Abnormal Grain Growth Approached by Sub-Boundary Enhanced Solid-State Wetting

2012 ◽  
Vol 715-716 ◽  
pp. 542-542
Author(s):  
Nong Moon Hwang
Keyword(s):  
Solid State ◽  
Cold Rolling ◽  
Grain Growth ◽  
Triple Junction ◽  
Secondary Recrystallization ◽  
Growth Front ◽  
Abnormal Grain Growth ◽  
Low Energy ◽  
Polycrystalline Materials ◽  
Goss Texture

Abnormal grain growth (AGG), which is also called the secondary recrystallization, often takes place after primary recrystallization of deformed polycrystalline materials. A famous example is the evolution of the Goss texture after secondary recrystallization of Fe-3%Si steel. A selective AGG of Goss grains has remained a puzzle over 70 years in the metallurgy community since its first discovery by Goss in 1935. We suggested the sub-boundary enhanced solid-state wetting as a mechanism of selective AGG of Goss grains. According to this mechanism, if Goss grains have sub-boundaries of low energy, they have an exclusively high probability to grow by solid-state wetting along a triple junction compared with other grains without sub-boundaries. This aspect has been confirmed by Monte-Carlo and Phase Field Model simulations. The simulations showed that if the abnormally-growing grain has a high fraction of low energy boundaries with the matrix grains, it favors the sub-boundary enhanced solid-state wetting and produces many island and peninsular grains frequently observed near the growth front of abnormally-growing Goss grains. For example, the {111}<112> orientation has a S9 relationship with a Goss grain. Therefore, grains with the {111}<112> orientation provide a favorable condition for sub-boundary enhanced solid-state wetting. Three or four-sided grains with convex-inward boundaries, which are observed on a two-dimensional section of polycrystalline structures, are not shrinking but are growing, indicating that they are growing by wetting along a triple junction. These and other microstructural evidences of solid-state wetting could be observed relatively easily near the growth front of abnormally-growing Goss grains. The existence of sub-boundaries exclusively in abnormally-growing Goss grains has been experimentally confirmed. In order to understand why only Goss grains have sub-boundaries, the cold rolling process of the hot-rolled Fe-3%Si steel was analyzed by finite element method (FEM). The analysis showed that a small portion of Goss grains formed during hot rolling survives after cold rolling; the survived Goss grains have the lowest stored energy and are expected to undergo only recovery without recrystallization, producing sub-boundaries.

New Understanding of Abnormal Grain Growth Approached by Solid-State Wetting along Grain Boundary or Triple Junction

2004 ◽  
Vol 467-470 ◽  
pp. 745-750 ◽  
Author(s):  
Nong Moon Hwang
Keyword(s):  
Solid State ◽  
Grain Boundary ◽  
Grain Growth ◽  
Triple Junction ◽  
Boundary Energy ◽  
Growth Front ◽  
Abnormal Grain Growth ◽  
Boundary Mobility ◽  
Grain Boundary Mobility ◽  
Mc Simulation

Although it has been generally believed that the advantage of the grain boundary mobility induces abnormal grain growth (AGG), it is suggested that the advantage of the low grain boundary energy, which favors the growth by solid-state wetting, induces AGG. Analyses based on Monte Carlo (MC) simulation show that the approach by solid-state wetting could explain AGG much better than that by grain boundary mobility. AGG by solid-state wetting is supported not only by MC simulations but also by the experimental observation of microstructure evolution near or at the growth front of abnormally growing grain. The microstructure shows island grains and solid-state wetting along grain boundary and triple junction.

Influence of New System Nano-Inhibitors on the Abnormal Grain Growth with Goss Crystallographic Orientation of Silicon Steels

2014 ◽  
Vol 783-786 ◽  
pp. 2579-2584
Author(s):  
František Kováč ◽  
Ivan Petryshynets ◽  
Jiří Buršík ◽  
Martin Sopko
Keyword(s):  
Grain Growth ◽  
Crystallographic Orientation ◽  
Secondary Recrystallization ◽  
Abnormal Grain Growth ◽  
Continuous Annealing ◽  
Preparation Time ◽  
Goss Texture ◽  
Whole Process ◽  
Long Time ◽  
New System

In the present work some new approaches have proposed for the grain oriented steel fabrication. This approach employs the new system of VC nanoprecipitates in the combination with dynamic continuous annealing for secondary recrystallization. The new system of VC inhibitors and dynamic annealing was applied to the grain oriented steel in order to obtain abnormal grain growth with Goss crystallographic orientation and considerably reduces the preparation time as the whole process lasts only several minutes. The EBSD analysis shown that suggested procedure led to evolution of the sufficiently strong {110}<001> Goss texture, which is comparable to that obtained in the conventionally treated GO steels. Moreover, the steels treated by this new method have the comparable final magnetic properties as the materials passed the conventional long – time heat treatment.

