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 ductile
thus 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
❡ Papyrus
3,000 BCE
❧Second polymer in use (after wood)
❧First processed polymer
❧Stems of papyrus plant are stripped, rotted
(retted), and pressed into a polymer 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 sap
of the percha
❧Bioinert, resilient
good electrical insulator
❧Sap was left in sun to
evaporate, leaving
thermoplastic latex
1000 CE
❡ Crucible steel
❧Iron + carbon
1500 CE
❡ Iron smelting
❡ Rubber
1700 CE
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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 inexpensive
purification 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
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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 nonrenewable
❡ 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
2,000
5,000
Device grade silicon