https://doi.org/10.1051/epjap:2000184
Effect of superimposed oscillations on characteristics of Al-40 wt.% Zn alloy
Physics Department, Faculty of Education, Ain Shams University, Cairo, Egypt
Corresponding author: assaad_abdelkahlk@yahoo.com
Received:
22
November
1999
Revised:
23
May
2000
Accepted:
27
September
2000
Published online: 15 December 2000
Marked effect of imposed low frequency oscillations with amplitudes of
6.6 × 10−4−11.6 × 10−4 during creep of pre-aged Al-40 wt.% Zn alloy samples under
constant stress at 423 K, was observed. Increasing the frequency or amplitude at a
certain temperature, increased both n and 
but decreased β values. The value of the
ratio γ (0.75−0.77) shows the high dependence of the steady creep on the transient
creep stage. The results were explained in view of the nature of the thermally induced
structures during aging and their mode of interaction with lattice defects generated by
the applied stress and the imposed oscillations. Grain boundary sliding and grain
boundary diffusion of Zn and Al are suggested as the rate controlling mechanisms for
both the transient and steady creep stages, respectively.
PACS: 61.72.Lk – Linear defects: dislocations, disclinations / 61.72.Ss – Impurity concentration, distribution, and gradients / 61.72.Yx – Interaction between different crystal defects; gettering effect
© EDP Sciences, 2000
