Simulations of Microstructure Evolution During Friction Stir Blind Riveting Using a Cellular Automaton Method

2017 ◽  
Author(s):  
Avik Samanta ◽  
Ninggang Shen ◽  
Haipeng Ji ◽  
Weiming Wang ◽  
Hongtao Ding ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Cellular Automaton ◽  
Microstructure Evolution ◽  
Deformation Gradient ◽  
Microstructural Analysis ◽  
Numerical Approach ◽  
Friction Stir ◽  
Large Gradient ◽  
Gradient Microstructure ◽  
Ca Model

Friction stir blind riveting (FSBR) is a novel and highly efficient joining technique for lightweight metal materials, such as aluminum alloys. The FSBR process induced large gradients of plastic deformation near the rivet hole surface and resulted in a distinctive gradient microstructure in this domain. In this study, microstructural analysis is conducted to analyze the final microstructure after the FSBR process. Dynamic recrystallization (DRX) is determined as the dominant microstructure evolution mechanism due to the significant heat generation during the process. To better understand the FSBR process, a two-dimensional Cellular Automaton (CA) model is developed to simulate the microstructure evolution near the rivet hole surface by considering the FSBR process loading condition. To model the significant microstructure change near the rivet hole surface, spatial distributed temporal thermal and mechanical loading conditions are applied to simulate the effect of the large gradient plastic deformation near the hole surface. The distribution grain topography and recrystallization fraction are obtained through the simulations, which agree well with the experimental data. This study presents a reliable numerical approach to model and simulate microstructure evolution governed by DRX under the large plastic deformation gradient in FSBR.

Cellular Automaton Simulation of Microstructure Evolution for Friction Stir Blind Riveting

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Avik Samanta ◽  
Ninggang Shen ◽  
Haipeng Ji ◽  
Weiming Wang ◽  
Jingjing Li ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Cellular Automaton ◽  
Microstructure Evolution ◽  
Numerical Approach ◽  
Dislocation Dynamics ◽  
Grain Structure ◽  
Workpiece Material ◽  
Friction Stir ◽  
Ca Model

Friction stir blind riveting (FSBR) process offers the ability to create highly efficient joints for lightweight metal alloys. During the process, a distinctive gradient microstructure can be generated for the work material near the rivet hole surface due to high-gradient plastic deformation and friction. In this work, discontinuous dynamic recrystallization (dDRX) is found to be the major recrystallization mechanism of aluminum alloy 6111 undergoing FSBR. A cellular automaton (CA) model is developed for the first time to simulate the evolution of microstructure of workpiece material during the dynamic FSBR process by incorporating main microstructure evolution mechanisms, including dislocation dynamics during severe plastic deformation, dynamic recovery, dDRX, and subsequent grain growth. Complex thermomechanical loading conditions during FSBR are obtained using a mesh-free Lagrangian particle-based smooth particle hydrodynamics (SPH) method, and are applied in the CA model to predict the microstructure evolution near the rivet hole. The simulation results in grain structure agree well with the experiments, which indicates that the important characteristics of microstructure evolution during the FSBR process are well captured by the CA model. This study presents a novel numerical approach to model and simulate microstructure evolution undergoing severe plastic deformation processes.

scholarly journals Cellular Automaton Modeling of Phase Transformation of U-Nb Alloys during Solidification and Consequent Cooling Process

2019 ◽  
Vol 38 (2019) ◽  
pp. 567-575 ◽  
Author(s):  
Qingfu Tang ◽  
Dong Chen ◽  
Bin Su ◽  
Xiaopeng Zhang ◽  
Hongzhang Deng ◽  
...  
Keyword(s):  
Cellular Automaton ◽  
Microstructure Evolution ◽  
Optical Microscope ◽  
Phase Precipitation ◽  
Cooling Process ◽  
Dendrite Morphology ◽  
Ca Model ◽  
Measuring Experiment ◽  
Kinetics Of ◽  
Cast Microstructure

AbstractThe microstructure evolution of U-Nb alloys during solidification and consequent cooling process was simulated using a cellular automaton (CA) model. By using this model, ϒ phase precipitation and monotectoid decomposition were simulated, and dendrite morphology of ϒ phase, Nb microsegregation and kinetics of monotectoid decomposition were obtained. To validate the model, an ingot of U-5.5Nb (wt.%) was produced and temperature measuring experiment was carried out. As-cast microstructure at different position taken from the ingot was investigated by using optical microscope and SEM. The effect of cooling rate on ϒ phase precipitation and monotectoid decomposition of U-Nb alloys was also studied. The simulated results were compared with the experimental results and the capability of the model for quantitatively predicting the microstructure evolution of U-Nb alloys during solidification and consequent cooling process was assessed.

scholarly journals Microstructure Evolution and Mechanical Property Characterization of 6063 Aluminum Alloy Tubes Processed with Friction Stir Back Extrusion

JOM ◽  
2019 ◽  
Vol 71 (12) ◽  
pp. 4436-4444
Author(s):  
Suhong Zhang ◽  
Alan Frederick ◽  
Yiyu Wang ◽  
Mike Eller ◽  
Paul McGinn ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Microstructure Evolution ◽  
Electron Backscatter Diffraction ◽  
Deformation Gradient ◽  
Optical Microscope ◽  
Grain Structure ◽  
Frictional Heat ◽  
Friction Stir ◽  
Metal Extrusion ◽  
Backscatter Diffraction

Abstract Friction stir back extrusion (FSBE) is a technique for lightweight metal extrusion. The frictional heat and severe plastic deformation of the process generate an equiaxed refined grain structure because of dynamic recrystallization. Previous studies proved that the fabrication of tube and wire structures is feasible. In this work, hollow cylindrical billets of 6063-T6 aluminum alloy were used as starting material. A relatively low extrusion ratio allows for a temperature and deformation gradient through the tube wall thickness to elucidate the effect of heat and temperature on the microstructure evolution during FSBE. The force and temperature were recorded during the processes. The microstructures of the extruded tubes were characterized using an optical microscope, energy-dispersive x-ray spectroscopy, electron backscatter diffraction, and hardness testing. The process reduced the grain size from 58.2 μm to 20.6 μm at the inner wall. The microhardness of the alloy was reduced from 100 to 60–75 HV because of the process thermal cycle.

