Ductile failure is characterized by which of the following?

Ductile failure is characterized by which of the following?

• A. It is sudden and without any plastic deformation
• B. Preceded by local plastic deformation, with shear lips
• C. Occurs with necking but no plastic deformation
• D. Requires low temperature to occur

Answer: (B)

Ductile failure happens after the material has undergone substantial plastic deformation. In a typical tensile-like loading, you’ll see necking where the cross-section reduces and the material stretches significantly before breaking. The fracture surface often shows shear lips—areas of localized plastic shear around the neck—along with a cup-and-cone or dimpling appearance from micro-void coalescence. This combination—local plastic deformation followed by fracture with shear lips—is what identifies ductile failure. That’s why the description of being preceded by local plastic deformation, with shear lips, is the best fit. The other options describe brittle behavior (sudden fracture with little plasticity), a contradiction (necking without plastic deformation), or a condition (low temperature) that can influence whether a material is ductile or brittle but isn’t what defines ductile failure itself.

Ductile failure happens after the material has undergone substantial plastic deformation. In a typical tensile-like loading, you’ll see necking where the cross-section reduces and the material stretches significantly before breaking. The fracture surface often shows shear lips—areas of localized plastic shear around the neck—along with a cup-and-cone or dimpling appearance from micro-void coalescence. This combination—local plastic deformation followed by fracture with shear lips—is what identifies ductile failure.

That’s why the description of being preceded by local plastic deformation, with shear lips, is the best fit. The other options describe brittle behavior (sudden fracture with little plasticity), a contradiction (necking without plastic deformation), or a condition (low temperature) that can influence whether a material is ductile or brittle but isn’t what defines ductile failure itself.