Creep
Definition
Time-dependent plastic deformation of a material under sustained stress at elevated temperature, occurring at stress levels below the conventional yield strength.
- Type
- Time-dependent plastic deformation
- Condition
- Sustained stress at elevated temperature
- Threshold
- Occurs below conventional yield strength
- Field
- Elevated-temperature failure analysis
Common questions
How does creep failure differ from a normal overload failure?+
An overload failure happens when stress exceeds yield strength at the time of loading, while creep accumulates deformation gradually under stress that is below yield, so failure develops over sustained time at temperature rather than instantly.
Why does temperature matter so much to creep behaviour?+
Creep becomes significant only once a material is held at a large fraction of its melting temperature, because that is when atomic diffusion mechanisms that allow gradual deformation become active.
Related terms
- Grain-Boundary Sliding
- Relative motion of adjacent grains along their shared boundary, a key deformation mechanism at elevated temperature that opens voids at triple points...
- Hot Corrosion
- Accelerated degradation of a superalloy or coated turbine component by molten sulfate or vanadate deposits that flux and dissolve the protective oxide...
- Larson-Miller Parameter (LMP)
- A temperature-time combination parameter T(C + log t_r) used to correlate and predict rupture life across different temperature-stress combinations for a given...
- Minimum Creep Rate
- The steady-state strain rate during secondary creep, the single most important material parameter for structural life assessment under creep conditions.
- Reheat Cracking
- Intergranular cracking in the heat-affected zone of welds in certain alloy steels during post-weld heat treatment or early elevated-temperature service, caused by...