scholarly journals The Influence of Crystallographic Texture on Dynamic Recrystallization

1999 ◽  
Vol 32 (1-4) ◽  
pp. 47-63 ◽  
Author(s):  
R. Kaibyshev ◽  
B. Sokolov ◽  
A. Galiyev
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Crystallographic Texture ◽  
Strong Dependence ◽  
Dislocation Slip ◽  
Recrystallization Process ◽  
Compression Axis ◽  
Initial Texture ◽  
Recrystallized Grain Size ◽  
Kinetics Of

The influence of a crystallographic texture (CT) on Dynamic Recrystallization (DRX) was investigated at T= 300℃ and 2.8 x 10-3 s-1 in Mg–5.8% Zn–0.65% Zr in detail. It was shown that mechanics and kinetics of DRX are in strong dependence on location of basal planes. Initial texture effects recrystallized grain size too. Extensive recrystallization process was observed in cases when basal planes locate parallelly or at right angles to a compression axis. Almost full recrystallization structure was formed after moderate strains. If basal planes locate at 45° to the compression axis DRX occurs slowly and the formed grain size is less as compared to the other two cases. Microstructure evolution was considered in context of relationship between DRX and mechanisms of plastic deformation. It was established that the effect of initial texture on DRX is promoted by its influence on the character of dislocation slip. The reasons for the influence of the character of dislocation slip on DRX are discussed.

Study of Dynamic Precipitation during Hot Deformation of Mg-Al-Sn Alloys

2013 ◽  
Vol 765 ◽  
pp. 461-465 ◽  
Author(s):  
Abu Syed Humaun Kabir ◽  
Jing Su ◽  
In Ho Jung ◽  
Stephen Yue
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Hot Deformation ◽  
Deformation Behaviour ◽  
Recrystallization Process ◽  
Dynamic Precipitation ◽  
Deformation Degree ◽  
Pinning Effect ◽  
Modeling Software ◽  
Recrystallized Grain Size

The objective of this work is to investigate the effect of dynamic precipitation on the hot deformation behaviour of magnesium. Mg-Al-Sn alloys have been designed using thermodynamic modeling software, FactSage, based on precipitation of Mg2Sn at hot deformation temperatures. Uniaxial compression has been introduced at the temperature range of 250-350 °C to enhance the formation of precipitates. The flow behaviour and microstructural evolvement were studied for a strain rate of 0.01 /sand deformation degree of 90 %. Dynamic recrystallization (DRX) occurs in this study and it is found that the volume percent of dynamic recrystallization and dynamically recrystallized grain size are related to the amount of precipitation formed during deformation. The formation of Mg2Sn precipitates during the dynamic recrystallization process may retard the dynamic recrystallization and slow down the grain growth by precipitation pinning effect at the DRX grain boundaries, resulting in a finer grain size.

Recrystallization of 304SS during and after High Strain Rate Deformation

2013 ◽  
Vol 753 ◽  
pp. 403-406
Author(s):  
Adam S. Taylor ◽  
Peter D. Hodgson
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Austenitic Stainless Steels ◽  
Avrami Equation ◽  
Recrystallization Process ◽  
Hollomon Parameter ◽  
Softening Mechanism ◽  
Recrystallization Kinetics ◽  
Kinetics Of ◽  
Shape Changes

During the hot working of austenitic stainless steels the shape of the flow curve is strongly influenced by the strain rate. Low strain rate deformation results in flow curves typical of dynamic recrystallization (DRX) but as the strain rate increases the shape changes to a ‘flat-top’ curve. This has traditionally been thought to indicate no DRX is taking place and that dynamic recovery (DRV) is the only operating softening mechanism. Examining the work-hardening behaviour and corresponding deformation microstructures showed this is not the case for austenitic stainless steel, as clear evidence of dynamic recrystallization process can be seen. The post-deformation recrystallization kinetics can be modelled using a standard Avrami equation with an Avrami exponent, n, of 1.15. With an increasing value of the Zener-Hollomon parameter it was found that the kinetics of recrystallization become less strain rate sensitive until at the highest values (highest strain rates/lowest temperatures) the recrystallization kinetics become strain rate insensitive.

