Suppression of abnormal grain growth in K0.5Na0.5NbO3: phase transitions and compatibility

AbstractThis work presents the suppression of abnormal grain growth in bulk ceramic K0.5Na0.5NbO3 (KNN). The suppression is enabled by precise control of the starting powder morphology through match of milling and calcination duration. A comparative temperature-dependent analysis of the resulting sample morphology, phase transitions and related electronic material properties reveals that abnormal grain growth is indeed a major influence in material property deterioration, as has theoretically been suggested in other works. However, it is shown that this abnormal grain growth originates from the calcined powder and not from sintering and that all subsequent steps mirror the initial powder morphology. In specific, the results are discussed with respect to the predictions of the compatibility theory and microstructure. Despite the material’s multi-scale heterogeneity, the suppression of abnormal grain growth allows for the achievement of significantly improved functional properties and it is reported that this development is correctly predicted by the compatibility theory within the borders of microstructural integrity. It could be demonstrated that functional fatigue is strongly minimised, while thermal and electronic properties are improved when abnormal grain growth is suppressed by powder morphology control.

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On the Abnormal Grain Growth in Pure Magnesium

SSRN Electronic Journal ◽

10.2139/ssrn.3287447 ◽

2018 ◽

Author(s):

Risheng Pei ◽

Sandra Korte-Kerzel ◽

Talal Al-Samman

Keyword(s):

Grain Growth ◽

Abnormal Grain Growth ◽

Pure Magnesium

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Abnormal grain growth with {1 0 0} planar interface in the electrodeposited nickel

Materials Research Innovations ◽

10.1179/1432891715z.0000000001554 ◽

2015 ◽

Vol 19 (sup4) ◽

pp. S251-S254 ◽

Cited By ~ 2

Author(s):

B. B. Zhao

Keyword(s):

Grain Growth ◽

Planar Interface ◽

Abnormal Grain Growth ◽

Electrodeposited Nickel

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Precipitation Criterion for Inhibiting Austenite Grain Coarsening during Carburization of Al-Containing 20Cr Gear Steels

Metals ◽

10.3390/met11030504 ◽

2021 ◽

Vol 11 (3) ◽

pp. 504

Author(s):

Huasong Liu ◽

Yannan Dong ◽

Hongguang Zheng ◽

Xiangchun Liu ◽

Peng Lan ◽

...

Keyword(s):

Grain Growth ◽

Abnormal Grain Growth ◽

Grain Structure ◽

Pinning Force ◽

Grain Coarsening ◽

Zener Pinning ◽

Austenite Grain ◽

Composition Optimization ◽

Gear Steels ◽

Grain Growth Behavior

AlN precipitates are frequently adopted to pin the austenite grain boundaries for the high-temperature carburization of special gear steels. For these steels, the grain coarsening criterion in the carburizing process is required when encountering the composition optimization for the crack-sensitive steels. In this work, the quantitative influence of the Al and N content on the grain size after carburization is studied through pseudocarburizing experiments based on 20Cr steel. According to the grain structure feature and the kinetic theory, the abnormal grain growth is demonstrated as the mode of austenite grain coarsening in carburization. The AlN precipitate, which provides the dominant pinning force, is ripened in this process and the particle size can be estimated by the Lifshitz−Slyosov−Wagner theory. Both the mass fraction and the pinning strength of AlN precipitate show significant influence on the grain growth behavior with the critical values indicating the grain coarsening. These criteria correspond to the conditions of abnormal grain growth when bearing the Zener pinning, which has been analyzed by the multiple phase-field simulation. Accordingly, the models to predict the austenite grain coarsening in carburization were constructed. The prediction is validated by the additional experiments, resulting in accuracies of 92% and 75% for the two models, respectively. Finally, one of the models is applied to optimize the Al and N contents of commercial steel.

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Orientation mapping linked to fractal analysis: A method for studying abnormal grain growth in nanocrystalline PdAu

Journal of Applied Physics ◽

10.1063/5.0029832 ◽

2020 ◽

Vol 128 (18) ◽

pp. 185109

Author(s):

Christian Braun ◽

Raphael A. Zeller ◽

Hanadi Menzel ◽

Jörg Schmauch ◽

Carl E. Krill ◽

...

Keyword(s):

Grain Growth ◽

Fractal Analysis ◽

Abnormal Grain Growth ◽

Orientation Mapping

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Mean Field Analysis of Orientation Selective Grain Growth Driven By Interface-Energy Anisotropy

MRS Proceedings ◽

10.1557/proc-343-65 ◽

1994 ◽

Vol 343 ◽

Cited By ~ 2

Author(s):

J. A. Floro ◽

C. V. Thompson

Keyword(s):

Grain Size ◽

Size Distribution ◽

Grain Growth ◽

Texture Evolution ◽

Mean Field ◽

Orientation Distribution ◽

Interface Energy ◽

Abnormal Grain Growth ◽

Field Analysis ◽

Energy Anisotropy

ABSTRACTAbnormal grain growth is characterized by the lack of a steady state grain size distribution. In extreme cases the size distribution becomes transiently bimodal, with a few grains growing much larger than the average size. This is known as secondary grain growth. In polycrystalline thin films, the surface energy γs and film/substrate interfacial energy γi vary with grain orientation, providing an orientation-selective driving force that can lead to abnormal grain growth. We employ a mean field analysis that incorporates the effect of interface energy anisotropy to predict the evolution of the grain size/orientation distribution. While abnormal grain growth and texture evolution always result when interface energy anisotropy is present, whether secondary grain growth occurs will depend sensitively on the details of the orientation dependence of γi.

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