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.

A New Kind of FDM/FEM Squeeze Casting Temperature Field Calculation Model

2013 ◽  
Vol 641-642 ◽  
pp. 303-308
Author(s):  
Yu Hong Zhao ◽  
Wei Ming Yang ◽  
Hua Hou
Keyword(s):  
Temperature Field ◽  
Melting Temperature ◽  
Squeeze Casting ◽  
Solidification Process ◽  
Pressure Change ◽  
Calculation Model ◽  
Physical Parameters ◽  
Field Calculation ◽  
Fem Model ◽  
Relationship Of

A new FDM/ FEM model is developed to simulate the temperature field during the solidification process of squeeze casting. So we can transform the FDM mesh into FEM mesh directly ,then established the relationship of pressure change and melting temperature change and correct the size of melting temperature value and other thermal physical parameters (such as the thermal conductivity)which is related to the temperature ,and establish the temperature and thermal physical parameter relationship to get a data base. The solidification process of AM50A magnesium alloy is simulated. Squeeze casting experiments are also incited for validating the new FDM/FEM model. It is shown that the results of numerical simulation are in agreement with the experimental results.

The Finite Element Analysis of Flow Field and Temperature Field in the Molten Pool of Surface Treatment by Electron Beam

2012 ◽  
Vol 591-593 ◽  
pp. 908-911
Author(s):  
Rong Wang ◽  
Guo Bin Shen ◽  
De Qiang Wei
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Electron Beam ◽  
Liquid Metal ◽  
Flow Field ◽  
Flow Velocity ◽  
Molten Pool ◽  
Driving Forces ◽  
Specimen Thickness ◽  
Beam Spot

A finite element model was established to describe the flow field and temperature field during the surface modification by electron beam in this paper. The driving forces of molten pool were considered in the mode. The flow of liquid metal was different between the inside and outside of the beam spot; the direction of the flow was along the surface to the specimen thickness. When the liquid metal was in the bottom of the pool, it flowed along the bottom to the pool edge. The largest flow velocity was 0.28m/s in the center of the beam spot, the minimum flow velocity was 0.11 m/s in the bottom of molten pool. The temperature of sample is uniform distribution, the temperature distribution show a gradient distribution in cross section.

The Numerical Simulation of Directional Solidification Process Temperature Field for Large-Scale Frustum of a Cone Ingot

2011 ◽  
Vol 189-193 ◽  
pp. 1476-1481
Author(s):  
Kun Liu ◽  
Zhe Wang ◽  
Ren Zhi Han ◽  
Zi Ping Ren
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Temperature Field ◽  
Directional Solidification ◽  
Large Scale ◽  
Solidification Process ◽  
Directional Solidification Process ◽  
Ingot Quality ◽  
Fluent Software ◽  
The Mathematical Model

By using Fluent software, the mathematical model of temperature field is established on directional solidification process for large-scale frustum of a cone ingot, and the result is analyzed by Origin software, Tecplot. The influences of different width/thickness ratio to directional solidification process of cone ingot are discussed in order to provide basis for design optimization and ingot quality improvement.

Simulation and Calculation to Segregation of High Nitrogen Steels Solidification Process Based on PROCAST Software

2011 ◽  
Vol 217-218 ◽  
pp. 1185-1190 ◽  
Author(s):  
Wan Ming Li ◽  
Zhou Hua Jiang ◽  
Hua Bing Li
Keyword(s):  
Mathematical Model ◽  
Temperature Field ◽  
Stainless Steels ◽  
Pressure Field ◽  
Solidification Process ◽  
High Nitrogen ◽  
Dynamic Variation ◽  
Nitrogen Steels ◽  
Zone Segregation

Segregation and liberation occur easily in high nitrogen stainless steels, which can result in the formation of pores and the discarding of the steels. So it is very important to investigate the segregation and liberation theory during the solidification process of high nitrogen stainless steels. In the manuscript, the pouring and solidification progress of high nitrogen steels ingots were simulated through Pro Engineer and PROCAST software. The dynamic variation of temperature field and pressure field were obtained. With the results of PROCAST, the macrosegregation of 20kg weight ingot and 1.7 tons weight ingot were predicted using mathematical model of zone segregation. The predicted results show that 20kg weight ingot has no obvious macrosegregation and 1.7 tons weight ingot has obvious macrosegregation, which is consistent with measuring results. It shows that the accuracy of simulation and calculation to segregation of high nitrogen steels solidification process based on PROCAST software is high.

