SUBGRAIN Meaning and
Definition
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Subgrain refers to a discrete crystalline structure that develops within a larger crystal, typically resulting from deformation or recrystallization processes. It is smaller in size and slightly misoriented compared to the surrounding region of the main crystal. Subgrains form as a result of mechanical stresses, such as plastic deformation or annealing, which cause the atoms in the crystal lattice to rearrange and create new boundaries between these smaller grains.
Subgrains are characterized by their distinct crystallographic orientations within the host crystal, thus exhibiting a subtle deviation from the original crystal lattice. They often possess a higher dislocation density, aiding in the accommodation of the applied stresses. With further deformation or recrystallization, subgrains can gradually grow into larger grains or merge with neighboring subgrains to form boundaries between new grains.
Researchers often utilize subgrains as indicators or tracers to understand the deformation history, plasticity, or recrystallization mechanisms of materials. The study of subgrains provides valuable insights into the behavior and structure of a crystal at smaller scales. Subgrain boundaries can also influence material properties, such as mechanical strength and electrical conductivity, as they act as obstacles to dislocation motion within the crystal lattice. Understanding the formation and evolution of subgrains is crucial for various scientific disciplines, including materials science, geology, and metallurgy.
Etymology of SUBGRAIN
The word "subgrain" has a specialized meaning in materials science and metallurgy, relating to the microscopic structures found within a grain of a crystalline material. However, its etymology is not clear-cut, as it is a compound word formed from two common English words: "sub" and "grain".
1. "Sub" comes from Latin and means "under" or "beneath". It is commonly used as a prefix in English to indicate a lower rank, position, or degree. For example, "submarine" (literally "under the sea") and "subway" (literally "under the way").
2. "Grain" derives from the Old English word "graegen", meaning "a small particle". It originally referred to the seed of cereal plants, such as wheat or barley. Over time, its meaning extended to include the texture, pattern, or structure of a material.
