Page 111 - Manufacturing Engineering and Technology - Kalpakjian, Serope : Schmid, Steven R.

90 Chapter 3 Physical Properties of Materials

TABLE 3.2
Physieai Properties of Materials, in Descending Qrder
Melting Specific Thermal Thermal Electrical
Density point heat conductivity expansion conductivity
Platinum Tungsten Wood Silver Plastics Silver
Gold Tantalum Beryllium Copper Lead Copper
Tungsten Molybdenum Porcelain Gold Tin Gold
Tantalum Columbium Aluminum Aluminum Magnesium Aluminum
Lead Titanium Graphite Magnesium Aluminum Magnesium
Silver Iron Glass Graphite Copper Tungsten
Molybdenum Beryllium Titanium Tungsten Steel Beryllium
Copper Copper Iron Beryllium Gold Steel
Steel Gold Copper Zinc Ceramics Tin
Titanium Silver Molybdenum Steel Glass Graphite
Aluminum Aluminum Tungsten Tantalum Tungsten Ceramics
Beryllium Magnesium Lead Ceramics Glass
Glass Lead Titanium Plastics
Magnesium Tin Glass Quartz
Plastics Plastics Plastics

Weight saving is particularly important for aircraft and aerospace structures,
for automotive bodies and components, and for other products Where energy con-
sumption and power limitations are major concerns. Substitution of materials for
the sake of Weight savings and economy is a major factor in the design both of
advanced equipment and machinery and of consumer products such as automobiles.
A significant role that density plays is in the strength-to-weight ratio (specific
strength) and stiffness-to-weight ratio (specific stiffness) of materials and structures.
ff ;§S7§ fif.
Figure 3.1 shows the ratio of maximum yield stress to density for a variety of metal
alloys. Note that titanium and aluminum are at the top of the list; consequently, and

Titanium
Aluminum
Steels

Magnesium
Nickel
COPPGV
Tantalum
Molybdenum

Lead i
0 0.;5 1.50 2.é5 3.00 3.75
Yield strength/density (m >< 104)

FIGURE 3.l Ratio of maximum yield stress to density for selected metals.