Metal Foams: A Design Guide

108 Metal Foams: A Design Guide
is close to the value n D 4.0 for solid 6101-T6 aluminum. The measured
activation energy, 166 kJ/mole, corresponds well with that for the solid metal
(Q D 173 kJ/mole). The dependence of the strain rate on foam density is found
from a plot of log(steady-state strain rate) against log(relative density), shown
in Figure 9.4: the measured power of 6.4 compares well with the expected
value of 6.5 from equation (9.3). The steady-state strain rate of the foam is
the same in tension and compression. The reference stress 0 D 31.6MPa.
The results of creep tests on a closed-cell Alporas aluminum foam indicate
that it, too, is well described by equation (9.3) at low stresses and temperatures
(