Longitudinal Section ◽  
Withdrawal Rate ◽  
Bottom Part ◽  
Rate Maximum ◽  
Predicted Values

Abstract The analysis of influence of mould withdrawal rate on the solidification process of CMSX-4 single crystal castings produced by Bridgman method was presented in this paper. The predicted values of temperature gradient, solidification and cooling rate, were determined at the longitudinal section of casting blade withdrawn at rate from 1 to 6mm/min using ProCAST software. It was found that the increase of withdrawal rate of ceramic mould results in the decrease of temperature gradient and the growth of cooling rate, along blade height. Based on results of solidification parameter G/R (temperature gradient/solidification rate), maximum withdrawal rate of ceramic mould (3.5 mm/min), which ensures lower susceptibility to formation process of new grain defects in single crystal, was established. It was proved that these defects can be formed in the bottom part of casting at withdrawal rate of 4 mm/min. The increase of withdrawal rate to 5 and 6 mm/min results in additional growth of susceptibility of defects formation along the whole height of airfoil.

Microstructures in Solidification Simulation of Electron Beam Scanning with MC in Molten Pool

2014 ◽  
Vol 898 ◽  
pp. 168-172 ◽  
Author(s):  
Rong Wang ◽  
Yi Liu ◽  
De Qiang Wei
Keyword(s):  
Mathematical Model ◽  
Temperature Field ◽  
Electron Beam ◽  
Grain Growth ◽  
Molten Pool ◽  
Growth Process ◽  
Solidification Process ◽  
Optical Microscope ◽  
Physical Parameters ◽  
Beam Scanning

The solidification microstructure of electron beam scanning is important to product performance. The solidification process of molten pool temperature field and 2D simulation mathematical model of grain growth was established based on heat transfer and the physics of growth process of crystal grains. The heat distribution, thermal physical parameters and influence of thermal radiation on the temperature field was considered during the analysis process. The distribution of temperature field was solved by COMSOL. The process of solidification was simulated by using Monte Carlo method. Using optical microscope to observe the solidified microstructure of bath. The simulation results show that the mathematical model can reasonably describe the grain growth process, the temperature field and the simulation of microstructure morphology.

Effect of Cooling Rate on Boron Removal and Solidification Behavior of Al-Si Alloy

2015 ◽  
Vol 34 (1) ◽  
Author(s):  
Yanlei Li ◽  
Jian Chen ◽  
Boyuan Ban ◽  
Taotao Zhang ◽  
Songyuan Dai
Keyword(s):  
Cooling Rate ◽  
Removal Rate ◽  
Solidification Process ◽  
Alloy System ◽  
Primary Silicon ◽  
Boron Removal ◽  
Segregation Coefficient ◽  
Solidification Behavior ◽  
Solidification Temperature ◽  
Average Width

AbstractThe effect of cooling rate on boron removal and solidification behavior of Al-Si alloy with different silicon contents were studied during solar grade silicon purification. It is found that the boron removal rate is controlled by kinetic factor. A method is proposed to calculate apparent segregation coefficient of solidification process that spans over a temperature range. This apparent segregation coefficient is used to evaluate purification effect in alloy system with changing segregation coefficients. When average solidification temperature decreases, the apparent segregation coefficient of boron decreases. The average width and mass of primary silicon flakes decrease with increasing cooling rate. Impurity elements form intermetallic compound phases such as α-Al

Effect of Ta on the Solidification Behavior of Ni3Al-Base Single-Crystal Superalloys

2014 ◽  
Vol 788 ◽  
pp. 426-432 ◽  
Author(s):  
Tian Tian Zheng ◽  
Shu Suo Li ◽  
Yan Ling Pei ◽  
Cheng Ai ◽  
Sheng Kai Gong
Keyword(s):  
Differential Scanning Calorimetry ◽  
Single Crystal ◽  
Early Stage ◽  
Solidification Rate ◽  
Solidification Process ◽  
Primary Phase ◽  
Isothermal Quenching ◽  
Solidification Behavior ◽  
Scanning Calorimetry

Two kinds of Ni3Al-base SC superalloys, including IC31A (3wt.%Ta) and IC31B (6wt.%Ta) were investigated in the present study by using the differential scanning calorimetry (DSC) and isothermal quenching technology. The results showed that the larger amount of blocky γ′ phases existed in IC31B than that in IC31A. In the solidification process, the primary phase in IC31B was γ′ phases while in alloy IC31A the primary phase was γ phases. Besides, the solidification rate of IC31B in the early stage was lower than that in IC31A.

