Quasi-in-situ observations of low-angle grain boundaries, twins and texture evolution during continuous annealing in a cold-rolled Mg-Zn-Gd alloy

2020 ◽  
Vol 170 ◽  
pp. 110697
Author(s):  
L.Y. Zhao ◽  
H. Yan ◽  
R.S. Chen ◽  
En-Hou Han
Keyword(s):  
Grain Boundaries ◽  
Texture Evolution ◽  
Continuous Annealing ◽  
In Situ Observations ◽  
Cold Rolled

In-Situ SEM Observations of Moving Interfaces during Recrystallisation

2006 ◽  
Vol 519-521 ◽  
pp. 1341-1348 ◽  
Author(s):  
Sybrand van der Zwaag ◽  
E. Anselmino ◽  
A. Miroux ◽  
David J. Prior
Keyword(s):  
Grain Boundaries ◽  
Small Groups ◽  
Detailed Understanding ◽  
Small Areas ◽  
Orientation Contrast ◽  
Moving Interfaces ◽  
Innovative Method ◽  
Before And After ◽  
In Situ Observations

To obtain further progress and a more detailed understanding of the mechanisms involved in recrystallisation, new and more accurate techniques such as in-situ observations are necessary. This innovative method has been used to monitor the recrystallisation process in a FEGSEM equipped with hot stage. Observations are done in backscatter mode with particular attention to orientation contrast. EBSD maps of the observed areas can be acquired before and after recrystallisation. Details of the movement of the interfaces between the recrystallised region and the parent structure are recorded and analysed. The results show that the grain boundaries observed do not move smoothly but with a jerky motion. The recrystallising front sweeps through small areas, corresponding to single sub-grains or small groups of them, very rapidly and then stops at other sub-grain boundaries for varying time before progressing to the following area.

Laser-Ultrasonics as a Technique to Study Recrystallisation and Grain Growth

2004 ◽  
Vol 467-470 ◽  
pp. 1353-1362 ◽  
Author(s):  
Eva Lindh-Ulmgren ◽  
Mattias Ericsson ◽  
Dorota Artymowicz ◽  
W. Bevis Hutchinson
Keyword(s):  
Carbon Steels ◽  
Laser Ultrasonics ◽  
Continuous Annealing ◽  
Low Carbon ◽  
Steel Sheets ◽  
On Line ◽  
Cold Rolled ◽  
Dynamic Heating ◽  
Good Agreement

Laser-Ultrasonics (LUS) provides a means of obtaining microstructure information continuously and non-destructively both in the laboratory and for quality control on-line in industry. Ultrasound is both generated and recorded using lasers which permits remote, non-contact operation with fast sampling and also the capability of working at high temperatures or at moving surfaces, for example during industrial continuous annealing. Examples of dynamic heating trials will be presented for samples of cold rolled steel sheets where primary recrystallisation and ferrite austenite transformation are monitored in-situ as a function of temperature. Examples are also presented where the grain size of low carbon steels have been quantitatively analysed and show very good agreement with microscopy methods.

In Situ EBSP Observations of Recrystallization in Commercial Purity Aluminum

2007 ◽  
Vol 558-559 ◽  
pp. 223-228 ◽  
Author(s):  
Katsura Kajihara
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Early Stage ◽  
Boundary Motion ◽  
Commercial Purity ◽  
Solute Content ◽  
In Situ Observations ◽  
Commercial Purity Aluminum ◽  
Grain Boundary Motion

This study presents in-situ EBSP observations of recrystallization in commercial purity aluminum sheets with different concentrations of solutes and different states of precipitation. The in-situ observations demonstrate clearly the behaviors of the nucleation and growth of recrystallized grains, and the movements of grain boundaries at an early stage of recrystallization. The high mobility of grain boundaries neighboring the deformed matrix was generally observed presumably due to strain-induced grain boundaries migration. The grain boundary motion was also found to strongly depend to the solute content level. These in-situ observations provide important evidence to show that the behaviors of grain boundary motion at an early stage of recrystallization leads to the grain size distribution and the curvature of grain boundaries after the primary recrystallization.

