Intergranular Fracture
Definition
Fracture path running along grain boundaries rather than through grains. Indicates boundary weakness from segregation, embrittlement, or environmental attack, and produces a rock-candy or faceted surface under SEM.
- Field
- Metallurgical fracture analysis
- Path
- Along grain boundaries
- Causes
- Segregation, embrittlement, environmental attack
- SEM appearance
- Rock-candy or faceted surface
- Contrasts with
- Transgranular fracture (through the grains)
Common questions
Why does an intergranular fracture point to a specific failure cause rather than just overload?+
Simple overload from applied stress tends to fracture through the grains, so a boundary-following path signals that the grain boundaries themselves were weakened beforehand, directing investigators toward causes such as impurity segregation, hydrogen embrittlement, or corrosive attack rather than pure mechanical overload.
What environmental conditions commonly produce intergranular fracture in forensic metallurgy cases?+
Sustained exposure to corrosive environments, hydrogen charging from certain manufacturing or service conditions, and prolonged high temperature that allows impurities to segregate to grain boundaries are common contributors examined in failure investigations.
Related terms
- Brittle Fracture
- Fracture with little or no plastic deformation, occurring by rapid cleavage through grains or along grain boundaries. The surface is flat, often...
- Cleavage
- Fracture by separation along specific crystallographic planes, typically {100} planes in body-centred-cubic metals. The fracture surface is flat at the grain scale...
- Cup-and-Cone Fracture
- The classic macroscopic appearance of ductile tensile fracture in round bar: a flat central zone (the cup) formed by void coalescence surrounded...
- Ductile Fracture
- Fracture preceded by extensive plastic deformation, in which microvoids nucleate at inclusions, grow, and coalesce to form the fracture surface. The surface...
- SEM Fractography
- The use of scanning electron microscopy to image fracture surfaces at magnifications beyond the optical limit, revealing dimple size and distribution in...