Dislocation Density-Based Grain Refinement Modeling of Orthogonal Cutting of Titanium

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Hongtao Ding ◽  
Yung C. Shin
Keyword(s):  
Grain Size ◽  
Finite Element ◽  
Dislocation Density ◽  
Mechanical Behavior ◽  
Grain Refinement ◽  
Orthogonal Cutting ◽  
Cutting Process ◽  
Plasticity Model ◽  
Numerical Work ◽  
Cp Ti

Recently, orthogonal cutting has been exploited as a means for producing ultrafine grained (UFG) and nanocrystalline microstructures for various metal materials, such as aluminum alloys, copper, stainless steel, titanium and nickel-based super alloys, etc. However, no predictive, analytical or numerical work has ever been presented to quantitatively predict the change of grain sizes during plane-strain orthogonal cutting. In this paper, a dislocation density-based material plasticity model is adapted for modeling the grain size refinement mechanism during orthogonal cutting by means of a finite element based numerical framework. A coupled Eulerian–Lagrangian (CEL) finite element model embedded with the dislocation density subroutine is developed to model the severe plastic deformation and grain refinement during a steady-state cutting process. The orthogonal cutting tests of a commercially pure titanium (CP Ti) material are simulated in order to assess the validity of the numerical solution through comparison with experiments. The dislocation density-based material plasticity model is calibrated to reproduce the observed material constitutive mechanical behavior of CP Ti under various strains, strain rates, and temperatures in the cutting process. It is shown that the developed model captures the essential features of the material mechanical behavior and predicts a grain size of 100–160 nm in the chips of CP Ti at a cutting speed of 10 mm/s.

scholarly journals Dislocation Density-Based Grain Refinement Modeling of Orthogonal Cutting of Commercially Pure Titanium

2011 ◽  
Author(s):  
Hongtao Ding ◽  
Yung C. Shin
Keyword(s):  
Grain Size ◽  
Finite Element ◽  
Dislocation Density ◽  
Mechanical Behavior ◽  
Grain Refinement ◽  
Orthogonal Cutting ◽  
Pure Titanium ◽  
Commercially Pure Titanium ◽  
Commercially Pure ◽  
Cp Ti

Recently, machining has been exploited as a means for producing ultra-fine grained (UFG) and nanocrystalline microstructures for various metal materials, such as aluminum alloys, copper, stainless steel, titanium and nickel-based super alloys, etc. However, no predictive, analytical or numerical work has ever been presented to quantitatively predict the change of grain sizes during machining. In this paper, a dislocation density-based viscoplastic model is adapted for modeling the grain size refinement mechanism during machining by means of a finite element based numerical framework. A novel Coupled Eulerian-Lagrangian (CEL) finite element model embedded with the dislocation density subroutine is developed to model the severe plastic deformation and grain refinement during a steady-state cutting process. The orthogonal cutting tests of a commercially pure titanium (CP Ti) material are simulated in order to assess the validity of the numerical solution through comparison with experiments. The dislocation density-based material model is calibrated to reproduce the observed material constitutive mechanical behavior of CP Ti under various strains, strain rates and temperatures in the cutting process. It is shown that the developed model captures the essential features of the material mechanical behavior and predicts a grain size of 100–160 nm in the chips of CP Ti at a cutting speed of 10 mm/s.

Computation on continuous grain refinement in AA1050 aluminum during repetitive tube expansion and shrinking technique

2015 ◽  
Vol 232 (4) ◽  
pp. 307-318
Author(s):  
H Jafarzadeh ◽  
K Abrinia
Keyword(s):  
Finite Element Method ◽  
Plastic Deformation ◽  
Grain Size ◽  
Finite Element ◽  
Dislocation Density ◽  
Severe Plastic Deformation ◽  
Grain Refinement ◽  
Half Cycle ◽  
Tube Expansion ◽  
Element Method

