Determination of activation parameters using impression creep data

Impression creep technique is a modified indentation creep test wherein the conical or ball indenter is replaced by a cylindrical, flat bottomed punch. In this study, the impression creep behavior of a few Al-U-Zr alloys was studied in the temperature range 693-783K at different stresses. Impression creep curves generated for Al-22U-2Zr and Al-46U-3Zr (composition in wt %) show a wavy pattern. The reason for the unusual creep curve is found to be in the fact that microstructure is not stable at the creep testing temperature. The velocity of the punch at different stresses and temperatures were evaluated for each of the alloy covered in this study. The stress exponents and thermal activation parameters of the above alloys were determined.