Grain Boundary Strengthening
Grain-boundary strengthening (or Hall–Petch strengthening) is a method of strengthening materials by changing their average crystallite (grain) size. It is based on the observation that grain boundaries impede dislocation movement and that the number of dislocations within a grain have an effect on how easily dislocations can traverse grain boundaries and travel from grain to grain. So, by changing grain size one can influence dislocation movement and yield strength. For example, heat treatment after plastic deformation and changing the rate of solidification are ways to alter grain size.
Other articles related to "grain boundary strengthening, grain, grains, grain boundary, boundary":
... Grain refinement, also known as inoculation, is the set of techniques used to implement grain boundary strengthening in metallurgy ... One method for controlling grain size in aluminum alloys is by introducing particles to serve as nucleants, such as Al–5%Ti ... Grains will grow via heterogeneous nucleation that is, for a given degree of undercooling beneath the melting temperature, aluminum particles in the melt will nucleate on the surface of the added ...
... Where a buildup of dislocations at a grain boundary causes a repulsive force between dislocations ... As grain size decreases, the surface area to volume ratio of the grain increases, allowing more buildup of dislocations at the grain edge ... Since it requires a lot of energy to move dislocations to another grain, these dislocations build up along the boundary, and increase the yield stress of the material ...
... In a polycrystalline metal, grain size has a tremendous influence on the mechanical properties ... Because grains usually have varying crystallographic orientations, grain boundaries arise ... Grain boundaries act as an impediment to dislocation motion for the following two reasons 1 ...
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