Creep in an Al-5356 solid solution alloy with an intercept grain size, d_g=5+-0.5 um was investigated using the helicoid spring specimen technique. The testing temperatures ranged from 423 K to 523 K (0.47 to 0.58 Tm) and the applied stresses from 0.20 MPa to 4.02 MPa. It was found that under the above conditions, viscous creep of Bingham type occurs, characterized by a threshold stress which decreases with increasing temperature. The activation energy is Qc = 44 +- 7 kJ/mol. No microstructural changes were observed in recrystallized and the as-crept specimens. The measured creep rates were found to be four orders faster than that predicted by Coble creep model.
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