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.
a) Define creep and specify the conditions under which it occurs? Creep is the tendency of a solid material to deform permanently under the influence of persistent mechanical stresses. It can occur as a result of long-term exposure to high levels of stress that are still below the yield strength of the material. b) Discuss three metallurgical/Processing techniques that are employed to enhance the creep resistance of metal alloys . Generally, materials have better creep resistance if they have higher melting temperatures, lower diffusivity, and higher shear strength. Close-packed structures are usually more creep resistant as they tend to have lower diffusivity than non-close-packed structures. Common methods to reduce creep include: Solid solution strengthening: adding other elements in solid solution can slow diffusion, as well as slow dislocation motion via the mechanism of so...