What type of damage occurs when metal is stretched beyond its elastic limit?

What type of damage occurs when metal is stretched beyond its elastic limit?

• A. Plastic deformation
• B. Elastic rebound
• C. Fatigue failure
• D. Brittle fracture

Answer: (A)

When metal is stretched beyond its elastic limit, it undergoes plastic deformation. This means the material experiences permanent shape change because the internal crystal structure has yielded and dislocations have moved, so it does not return to its original form after the load is removed. This differs from elastic rebound, which is the return to the original shape when the load is within the elastic range. Fatigue failure involves failure from many cycles of loading, not a single stretch beyond the elastic limit. Brittle fracture occurs with little or no plastic deformation, which isn’t the typical outcome when a ductile metal is yielded; the immediate effect of exceeding the elastic limit is permanent deformation (plastic deformation).

When metal is stretched beyond its elastic limit, it undergoes plastic deformation. This means the material experiences permanent shape change because the internal crystal structure has yielded and dislocations have moved, so it does not return to its original form after the load is removed.

This differs from elastic rebound, which is the return to the original shape when the load is within the elastic range. Fatigue failure involves failure from many cycles of loading, not a single stretch beyond the elastic limit. Brittle fracture occurs with little or no plastic deformation, which isn’t the typical outcome when a ductile metal is yielded; the immediate effect of exceeding the elastic limit is permanent deformation (plastic deformation).