Mechanical Properties of Metals Flashcards
Metals are known to be:
Malleable & Ductile
High density
High Melting Point
High Thermal Conductivity
High Electric Conductivity
how much force an
object can withstand without bending or breaking (compression, tension, & shear)
STRENGTH
refers to a material’s
response to tensile stress, or its
ability to be stretched, rolled or extruded without breaking.
Ductility
refers to compressive stress, as in flattening.
Malleability
represents an ideal
balance between strength and ductility. The toughest metals are those that can absorb the highest amounts of energy before fracturing
Toughness
is a measure of a
part’s ability to undergo repeated,
cyclical stress without fracturing or
permanently deforming.
Fatigue resistance
A material’s power to
resist a permanent change in shape when acted upon by an external force
Hardness
FCC Mechanical Properties
Low young modulus
Low yield strength
Low hardness
Good ductility and high ability for forming.
BCC Mechanical properties
High yield strength
High young modulus
High hardness
High tensile strength
Limited ability to forming
HCP Mechanical properties
Brittle
Low yield strength
Inability to forming
Key mechanical design properties are
stiffness, strength, hardness, ductility, and toughness.
A specimen is deformed, usually to
fracture, with a gradually increasing tensile load that is applied uniaxially along the long axis of a specimen.
Tension Tests
conducted in a manner similar to the tensile test, except that the force is compressive and the specimen contracts along
the direction of the stress.
Compression stress–strain tests
a variation of pure shear in which a
structural member is twisted in the manner of torsional forces produce a rotational motion about
the longitudinal axis of one end of the member relative to the other end.
Torsion
a function of the orientations of the
planes upon which the stresses are taken to act.
stress state
non-permanent, which means that when the applied load is released, the piece returns to its original
shape.
Elastic deformation
The stress necessary to
continue plastic deformation
in metals increases to a
maximum, point M and then
decreases to the eventual
fracture, point F. Unit Mpa
or psi
Tensile Strength (TS)
It is a measure of the degree of plastic deformation that has been
sustained at fracture
DUCTILITY
Knowledge of the ductility of materials is important for at
least two reasons.
1.) It indicates to a designer the degree to which a structure will deform plastically before before fracture
2.) It specifies the degree of allowable deformation during fabrication operations.
Metal that experiences
very little or no plastic deformation upon fracture
Brittle
Is the capacity of a material to
absorb energy when it is deformed elastically and then, upon unloading, to have this energy recovered.
Resilience
is the ability of a material to absorb energy and plastically deform before fracturing
Toughness
which is a measure of a material’s resistance to localized plastic deformation (e.g., a small dent or
a scratch).
Hardness
