scholarly journals Establishment of Prediction Model of Microstructure and Properties of 3003 Aluminum Alloy during Hot Deformation

2019 ◽  
Vol 25 (4) ◽  
pp. 369-375 ◽  
Author(s):  
Guiqing CHEN ◽  
Gaosheng FU ◽  
Tianyun WEI ◽  
Chaozeng CHENG ◽  
Huosheng WANG ◽  
...  
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Steady State ◽  
Flow Stress ◽  
Prediction Model ◽  
Hot Deformation ◽  
Steady State Flow ◽  
State Flow ◽  
Average Grain Size ◽  
The Relationship

The 3003 aluminum alloy was deformed by isothermal compression in the range of deformation temperature 300 – 500 ℃ at strain rate 0.0l – 10.0 s-1 with Gleeble-1500 thermal simulator. A constitutive equation is established from the flow stress of the hot deformation. It is found that the average grain size of the 3003 aluminum alloy increases with the decrease of Zener-Hollomon (Z) value, and there is a linear correlation between them. The prediction model of the steady-state flow stress and the average grain size is established. The steady-state flow stress increases with the decrease of the average grain size. The microhardness of the 3003 aluminum alloy has a positive linear relationship with lnZ, and the relationship between the microhardness and the grain size meets the Hall-Petch equation, which can provide a reference for the microstructure control and rolling equipment selection of the 3003 aluminum alloy under hot deformation conditions.

Effect of Grain Size on Mechanical Properties of Single Phase Co-Ni-Cr-Mo Based Superalloy

2005 ◽  
Vol 475-479 ◽  
pp. 631-634 ◽  
Author(s):  
Jun Kyung Sung ◽  
Mok Soon Kim ◽  
Won Yong Kim ◽  
Akihiko Chiba
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Steady State ◽  
Yield Strength ◽  
Flow Behavior ◽  
Strain Curve ◽  
Steady State Flow ◽  
State Flow ◽  
Average Grain Size

A recrystallized Co-Ni-Cr-Mo based superalloy was produced by cold working of 72% and subsequent recrystallization heat treatment. Microstructural observation revealed that a full recrystallization of the cold-worked alloy occured when heat treatment was performed at and above 1273K for 1h. So that, recrystallization heat treatment was carried out in a temperature range from 1273K to 1473K for 1h~24h, by which the average grain size was controlled to 28µm～238µm. Tensile tests were carried out from room temperature (RT) to 1073K in order to understand the effect of grain size on the mechanical properties of the Co-Ni-Cr-Mo based superalloy. At RT and 943K, yield strength, tensile strength and elongation of the recrystallized alloy were improved with decreasing grain size. The alloy having a grain size less than 42µm exhibited a steady-state flow behavior in the true stress-true strain curve at 943K. However, the alloy having a grain size of 28µm showed lower yield strength than that of 42µm at 1073K. It was found that the steady state flow is closely related to the occurrence of {111}<112> deformation twinning in the Co-Ni-Cr-Mo based superalloy.

Hot Deformation Behavior and Microstructure of 6069 Aluminum Alloy

2014 ◽  
Vol 788 ◽  
pp. 201-207 ◽  
Author(s):  
Hui Zhong Li ◽  
Jun Jiang ◽  
Min Deng ◽  
Xiao Peng Liang ◽  
Jie Ouyang
Keyword(s):  
Aluminum Alloy ◽  
Steady State ◽  
Flow Stress ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Constant Strain Rate ◽  
Strain Rates ◽  
Steady State Flow ◽  
State Flow

The deformation behavior and microstructure of 6069 aluminum alloy have been studied by isothermal compression at temperature ranging from 300°C to 450°C on Gleeble-1500 machine at strain rates from 0.01 to 10s-1. The results show that the deformation temperature and strain rate is essential to the flow characteristic, and the main deformation mechanism for 6069 aluminum alloy is dynamic recovery at low strain rates. The dynamic recrystallization take place at the strain rates of 10s-1 and deformation temperature ranges of 300~350°C. At constant strain rate, the flow stress and steady-state flow stress decrease with deformation temperature increasing. While at constant temperature, the flow stress and steady-state flow stress increase with increasing strain rate. The processing map at the strain of 0.7 is obtained and the map exhibits two safe deformation domains (300~350°C at 1~10s-1 and 380~450°C at 0.01~0.3s-1).

Submicrocrystalline Structure Formation in Ti and Ti-64 Alloy by Warm “abc” Deformation

2007 ◽  
Vol 551-552 ◽  
pp. 183-188 ◽  
Author(s):  
Sergey V. Zherebtsov ◽  
Sergey Mironov ◽  
Gennady A. Salishchev
Keyword(s):  
Grain Size ◽  
Titanium Alloy ◽  
Steady State ◽  
Mechanical Behavior ◽  
Structure Formation ◽  
Microstructure Evolution ◽  
Superplastic Flow ◽  
Steady State Flow ◽  
Two Phase ◽  
State Flow

Mechanical behavior and microstructure evolution of Ti and Ti-64 titanium alloy during warm “abc” deformation has been studied. The “abc” deformation was consisted of successive compression of a sample along three orthogonal directions. Mechanical behavior of each material was described by set of successive σ-ε curves combined into cumulative σ-Σε curve. Microstructure of Ti was found to be refined to a grain size of about 0.4 μm due to formation of deformation-induced boundaries within initial grains. Although a stage like steady state flow was observed at the cumulative σ-Σε curve such mechanical behavior was hardly associated with superplastic flow. In two-phase Ti-64 alloy the structure was found to be refined to a grain size of about 0.4 μm after warm “abc” deformation due to globularization α- and β-particles following breaking down of α-lamellar and β- layers. Microstructure refinement of the alloy was associated with softening and superplastic flow.

