Structures and Properties of Materials Chapter 1

the responses of a material to the application of a magnetic field; common magnetic properties include magnetic susceptibility and magnetization

magnetic properties

designing or engineering the structure of a material to produce a predetermined set of properties

materials engineering

investigating the relationships that exist between the structures and properties of materials (i.e., why materials have their properties)

materials science

relate deformation to an applied load or force; examples include elastic modulus (stiffness), strength, and resistance to fracture.

mechanical properties

Dense, stiff, and strong but ductile ∙ High resistance to fracture ∙ Good conductors of electricity and heat

metals

composed of one or more metallic elements (e.g., iron, aluminum, copper, titanium, gold, nickel), and often also nonmetallic elements (e.g., carbon, nitrogen, oxygen) in relatively small amounts

metals

three categories of solid materials

metals, ceramics, polymers

those that occur in nature; for example, wood, leather, and cork

natural materials

electrons are not bound to particular atoms

nonlocalized electrons

their tendency to soften and/or decompose at modest temperatures, which, in some instances, limits their use

one drawback to polymers

the stimulus is electromagnetic or light radiation; index of refraction and reflectivity are representative optical properties

optical properties

Extremely ductile and pliable ∙ Generally inert and unreactive ∙ Soften at modest temperature

polymers

familiar plastic and rubber materials. Many of them are organic compounds that are chemically based on carbon, hydrogen, and other nonmetallic elements (i.e., O, N, and Si). Furthermore, they have very large molecular structures, often chainlike in nature, that often have a backbone of carbon atoms

polymers

a material trait in terms of the kind and magnitude of response to a specific imposed stimulus

property

has a high degree of perfection, leading to transparency

single crystal

achieve a combination of properties that is not displayed by any single material and also to incorporate the best characteristics of each of the component materials

the design goal of a composite

are related to changes in temperature or temperature gradients across a material; examples of thermal behavior include thermal expansion and heat capacity

thermal properties

naturally occurring materials that are composites

wood and bone

Are definitions of properties independent of shape and size?

yes

Hard, stiff, and strong ∙ Brittle and susceptible to fracture ∙ Good insulators of electricity and heat

ceramics

compounds between metallic and nonmetallic elements; they are most frequently oxides, nitrides, and carbides

ceramics

composed of two (or more) individual materials that come from the categories previously discussed—metals, ceramics, and polymers

composite

Combine other types of materials ∙ Tailor material properties for specific uses ∙ Properties can differ based on fiber direction

composites

relate to the chemical reactivity of materials; for example, corrosion resistance of metals

deteriorative characteristics

capable of large amounts of deformation without fracture

ductile

polymeric materials that display rubbery-like behavior (high degrees of elastic deformation)

elastomers

the stimulus is an applied electric field; typical properties include electrical conductivity and dielectric constant

electrical properties

One of the most common and familiar composites

fiberglass

small glass fibers are embedded within a polymeric material (normally an epoxy or polyester). relatively stiff, strong, and flexible with a low density

fiberglass

typically polymeric materials that have high porosities (contain a large volume fraction of small pores), which are often used for cushions and packaging

foams

what does the structure of a material depend on

how it is processed