NEBOSH Practice Test

Which of the following describes brittle fracture?

1. Slow deformation with time

2. Rapid crack propagation with no plastic deformation

3. Elastic stretch under weight

4. Long-term fatigue failure

The correct answer is: Rapid crack propagation with no plastic deformation

Brittle fracture is characterized by the rapid propagation of cracks through a material with little to no prior plastic deformation. It occurs when a material fails suddenly under stress, typically at lower temperatures or due to specific material properties, such as being hard and brittle. The fracture surface is often flat and perpendicular to the direction of applied stress, indicating that the failure occurred without significant deformation in the material. In the context of materials science, brittle fracture differs from ductile fracture, where the material undergoes significant plastic deformation before failure. Understanding brittle fracture is crucial for assessing material performance, especially in structural applications where sudden failures can have serious safety implications. Recognizing the signs of potential brittle fracture can help in the selection of appropriate materials for specific applications and in the design of safety measures to prevent such failures. The other options describe behaviors that are associated with different failure modes or material interactions, such as gradual deformation over time, elastic responses, or failures due to long-term fatigue. These are not characteristics of brittle fracture, which is defined by its rapid and catastrophic nature.