The microstructure evolution during recently developed severe plastic deformation method named repetitive tube expansion and shrinking of commercially pure AA1050 aluminum tubes has been studied in this paper. The behavior of the material under repetitive tube expansion and shrinking including grain size and dislocation density was simulated using the finite element method. The continuous dynamic recrystallization of AA1050 during severe plastic deformation was considered as the main grain refinement mechanism in micromechanical constitutive model. Also, the flow stress of material in macroscopic scale is related to microstructure quantities. This is in contrast to the previous approaches in finite element method simulations of severe plastic deformation methods where the microstructure parameters such as grain size were not considered at all. The grain size and dislocation density data were obtained during the simulation of the first and second half-cycles of repetitive tube expansion and shrinking, and good agreement with experimental data was observed. The finite element method simulated grain refinement behavior is consistent with the experimentally obtained results, where the rapid decrease of the grain size occurred during the first half-cycle and slowed down from the second half-cycle onwards. Calculations indicated a uniform distribution of grain size and dislocation density along the tube length but a non-uniform distribution along the tube thickness. The distribution characteristics of grain size, dislocation density, hardness, and effective plastic strain were consistent with each other.

Numerical Investigation of Dislocation Density and Grain Size Evolution in Orthogonal Cutting of Pure Titanium Using Microgrooved Cutting Tools

2018 ◽  
Author(s):  
Han Wu ◽  
J. Ma ◽  
Shuting Lei
Keyword(s):  
Grain Size ◽  
Dislocation Density ◽  
Orthogonal Cutting ◽  
Cutting Tools ◽  
Pure Titanium ◽  
Commercially Pure Titanium ◽  
Machined Surface ◽  
Fem Model ◽  
Commercially Pure ◽  
Cp Ti

In this paper, a coupled Eulerian-Lagrangian (CEL) finite element model is developed based on FEM software package Abaqus to solve the evolution of the dislocation density and grain size simultaneously. This validated CEL FEM model is then utilized to investigate the effects of microgrooved cutting tools on the evolution of dislocation density and grain size in orthogonal cutting of commercially pure titanium (CP Ti). Microgrooved cutting tools are cemented carbide (WC/Co) cutting inserts with microgrooves on the rake face. The effects of microgroove width and microgroove convex width are investigated in terms of cutting force, chip morphology, dislocation density, and grain size. It is concluded that this CEL FEM model can capture the essential features of orthogonal cutting of commercially pure titanium (CP Ti) alloy using microgrooved cutting tools. It is also concluded that microgroove width and convex width have substantial influence on the dislocation density profiles and grain size profiles along the depth from the machined surface and the tool-chip interface, respectively. This conclusion provides insightful guidance for altering the surface integrity of the machined surface based on needs.

Modeling of Microstructure Effects on the Mechanical Behavior of Ultrafine-Grained Nickels Processed by Severe Plastic Deformation by Crystal Plasticity Finite Element Model

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Thê-Duong Nguyen ◽  
Van-Tung Phan ◽  
Quang-Hien Bui
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Finite Element ◽  
Dislocation Density ◽  
Severe Plastic Deformation ◽  
Mechanical Behavior ◽  
Element Model ◽  
Crystal Plasticity Finite Element ◽  
Ultrafine Grained ◽  
Microstructure Effects

In this study, a crystal plasticity finite element model (CPFEM) has been revisited to study the microstructure effects on macroscopic mechanical behavior of ultrafine-grained (UFG) nickels processed by severe plastic deformation (SPD). The microstructure characteristics such as grain size and dislocation density show a strong influence on the mechanical behavior of SPD-processed materials. We used a modified Hall–Petch relationship at grain level to study both grain size and dislocation density dependences of mechanical behavior of SPD-processed nickel materials. Within the framework of small strain hypothesis, it is quite well shown that the CPFEM predicts the mechanical behavior of unimodal nickels processed by SPD methods. Moreover, a comparison between the proposed model and the self-consistent approach will be shown and discussed.

