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The effect of aging treatment on mechanical properties ofaa6082 alloy: Modelingand experiment
, Article Iranian Journal of Materials Science and Engineering ; Volume 7, Issue 2 , 2010 , Pages 14-21 ; 17350808 (ISSN) ; Taheri, K ; Sharif University of Technology
2010
Abstract
A novel constitutive equation has been proposed to predict the effect of aging treatment on mechanical properties of AA6082 aluminum alloy. Considering that aging phenomenon affects the distribution of alloying element in matrix, and the fact that different distribution of alloying elements has different impediments to dislocation movement, a material model based on microstructure, has been developed in this research. A relative volume fraction or mean radius of precipitations is introduced into the flow stress by using the appropriate relationships. The GA-based optimization technique is used to evaluate the material constants within the equations from the uni-axial tensile test data of...
Microstructure based modelling of flow behaviour of Al-Mg-Si alloy at different temper conditions
, Article Materials Science and Technology (United Kingdom) ; Volume 29, Issue 8 , 2013 , Pages 968-974 ; 02670836 (ISSN) ; Karimi Taheri, A ; Sharif University of Technology
2013
Abstract
A new integrated physically based constitutive model was developed for an age hardenable Al- Mg-Si alloy. The kinetics of precipitation during various stages of aging was modelled. The precipitate features consisted of particle radius and volume fraction obtained from the kinetics model, which was used to compute the alloy yield strength/hardness. A published multiinternal variable workhardening model was improved to take into account the effects of solute solution and precipitates on the alloy hardening capacity after performing different cycles of aging treatment. The flow curves and hardness predicted by the model were in good agreement with the experimental results. The model is able to...
Physically based material model for evolution of stress-strain behavior of heat treatable aluminum alloys during solution heat treatment
, Article Materials and Design ; Volume 31, Issue 1 , 2010 , Pages 433-437 ; 02641275 (ISSN) ; Karimi Taheri, A ; Sharif University of Technology
2010
Abstract
A mathematical model based on Kocks-Mecking-Bergstrom model, has been proposed to predict the flow behavior of age hardenable aluminum alloys, under different conditions of solution heat treatment and hot deformation. Considering the published literature, most researchers have taken into account the precipitation and solution strengthening contribution to the flow stress by a constant and some others have ignored these effects. So these available descriptions cannot be applicable directly to different conditions of solution heat treatment. In order to enable these constitutive descriptions to take into account the effects of soaking time and temperature, we introduce in this research a...
Corrigendum to “physically based material model for evolution of stress–strain behavior of heat treatable aluminum alloys during solution heat treatment” [mater. des. 31/1 (2010) 433–437](S0261306909002726)(10.1016/j.matdes.2009.05.045)
, Article Materials and Design ; Volume 183 , 2019 ; 02641275 (ISSN) ; Karimi Taheri, A ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
The authors regret to inform that the values of parameters α1 and α2, in Tables 2 and 3 have replaced with each other incorrectly. The correct values are as follows: Table 2: [Formula presented] Table 3: [Formula presented] [Formula presented] Author would like to apologize for the inconvenience caused. © 2019 Elsevier Ltd
Modeling the Microstructure Evolution and Mechanical Properties of Al-Mg-Si alloys During Thermomechanical Treatment
, Ph.D. Dissertation Sharif University of Technology ; Karimi Taheri, Ali (Supervisor)
Abstract
The Al-Mg-Si alloys are an important group of industrial materials used extensively in the automotive and aerospace industry, due to their high strength to weight ratio, good corrosion resistance and the recycle ability. In order to achieve a combination of optimized microstructure and properties during the production processes, the study of deformation behavior and heat treatment of these alloys is necessary. Therefore, the prediction of microstructural evolution and mechanical properties as a function of alloy chemical composition and thermomechanical treatment is important for these alloys, from both the scientific and industrial aspects. In the present research, the flow behavior of this...
Crystal plasticity modeling of the effect of precipitate states on the work hardening and plastic anisotropy in an Al-Mg-Si alloy
, Article Computational Materials Science ; Vol. 83 , 2014 , pp. 78-85 ; ISSN: 09270256 ; Karimi Taheri, A ; Kim, H. S ; Sharif University of Technology
2014
Abstract
In this study the influence of precipitates on the mechanical properties and plastic anisotropy of an age hardenable aluminum alloy during uniaxial loading was investigated using crystal plasticity modeling. The kinetics model of Myhr et al. was used to obtain the solute and precipitate features after different cycles of aging treatment. The amounts of solute, precipitate size and volume fraction, and dislocation density varying during deformation, were used to calculate the slip system strength. An explicit term was obtained based on the elastic inclusion model for the directional dependency of internal stress developed by non-shearable rod shape precipitates. Also, a dislocation evolution...
Simulation and experimental analyses of dynamic strain aging of a supersaturated age hardenable aluminum alloy
, Article Materials Science and Engineering A ; Volume 585 , 2013 , Pages 165-173 ; 09215093 (ISSN) ; Karimi Taheri, A ; Kim, H. S ; Sharif University of Technology
2013
Abstract
In this paper, dynamic strain aging (DSA) behavior in a temperature range of (25-235°C) and strain rate range of (10-4-5×10-2s-1) was investigated using a supersaturated age hardenable aluminum alloy. It was found that two mechanisms consisted of pinning of solute atoms to mobile dislocations and dynamic precipitation, were responsible for DSA in the testing conditions. The effects of both mechanisms on the macroscopic flow curve were studied using experimental and improved physically based material modeling approaches. It was shown that both phenomena lead to a negative strain rate hardening in the alloy. Dynamic precipitation acting at high temperature results in considerable work...
Constitutive modeling of hot deformation behavior of the AA6063 alloy with different precipitates
, Article Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science ; Volume 44, Issue 13 , December , 2013 , Pages 5853-5860 ; 10735623 (ISSN) ; Taheri, A. K ; Kim, H. S ; Sharif University of Technology
2013
Abstract
The current study proposes a simple constitutive model that integrates the kinetics of precipitation during static aging and the kinetics of precipitate dissolution during preheating to deformation temperature to predict the hot flow behavior of AA6063 alloy. The model relates the flow behavior of the age-hardenable alloy to the alloy chemistry, thermal history as well as deformation temperature, strain, and strain rate by means of a physically based model. Different aging conditions, including supersaturated solid solution and overaging conditions with different deformation parameters, were assessed. Each part of the model was in good agreement with those of experimental and other model...