Creep Instability of Aluminum under Varying Temperature
Creep under unsteady temperature is affected by changes in the mobility of elements of the micro-structural configuration produced by temperature variation, such as local density changes, changes in mobile dislocations due to their thermal break-away and grain-boundary migration. Since these changes are not instantaneous, it is to be expected that, following a temperature variation, a condition of steady-state creep will not immediately establish itself.
Results of elevated temperature creep experiments on pure aluminum indicate that a period of sharp creep-acceleration follows a rapid temperature increase until steady state creep establishes itself after several hours. The implications of this phenomenon on the results of creep and stability analysis of simple structural elements are discussed.
KeywordsCreep Rate Steady State Creep Mobile Dislocation Relaxation Modulus Steady State Creep Rate
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