Question

The slow and progressive deformation of a material with time at constant stress is called ___________

• A. machinability
• B. creep
• C. toughness
• D. fatigue

Answer 1

Answer:

B. creep

Creep is the slow deformation of a material at constant stress and elevated temperature. It occurs in three steps - primary, secondary, and tertiary. Factors affecting creep include material properties, exposure time, exposure temperature, and structural load. Creep resistance can be increased by using high strength and high Young's modulus materials, fine-grain materials for low temperature creep resistance, coarse-grain materials for high temperature creep resistance, and adding refractory metals to alloys for high- temperature creep resistance.