Abnormal Grain Growth and Texture Development

2005 ◽  
Vol 495-497 ◽  
pp. 1171-1176 ◽  
Author(s):  
Anthony D. Rollett
Keyword(s):  
Grain Boundary ◽  
Grain Growth ◽  
Abnormal Grain Growth ◽  
Polycrystalline Materials ◽  
Second Phase ◽  
Goss Texture ◽  
Electrical Steels ◽  
Second Phase Particles ◽  
Euler Space ◽  
Boundary Properties

A theory for abnormal grain growth (AGG) in polycrystalline materials is revisited and extended in order to predict AGG in textured polycrystals. The motivation for the work is to improve our understanding of the origins of the Goss texture component, {110}<001>, during annealing of Fe-Si sheet. Since the AGG phenomenon in grain-oriented electrical steels is known to be dependent on the presence of a dispersion of fine second phase particles, the grain boundary properties are treated as representative of the homogenized behavior of the material, and not necessarily the properties that would be measured directly. The predictions of AGG are presented in the form of maps in Euler space, showing which texture components are most likely to grow abnormally. For different models of grain boundary properties applied to a theoretically derived texture, different sets of texture components are predicted to grow; neither model, however, predicts growth of the Goss component.

Abnormal grain growth by solid-state wetting along grain boundary or triple junction

2001 ◽  
Vol 44 (7) ◽  
pp. 1153-1160 ◽  
Author(s):  
Nong M. Hwang ◽  
Sung B. Lee ◽  
Doh-Y. Kim
Keyword(s):  
Solid State ◽  
Grain Boundary ◽  
Grain Growth ◽  
Triple Junction ◽  
Abnormal Grain Growth

Abnormal Grain Growth of Fe-3%Si Steel Approached by Solid-State Wetting Mechanism

2007 ◽  
Vol 26-28 ◽  
pp. 65-68 ◽  
Author(s):  
Kyung Jun Ko ◽  
Pil Ryung Cha ◽  
Jong Tae Park ◽  
Jae Kwan Kim ◽  
Nong Moon Hwang
Keyword(s):  
Solid State ◽  
Grain Growth ◽  
Field Model ◽  
Phase Field Model ◽  
Abnormal Grain Growth ◽  
Metallic System ◽  
Goss Texture ◽  
New Approach ◽  
The Matrix ◽  
Goss Orientation

Abnormal grain growth (AGG) takes place in many metallic systems especially after recrystallization of deformed polycrystals. A famous example of AGG in metallic system is the Goss texture in Fe-3%Si steel. During high temperature annealing of Fe-3%Si sheet, a few near Goss {110} <001> grains grow exclusively fast and consume the matrix grains. Therefore, the grains which have near Goss orientation have special advantage over other grains. As a new approach to the growth advantage of AGG, we suggested the solid-state wetting mechanism, where a grain wets or penetrates the grain boundary or the triple junction of its neighboring grains. The solid-state wetting mechanism for the evolution of the Goss texture in Fe-3%Si steel was studied experimentally and by phase-field model (PFM) simulation.

Observation of Growth Front on the Initial Stage of Goss Abnormally-Growing Grain in Fe-3%Si Steel

2013 ◽  
Vol 753 ◽  
pp. 307-310
Author(s):  
Kyung Jun Ko ◽  
Jong Tae Park ◽  
Chan Hee Han
Keyword(s):  
Solid State ◽  
Grain Boundary ◽  
Three Dimensional ◽  
Secondary Recrystallization ◽  
Growth Front ◽  
Very High Frequency ◽  
Grain Boundary Mobility ◽  
Initial Stage ◽  
The Matrix