Dynamic Recrystallization during Hot Extrusion in AZ31 and AZ80 Alloys

2007 ◽  
Vol 26-28 ◽  
pp. 449-452 ◽  
Author(s):  
M. Honda ◽  
Tokuteru Uesugi ◽  
Yorinobu Takigawa ◽  
Hiroshi Mabuchi ◽  
Kenji Higashi
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Optical Microscopy ◽  
Hot Extrusion ◽  
Mg Alloys ◽  
Recrystallization Behavior ◽  
Hollomon Parameter ◽  
Dynamic Recrystallization Behavior ◽  
Recrystallized Grain Size

Dynamic recrystallization behavior that occurs during the hot extrusion was examined in two commercial Mg alloys, AZ31 and AZ80 alloys. The initial grain size, d0, and the dynamically recrystallized grain size, drec, after the extrusion was investigated using optical microscopy. The dynamically recrystallized grain size decreased with an increasing the Zener-Hollomon parameter.

scholarly journals Simulation of Dynamic Recrystallization Behavior under Hot Isothermal Compressions for as-extruded 3Cr20Ni10W2 Heat-Resistant Alloy by Cellular Automaton Model

2018 ◽  
Vol 37 (7) ◽  
pp. 635-647 ◽  
Author(s):  
Le Li ◽  
Li-yong Wang
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Cellular Automaton ◽  
Deformation Temperature ◽  
Experimental Result ◽  
Recrystallization Behavior ◽  
Dynamic Recrystallization Behavior ◽  
Ca Model ◽  
Recrystallized Grain Size

AbstractIn order to study dynamic recrystallization behavior of the as-extruded 3Cr20Ni10W2 under isothermal compression conditions, a cellular automaton (CA) model was applied to simulate hot compression. Analysis on the strain–stress curves indicates that dynamic recrystallization is the main softening mechanism for the 3Cr20Ni10W2 when the deformation occurred in the temperature range of 1203–1303 K with an interval of 50 K and strain rate range of 0.01–10 s−1. The deformation temperature and strain rate have a significant influence on the dynamically recrystallized grain size. Subsequently, a CA model is established to simulate the dynamic recrystallization behaviors of the studied alloy. The simulated results show that the mean grain size increases with the increased deformation temperature and decreases with the increased strain rate, which is consistent with the experimental result. In addition, the average absolute relative error, which is 13.14%, indicates that the process of the dynamic recrystallization and the dynamically recrystallized grain size can be well predicted by the present CA model.

Analytical and Numerical Predictions of Machining-Induced Residual Stress in Milling of Inconel 718 Considering Dynamic Recrystallization

2018 ◽  
Author(s):  
Yixuan Feng ◽  
Zhipeng Pan ◽  
Xiaohong Lu ◽  
Steven Y. Liang
Keyword(s):  
Residual Stress ◽  
Grain Size ◽  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Analytical Model ◽  
Inconel 718 ◽  
Milling Process ◽  
Stress Profile ◽  
Recrystallization Process ◽  
Numerical Predictions

A new analytical model is proposed to predict the residual stress in the milling process of Inconel 718 based upon the mechanics analysis of microstructural evolutions. The model proposes to quantify the effects of dynamic recrystallization process on the material flow stress under combined thermal-mechanical loadings in machining. Physics-based mechanistic model is applied to predict the percentage of dynamic recrystallization and the grain size as functions of the milling process parameters and materials constative attributes. The variation of grain size is expected to alter the yield stress, and such dependency relationship is applied to predict the flow stress, which is also dependent on strain, strain rate, and temperature. The time-varying trajectory of residual stress is then predicted at each milling rotation angle through the transformation from milling to equivalent orthogonal cutting, the calculation of stress distribution in loading process, and the stress change during relaxation. The results of analytical model are validated through numerical prediction. The residual stress profile predicted by proposed analytical model matches better with results from numerical model comparing with model without consideration of dynamic recrystallization, especially within subsurface area, with improved accuracy of peak compressive residual stress prediction.

