Fundamentals of Materials Science and Engineering: An Integrated Approach, 3e

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792 • Chapter 20 / Economic, Environmental, and Societal Issues

labor fringe benefits, supervisory and management labor, research and development,

property and rent, insurance, profit, taxes, and so on.

Environmental and Societal

Considerations

Our modern technologies and the manufacturing of their associated products impact

our societies in a variety of ways—some are positive, others are adverse. Further-

more, these impacts are economic and environmental in type, and international in

scope inasmuch as (1) the resources required for a new technology often come from

many different countries, (2) the economic prosperity resulting from technological

development is global in extent, and (3) environmental impacts may extend beyond

the boundaries of a single country.

Materials play a crucial role in this technology-economy-environment scheme.

A material that is utilized in some end product and then discarded passes through

several stages or phases; these stages are represented in Figure 20.1, which is some-

times termed the “total materials cycle” or just “materials cycle,” and represents

the “cradle-to-grave” life circuit of a material. Beginning on the far left side of Fig-

ure 20.1, raw materials are extracted from their natural earthly habitats by mining,

drilling, harvesting, and so on. These raw materials are then purified, refined, and

converted into bulk forms such as metals, cements, petroleum, rubber, and fibers.

Further synthesis and processing result in products that are what may be termed

“engineered materials”; examples include metal alloys, ceramic powders, glass, plas-

tics, composites, semiconductors, and elastomers. Next, these engineered materials

Raw

materials

Recycle/reuse

Waste

Engineered

materials

Product design,

manufacture,

assembly

Applications

Agriculture • Construction

Environmental • Defense

Information/Communications

Transportation • Energy • Health

Extraction/Production

Synthesis

and

processing

Figure 20.1 Schematic representation of the total materials cycle. (Adapted from M.

Cohen,Advanced Materials & Processes,Vol. 147, No. 3, p. 70, 1995. Copyright©c1995 by

ASM International. Reprinted by permission of ASM International, Materials Park, OH.)