Simulation Study of the Temperature Field for Squashed Presetting Laser Cladding Based on ANSYS

2010 ◽  
Vol 458 ◽  
pp. 319-324 ◽  
Author(s):  
Gang Chen ◽  
Xiang Feng Li ◽  
Dun Wen Zuo ◽  
Hong Yu Wang ◽  
Yan Jiang
Keyword(s):  
Temperature Field ◽  
Temperature Gradient ◽  
Contact Resistance ◽  
Laser Cladding ◽  
Process Parameters ◽  
Simulation Study ◽  
Molten Pool ◽  
Organizational Form ◽  
Physical Parameters ◽  
Pore Model

In the process of modeling the squashed piece of powders for the simulation of the temperature field of laser cladding, the metallurgical model and the pore model were proposed separately. The effects of the organizational form, the contact resistance and the thickness of the squashed piece of powders on the temperature were considered. Different values of physical parameters of the squashed piece of powders were converted, different contact resistances were calculated and the laser absorptivity for different process parameters of laser cladding was determined. The temperature curves of six typical nodes and the temperature gradient of two nodes in the molten pool of the substrate were discussed from different aspects.

Temperature Field Simulation of Electron Beam Surface Quenching on Ductile Iron QT600-3

2011 ◽  
Vol 228-229 ◽  
pp. 1118-1124
Author(s):  
De Qiang Wei ◽  
Yun Zhi Yi ◽  
Rong Wang
Keyword(s):  
Temperature Field ◽  
Electron Beam ◽  
Ductile Iron ◽  
Element Model ◽  
Processing Parameters ◽  
Physical Parameters ◽  
Fem Model ◽  
Heat Transfer Theory ◽  
Surface Quenching ◽  
Beam Surface

According to the actual experimental condition of the scanning electron beam welder, a 3-D finite element model(FEM) model of the temperature field for the electron beam quenching of ductile iron QT600-3 was established by using ANSYS parametric design language. In the course of analysis, the heat transfer theory was applied. The temperature relativity of the thermal physical parameters, the phase transformation and thermal radiation were considered. The size of the hardened zone was calculated and experimented. The results show that the obtained experimental results show a good agreement with the simulation results. It indicates that the established numerical model is correct and reliable. The model provides a guide for studying the rule which it is heating and solidifying process of electron beam surface quenching. And the FEM model can be well used to obtain and optimize the processing parameters.

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.

A theory of contamination in electron microscopes by surface diffusion

1978 ◽  
Vol 36 (1) ◽  
pp. 116-117
Author(s):  
J.T. Fourie
Keyword(s):  
Electron Beam ◽  
Surface Diffusion ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Physical Parameters ◽  
Carbon Compounds ◽  
Hydrocarbon Molecules ◽  
Electron Microscopes ◽  
Primary Electrons ◽  
Long Chain

Contamination in electron microscopes can be a serious problem in STEM or in situations where a number of high resolution micrographs are required of the same area in TEM. In modern instruments the environment around the specimen can be made free of the hydrocarbon molecules, which are responsible for contamination, by means of either ultra-high vacuum or cryo-pumping techniques. However, these techniques are not effective against hydrocarbon molecules adsorbed on the specimen surface before or during its introduction into the microscope. The present paper is concerned with a theory of how certain physical parameters can influence the surface diffusion of these adsorbed molecules into the electron beam where they are deposited in the form of long chain carbon compounds by interaction with the primary electrons.

STUDY OF THE GRAIN BOUNDARY MIGRATION IN A TRICRISTAL PURE ICE WITH BUBBLES

Anales AFA ◽  
2019 ◽  
Vol 30 (3) ◽  
pp. 47-51
Author(s):  
P.I. Achával ◽  
C. L. Di Prinzio
Keyword(s):  
Monte Carlo ◽  
Grain Boundary ◽  
Numerical Simulations ◽  
Triple Junction ◽  
Boundary Migration ◽  
Optical Microscope ◽  
Physical Parameters ◽  
Grain Boundary Migration

In this paper the migration of a grain triple junction in apure ice sample with bubbles at -5°C was studied for almost 3hs. This allowed tracking the progress of the Grain Boundary (BG) and its interaction with the bubbles. The evolution of the grain triple junction was recorded from successive photographs obtained witha LEICA® optical microscope. Simultaneously, numerical simulations were carried out using Monte Carlo to obtain some physical parameters characteristic of the BG migration on ice.

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