Civil Engineering Reference
In-Depth Information
Eutectoid
composition
Eutectic
composition
Liquid
Liquid
b
g
Eutectic
temperature
g
b
Eutectoid
temperature
a
g
a
b
a
b
A
B
Composition
FIGURE 2.17
Phase diagram for a eutectoid reaction.
■
2.2.6
Combined Effects
The topics of lattice structure, grain size, heat treatments, and alloying are
closely interrelated. The behavior of a metal is dictated by the combination
of each of these factors. Clearly, the properties of a metal depend on the ele-
mental make up, the refining and production process, and the types and
extent of alloys used in the metal. These topics are too complex for detailed
treatment in this text. A practicing engineer in this area must devote con-
siderable study to material characteristics and the impact of alloying and
heat treatments. Due to the importance of steel in civil engineering, the
phase diagram and heat treatment of steel will be presented in Chapter 3.
2.3
Inorganic Solids
Inorganic solids include all materials composed of nonmetallic elements or
a combination of metallic and nonmetallic elements. This class of materials
is sometimes referred to as ceramic materials. By definition, ceramic ele-
ments have five, six, and seven valence electrons. Ceramic materials are
formed by a combination of ionic and covalent bonds. In the generic sense,
ceramics encompass a broad range of materials, including glass, pottery,
inorganic cements, and various oxides. Fired clay products, including bricks
and pottery, are some of the oldest ceramic products made by humans. In
terms of tonnage, portland cement concrete is the most widely used manu-
factured material. In the 1980s, the search for highly durable products with
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