Metal Foams: A Design Guide

50 Metal Foams: A Design Guide
Figure 4.8 shows the first of these combinations. For reference, the value of
E/ for structural steel, in the units shown here, is 25 GPa/(Mg/m 3 ⊳,andthat
for c/ is 24 MPa/(Mg/m 3 ⊳. The values for the 1000 series aluminum alloys
are almost the same. Metal foams are have lower values of these two properties
than do steel and aluminum. Figure 4.9 shows E1/2 2/3
/ plotted against c / .
Values for steel are 1.8 and 4.3; for aluminum, 3.1 and 6.2, all in the units
shown on the figure. Metal foams can surpass conventional materials here.
Figure 4.10 shows E1/3 1/2
/ plotted against c / . Values for steel are 0.7 and
1.8; for aluminum, 1.5 and 3.7, all in the units shown on the figure. Metal
foams easily surpass conventional materials in these properties.
Modulus/Density (GPa/(Mg/m 3 ))
10
5
1
0.5
Specific stiffness vs.
Specific strength
Manual2.CMS; MFA 5-12-97; MetFoam DB
INCO (0.285)
Cymat (0.155)
Cymat (0.276)
Alporas (0.245)
INCO (0.385)
INCO (0.265)
Alporas (0.21)
Duocel (0.198)
Duocel (0.162)
GASAR (6.02)
light (0.95) Alulight (0.751)
Hydro 6(0.449)
Duocel (0.254)
Cymat (0.546)
Hydro (0.318)
Alulight (1)
Hydro (0.36)
Fraunhof er (1.1)
Hydro (0.56)
Hydro (0.5)
Hydro (Heiberg)
0.1
1 2 4 6 8 10 20 40 60 80 100
Compression strength/Density (MPa/Mg/m3 ))
Figure 4.8 Specific modulus E/ plotted against specific strength c / for
currently available metal foams
Thermal properties
Figure 4.11 captures a great deal of information about thermal properties. As
before, only some of the data have been identified for clarity. The numbers
in parentheses are the foam density in Mg/m 3 . The figure shows the thermal
conductivity, , plotted against the specific heat per unit volume, C p .Tothis
can be added contours of thermal diffusivity
a D Cp