Simulation of Recrystallization Behavior and Austenite Grain Size Evolution during Hot Deformation of Low Carbon Steel Using the Flow Stress

2011 ◽  
Vol 337 ◽  
pp. 178-183 ◽  
Author(s):  
Jian Wang ◽  
Hong Xiao ◽  
Hong Biao Xie ◽  
Xiu Mei Xu
Keyword(s):  
Grain Size ◽  
Flow Stress ◽  
Dislocation Density ◽  
Microstructure Evolution ◽  
Hot Deformation ◽  
Process Model ◽  
Model Parameters ◽  
Flow Curves ◽  
Austenite Grain Size ◽  
Average Grain Size

Microstructure evolution can cause changes in dislocation density during hot plastic formation of metals and greatly influence the shape of flow curves. Recrystallization kinetics and average grain size were simulated by the coupled flow stress model describing dislocation development and microstructure evolution. The model for microstructure evolution considered different kinds of recrystallization in the same process rooted from nucleation and grain growth. Flow stress was calculated from the average dislocation density determined by the dislocation density model, which took into account hardening and recovery during the hot deformation process. Model parameters were defined by inverse analysis of flow curves obtained from hot compression tests and were completed through solving a nonlinear least-squares problem with constraints using optimization methods. Finally, the results obtained by the proposed model were compared with experimental results.

The Effect of Grain Size Distribution on the Mechanical Properties of Nanometals

2008 ◽  
Vol 140 ◽  
pp. 185-190 ◽  
Author(s):  
T.B. Tengen ◽  
Tomasz Wejrzanowski ◽  
R. Iwankiewicz ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Flow Stress ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Deformation Mechanisms ◽  
Average Grain Size ◽  
Significant Interest ◽  
Size Dispersion ◽  
The Relationship

Predicting the properties of a material from knowledge of the internal microstructures is attracting significant interest in the fields of materials design and engineering. The most commonly used expression, known as Hall-Petch Relationship (HPR), reports on the relationship between the flow stress and the average grain size. However, there is much evidence that other statistical information that the grain size distribution in materials may have significant impact on the mechanical properties. These could even be more pronounced in the case of grains of the nanometer size, where the HPR is no longer valid and the Reverse-HPR is more applicable. This paper proposes a statistical model for the relationship between flow stress and grain size distribution. The model considered different deformation mechanisms and was used to predict mechanical properties of aluminium and copper. The results obtained with the model shows that the dispersion of grain size distribution plays an important role in the design of desirable mechanical properties. In particular, it was found that that the dependence of a material’s mechanical properties on grain size dispersion also follows the HPR to Inverse-HPR type of behaviour. The results also show that copper is more sensitive to changes in grain size distribution than aluminium.

Dynamic Recrystallization Mechanisms Operating under Different Processing Conditions

2012 ◽  
Vol 706-709 ◽  
pp. 2704-2709 ◽  
Author(s):  
Andrey Belyakov ◽  
Nadezhda Dudova ◽  
Marina Tikhonova ◽  
Taku Sakai ◽  
Kaneaki Tsuzaki ◽  
...  
Keyword(s):  
Grain Size ◽  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Hot Working ◽  
Structural Mechanism ◽  
Temperature Changes ◽  
Average Grain Size ◽  
Grain Formation ◽  
Power Law Function ◽  
The Relationship

Dynamic recrystallization (DRX) is one of the most important mechanisms for microstructure evolution during deformation of various metals and alloys. So-called discontinuous DRX usually develops in structural materials with low to medium stacking fault energy during hot working. The local migration, i.e. bulging, of grain boundaries leads to the formation of recrystallization nuclei, which then grow out consuming work-hardened surroundings. The cyclic character of nucleation and growth of new grains during deformation results in a dynamically constant average grain size. The dynamic grain size is sensitively dependent on temperature and strain rate and can be expressed by a power law function of flow stress with a grain size exponent of about-0.7 under conditions of hot working. Recent studies on DRX phenomenon suggest that a decrease in deformation temperature changes the structural mechanism for new grain formation. As a result, the grain size exponent in the relationship between the dynamic grain size and flow stress approaches about-0.25 under warm working conditions.

On the steady state flow stress of iron at low temperature and large strains

1974 ◽  
Vol 5 (2) ◽  
pp. 519-520 ◽  
Author(s):  
C. M. Young ◽  
L. J. Anderson ◽  
O. D. Sherby
Keyword(s):  
Steady State ◽  
Flow Stress ◽  
Low Temperature ◽  
Large Strains ◽  
Steady State Flow ◽  
State Flow

scholarly journals Steady-state modelling and performance of a rotary direct drive digital valve

2020 ◽  
Vol 53 (3-4) ◽  
pp. 311-319
Author(s):  
Yuesong Li
Keyword(s):  
Mathematical Model ◽  
Steady State ◽  
Angular Displacement ◽  
Stepper Motor ◽  
Direct Drive ◽  
Rotary Valve ◽  
Steady State Flow ◽  
Load Pressure ◽  
State Flow ◽  
The Relationship

A rotary direct drive digital valve driven by a stepper motor was proposed. By analysing its working principle, the steady-state mathematical model reflecting the relationship between the pressure, the flow and the angular displacement was deduced. Based on this mathematical model, the models of the null valve coefficients, the zero leakage flow and the steady-state flow torque were given. The simulation shows that the relationship between the pressure and the flow of the rotary valve is nonlinear; however, under a constant load pressure, the flow characteristics and the steady-state flow torque characteristics of the rotary valve with rectangular throttle orifices are linear. The experimental results show that the flow is directly proportional to the steps of the stepper motor, and the proposed mathematical models are valid.

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