STRUCTURE-INSENSITIVE PROPERTIES
Due to different working and / or heat treatments during manufacture of a material ,
physical properties
do not have much variation from one specimen to another ,
even if their microstructures are
different This kind of is called (microstructure insensitive and associated with the
property are
-
.
properties of the atoms within the material and the forces between them .
Density and elastic modulus are the most important structure -
insensitive properties , along with
some electrical and thermal characteristics as well .
In comparison
,
the
majority of mechanical properties are
significantly affected by any changes in the
called structure Yield and fracture strength
microstructure and are sensitive properties strength
-
.
are the most important structure sensitive properties
-
.
Metallic Bond
•
dominant bond in pure metals and alloys
In solid metal , some of the highest energy electrons (outer valence electrons) leave the parent
•
a or
atoms and become positive A cloud of electrons is formed from the positive electrons
'
ions
'
.
which permeate through the
crystal lattice compare to true covalent bonding where electrons
-
shared between atoms true ionic electrons donated
are or
bonding where are
by one atom
to another .
" ions
•f
.
• • • .
Schematic +
shows ordered
array of charged
.
. . an ve ions and
• • • •
cloud of ve
charged valence electrons that move
randomly
-
•
a
is uniform
always
•
.
.
between the ions so the overall distribution
.
• • • •
"
,
'
↑
'
cloud of e-
interaction between the negatively charged electron cloud and ions that result in
•
positively charged
a stable structure .
the disintegrate and the positive another if there
crystal would ions would repel one were no electron
•
cloud .
without the lattice of positive ions, the electron cloud could
•
not exist as the electrons would
repel one another .
•
the
high density crystal structures ( FCC , HCP and Bcc ) are formed by the metal ions packing
together as they have no directionality .
FCC -
face centered cubic
HCP hexagonal close packed
-
BCC
body centered cubic
-
Due to different working and / or heat treatments during manufacture of a material ,
physical properties
do not have much variation from one specimen to another ,
even if their microstructures are
different This kind of is called (microstructure insensitive and associated with the
property are
-
.
properties of the atoms within the material and the forces between them .
Density and elastic modulus are the most important structure -
insensitive properties , along with
some electrical and thermal characteristics as well .
In comparison
,
the
majority of mechanical properties are
significantly affected by any changes in the
called structure Yield and fracture strength
microstructure and are sensitive properties strength
-
.
are the most important structure sensitive properties
-
.
Metallic Bond
•
dominant bond in pure metals and alloys
In solid metal , some of the highest energy electrons (outer valence electrons) leave the parent
•
a or
atoms and become positive A cloud of electrons is formed from the positive electrons
'
ions
'
.
which permeate through the
crystal lattice compare to true covalent bonding where electrons
-
shared between atoms true ionic electrons donated
are or
bonding where are
by one atom
to another .
" ions
•f
.
• • • .
Schematic +
shows ordered
array of charged
.
. . an ve ions and
• • • •
cloud of ve
charged valence electrons that move
randomly
-
•
a
is uniform
always
•
.
.
between the ions so the overall distribution
.
• • • •
"
,
'
↑
'
cloud of e-
interaction between the negatively charged electron cloud and ions that result in
•
positively charged
a stable structure .
the disintegrate and the positive another if there
crystal would ions would repel one were no electron
•
cloud .
without the lattice of positive ions, the electron cloud could
•
not exist as the electrons would
repel one another .
•
the
high density crystal structures ( FCC , HCP and Bcc ) are formed by the metal ions packing
together as they have no directionality .
FCC -
face centered cubic
HCP hexagonal close packed
-
BCC
body centered cubic
-
