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This is also known as intercrystalline fracture or grain-boundary separation. More rapid diffusion along grain boundaries than along grain interiors; Faster nucleation and growth of precipitates at the grain boundaries; Quench cracking, or crack growth following a quenching process, is another example of intergranular fracture and almost always ...
In materials science, a grain boundary is the interface between two grains, or crystallites, in a polycrystalline material. Grain boundaries are two-dimensional defects in the crystal structure, and tend to decrease the electrical and thermal conductivity of the material.
The fracture behavior of materials can be significantly changed by the use of precipitation-based grain boundary design. For example, Meindlhumer et. al. [9] produced a thin film of AlCrN containing a specific distribution of precipitates within the grain boundaries in precipitation-based grain boundary design. The precipitates acted as a ...
Figure 1: Hall–Petch strengthening is limited by the size of dislocations. Once the grain size reaches about 10 nanometres (3.9 × 10 −7 in), grain boundaries start to slide. In materials science, grain-boundary strengthening (or Hall–Petch strengthening) is a method of strengthening materials by changing their average crystallite (grain
Grain boundary sliding (GBS) is a material deformation mechanism where grains slide against each other. This occurs in polycrystalline material under external stress at high homologous temperature (above ~0.4 [1]) and low strain rate and is intertwined with creep.
To heal this, grain-boundary sliding occurs. The diffusional creep rate and the grain boundary sliding rate must be balanced if there are no voids or cracks remaining. When grain-boundary sliding can not accommodate the incompatibility, grain-boundary voids are generated, which is related to the initiation of creep fracture.
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 much energy to move dislocations to another grain, these dislocations build up along the boundary, and increase the yield stress of the material.
Dispersions of AlMn bind oversaturated silicon during cooling after solution annealing. This improves crystallization and avoids excretion-free zones that otherwise arise at the grain boundaries. This improves the fracture behaviour from brittle to ductile and intragranular. [3]