Grain Boundaries - Revision history

Cpeterson70: /* Applications */

2025-03-09T20:21:05Z

Applications

← Older revision		Revision as of 16:21, 9 March 2025
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	== Applications ==		== Applications ==
	~~Understanding and controlling grain boundaries is critical in various applications, including:~~
	* Metallurgy: Improving the strength, ductility, and corrosion resistance of metals and alloys.		* Metallurgy: Improving the strength, ductility, and corrosion resistance of metals and alloys.
	* Semiconductors: Enhancing the performance of electronic devices by controlling grain boundary effects.		* Semiconductors: Enhancing the performance of electronic devices by controlling grain boundary effects.

Cpeterson70: Add to theory category

2025-03-09T20:20:27Z

Add to theory category

← Older revision		Revision as of 16:20, 9 March 2025
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	* Ceramics: Tailoring the mechanical and thermal properties of ceramic materials.		* Ceramics: Tailoring the mechanical and thermal properties of ceramic materials.
	* Energy Materials: Optimizing grain boundaries in batteries, fuel cells, and thermoelectric materials for improved efficiency.		* Energy Materials: Optimizing grain boundaries in batteries, fuel cells, and thermoelectric materials for improved efficiency.

			__NOTOC__
			[[Category:Theory]]

Cpeterson70: Fix formatting

2025-03-07T16:48:19Z

Fix formatting

← Older revision		Revision as of 12:48, 7 March 2025
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	Grain boundaries are broadly classified into two categories based on the misorientation angle between adjacent grains:		Grain boundaries are broadly classified into two categories based on the misorientation angle between adjacent grains:

	1. Low-Angle Grain Boundaries: These occur when the misorientation between adjacent grains is less than approximately 15 degrees. The boundary consists of an array of dislocations, which are line defects in the crystal lattice. The energy of low-angle boundaries is relatively low because the lattice distortion is localized around the dislocations.		# Low-Angle Grain Boundaries: These occur when the misorientation between adjacent grains is less than approximately 15 degrees. The boundary consists of an array of dislocations, which are line defects in the crystal lattice. The energy of low-angle boundaries is relatively low because the lattice distortion is localized around the dislocations.
			# High-Angle Grain Boundaries: These occur when the misorientation exceeds approximately 15 degrees. High-angle boundaries are more complex and disordered, often resembling an amorphous structure. They have higher energy compared to low-angle boundaries and are more chemically active, making them prone to segregation of impurities and diffusion.
	2. High-Angle Grain Boundaries: These occur when the misorientation exceeds approximately 15 degrees. High-angle boundaries are more complex and disordered, often resembling an amorphous structure. They have higher energy compared to low-angle boundaries and are more chemically active, making them prone to segregation of impurities and diffusion.

	=== Tilt Boundary ===		=== Tilt Boundary ===
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	Grain boundaries significantly influence the properties of polycrystalline materials. Some key effects include:		Grain boundaries significantly influence the properties of polycrystalline materials. Some key effects include:

	1. Mechanical Properties: Grain boundaries act as barriers to dislocation motion, which strengthens the material (Hall-Petch effect). However, they can also serve as sites for crack initiation and propagation, reducing toughness.		# Mechanical Properties: Grain boundaries act as barriers to dislocation motion, which strengthens the material (Hall-Petch effect). However, they can also serve as sites for crack initiation and propagation, reducing toughness.
			# Diffusion and Segregation: Grain boundaries are pathways for rapid diffusion of atoms and impurities due to their disordered structure. This can lead to segregation of solute atoms at the boundaries, affecting the material's chemical and mechanical properties.
	2. Diffusion and Segregation: Grain boundaries are pathways for rapid diffusion of atoms and impurities due to their disordered structure. This can lead to segregation of solute atoms at the boundaries, affecting the material's chemical and mechanical properties.		# Electrical and Thermal Conductivity: Grain boundaries scatter electrons and phonons, reducing electrical and thermal conductivity. This is particularly important in semiconductors and thermoelectric materials.
			# Corrosion and Oxidation: Grain boundaries are often more chemically reactive than the grain interiors, making them susceptible to corrosion and oxidation.
	3. Electrical and Thermal Conductivity: Grain boundaries scatter electrons and phonons, reducing electrical and thermal conductivity. This is particularly important in semiconductors and thermoelectric materials.

	4. Corrosion and Oxidation: Grain boundaries are often more chemically reactive than the grain interiors, making them susceptible to corrosion and oxidation.