Dynamic Recrystallization during Hot Extrusion in Mg-3Al-0.1Y Alloy

2007 ◽  
Vol 26-28 ◽  
pp. 433-436 ◽  
Author(s):  
T. Noro ◽  
Tokuteru Uesugi ◽  
Yorinobu Takigawa ◽  
Masato Tsujikawa ◽  
Hiroshi Mabuchi ◽  
...  
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Hot Extrusion ◽  
Al Alloys ◽  
Recrystallization Behavior ◽  
Hollomon Parameter ◽  
Fine Microstructure ◽  
Dynamic Recrystallization Behavior ◽  
Recrystallized Grain Size ◽  
The Relationship

Dynamic recrystallization behavior of Mg-3.1wt.%Al-0.1wt.%Y alloy was investigated. During extrusion, dynamic recrystallization occurred and very fine microstructure was obtained. We compared the relationship between Zener-Hollomon parameter, Z, and the dynamically recrystallized grain size, drec, and between the normalized recrystallized grain size, drec/d0, where d0 is the initial grain size, and Z for Mg-3.1wt. %Al-0.1wt.%Y with commercial Mg-3Al-0.5Zn alloy. As the result, the dynamically recrystallized grain size of Mg-3Al-0.1Y was finer than that of Mg-3Al-0.5Zn alloy under the equivalent Z, while the initial grain size of Mg-3Al-0.1Y was coarser than Mg-3Al-0.5Zn alloy. The normalized grain size for Mg-3Al-0.1Y alloy was much smaller than that of Mg-3Al-0.5Zn alloy under the equivalent Z. We conclude that small addition of Y to Mg-Al alloys is effective for grain refinement by dynamic recrystallization.

Simulation of the FGH96 Superalloy Microstructural Changes under Different Deformation Conditions

2008 ◽  
Vol 575-578 ◽  
pp. 455-461 ◽  
Author(s):  
Xiao Na Wang ◽  
Fu Guo Li ◽  
Yu Hong Liu
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Mathematic Model ◽  
Regression Method ◽  
Peak Strain ◽  
Deformation Degree ◽  
Forging Process ◽  
Deformation Velocity ◽  
Work Hardening Rate ◽  
Recrystallized Grain Size

This paper studies FGH96 P/M Superalloy dynamic recrystallization phenomenon under isothermal forging conditions. Curves of work hardening rate θ versus flow stress σ and RTT curve of dynamic recrystallization are gained through the analysis. At the same time, some parameters are confirmed including peak strain, critical strain and the maximal softening strain. On the basis of the analysis, the type of FGH96 P/M Superalloy dynamic recrystallization is exactly estimated. The quantitative metallography method is adopted to determine the recrystallized grain size. With combining the obtained data and parameters, FGH96 P/M Superalloy dynamic recrystallization mathematic model is established by regression method. At the same time, the forging process of FGH96 P/M superalloy is simulated by using software MSC/Superform under different deformation conditions such as deformation temperature and deformation velocity. The contour images of the grain size distribution under different conditions and different deformation degree are gained and analyzed. With the analysis, it is known that the effect of the different deformation conditions on the microstructure of the forging is obvious and there is different distribution of the grain size on various locations, which indicates that the deformation degree of the billet also has influence on the grain size.

