Notes on Various Fractures

Hello Everyone,

Have a blessed day. Hoping your preparation is going cool unlike mine. I just thought I will share brief notes on various fractures to give a brief overview.

Brittle Fracture

     A fracture which takes place by rapid propagation of crack with a negligible deformation. In amorphous materials, the fracture is completely brittle. In crystalline materials, it occurs after small deformation.

Ductile Fracture:

     A fracture which takes place by a slow propagation of crack with appreciable plastic deformation. This type of fracture comes into play in materials which don't work harden much. 

Creep Fracture

     A fracture which takes place due to excessive creeping of materials, under steady load. Creep is exhibited in iron, nickel, copper and alloys at higher temperature.  Creep resistance may be increased by addition of certain elements such as cobalt, nickel , manganese, tungsten, ...

Fatigue Fracture:

    A fracture that occurs when a material is subjected to cyclic loading. If the loads are above a certain threshold, microscopic cracks will begin to form at the surface. Eventually a crack will reach a critical size, and the structure will suddenly fracture.

Don't forget to grab a copy of Material Science and Engineering book, which is essential for preparing for AMIE, Material Science.

with warm regards

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Brittle Fracture VS Ductile Fracture

Brittle Fracture:

• Caused due to high impact blows on the material
• Plastic deformation is zero or very very less
• Once crack is formed,  the crack is unstable in nature and propagates very rapidly.
• Crack propagates nearly perpendicular to the direction of the applied stress
• Crack often propagates by cleavage - breaking of atomic bonds along specific crystallographic planes (cleavage planes).

Ductile Fracture:

• Caused due to tensile forces acting on the material
• Necking can be observed i.e. excessive plastic deformation takes place
• Crack is stable i.e. once crack is formed, it resists propagation unless further stress is applied
• Micro-voids are formed fist, then by shear forces the crack propagates and results in fracture

Good material about about Fractures is available here & here

Don't forget to grab a copy of Material Science and Engineering book, which is essential for preparing for AMIE, Material Science.

with warm regards

AllMyPosts