An intergranular fracture is a fracture

Fracture

A fracture is the separation of an object or material into two, or more, pieces under the action of stress.The word fracture is often applied to bones of living creatures , or to crystals or crystalline materials, such as gemstones or metal...

 that follows the grain

GRAIN

GRAIN is a small international non-profit organisation that works to support small farmers and social movements in their struggles for community-controlled and biodiversity-based food systems. Our support takes the form of independent research and analysis, networking at local, regional and...

s of the material. If the material has multiple lattice

Crystal structure

In mineralogy and crystallography, crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid. A crystal structure is composed of a pattern, a set of atoms arranged in a particular way, and a lattice exhibiting long-range order and symmetry...

 organizations, when one lattice ends and another begins, the fracture changes direction to follow the new grain. This results in a fairly jagged looking fracture with bumpy edges.

Intergranular fractures are cracks that take place along the grain boundary of a material. Straight edges of the grain and shiny surface may be seen. There are several processes that can lead to intergranular fracture.

• Microvoid nucleation and coalescence at inclusions or second phase particles located along grain boundaries

• Grain boundary crack and cavity formation associated with elevated temperature stress rupture condition.

• Decohesion between contiguous grain due to presence of impurity at grain boundaries and in the presence of hydrogen and liquid metals.

• Stress corrosion cracking associated with chemical dissolution along grain boundaries.

• Cyclic loading when the material insufficient number of independent slip systems to accommodate plastic deformation between contiguous grain leading to grain boundaries.

Think of several wooden jigsaw puzzle

Jigsaw puzzle

A jigsaw puzzle is a tiling puzzle that requires the assembly of numerous small, often oddly shaped, interlocking and tessellating pieces.Each piece usually has a small part of a picture on it; when complete, a jigsaw puzzle produces a complete picture...

 pieces with the grains showing, but with each piece having grains running in a different direction. A Transgranular fracture follows the grains in the wood, not the edges of the puzzle pieces

This is opposed to a Transgranular fracture

Transgranular fracture

A Transgranular fracture is a fracture that follows the edges of lattices in a granular material, ignoring the grains in the individual lattices...

.