NEBOSH Practice Test

What does creep in materials refer to?

1. Rapid deformation at high temperatures

2. Slow movement under stress

3. Immediate cracking under pressure

4. Loss of elasticity over time

The correct answer is: Slow movement under stress

Creep in materials is defined as the slow, continuous deformation that occurs when a material is subjected to a constant load or stress over a prolonged period, especially at elevated temperatures. This phenomenon often takes place in materials like metals and polymers, where the atomic structure allows for gradual movement or sliding of dislocations within the material. Understanding creep is essential, particularly in engineering and materials science, as it can lead to failure in structures or components if not considered in design. For example, in applications such as turbine blades in jet engines, where materials experience high temperatures and sustained stress, engineers must account for creep to ensure safety and durability. The other options describe behaviors that do not align with the definition of creep. Rapid deformation at high temperatures refers more to plastic deformation or thermal effects, while immediate cracking and loss of elasticity relate to other failure mechanisms, such as fatigue or aging, rather than the slow progression characteristic of creep.