Which materials are likely to undergo significant deformation before failing?

The correct choice is ductile materials, which are characterized by their ability to undergo significant deformation before they ultimately fail. Ductility is a measure of a material's ability to stretch or deform under tensile stress. Materials that are ductile can exhibit large strains, allowing them to absorb energy and deform without breaking. Common examples of ductile materials include metals such as steel and aluminum, which can be drawn into wires or shaped without fracturing.

Understanding this property is critical in various engineering applications, particularly in structural design, where the ability to handle unexpected loads and strains without immediate failure is crucial for safety and durability. Ductile materials can provide visual warnings of failure because they often deform noticeably before breaking, allowing for preventive measures to be taken.

In contrast, brittle materials, such as glass or certain ceramics, typically fail with little to no plastic deformation, meaning they will fracture suddenly when their stress limit is exceeded. Plastic materials can also exhibit deformation, but they may not return to their original shape after the load is removed and do not have the same energy-absorbing capacity as ductile materials before failing. Elastic materials, on the other hand, return to their original shape after the load is removed and do not undergo significant deformation under normal conditions.