regard to mechanical characteristics, these materials are relatively stiff (Figure 1.4)
and strong yet are ductile (i.e., capable of large amounts of deformation
without fracture), and are resistant to fracture , which accounts for their
widespread use in structural applications. Metallic materials have large numbers of
nonlocalized electrons; that is, these electrons are not bound to particular atoms.Many
properties of metals are directly attributable to these electrons. For example, metals
are extremely good conductors of electricity and heat, and are not trans-
parent to visible light; a polished metal surface has a lustrous appearance. In addi-
tion, some of the metals (viz., Fe, Co, and Ni) have desirable magnetic properties.
Figure 1.8 is a photograph that shows several common and familiar objects that
are made of metallic materials. Furthermore, the types and applications of metals