In Situ Observations of Precipitation

1973 ◽  
Vol 31 ◽  
pp. 168-169
Author(s):  
E.P. Butler ◽  
P.R. Swann
Keyword(s):  
Grain Boundaries ◽  
Experimental Evidence ◽  
Imperial College ◽  
Cellular Reaction ◽  
Cellular Decomposition ◽  
Temperature Range ◽  
In Situ Observations ◽  
Precipitation Reactions ◽  
Cell Interface

This paper reports preliminary observations of precipitation in several alloy systems obtained with an accurately calibrated hot stage in the AEI EM7 1MeV microscope at Imperial College. These observations, in >1μ thick specimens where precipitation is generally more characteristic of bulk, provide experimental evidence which allows existing theories of precipitation reactions to be examined and critically evaluated.Cellular decomposition in Al-Zn and Mg-Al The cellular reaction in Al-48wt%Zn has been studied in the temperature range 75-250°C. Nucleation occurs rapidly on grain boundaries by the formation of individually nucleated ‘nodules’ which quickly impinge to form an approximately planar cell interface.

Microstructure and Texture Evolution during Recrystallization of a Fe-Mn-C Alloy

2013 ◽  
Vol 753 ◽  
pp. 177-180 ◽  
Author(s):  
Fa Yun Lu ◽  
Christian Haase ◽  
Luis Antonio Barrales-Mora ◽  
Dmitri A. Molodov ◽  
Ping Yang
Keyword(s):  
Grain Boundaries ◽  
Texture Evolution ◽  
Shear Bands ◽  
Strong Impact ◽  
Triple Junctions ◽  
Low Intensity ◽  
Nucleation Sites ◽  
Annealing Twins ◽  
Preferential Nucleation ◽  
Cold Rolled

Microstructure and texture evolution of a 60% cold-rolled Fe-22.3Mn-0.3C alloy during annealing at 550°C were studied. Shear bands, triple junctions and grain boundaries were found to be the preferential nucleation sites. The orientations of the nuclei from these sites were found to be mainly random, but also partly located in α-(//ND) and γ-fibers (//ND). After annealing, fine recrystallized grains formed with abundant annealing twins which had a strong impact on the texture development. The final texture was of low intensity and revealed a weak α-fiber.

Grain Boundary Migration and Grain Growth Texture Evolution in Zn in a High Magnetic Field

2011 ◽  
Vol 702-703 ◽  
pp. 635-638
Author(s):  
Christoph Günster ◽  
Dmitri A. Molodov ◽  
Günter Gottstein
Keyword(s):  
Magnetic Field ◽  
Grain Boundary ◽  
Grain Growth ◽  
Texture Evolution ◽  
Boundary Migration ◽  
Activation Parameters ◽  
Boundary Plane ◽  
Grain Boundary Migration ◽  
Cold Rolled

The magnetically driven motion of planar symmetrical and asymmetrical <> tilt grain boundaries in high purity (99,995%) zinc bicrystals was measured in-situ by means of a po­la­rization microscopy probe in the temperature range between 330°C and 415°C and the corres­pon­ding migration activation parameters were obtained. The results revealed that grain boundary mobi­lity essentially depends on the misorientation angle and the inclination of the boundary plane. The magnetic annealing of the cold rolled (90%) Zn-1.1%Al sheet specimens resulted in an asymmetry of the two major texture components. This effect is attributed to a magnetic driving force for grain growth. The grain microstructure evolution was also essentially affected by a magnetic field.

In Situ Observations of the Interaction of Liquid Lead Inclusions with Grain Boundaries in Aluminum

1998 ◽  
Vol 4 (3) ◽  
pp. 286-293 ◽  
Author(s):  
Heike Gabrisch ◽  
Ulrich Dahmen ◽  
Erik Johnson
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Ostwald Ripening ◽  
Wetting Transition ◽  
Liquid Lead ◽  
In Situ Tem ◽  
Triple Junctions ◽  
Temperature Range ◽  
In Situ Observations

The evolution of liquid lead (Pb) inclusions at grain boundaries in aluminum (Al) was investigated by direct in situ TEM observation in the temperature range from 330°–643°C, In agreement with earlier reports on quenched alloys, the characteristic contact angle of the lens-shaped grain boundary inclusions was found to be near 120°. This angle remained approximately constant over the entire temperature range, ruling out the possibility of a wetting transition. Coarsening of grain boundary inclusions was observed to proceed mainly by Ostwald ripening, although coalescence could also be observed. Inclusions at grain boundaries, at triple junctions, and at the intersection of grain boundaries with the foil surfaces adopted characteristic shapes that were shown to be equilibrium forms. At the highest temperatures, the grain boundaries were observed to detach from the inclusions and the interaction of a migrating grain boundary with inclusions could be observed.

