scholarly journals Anisotropic Plasticity and Fracture of Three 6000-Series Aluminum Alloys

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 557
Author(s):  
Susanne Thomesen ◽  
Odd Sture Hopperstad ◽  
Tore Børvik
Keyword(s):  
Aluminum Alloys ◽  
Work Hardening ◽  
Failure Strain ◽  
Texture Evolution ◽  
Extrusion Direction ◽  
Extrusion Process ◽  
Deformation Texture ◽  
Grain Structure ◽  
Anisotropic Plasticity ◽  
Experimental Findings

The influence of microstructure on plasticity and fracture of three 6000-series aluminum alloys is studied with emphasis on the anisotropy caused by the extrusion process. Tension tests on smooth and notched specimens are performed in different directions with respect to the extrusion direction, where the stress and strain to fracture are based on local measurements inside the neck or notch. The microstructure of the alloys, i.e., grain structure, crystallographic texture and size distribution of constituent particles, is characterized and used to explain the experimental findings. The experiments show considerable differences in the directional variation of the yield stress, the plastic flow, the work hardening, and the failure strain between alloys exhibiting recrystallization texture and deformation texture. The alloys with recrystallized microstructure exhibited substantial anisotropic work hardening caused by texture evolution and a stronger notch sensitivity of the failure strain than the alloy with deformed, non-recrystallized microstructure. Comparisons are made with previous experiments on the same alloys in the cast and homogenized condition, and the effects of the microstructural changes caused by the extrusion process on the macroscopic response are discussed.

Extrusion Simulation and Texture Study on Mg-Y Alloy

2015 ◽  
Vol 817 ◽  
pp. 531-537 ◽  
Author(s):  
Tao Tang ◽  
Yi Chuan Shao ◽  
Da Yong Li ◽  
Ying Hong Peng
Keyword(s):  
Steady State ◽  
Texture Evolution ◽  
Hot Extrusion ◽  
Extrusion Process ◽  
Deformation Texture ◽  
Arbitrary Lagrangian Eulerian ◽  
Fe Method ◽  
Tracer Particles ◽  
Numerical Simulation Methods ◽  
Crystal Plasticity Theory

In order to study the influence of extrusion process on texture development of alloys, numerical simulation methods were used to simulate the round and shape extrusion process and deformation texture. Extrusion of Mg-Y magnesium alloy was carried out at the temperature of 673K with different ram speeds to verify the simulation results. Instead of using the Lagrangian FE method, the Arbitrary Lagrangian-Eulerian (ALE) method was employed in this study so that a more accurate description of the steady-state extrusion process can be achieved. By obtaining strain histories of specified material tracer particles, the coupling of deformation and crystal plasticity theory was applied to simulate the texture evolution in hot extrusion. The results showed that the texture simulation corresponded well with the experimental ones. The study proposes a method to analyze the steady-state extrusion process and texture evolution, and can be used as a useful tool in optimizing the extrusion process.

Characterization and Modelling of the Microstructure and Texture Evolution in AlMgSi-Extrusions

2016 ◽  
Vol 879 ◽  
pp. 1239-1244 ◽  
Author(s):  
Kai Zhang ◽  
Knut Marthinsen ◽  
Bjørn Holmedal ◽  
Jesper Friis ◽  
Tanja Pettersen ◽  
...  
Keyword(s):  
Subgrain Size ◽  
Texture Evolution ◽  
Deformation Texture ◽  
Grain Structure ◽  
Structure Evolution ◽  
Model Framework ◽  
Surface Appearance ◽  
Texture Model ◽  
Modelling Framework ◽  
Aluminium Extrusion