Computer Simulation of AISI D2 Orthogonal Cutting Using Finite Element Method

2012 ◽  
Vol 499 ◽  
pp. 39-44
Author(s):  
L. Yan ◽  
Feng Jiang ◽  
Y.M. Rong
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Cutting Tool ◽  
Orthogonal Cutting ◽  
Damage Model ◽  
Chip Morphology ◽  
Simulation Method ◽  
Cutting Process ◽  
Aisi D2 ◽  
Cutting Processes

This paper presented a finite element simulation model for the analysis of AISI D2 orthogonal cutting process using TiAlN coated inserts. Firstly, AISI D2 material constitutive model was built based on power law model, which was used in the FEM codes to describe the effect of strain, strain rate and temperature on the material flow stress. In modeling the chip formation, a damage model was employed to predict the chip separation. Then cutting edge radius and thickness of TiAlN coating of cutting tool were measured by SEM. Friction coefficients of cutting tool against AISI D2 steel were obtained by ball-on-plate friction tests on UMT-2 high speed tribometer. Finally, finite element simulations of AISI D2 orthogonal cutting processes were performed using AdvantedgeTM software. The simulated results of cutting forces and chip morphology showed good agreement with the experimental results, which validated the reliability of the cutting process simulation method.

scholarly journals Finite element simulation of the C70 orthogonal cutting process

2017 ◽  
Vol 112 ◽  
pp. 06011
Author(s):  
Vlad-Bogdan Tomoiagă ◽  
Marcel Sabin Popa ◽  
Stefan Sattel ◽  
Glad Conțiu ◽  
Marius Bozga
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Orthogonal Cutting ◽  
Cutting Process ◽  
Element Simulation

Application of the Nodal Integrated Finite Element Method to Cutting: a Preliminary Comparison with the “Traditional” FEM Approach

2011 ◽  
Vol 223 ◽  
pp. 172-181 ◽  
Author(s):  
Francesco Greco ◽  
Domenico Umbrello ◽  
Serena Di Renzo ◽  
Luigino Filice ◽  
I. Alfaro ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Large Deformation ◽  
Orthogonal Cutting ◽  
Fem Simulation ◽  
Cutting Process ◽  
Integration Technique ◽  
Mesh Distortion ◽  
Nodal Integration ◽  
Element Method

FEM implicit formulation shows specific limitations in processes such as cutting, where large deformation results in a heavy mesh distortion. Powerful rezoning-remeshing algorithms strongly reduce the effects of such a limitation but the computational times are significantly increased and additional errors are introduced. Nodal Integration is a recently introduced technique that allows finite element method to provide more reliable results when mesh becomes distorted in traditional FEMs. Furthermore, volumetric locking phenomenon seems to be avoided by using this integration technique instead of other methods, such as the coupled formulations. In this paper, a comparison between a “classical” FEM simulation and the Nodal Integration one is carried out taking into account a simple orthogonal cutting process.

scholarly journals Effect of Rolling Speed on Microstructural and Microtextural Evolution of Nb Tubes during Caliber-Rolling Process

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 500 ◽  
Author(s):  
Jongbeom Lee ◽  
Haguk Jeong
Keyword(s):  
Grain Size ◽  
Dislocation Density ◽  
Ambient Temperature ◽  
Strain Rate ◽  
Internal Energy ◽  
Grain Refinement ◽  
Rolling Process ◽  
Fiber Texture ◽  
Rolling Speed ◽  
Low Energy

This study investigated the fabrication of Nb tubes via the caliber-rolling process at various rolling speeds from 1.4 m/min to 9.9 m/min at ambient temperature, and the effect of the caliber-rolling speed on the microstructural and microtextural evolution of the Nb tubes. The caliber-rolling process affected the grain refinement when the Nb tube had a higher fraction of low angle grain boundaries. However, the grain size was identical regardless of the rolling speed. The dislocation density of the Nb tubes increased with the caliber-rolling speed according to the Orowan equation. The reduction of intensity for the <111> fiber texture and the development of the <112> fiber texture with the increase of the strain rate are considered to have decreased the internal energy by increasing the fraction of the low-energy Σ3 boundaries.

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