Dynamic Recrystallization of Dense Polycrystalline NaCl: Dependence of Grain Size Distribution on Stress and Temperature

2004 ◽  
Vol 467-470 ◽  
pp. 1187-1192 ◽  
Author(s):  
J.H. ter Heege ◽  
J.H.P. de Bresser ◽  
C.J. Spiers
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Boundary Migration ◽  
Elevated Pressure ◽  
Dislocation Creep ◽  
Grain Boundary Migration ◽  
Subgrain Rotation ◽  
Recrystallized Grain Size ◽  
Flow Laws ◽  
Size Data

Only few models explain the development of a steady state grain size during dynamic recrystallization, and their microphysical basis is poorly understood. In this study, we investigate mechanical and microstructural data on dry and wet NaCl, deformed at a range of stresses and temperatures at elevated pressure, with the aim to evaluate the different models. The results show that dry NaCl continuously work hardens and shows evidence for recrystallization dominated by progressive subgrain rotation, while the wet material shows, at similar conditions, oscillating stressstrain behaviour and recrystallization dominated by grain boundary migration. Taking into account the distribution of grain size, deformation of wet NaCl is best described by flow laws based on composite grain size sensitive (GSS) solution-precipitation creep and grain size insensitive (GSI) dislocation creep. The recrystallized grain size data in wet NaCl can be modeled with the hypothesis that recrystallized grain size organises itself in the boundary between the GSS and GSS creep domains.

scholarly journals Simulation of Dynamic and Meta-Dynamic Recrystallization Behavior of Forged Alloy 718 Parts Using a Multi-Class Grain Size Model

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 111
Author(s):  
Christian Gruber ◽  
Peter Raninger ◽  
Aleksandar Stanojevic ◽  
Flora Godor ◽  
Markus Rath ◽  
...  
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Strong Dependence ◽  
Grain Structure ◽  
Alloy 718 ◽  
Recrystallization Behavior ◽  
Production Route ◽  
Grain Size Distributions ◽  
Dynamic Recrystallization Behavior ◽  
Size Model

Dynamic and meta-dynamic recrystallization occur during forging of alloy 718 aircraft parts and thus change the microstructure during a multistep production route. Since the prediction of the resulting grain structure in a single grain fraction is not able to describe microstructures with bimodal or even multimodal distributions, a multi-class grain size model has been deployed to describe the recrystallization mechanisms during thermomechanical treatments and predict the resulting grain size distributions more accurately. As forging parameters, such as temperature, strain rate and maximum strain influence the flow curve and consequently the recrystallization behavior, a series of double cone compression experiments has been carried out and used to verify and adapt the material parameters for the multi-class grain size model. The recrystallized fractions of the numerical and experimental results are compared and differentiated in view of the recrystallization mechanism, i.e., dynamic and meta-dynamic recrystallization. The strong dependence of the recrystallization kinetics on the initial grain size is highlighted, as well as the influence of different strain rates, which shall represent typical forging equipment.

Physical Simulation of Dynamic Recrystallization Behavior of 7050 Aluminum Alloy

2008 ◽  
Vol 575-578 ◽  
pp. 1083-1085
Author(s):  
You Ping Yi ◽  
Yan Shi
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Physical Simulation ◽  
Simulation Method ◽  
Strain Rate Range ◽  
Compression Tests ◽  
7050 Aluminum Alloy ◽  
Recrystallized Grain Size

This work aims to investigate the influence of hot deformation on dynamic recrystallization(DRX) behavior of 7050 aluminum alloy by means of physical simulation method. The hot compression tests were carried out on Gleeble 1500 machine in temperature range of 250-450°C and strain rate range of 0.01–10 s-1. Transmission electronic microscopy (TEM) was employed to observe and analyze the microstructure and DRX behavior in different deformation conditions. The results show that the effects of deformation temperature and strain rate on microstructural evolution of the alloy are remarkable. When temperature is lower than 350°C, only the dynamical recovery( DRV) occurs and typical sub-grains appear. In the range of 350-400°C, the incomplete DRX occurs and the recrystallized grain size increases with increasing temperature. The complete DRX occurs at 450°C and the fine equiaxied grains with high-angle boundaries develop resultantly. The DRX grain size increases as strain rate decreases. The desirable microstructure and properties can be obtained by optimizing the forging process parameters.

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