The gradual, time-dependent plastic yielding of metallic materials under steady stress is known as________________?
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Answer: A. creep
Explanation
Creep is the slow, time-dependent permanent deformation of materials subjected to a constant mechanical stress over a long period. Metals operating at high temperatures experience atomic dislocation movement that gradually alters their physical dimensions. This phenomenon accumulates progressively until the structural component suffers rupture or functional failure. Creep deformation typically becomes significant when metallic structures operate above forty percent of their absolute melting point. Standard creep curves feature primary, secondary, and tertiary stages ending in material fracture. Metallurgists alloy steels with refractory elements like chromium and molybdenum to enhance high-temperature creep resistance.
Fatigue involves structural degradation and cracking caused by fluctuating or cyclic mechanical stress repetitions. Endurance limit represents the maximum stress level a material can withstand for infinite cycles without fatigue failure. Plastic deformation refers to permanent shape change occurring immediately once stress exceeds the yield strength.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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