The properties and surface appearance of aluminium extrusion are critically dependent on the microstructure and texture of the extruded profiles, and the requirements with respect to these aspects may vary with applications. Moreover it is often a challenge to produce extrusions with a consistent and homogenous grain structure and texture along as well as through the cross section of the profiles. It is thus vital to understand and be able to predict (model) how different microstructures and textures are formed and how they evolve during and after extrusion. In the present work a model framework has been implemented which includes a FEM model to account for the strain, strain rate and temperature along a set of particle paths during extrusion. From these the deformation texture and grain structure are calculated with an appropriate deformation texture model and a sub-structure evolution model, respectively. The sub-structure model have in the present work been coupled to a crystal plasticity model to provide an orientation dependent subgrain size and dislocation density during deformation which provides the driving force for the post-extrusion recovery and possible recrystallization behaviour. The post-extrusion microstructure and texture evolution is calculated with a recovery and recrystallization model, which is accompanied by a recrystallization texture model. The framework and its constituent models and their interplay are presented, and some preliminary results when applying this modelling framework to Al-Mg-Si extrusions are presented and discussed in view of corresponding experimental results.

scholarly journals Simulation of Primary Particle Development and Their Impact on Microstructural Evolution of Sc-Modified Aluminum Alloys during Additive Manufacturing

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1056
Author(s):  
Mohammad Sadegh Mohebbi ◽  
Vasily Ploshikhin
Keyword(s):  
Aluminum Alloys ◽  
Scanning Speed ◽  
Grain Structure ◽  
Coarse Grained ◽  
2D Simulation ◽  
Fine Grain ◽  
Precipitation Model ◽  
Intermetallic Particles ◽  
Experimental Findings

The microstructures of additively manufactured Sc- and Zr-modified aluminum alloys are significantly influenced by the nucleation role of solid intermetallic particles in undercooled liquid. To replicate such effects, a precipitation model relying on L12-Al3Sc particles is developed. An initiation criterion is proposed based on the precipitation kinetics of primary particles to address solute trapping under high solidification rates. Avrami’s equation is then used to estimate the progress of precipitation. The model is integrated into a cellular automata (CA) analysis to simulate the resulting solidified microstructure, in that the precipitation model is performed implicitly within the CA cells. It is shown that, in accordance with the experimental findings, the proposed simulation approach can predict the distinct fine- (FG) and coarse-grained (CG) zones at the fusion boundary and the meltpool core, respectively. The model can also deliver the reported enhancement of the FG zone under lower scanning speed and higher platform temperatures. These findings are explained in terms of particle number densities at different meltpool regions. Moreover, a semi-2D simulation with a very small cell size is suggested to address the extremely fine grain structure within the FG zone.

Combined Numerical Simulation and Microstructure Characterization for Prediction of Physical Properties in Extruded Aluminum Alloys

2009 ◽  
Vol 424 ◽  
pp. 1-8
Author(s):  
Wojciech Z. Misiolek ◽  
William R. Van Geertruyden
Keyword(s):  
Numerical Simulation ◽  
Aluminum Alloys ◽  
Software Package ◽  
Metal Flow ◽  
Extreme Case ◽  
Extrusion Process ◽  
Grain Structure ◽  
Coarse Grain ◽  
Alloy Chemistry ◽  
Points Of View

The extrusion process provides conditions for non-uniform metal flow depending on strain, strain rate and temperature of deformation as well as deformation zone geometry. As a result of these conditions significant microstructure gradients are present within the extrudate. The extreme case of the microstructure gradient is a formation of the peripheral coarse grain structure (PCG). This phenomenon is present in many structural aluminum alloys extrudates and its presence should be eliminated or at least significantly reduced because of the mechanical properties and aesthetic points of view. A number of experiments, including physical and numerical simulations, were performed in order to understand and model the origin of the PCG in indirect extrusion of 6xxx alloys. These experiments included different alloy chemistry, various temperatures, extrusion ratios and extrusion speeds allowing analysis of their influence. Parallel to the experimental results the numerical simulation of the metal flow showing the origin of the metal in different extrudate location was performed using software package DEFORM TM. A review of performed research will be followed by the analysis of the results and discussion of future needs.

scholarly journals Investigation of the Intermetallic Compounds Fragmentation Impact on the Formation of Texture during the as Cast Structure Thermomechanical Treatment of Aluminum Alloys

