Pre-History

❡Stone❡Flint❡Wood

20,000 BCE

❡Gold❧Easy to form (Malleable)❧Although 20,000 BCE is an estimate,

gold is the earliest metal to be processed by humans.

7,000 BCE

❡Copper, Silver❧Native metals (gold, copper, silver) were

discovered and found to be ductilethus easy to form

5,000 BCE

❡Pottery❡Cement❡Glass❡Smelted copper

❧Heating and reducing substances (like charcoal) that react with the oxidizing elements

3,500 BCE

❡Tin❡Bronze

❧Alloy of Copper and Tin.❧Earliest Bronze pieces had about 2% tin,

suggesting it was an accident❧Later tin content increased and suggests

intention

3,000 BCE❡Papyrus

❧Second polymer in use (after wood)❧First processed polymer❧Stems of papyrus plant are stripped, Stems of papyrus plant are stripped,

rotted (retted), and pressed into a rotted (retted), and pressed into a polymer sheetpolymer sheet

1,500 BCE

❡Iron❧Needs higher temperature than bronze❧Much more abundant than copper

1,000 BCE❡Lacquer

❧Extracted from tree sap❧Used to preserve wood

100 BCE – 100 CE

❡Amber❡Horn❡Paper

❧Starting to develop more methods of extracting natural resources and converting to modern needs

800 CE

❡Gutta percha❧Natural latex is

produced from the sapof the percha

❧Bioinert, resilientgood electrical insulator

❧Sap was left in sun toevaporate, leaving thermoplastic latex

1000 CE

❡Crucible steel❧Iron + carbon

1500 CE❡Iron smelting❡Rubber

1700 CE

❡Platinum❡Cobalt❡Zinc❡Nickel❡Tungsten❡Zirconium❡Uranium❡Strontium❡Titanium

1800-1850

❡Magnesium❡Aluminum❡Silicon❡Cellulose Nitrate

❧Flash paper, guncotton

❡Vulcanized rubber❡Reinforced concrete

1850-1900

❡Ebonite❡Bessemer steel

❧First inexpensivepurification method

❡Glass fiber❡Cellulose acetate❡Aluminum oxide

1900-1920

❡Bakelite❧First truly synthesized polymer❧Thermoset phenol formaldehyde

❡Stainless steel❡Synthetic rubber❡Nylon

1920-1940

❡Neoprene❡PMMA❡PVC❡PU❡PET❡PTFE❡Plutonium

1940-1960

❡ Formica❡ Lycra❡ PS❡ Composites❡ Super alloys❡ Acetal❡ POM❡ PC❡ PP❡ Amorphous metals

❧Metallic glasses

1960-1980

❡Polyimides❡Polysulfone❡PPO

❡LLDPE❡Shape memory

alloys❡Carbon fiber

1980-2000

❡PEEK❡PES❡PPS

❡Warm superconductors

❡Nano materials❡Biopolymers

Reliance on materials

❡We are totally dependent on materials❧We have shifted from renewable to non-

renewable

❡Transportation, communications, ordinance

Materials Consumption

❡About 10 tons per person per year in US

❡Thomas Malthus, 1798:The power of population is so superior to the power of the Earth to produce subsistence for man that premature death must in some shape or other visit the human race.

Consumption

❡Club of Rome (1972)…if [current trends] continue unchanged … humanity is destined to reach the natural limits of development within the next 100 years.

Is this the end?❡ World Commission on Environment and Development (1987)

many aspects of developed societies are approaching saturation, in the sense that things cannot go on growing much longer without reaching fundamental limits. This does not mean that growth will stop in the next decade, but that a declining rate of growth is foreseeable in the lifetime of many people now alive. In a society accustomed to 300 years of growth, this is something quite new, and will require considerable adjustment.

Competence

❡Humans differ from other species in our competence to make things from materials❧Termites, beavers, birds, etc. make things❧Difference is competence shown by humans❧Ability to expand and adapt through

research and development

❡Are materials the servant or master?

Exercise

❡It takes energy to make materials, called “embodied energy” and expressed in terms of the energy per unit mass (MegaJoules/kilogram = MJ/kg).

❡If you could reduce consumption by 10%, rank the following 5 Engineering materials in order of greatest global energy savings to least.

❡Explain your conclusions and show calculations to support them.❧Details on next page show embodied energy

and total tons (1,000 kg) consumed in a year.

Material Embodied Energy (MJ/kg) Annual Global Consumption (tons/year)

Steels 29 1.1 billion

Aluminum alloys 200 32 million

Polyethylene 80 68 million

Concrete 1.2 15 billion

Device grade silicon 2,000 5,000