Definition - What does Flat Fracture mean?
A flat fracture is a type of failure typically observed in brittle materials such as concrete, ice, ceramics and cold metals when subjected to a uniaxial force. It is essentially the separation of a brittle body into two separate pieces due to the application of excessive tensile stress. This type of fracture is characterized by a flat and typically straight fracture line perpendicular to the line of action of the tensile force.
Corrosionpedia explains Flat Fracture
Unlike ductile materials, which exhibit plastic deformation and necking before fracture, flat fractures in brittle materials seldom show warning signs, and the resulting failure is usually sudden.
As the force increases to the failure load of the material, cracks develop and quickly propagate across the cross-section of the material in a direction perpendicular to the tensile force. This is in contrast to other failure modes, such as cup and cone fracture, where cracks develop much slower and occur in stages. At the fractured ends of the specimen, no reduction in the cross-sectional area is observed.