Predicting microstructure evolution for friction stir extrusion using a cellular automaton method

2019 ◽  
Vol 27 (3) ◽  
pp. 035006 ◽  
Author(s):  
Reza Abdi Behnagh ◽  
Avik Samanta ◽  
Mohsen Agha Mohammad Pour ◽  
Peyman Esmailzadeh ◽  
Hongtao Ding
Keyword(s):  
Cellular Automaton ◽  
Microstructure Evolution ◽  
Friction Stir ◽  
Friction Stir Extrusion ◽  
Cellular Automaton Method

scholarly journals Microstructure evolution of 20Cr steel spider during cold forging using cellular automaton method

2018 ◽  
Vol 24 (1) ◽  
pp. 43
Author(s):  
Kun Xia Wei ◽  
Ling Niu ◽  
Wei Wei ◽  
Qing Bo Du ◽  
Igor V. Alexandrov ◽  
...  
Keyword(s):  
Grain Size ◽  
Microstructure Evolution ◽  
Effective Strain ◽  
Numerical Approach ◽  
Cold Forging ◽  
Forging Process ◽  
Microhardness Distribution ◽  
Ca Model ◽  
Simulation Results ◽  
Cellular Automaton Method

<p class="AMSmaintext"><span lang="EN-GB">The microstructure evolution of 20Cr steel spider in the cold forging process was simulated and analyzed by CA method, and verified by the experimental results. The CA simulation results show that the grain size becomes smaller with an increase of forging reduction. When the reduction is 60%, the grain size is the smallest. After that, the microstructure is inhomogeneous. At the same forging reduction, the microhardness at the root of the pin is higher than that at the head of the pin. It is well agreed with the distribution of the effective strain. The CA results agree well with the experimental data in terms of microstructure evolution and microhardness distribution, suggesting that the CA model is a reliable numerical approach for predicting microstructure evolution during cold forging for 20Cr steel spider.</span></p>

scholarly journals Influence of Hydrostatic Extrusion on the Mechanical Properties of the Model Al-Mg Alloys

2021 ◽  
Author(s):  
Aleksandra Towarek ◽  
Wojciech Jurczak ◽  
Joanna Zdunek ◽  
Mariusz Kulczyk ◽  
Jarosław Mizera
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Tensile Strength ◽  
Microstructural Analysis ◽  
Tensile Tests ◽  
Hydrostatic Extrusion ◽  
Microstructure Formation ◽  
Initial State ◽  
Degree Of Deformation ◽  
Al Mg Alloys

AbstractTwo model aluminium-magnesium alloys, containing 3 and 7.5 wt.% of Mg, were subjected to plastic deformation by means of hydrostatic extrusion (HE). Two degrees of deformation were imposed by two subsequent reductions of the diameter. Microstructural analysis and tensile tests of the materials in the initial state and after deformation were performed. For both materials, HE extrusion resulted in the deformation of the microstructure—formation of the un-equilibrium grain boundaries and partition of the grains. What is more, HE resulted in a significant increase of tensile strength and decrease of the elongation, mostly after the first degree of deformation.

Investigations on Microstructure Evolution and Deformation Behavior of Aged and Ultrafine Grained Al-Zn-Mg Alloy Subjected to Severe Plastic Deformation

2010 ◽  
Vol 667-669 ◽  
pp. 253-258
Author(s):  
Wei Ping Hu ◽  
Si Yuan Zhang ◽  
Xiao Yu He ◽  
Zhen Yang Liu ◽  
Rolf Berghammer ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Microstructure Evolution ◽  
Deformation Behavior ◽  
Deformation Mechanisms ◽  
Mg Alloy ◽  
Ultrafine Grained

An aged Al-5Zn-1.6Mg alloy with fine η' precipitates was grain refined to ~100 nm grain size by severe plastic deformation (SPD). Microstructure evolution during SPD and mechanical behaviour after SPD of the alloy were characterized by electron microscopy and tensile, compression as well as nanoindentation tests. The influence of η' precipitates on microstructure and mechanical properties of ultrafine grained Al-Zn-Mg alloy is discussed with respect to their effect on dislocation configurations and deformation mechanisms during processing of the alloy.

Texture and Microstructure Evolution in Friction Stir Welded Cu-Al Sheets Characterized by EBSD

2011 ◽  
Vol 702-703 ◽  
pp. 574-577 ◽  
Author(s):  
Daniel Goran ◽  
G. Ji ◽  
M. N. Avettand-Fènoël ◽  
R. Taillard
Keyword(s):  
Microstructure Evolution ◽  
Electron Backscatter Diffraction ◽  
Texture Evolution ◽  
Weld Interface ◽  
Friction Stir ◽  
Electron Backscatter ◽  
Ebsd Technique ◽  
Backscatter Diffraction

Texture and microstructure of FSW joined Al and Cu sheets were investigated by means of electron backscatter diffraction (EBSD) technique. The analysis has revealed a strong texture evolution on both sides of the weld interface as well as a very complex microstructure. Grains were found to be fully recrystallized on both sides of the weld and with different average diameters at different specific zones of the weld.

Sign in / Sign up

Export Citation Format

Share Document