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 507
Author(s):  
Evgenii Aryshenskii ◽  
Jurgen Hirsch ◽  
Sergey Konovalov
Keyword(s):  
Aluminum Alloys ◽  
Intermetallic Compounds ◽  
Hot Rolling ◽  
Texture Evolution ◽  
Intermetallic Particle ◽  
Grain Structure ◽  
Deformation Degree ◽  
Cast Material ◽  
Cast Structure ◽  
Intermetallic Particles

In this work, the influence of the intermetallic particle fragmentation during hot rolling of the as cast structure on the evolution of textures in aluminum alloys 8011, 5182 and 1565 was investigated. For this purpose, laboratory multi-pass rolling of the cast material was carried out. At various degrees of hot rolling deformation, the process was stopped, and the metal was quenched and sent for optical and electron microscopy to investigate the large intermetallic particles. In addition, the grain structure was studied and an X-ray analysis was carried out in order to determine the main texture components. Some of the samples were held at a temperature above the recrystallization threshold and then cooled in air; the grain structure and texture composition were also studied. In addition, the simulation of the texture evolution was carried out under various modes of rolling of aluminum alloys, taking into account the process of fragmentation of intermetallic particles. The investigation showed that intermetallic compounds with a deformation degree of 1.8, on average, decrease the particle size by 5–7 times. The large eutectic particles remaining after homogenization are drawn out in the direction of deformation and are crushed, increasing their number accordingly. Therefore, the most favorable stage for the formation of recrystallization nuclei on particles is the moment when they are already numerous and their sizes are much larger than subgrains. Simulation of hot rolling of the investigated alloys showed that considering the factor of fragmentation of intermetallic particles during hot deformation of the as-cast structure significantly increases the accuracy of the results.

Microstructure and Texture Evolution in Nickel during Accumulative Roll Bonding

2016 ◽  
Vol 879 ◽  
pp. 454-458 ◽  
Author(s):  
Jia Qi Duan ◽  
Md Zakaria Quadir ◽  
Michael Ferry
Keyword(s):  
Grain Boundaries ◽  
Accumulative Roll Bonding ◽  
Texture Evolution ◽  
Shear Bands ◽  
Rolling Direction ◽  
Sample Surface ◽  
Deformation Texture ◽  
Roll Bonding ◽  
Equiaxed Grains ◽  
Electron Back Scattered Diffraction

Microstructure and texture evolution of commercially pure Ni processed by accumulative roll-bonding (ARB) up to eight cycles were studied using electron back scattered diffraction (EBSD). During ARB processing, the original coarse equiaxed grains were gradually transformed into refined lamellar grains along the rolling direction (RD). Shear bands started forming after three cycles. The fraction of low angle grain boundaries (LAGBs) increased after the first and second cycle because of orientation spreading within the original grains. However, their fraction decreased with the evolution of high angle grain boundaries (HAGBs) during subsequent deformations, until saturation was reached after six cycles. Overall, the typical deformation texture components (S, Copper and Brass) were enhanced up to six ARB cycles and then only Copper was further strengthened. At higher cycles a higher Copper concentration was found near sample surface than the interiors due to a high frictional shear of ARB processing.

scholarly journals Simulation of the Texture Evolution During Annealing of Cold Rolled Bcc and Fcc Metals Using a Cellular Automation Approach

1997 ◽  
Vol 28 (3-4) ◽  
pp. 211-218 ◽  
Author(s):  
V. Marx ◽  
D. Raabe ◽  
O. Engler ◽  
G. Gottstein
Keyword(s):  
Static Recrystallization ◽  
Texture Evolution ◽  
Three Dimensional ◽  
Deformation Texture ◽  
Three Dimensional Model ◽  
Static Recovery ◽  
Fcc Metals ◽  
Cellular Automation ◽  
Texture Change ◽  
Cold Rolled

