Interpretation of primary creep deformation mechanism through activation energy measurements

Abstract

Primary creep behaviors of the lamellar structured Ti-46.6Al-1.4Mn-2Mo (at.%) alloy (EPM alloy), which is fabricated by hot extrusion of a blended elemental powder mixture (EPM), are investigated in an air environment over the temperature range of from 775 to 900 degrees C under constant stress ranging from 150 to 250MPa. The apparent activation energy of the primary creep deformation is measured to be increased with the creep strain and found to be saturated to the value of the activation energy of the steady start creep deformation. Reduction of effective stress with creep strain in the primary region is suggested to be responsible for the increase in the apparent activation energy. All the creep rates normalized by the apparent activation energies measured at the given creep strain within the primary region show the stress exponent of 4.2 when plotted against the applied stress.