Voids in Quenched Nickel

1968 ◽  
Vol 26 ◽  
pp. 266-267
Author(s):  
J. J. Laidler
Keyword(s):  
Electron Beam ◽  
Ambient Temperature ◽  
Cooling Rate ◽  
Three Dimensional ◽  
Cooling Curve ◽  
Polycrystalline Nickel ◽  
Quenching Temperature ◽  
Long Tail ◽  
Diffusion Pump

The presence of three-dimensional voids in quenched metals has long been suspected, and voids have indeed been observed directly in a number of metals. These include aluminum, platinum, and copper, silver and gold. Attempts at the production of observable quenched-in defects in nickel have been generally unsuccessful, so the present work was initiated in order to establish the conditions under which such defects may be formed.Electron beam zone-melted polycrystalline nickel foils, 99.997% pure, were quenched from 1420°C in an evacuated chamber into a bath containing a silicone diffusion pump fluid . The pressure in the chamber at the quenching temperature was less than 10-5 Torr . With an oil quench such as this, the cooling rate is approximately 5,000°C/second above 400°C; below 400°C, the cooling curve has a long tail. Therefore, the quenched specimens are aged in place for several seconds at a temperature which continuously approaches the ambient temperature of the system.

Nanoscale Self-Assembly Using Ion and Electron Beam Techniques: A Rapid Review

MRS Advances ◽  
2020 ◽  
Vol 5 (64) ◽  
pp. 3507-3520
Author(s):  
Chunhui Dai ◽  
Kriti Agarwal ◽  
Jeong-Hyun Cho
Keyword(s):  
Electron Beam ◽  
Self Assembly ◽  
Ion Beam ◽  
Three Dimensional ◽  
The Self ◽  
Stress Generation ◽  
Rapid Review ◽  
High Yield ◽  
3D Nanostructures ◽  
Self Assembled

AbstractNanoscale self-assembly, as a technique to transform two-dimensional (2D) planar patterns into three-dimensional (3D) nanoscale architectures, has achieved tremendous success in the past decade. However, an assembly process at nanoscale is easily affected by small unavoidable variations in sample conditions and reaction environment, resulting in a low yield. Recently, in-situ monitored self-assembly based on ion and electron irradiation has stood out as a promising candidate to overcome this limitation. The usage of ion and electron beam allows stress generation and real-time observation simultaneously, which significantly enhances the controllability of self-assembly. This enables the realization of various complex 3D nanostructures with a high yield. The additional dimension of the self-assembled 3D nanostructures opens the possibility to explore novel properties that cannot be demonstrated in 2D planar patterns. Here, we present a rapid review on the recent achievements and challenges in nanoscale self-assembly using electron and ion beam techniques, followed by a discussion of the novel optical properties achieved in the self-assembled 3D nanostructures.

scholarly journals Comparison of Phase Characteristics and Residual Stresses in Ti-6Al-4V Alloy Manufactured by Laser Powder Bed Fusion (L-PBF) and Electron Beam Powder Bed Fusion (EB-PBF) Techniques

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 796
Author(s):  
Aya Takase ◽  
Takuya Ishimoto ◽  
Naotaka Morita ◽  
Naoko Ikeo ◽  
Takayoshi Nakano
Keyword(s):  
Electron Beam ◽  
Residual Stresses ◽  
Cooling Rate ◽  
Process Parameters ◽  
Phase Evolution ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Solidification Temperature ◽  
Powder Bed ◽  
Β Phase