In this study both primary static recrystallization and static recovery of cold rolled bcc and fcc metals and alloys are numerically simulated using a three-dimensional model that is based on a modified cellular automaton approach. The model considers the influence of the initial deformation texture and microstructure on both static recovery and primary static recrystallization with a high spatial resolution. The cellular automat technique provides both local and statistical information about the kinetics, the morphology and the texture change during annealing. The influence of nucleation and growth can be studied in detail. The simulations are compared to experimental results obtained on fcc and bcc polycrystals.

scholarly journals Deformation Texture Evolution in Flat Profile AlMgSi Extrusions: Experiments, FEM, and Crystal Plasticity Modeling

2021 ◽  
Vol 8 ◽  
Author(s):  
Tomas Manik ◽  
Knut Marthinsen ◽  
Kai Zhang ◽  
Arash Imani Aria ◽  
Bjørn Holmedal
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Crystal Plasticity ◽  
Texture Evolution ◽  
Rate Sensitivity ◽  
Deformation Texture ◽  
Fiber Texture ◽  
Electron Back Scatter Diffraction ◽  
Slip Systems ◽  
Flat Profile

In the present work, the deformation textures during flat profile extrusion from round billets of an AA6063 and an AA6082 aluminium alloy have been numerically modeled by coupling FEM flow simulations and crystal plasticity simulations and compared to experimentally measured textures obtained by electron back-scatter diffraction (EBSD). The AA6063 alloy was extruded at a relatively low temperature (350°C), while the AA6082 alloy, containing dispersoids that prevent recrystallization, was extruded at a higher temperature (500°C). Both alloys were water quenched at the exit of the die, to maintain the deformation texture after extrusion. In the center of the profiles, both alloys exhibit a conventional β-fiber texture and the Cube component, which was significantly stronger at the highest extrusion temperature. The classical full-constraint (FC)-Taylor and the Alamel grain cluster model were employed for the texture predictions. Both models were implemented using the regularized single crystal yield surface. This approach enables activation of any number and type of slip systems, as well as accounting for strain rate sensitivity, which are important at 350°C and 500°C. The strength of the nonoctahedral slips and the strain-rate sensitivity were varied by a global optimization algorithm. At 350°C, a good fit could be obtained both with the FC Taylor and the Alamel model, although the Alamel model clearly performs the best. However, even with rate sensitivity and nonoctahedral slip systems invoked, none of the models are capable of predicting the strong Cube component observed experimentally at 500°C.

Modeling and Simulation of Microstructure Evolution in Extruded Aluminum Profiles

2009 ◽  
Vol 424 ◽  
pp. 43-50
Author(s):  
Farhad Parvizian ◽  
T. Kayser ◽  
Bob Svendsen
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloys ◽  
Modeling And Simulation ◽  
Microstructure Evolution ◽  
Internal State ◽  
Extrusion Process ◽  
State Variables ◽  
Cooling Process ◽  
Microstructure Parameters ◽  
Simulation Results

The purpose of this work is to predict the microstructure evolution of aluminum alloys during hot metal forming processes using the Finite Element Method (FEM). Here, the focus will be on the extrusion process of aluminum alloys. Several micromechanical mechanisms such as diffusion, recovery, recrystallization and grain growth are involved in various subsequent stages of the extrusion and the cooling process afterward. The evolution of microstructure parameters is motivated by plastic deformation and temperature. A number of thermomechanical aspects such as plastic deformation, heat transfer between the material and the container, heat generated by friction, and cooling process after the extrusion are involved in the extrusion process and result in changes in temperature and microstructure parameters subsequently. Therefore a thermomechanically coupled modeling and simulation which includes all of these aspects is required for an accurate prediction of the microstructure evolution. A brief explanation of the isotropic thermoelastic viscoplastic material model including some of the simulation results of this model, which is implemented as a user material (UMAT) in the FEM software ABAQUS, will be given. The microstructure variables are thereby modeled as internal state variables. The simulation results are finally compared with some experimental results.

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