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Unformatted text preview: in longlife applications. Another parameter, especially important in shortlife creep situations, is time to rupture, or the rupture lifetime, t r . t / s Δ ε Δ = ε & t r Δε / Δ t 29 MSE 2090: Introduction to Materials Science Chapter 8, Failure Creep: stress and temperature effects With increasing stress or temperature: ¾ The instantaneous strain increases ¾ The steadystate creep rate increases ¾ The time to rupture decreases 30 MSE 2090: Introduction to Materials Science Chapter 8, Failure Creep: stress and temperature effects The stress/temperature dependence of the steadystate creep rate can be described by ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ − σ = ε RT Q exp K c n 2 s & where Q c is the activation energy for creep, K 2 and n are material constants. (Remember the Arrhenius dependence on temperature for thermally activated processes that we discussed for diffusion)...
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This note was uploaded on 02/14/2012 for the course MSE 2090 taught by Professor Leoindzhiglei during the Fall '10 term at UVA.
 Fall '10
 leoindzhiglei

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