Ti-6Al-4V alloy fabricated by laser powder bed fusion (L-PBF) and electron beam powder bed fusion (EB-PBF) techniques have been studied for applications ranging from medicine to aviation. The fabrication technique is often selected based on the part size and fabrication speed, while less attention is paid to the differences in the physicochemical properties. Especially, the relationship between the evolution of α, α’, and β phases in as-grown parts and the fabrication techniques is unclear. This work systematically and quantitatively investigates how L-PBF and EB-PBF and their process parameters affect the phase evolution of Ti-6Al-4V and residual stresses in the final parts. This is the first report demonstrating the correlations among measured parameters, indicating the lattice strain reduces, and c/a increases, shifting from an α’ to α+β or α structure as the crystallite size of the α or α’ phase increases. The experimental results combined with heat-transfer simulation indicate the cooling rate near the β transus temperature dictates the resulting phase characteristics, whereas the residual stress depends on the cooling rate immediately below the solidification temperature. This study provides new insights into the previously unknown differences in the α, α’, and β phase evolution between L-PBF and EB-PBF and their process parameters.

scholarly journals Nucleation Behavior of a Single Al-20Si Particle Rapidly Solidified in a Fast Scanning Calorimeter

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2920
Author(s):  
Qin Peng ◽  
Bin Yang ◽  
Benjamin Milkereit ◽  
Dongmei Liu ◽  
Armin Springer ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Rapid Solidification ◽  
Heterogeneous Nucleation ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Solidification Behavior ◽  
Nucleation Kinetics ◽  
Nucleation Behavior ◽  
Nucleation Undercooling ◽  
Primary Si

Understanding the rapid solidification behavior characteristics, nucleation undercooling, and nucleation mechanism is important for modifying the microstructures and properties of metal alloys. In order to investigate the rapid solidification behavior in-situ, accurate measurements of nucleation undercooling and cooling rate are required in most rapid solidification processes, e.g., in additive manufacturing (AM). In this study, differential fast scanning calorimetry (DFSC) was applied to investigate the nucleation kinetics in a single micro-sized Al-20Si (mass%) particle under a controlled cooling rate of 5000 K/s. The nucleation rates of primary Si and secondary α-Al phases were calculated by a statistical analysis of 300 identical melting/solidification experiments. Applying a model based on the classical nucleation theory (CNT) together with available thermodynamic data, two different heterogeneous nucleation mechanisms of primary Si and secondary α-Al were proposed, i.e., surface heterogeneous nucleation for primary Si and interface heterogenous nucleation for secondary α-Al. The present study introduces a practical method for a detailed investigation of rapid solidification behavior of metal particles to distinguish surface and interface nucleation.

Temperature Distribution and Fluid Flow Modeling of Electron Beam Melting® (EBM)

2012 ◽  
Author(s):  
M. Jamshidinia ◽  
F. Kong ◽  
R. Kovacevic
Keyword(s):  
Electron Beam ◽  
Fluid Flow ◽  
Temperature Distribution ◽  
Molten Pool ◽  
Electron Beam Melting ◽  
Control Volume ◽  
Thermal Analyses ◽  
Scanning Speed ◽  
Flow Modeling ◽  
Fluid Flow Modeling

A three-dimensional (3D) numerical model is developed by using control volume method to analyze the effects of the electron beam scanning speed on the temperature distribution and fluid flow of the liquid phase in the electron beam melting® (EBM) of Ti-6Al-4V powder. The numerical calculations are performed by Fluent codes, in which thermal analyses with and without considering fluid flow in the molten pool are compared. A series of experiments are performed with an Electron Beam Melting® machine to verify the numerical accuracy. Compared to thermal analysis without considering convection in the molten pool, a closer numerical prediction of geometrical size of molten pool to the experimental data can be achieved by using thermal and fluid flow modeling. The difference between the melt pool geometry in the two models is due to the consideration of the effects of the outward flow in the fluid flow model caused by surface tension.

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