MODULE 1 Flashcards
what are the four components of material science?
processing,structure,properties and performance
Refers to the group of materials that are used in the construction of manmade structures and components.
Engineering materials
What are the major classifications of engineering materials?
inclue metals,polymers, ceramics and composites.
Materials are classified into two?
Metallic and Non-metallic
involves investigating the relationships that exist between the structures and
properties of materials (i.e., why materials have their properties)
materials
science
involves, on the basis of these structure–property correlations, designing or
engineering the structure of a material to produce a predetermined set of properties.
materials
engineering
role of a material scientist
s to develop or synthesize
new materials
role of a material engineer
is called upon to create new products or
systems using existing materials and/or to develop techniques for processing materials
material usually relates to the arrangement of its internal components.
structure
involves electrons within the individual atoms, their energies
and interactions with the nuclei
Subatomic structure
involves electrons within the individual atoms, their energies
and interactions with the nuclei
Subatomic structure
relates to the organization of atoms to yield molecules or crystals.
Atomic structure
deals with aggregates of atoms that form particles (nanoparticles)
that have nanoscale dimensions (less that about 100 nm).
Nanostructure
those structural elements that are subject to direct observation using
some type of microscope (structural features having dimensions between 100 nm
and several millimeters).
Microstructure
structural elements that may be viewed with the naked eye (with
scale range between several millimeters and on the order of a meter).
Macrostructure
a material trait in terms of the kind and magnitude of response to a
specific imposed stimulus
property
relate deformation to an applied load or force; examples
include elastic modulus (stiffness), strength, and resistance to fracture.
Mechanical properties
the stimulus is an applied electric fi eld; typical properties include electrical conductivity and dielectric constant.
Electrical properties
are related to changes in temperature or temperature gradients
across a material; examples of thermal behavior include thermal expansion and heat
capacity.
Thermal properties
the responses of a material to the application of a magnetic
fi eld; common magnetic properties include magnetic susceptibility and magnetization
Magnetic properties
—the stimulus is electromagnetic or light radiation; index of refraction and refl ectivity are representative of _____
Optical properties
relate to the chemical reactivity of materials; for
example, corrosion resistance of metals.
Deteriorative characteristics
the structure of a material
depends on how it is???
processed
a material’s performance is a function of??
properties
means a model or set of ideas.)
“paradigm
The four components of the discipline of materials science and
engineering and their interrelationship
processing - structure - properties - performance
Solid materials
metals,
ceramics, and polymers
are 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
Atoms of metals?
arranged in avery orderly manner aand and are relatively dense in comparison
to the ceramics and polymers
mechanical characteristics of metals
these materials are relatively stiff and strong, yet are ductile (i.e., capable of large amounts of deformation without fracture), and are resistant to
fracture
Properties of metals
are extremely good conductors of electricity
and heat
2. not transparent to visible light
3. a polished metal surface
4. has a lustrous appearance
are compounds between metallic and nonmetallic elements; they are most frequently oxides, nitrides, and carbides
Ceramics
mechanical behavior of ceramics?
are relatively stiff and strong—stiffnesses and strengths are comparable to those of the metals
2. they are typically
very hard
3. extreme brittleness (lack of ductility)
4. highly susceptible to fracture
Ceramic materials are typically?
insulative to the passage of heat and electricity (i.e., have low electrical conductivities, and are
more resistant to high temperatures and harsh environments than are metals and polymers.
include the 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)
Polymers
Properties of polymers
- low densities
2.their stiffnesses and strengths on a per-mass basis are comparable to those
of the metals and ceramics - extremely ductile and pliable (i.e., plastic), which means they are easily formed into complex shapes.
- e low electrical conductivities
- nonmagnetic
composed of two (or more) individual materials that come from the
categories previously discussed—metals, ceramics, and polymers
composite
include semiconductors, biomaterials, and what we
may term materials of the future (i.e., smart materials and nanoengineered materials),
Advanced materials
have electrical properties that are intermediate between those of electrical conductors (i.e., metals and metal alloys) and insulators (i.e., ceramics and polymers)
Semiconductors
nonviable (i.e., nonliving) materials that are
implanted into the body, so that they function in a reliable, safe, and physiologically
satisfactory manner, while interacting with living tissue
biomaterial
compatible with body tissues and fluids with which they are in contact
over acceptable time periods.
biocompatible
hey are not distinguished on the basis of their chemistry but rather their size; the nano prefix denotes that the dimensions of these structural entities are on the order of a nanometer (10−9
m)—as a rule, less than 100 nanometers (nm; equivalent to the diameter of approximately 500 atoms)
nanomaterials,
Each chemical element is characterized by the number of protons in the nucleus, or the
atomic number
of a specific atom may be expressed as the sum of the masses of protons and neutrons within the nucleus.
atomic mass
atoms of some elements
have two or more different atomic masses,
isotopes.
corresponds to the weighted average of the atomic masses of the atom’s naturally
occurring isotopes.
atomic weight
may be used for computations of atomic weight.
atomic mass unit (amu)
1 amu/atom (or molecule)
1 g/mol
; protons and neutrons
1.67 × 10−27 kg
electron
9.11 × 10−31 kg
The mass number of the atom (M) is equal to
the sum of the number of protons and neutrons in the nucleus
Bonding that is always found in
compounds composed of both metallic and nonmetallic elements
Ionic bonding
what is the direction of ionic bonding?
nondirectional
magnitude of the bond is equal
in all directions around an ion.
nondirectional
What boonding has the lowest bonding energy?
van der Waals
Bonding that happens between nonmetals?
Covalent bonding
What happens in covalent bonding?
sharing of electrons
What type of bond is there in covalent bonding?
Directional bond
it is between specific atoms and may exist only in the direction between one atom and another that participates in the electron sharing.
directional
Bonding found in metals and their alloys?
Metallic Bonding
What type of bond is there in metaalic bonding?
Nondirectional
It exists whenever there is some separation of positive and negative portions of an atom or
molecule.
electric dipoles
a special type of secondary bonding, is found to
exist between some molecules that have hydrogen as one of the constituents.
Hydrogen bonding,
3 Types of van der Waals bonds?
- Fluctuating Induced Dipole Bonds
- Polar Molecule-Induced Dipole Bonds
- Permanent Dipole Bonds
a special type of secondary bonding, is found to exist between some molecules that have hydrogen as one of the constituents.
Hydrogen Bonding
Electric charge amount
1.60 x10 -19 C,
using naturally occuring materials with only changes in shape I
Stone Age
Ability to modify materials by refining (using heat), chemical modifications (alloying)
and mechanical deformation (cold working)
Bronze Age
Ability to heat treat at high temperature, control microstructure at different length scale and ability to design specific microstructures for specific properties
Iron Age
Discovery of polymers, and the ability to synthesize and process polymers
Plastic Age
Ability to control alloying accurately, ability to make thin films.
Silicon Age
