Question

One of the primary functions of impact testing is to determine whether a material experiences a ductile-to-brittle transition. Clearly explain what it means when a material exhibits “ductile-to-brittle transition” behavior?

Answer 1

In plastic materials,

At low temperatures there is more tendency to be brittle.

At high temperatures there is good ductility and high impact toughness.

Ductility is the ability to deform under load.

Brittleness means a material breaks easily.

As we increase the temperature of a material, its properties change and it becomes ductile from earlier brittle. It is seen in many metals and alloys. It is also called cold shortness.

solids get brittle as it gets cold. It can prove as an issue when solids are used in cold temperatures. However,it can also be a boon in industry when ductility is the target. The temperature at which this transition occurs is key feature of the solid i.e. ductile-brittle transition temperature(DBTT)

Smaller grain size decreases DBTT and increases ductility.

Failure can occur in both regimes i.e. brittle fracture ( here cracks propagate fast) and ductile fracture(here high plastic deformation occurs). Brittle fracture occurs in low toughness region and ductile fracture occurs in high toughness region.