During abnormal grain growth, a few Goss grains grow exclusively fast and consume the matrix grains. The Goss abnormally-growing grain (AGG) has peculiar features which are irregular grain boundaries and very high frequency of peninsular grains nearby the growth front of AGG and island grains trapped inside AGG. These features might provide a clue for clarifying the mechanism of Goss AGG. The experimentally-observed microstructural feature and grain boundary characterization of Goss were approached by the solid-state wetting mechanism. In this study, observing the three-dimensional wetting morphology in serial section images of Goss AGG by EBSD, we report some direct microstrucrual evidence supporting solid-state wetting mechanism for Goss AGG. The solid-state wetting mechanism for the evolution of the Goss AGG in Fe-3%Si steel explains the microstructural features evolved during secondary recrystallization, which cannot be approached by the conventional theories based on the grain boundary mobility.

scholarly journals The influence of Mg and Mn content on abnormal grain growth in AA5182 type alloys

10.30544/463 ◽  
2020 ◽  
Vol 25 (04) ◽  
pp. 315-323
Author(s):  
Tamara Radetić ◽  
Miljana Popović ◽  
Bojan Gligorijević ◽  
Ana Alil ◽  
Endre Romhanji
Keyword(s):  
Cold Rolling ◽  
Grain Growth ◽  
Processing Parameters ◽  
Abnormal Grain Growth ◽  
Strong Anisotropy ◽  
Grain Boundary Mobility ◽  
Zener Pinning ◽  
Cold Rolling Reduction ◽  
Mn Content ◽  
Aa5182 Alloy

The occurrence of abnormal grain growth (AGG) in AA5182 alloy during annealing imposes severe restrictions on processing parameters and deteriorates mechanical properties. In this work, we investigated the effect of chemical composition on the appearance of abnormal grain growth by varying Mg and Mn content in the range of composition limits for standard AA5182 alloy, 4.0-5.0% Mg, and 0.2-0.5% Mn, respectively. Thermo-mechanical processing of alloys included cold rolling with reductions ranging from 40 to 85%, followed by annealing in the temperature range from 350 to 520 °C. The results showed that the rise in alloying elements content drives the onset of abnormal grain growth toward higher temperatures. The increase in the cold rolling reduction degree promotes abnormal grain growth and lowers its onset temperature. Abnormal grain growth and grain boundary mobility showed strong anisotropy related to rod-like shape and alignment of Al6Mn(Fe) dispersoids through Zener pinning.

A Role of Low Energy Grain Boundaries in the Abnormal Grain Growth in Fe-3%Si Alloy

2011 ◽  
Vol 127 ◽  
pp. 89-94 ◽  
Author(s):  
Ye Chao Zhu ◽  
Jiong Hui Mao ◽  
Fa Tang Tan ◽  
Xue Liang Qiao
Keyword(s):  
Grain Boundaries ◽  
Grain Growth ◽  
Electron Backscatter Diffraction ◽  
Dominant Role ◽  
Coincidence Site Lattice ◽  
Diffraction Method ◽  
Abnormal Grain Growth ◽  
Low Energy ◽  
Backscatter Diffraction

Low energy grain boundaries were considered to be important in abnormal grain growth by theoretical deduction. The disorientation angles and coincidence site lattice grain boundaries distribution of more than 20 Goss grains and their neighboring matrix grains in primary recrystallized Fe-3%Si alloy were investigated using an electron backscatter diffraction method. It was found that the frequency of low energy grain boundaries of Goss grains which are more likely to abnormally grow are higher than their neighboring matrix grains, which indicated that low energy grain boundaries play a dominant role in the abnormal grain growth of Fe-3%Si alloy. The result meets well with the abnormal grain growth theory.

Monte-Carlo Simulation of Goss Abnormal Grain Growth in Fe-3%Si Steel by Sub-Boundary Enhanced Solid-State Wetting

2012 ◽  
Vol 715-716 ◽  
pp. 146-151
Author(s):  
K.J. Ko ◽  
A.D. Rollett ◽  
N.M. Hwang
Keyword(s):  
Monte Carlo ◽  
Solid State ◽  
Grain Boundary ◽  
Grain Growth ◽  
Boundary Energy ◽  
Three Dimensional ◽  
Abnormal Grain Growth ◽  
Grain Boundary Energy ◽  
Simulation Based ◽  
Mc Simulation

The selective abnormal grain growth (AGG) of Goss grains in Fe-3%Si steel was investigated using a parallel Monte-Carlo (MC) simulation based on the new concept of sub-boundary enhanced solid-state wetting. Goss grains with low angle sub-boundaries will induce solid-state wetting against matrix grains with a moderate variation in grain boundary energy. Three-dimensional MC simulations of microstructure evolution with textures and grain boundary distributions matched to experimental data is using in this study.

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