A Criterion for Conventional Dynamic Recrystallization: Application to Magnesium Alloys

2007 ◽  
Vol 550 ◽  
pp. 369-374
Author(s):  
Matthew R. Barnett ◽  
Aiden G. Beer
Keyword(s):  
Grain Size ◽  
Steady State ◽  
Dynamic Recrystallization ◽  
Magnesium Alloys ◽  
High Temperatures ◽  
Working Conditions ◽  
Analytical Approximation ◽  
Hot Working ◽  
Strain Rates ◽  
Recrystallized Grain Size

An analytical approximation for the steady state dynamic recrystallized grain size is combined with a simple nucleation criterion to assess the propensity for dynamic recrystallization. In line with observation, the criterion predicts dynamic recrystallization in 99.9995% pure Al but not in material 99.5% pure. It also agrees with the observation that zone refined ferrite can display dynamic recrystallization at high temperatures and low strain rates but not at lower hot working temperatures. The criterion is applied here to common wrought magnesium alloys to argue that conventional dynamic recrystallization is expected under "normal" hot working conditions.

scholarly journals Dynamic Recrystallization Behavior and Processing Map of the 6082 Aluminum Alloy

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1042 ◽  
Author(s):  
Dao-chun Hu ◽  
Lei Wang ◽  
Hong-jun Wang
Keyword(s):  
Dynamic Recrystallization ◽  
Critical Strain ◽  
High Efficiency ◽  
Processing Map ◽  
Testing Machine ◽  
Hot Compression ◽  
Hot Working ◽  
Al Alloy ◽  
Strain Rates ◽  
6082 Al Alloy

Multiple hot-compression tests were carried out on the 6082 aluminum (Al) alloy using a Gleeble-1500 thermal simulation testing machine. Data on flow stresses of the 6082 Al alloy at deformation temperatures of 623 to 773 K and strain rates from 0.01 to 5 s−1 were attained. Utilizing electron backscatter diffraction (EBSD) and a transmission electron microscope (TEM), the dynamic recrystallization behaviors of the 6082 Al alloy during hot compression in isothermal conditions were explored. With the test data, a hot-working processing map for the 6082 Al alloy (based on dynamic material modeling (DMM)) was drawn. Using the work-hardening rate, the initial critical strain causing dynamic recrystallization was determined, and an equation for the critical strain was constructed. A dynamic model for the dynamic recrystallization of the 6082 Al alloy was established using analyses and test results from the EBSD. The results showed that the safe processing zone (with a high efficiency of power dissipation) mainly corresponded to a zone with deformation temperatures of 703 to 763 K and strain rates of 0.1 to 0.3 s−1. The alloy was mainly subjected to continuous dynamic recrystallization in the formation of the zone. According to the hot-working processing map and an analysis of the microstructures, it is advised that the following technological parameters be selected for the 6082 Al alloy during hot-forming: a range of temperatures between 713 and 753 K and strain rates between 0.1 and 0.2 s−1.

A Different View on Dynamic Recrystallization

2012 ◽  
Vol 715-716 ◽  
pp. 235-242 ◽  
Author(s):  
Günter Gottstein
Keyword(s):  
Grain Size ◽  
Steady State ◽  
Dynamic Recrystallization ◽  
Grain Boundaries ◽  
Experimental Results ◽  
Critical Conditions ◽  
New Approach ◽  
Theoretical Predictions

A new approach to dynamic recrystallization (DRX) is introduced. It is based on the assumption that the critical conditions for DRX and the arrest of DRX grain boundaries are related to the development of mobile subboundaries. The theoretical predictions are compared to experimental results during incipient and steady-state DRX. The grain size sensitivity of the DRX grains establishes the desired link between deformation and DRX microstructure.

Flow Stress Behavior of Nanometric Al2O3 Particulate Reinforced Al Alloy Composites Manufactured by Casting

2012 ◽  
Vol 430-432 ◽  
pp. 1294-1297
Author(s):  
Zhi Min Zhang ◽  
Yong Biao Yang ◽  
Xing Zhang
Keyword(s):  
Grain Size ◽  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Al Alloy ◽  
Strain Rates ◽  
Stress Behavior ◽  
Flow Stress Behavior ◽  
Increasing Temperature ◽  
Particulate Reinforced ◽  
Temperature Dynamic

The flow stress behavior of nanometric Al2O3 particulate reinforced Al alloy composites were investigated using thermal simulation machine Gleeble-1500. Microsturctural analysis were carried out on optical microscopy. The results showed that the flow stress increased with increasing strain rate and decreased with decreasing temperature. Dynamic recovery and dynamic recrystallization occurred during hot compression of the Al composites. The grain size increased with increasing temperature (590k-710k) and decreased at 750k due to dynamic recrystallization. The grain size decreased with increasing strain rates at 750k.

scholarly journals Study of Static Recrystallization Kinetics and the Evolution of Austenite Grain Size by Dynamic Recrystallization Refinement of an Eutectoid Steel

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1289
Author(s):  
Cesar Facusseh ◽  
Armando Salinas ◽  
Alfredo Flores ◽  
Gerardo Altamirano
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Static Recrystallization ◽  
Controlled Rolling ◽  
Strain Rates ◽  
Peak Strain ◽  
Compression Tests ◽  
Eutectoid Steel ◽  
Austenite Grain Size ◽  
Austenite Grain

Interrupted and continuous hot compression tests were performed for eutectoid steel over the temperature range of 850 to 1050 °C and while using strain rates of 0.001, 0.01, 0.1, and 1 s−1. The interrupted tests were carried out to characterize the kinetics of static recrystallization(SRX) and determinate the interpass time conditions that are required for initiation and propagation of dynamic recrystallization (DRX), while considering that the material does not contain microalloying elements additions for the recrystallization delay. Continuous testing was used to investigate the evolution of the austenite grain size that results from DRX. The results indicate that carbon content accelerates the SRX rate. This effect was observed when the retardation of recrystallization due to a decrease in deformation temperature from 1050 to 850 °C was only about one order of magnitude. The expected decelerate effect on the SRX rate when the initial grain size increases from 86 to 387 µm was not significant for this material. Although the strain parameter has a strong influence on SRX rate, in contrast to a lesser degree of strain rate, both of the effects are nearly independent of the chemical composition. The calculated maximum interpass times that are compatible with DRCR (Dynamic Recrystallization Controlled Rolling), for relatively low strain rates, suggest that the onset and maintaining of the DRX is possible. However, while using the empirical equations that were developed in the present work to estimate the maximum times for high strain rates, such as those observed in the wire and rod mills, indicate that the DRX start is feasible, but maintaining this mechanism for 5% softening in each pass after peak strain is not possible.

Grain Size in Mg Alloys: Recrystallization and Mechanical Consequences

2007 ◽  
Vol 558-559 ◽  
pp. 433-440 ◽  
Author(s):  
Matthew R. Barnett ◽  
Dale Atwell ◽  
Aiden G. Beer
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Grain Refinement ◽  
Magnesium Alloys ◽  
Mechanical Response ◽  
Deformation Twinning ◽  
Simultaneous Increase ◽  
The Impact ◽  
Strength And Ductility

The present paper examines the development of grain size during the recrystallization of magnesium alloys and the influence the grain size has on the mechanical response. In magnesium alloys grain refinement improves the strength-ductility balance. This simultaneous increase in both strength and ductility is ascribed to the impact the grain size has on deformation twinning. The mechanisms by which the grain size is established during hot working are shown to be conventional dynamic recrystallization followed by post-dynamic recrystallization. The role of alloying addition on both of these reactions is briefly considered.

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