A grain boundary is the interface between two grains, or crystallites, in a polycrystalline material. Grain boundaries are defects in the crystal structure, and tend to decrease the electrical and thermal conductivity of the material. The high interfacial energy and relatively weak bonding in most grain boundaries often makes them preferred sites for the onset of corrosion and for the precipitation of new phases from the solid. They are also important to many of the mechanisms of creep. On the other hand, grain boundaries disrupt the motion of dislocations through a material, so reducing crystallite size is a common way to improve strength, as described by the Hall–Petch relationship.
Read more about Grain Boundary: High and Low Angle Boundaries, Describing A Boundary, Boundary Energy, Boundary Migration
Famous quotes containing the words grain and/or boundary:
“Grow your tree of falsehood from a small grain of truth.
Do not follow those who lie in contempt of reality.
Let your lie be even more logical than the truth itself,
So the weary travelers may find repose.”
—Czeslaw Milosz (b. 1911)
“It appeared that he had once represented his tribe at Augusta, and also once at Washington, where he had met some Western chiefs. He had been consulted at Augusta, and gave advice, which he said was followed, respecting the eastern boundary of Maine, as determined by highlands and streams, at the time of the difficulties on that side. He was employed with the surveyors on the line. Also he called on Daniel Webster in Boston, at the time of his Bunker Hill oration.”
—Henry David Thoreau (1817–1862)