Exam Question
(a) Define creep and specify the conditions under which it occurs?
(b) Discuss three metallurgical/processing techniques that are employed to enhance the creep resistance of metal alloys.
Class 2 (2nd Engineer)
MEKG
📅 Nov 2022
Reference Answer
### (a) Definition of Creep and Conditions of Occurrence
**Definition of Creep:**
Creep is defined as the slow, time-dependent, and permanent plastic deformation of a material subjected to a constant stress (or load) at an elevated temperature. Crucially, this deformation occurs at stress levels well below the material's yield strength at that temperature. It is a progressive accumulation of strain over a long period of exposure to specific conditions, eventually leading to component failure or rupture.
The phenomenon is governed by thermally activated atomic-level processes, such as dislocation movement and grain boundary sliding, which become significant at higher temperatures.
**Definition of Creep:**
Creep is defined as the slow, time-dependent, and permanent plastic deformation of a material subjected to a constant stress (or load) at an elevated temperature. Crucially, this deformation occurs at stress levels well below the material's yield strength at that temperature. It is a progressive accumulation of strain over a long period of exposure to specific conditions, eventually leading to component failure or rupture.
The phenomenon is governed by thermally activated atomic-level processes, such as dislocation movement and grain boundary sliding, which become significant at higher temperatures.
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