	== Grain Boundary Engineering ==		== Grain Boundary Engineering ==
	Grain boundary engineering is a field focused on controlling the structure, distribution, and properties of grain boundaries to optimize material performance. Techniques include:		Grain boundary engineering is a field focused on controlling the structure, distribution, and properties of grain boundaries to optimize material performance. Techniques include:

	1. Thermomechanical Processing: Controlled rolling, annealing, and other processes are used to manipulate grain size and boundary character.		# Thermomechanical Processing: Controlled rolling, annealing, and other processes are used to manipulate grain size and boundary character.
	2. Alloying: Adding specific elements can alter grain boundary energy and segregation behavior.		# Alloying: Adding specific elements can alter grain boundary energy and segregation behavior.
	3. Grain Boundary Characterization: Microscopy and spectroscopy techniques, such as electron backscatter diffraction (EBSD), are used to study grain boundary structure and properties.		# Grain Boundary Characterization: Microscopy and spectroscopy techniques, such as electron backscatter diffraction (EBSD), are used to study grain boundary structure and properties.

	== Applications ==		== Applications ==
	Understanding and controlling grain boundaries is critical in various applications, including:		Understanding and controlling grain boundaries is critical in various applications, including:
	- Metallurgy: Improving the strength, ductility, and corrosion resistance of metals and alloys.		* Metallurgy: Improving the strength, ductility, and corrosion resistance of metals and alloys.
	- Semiconductors: Enhancing the performance of electronic devices by controlling grain boundary effects.		* Semiconductors: Enhancing the performance of electronic devices by controlling grain boundary effects.
	- Ceramics: Tailoring the mechanical and thermal properties of ceramic materials.		* Ceramics: Tailoring the mechanical and thermal properties of ceramic materials.
	- Energy Materials: Optimizing grain boundaries in batteries, fuel cells, and thermoelectric materials for improved efficiency.		* Energy Materials: Optimizing grain boundaries in batteries, fuel cells, and thermoelectric materials for improved efficiency.

Cpeterson70: Update article

2025-03-07T16:46:14Z

Update article

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-Grain boundaries are an interface between two different grains in a polycrystalline material. They are defects in the crystal structure that can significantly change the material's properties.
+== Structure ==
-== Structure ==
+. Low-Angle Grain Boundaries: These occur when the misorientation between adjacent grains is less than approximately 15 degrees. The boundary consists of an array of dislocations, which are line defects in the crystal lattice. The energy of low-angle boundaries is relatively low because the lattice distortion is localized around the dislocations.
-Generally, there are two different categories of grain boundaries: low-angle and high-angle. Low-angle boundaries occur when there is a misorientation of grains of generally less than 15 degrees. High-angle boundaries generally occur when the misorientation is greater than 15 degrees. These misorientations are different from the low-angle boundaries since the dislocations of the boundary are too small. These boundaries generally are more unstable than low-angle boundaries.
 === Tilt Boundary ===
-Tilt boundaries are formed when the misorientation is caused by the defect plane rotating about an axis parallel to the boundary plane. These boundaries are generally low energy, since the bending of the lattice can be supported by a wedge of supporting atoms.
+A tilt boundary is a type of grain boundary where the misorientation between adjacent grains is caused by a rotation about an axis that lies within the plane of the boundary. This results in a series of edge dislocations aligned along the boundary. Tilt boundaries are generally low-energy configurations because the lattice distortion can be accommodated by a wedge of atoms that supports the bending of the crystal lattice.
 === Twist Boundary ===
-Twist boundaries occur when the rotation is perpendicular to the boundary plane.
+A twist boundary is formed when the misorientation between adjacent grains results from a rotation about an axis perpendicular to the boundary plane. This type of boundary is characterized by a network of screw dislocations. Twist boundaries tend to have higher energy compared to tilt boundaries due to the more complex arrangement of dislocations.

Cpeterson70: Create and start work on Grain Boundaries page

2025-02-10T18:16:50Z

Create and start work on Grain Boundaries page

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Grain boundaries are an interface between two different grains in a polycrystalline material. They are defects in the crystal structure that can significantly change the material's properties.

== Structure ==
Generally, there are two different categories of grain boundaries: low-angle and high-angle. Low-angle boundaries occur when there is a misorientation of grains of generally less than 15 degrees. High-angle boundaries generally occur when the misorientation is greater than 15 degrees. These misorientations are different from the low-angle boundaries since the dislocations of the boundary are too small. These boundaries generally are more unstable than low-angle boundaries.

=== Tilt Boundary ===
Tilt boundaries are formed when the misorientation is caused by the defect plane rotating about an axis parallel to the boundary plane. These boundaries are generally low energy, since the bending of the lattice can be supported by a wedge of supporting atoms.

=== Twist Boundary ===
Twist boundaries occur when the rotation is perpendicular to the boundary plane.