scholarly journals Distinct Recrystallization Pathways in a Cold-Rolled Al-2%Mg Alloy Evidenced by In-Situ Neutron Diffraction

2018 ◽  
Vol 2 (3) ◽  
pp. 17 ◽  
Author(s):  
Grigoreta Stoica ◽  
Luc Dessieux ◽  
Alexandru Stoica ◽  
Sven Vogel ◽  
Govindarajan Muralidharan ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Texture Evolution ◽  
Deformation Texture ◽  
Mg Alloy ◽  
Scanning Calorimetry ◽  
Los Alamos ◽  
Oak Ridge ◽  
Quasi Monte Carlo ◽  
Cold Rolled

The time-of-flight neutron diffraction data collected in-situ on Oak Ridge National Laboratory’s (ORNL, Oak Ridge, TN, USA) VULCAN and Los Alamos National Laboratory’s (LANL, Los Alamos, NM, USA) High-Pressure-Preferred-Orientation (HIPPO) diffractometers have been analyzed complementarily to show the texture evolution during annealing of a cold-rolled Al-2%Mg alloy. The texture analysis aimed to identify the components present in the initial rolling (or deformation) texture and in the thermally-activated recrystallization texture, respectively. Using a quasi-Monte-Carlo (QMC) approach, a new method has been developed to simulate the weighted texture components, and to obtain inverse pole figures for both rolling and normal directions. As such, distinct recrystallization pathways during annealing in isochronal conditions, can be revealed in terms of the evolution of the texture components and their respective volume fractions. Moreover, the recrystallization kinetics associated with the cube and random texture components are analyzed quantitatively using a similar approach developed for differential scanning calorimetry (DSC).

Magnetically Controlled Grain Boundary Migration and Microstructure Evolution in Zn

2013 ◽  
Vol 333 ◽  
pp. 101-106
Author(s):  
Dmitri A. Molodov ◽  
Christoph Günster ◽  
Günter Gottstein
Keyword(s):  
Magnetic Field ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Microstructure Evolution ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Boundary Mobility ◽  
Grain Boundary Mobility ◽  
Cold Rolled

The migration of planar grain boundaries induced by a magnetic field was measured in specially grown zinc bicrystals (99.995%). Particularly, symmetrical and asymmetrical <> tilt grain boundaries with rotation angles in the range between 60° and 90° were investigated. Boundary migration was measured in-situ in the temperature range between 330°C and 415°C and the absolute values of grain boundary mobility were obtained. The results revealed that grain boundary mobility essentially depends on the misorientation angle and the inclination of the boundary plane. An application of a magnetic field during the annealing of cold rolled (90%) Zn-1.1%Al sheet specimens substantially affected the texture and microstructure evolution. This effect is attributed to the additional magnetic driving force for grain growth arising due to the magnetic anisotropy of zinc.

In situ investigation of the primary recrystallization of alpha titanium in HVEM

1978 ◽  
Vol 36 (1) ◽  
pp. 634-635
Author(s):  
S. Naka ◽  
R. Penelle ◽  
R. Valle
Keyword(s):  
Dimensional Analysis ◽  
Texture Evolution ◽  
Cold Work ◽  
Three Dimensional ◽  
Primary Recrystallization ◽  
Thin Foils ◽  
In Situ Investigation ◽  
Grain Growth Model ◽  
Alpha Titanium

The in situ experimentation technique in HVEM seems to be particularly suitable to clarify the processes involved in recrystallization. The material under investigation was unidirectionally cold-rolled titanium of commercial purity. The problem was approached in two different ways. The three-dimensional analysis of textures was used to describe the texture evolution during the primary recrystallization. Observations of bulk-annealed specimens or thin foils annealed in the microscope were also made in order to provide information concerning the mechanisms involved in the formation of new grains. In contrast to the already published work on titanium, this investigation takes into consideration different values of the cold-work ratio, the temperature and the annealing time.Two different models are commonly used to explain the recrystallization textures i.e. the selective grain growth model (Beck) or the oriented nucleation model (Burgers). The three-dimensional analysis of both the rolling and recrystallization textures was performed to identify the mechanismsl involved in the recrystallization of titanium.

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