Exam II Vocabulary
– a metallic substance composed of two or more elements –pg. 83
– concentration specification on the basis of the number of moles (or
atoms) relative to the total number of moles (or atoms) of all elements within an alloy.
Differs from weight percent because of density. –pr. 85
– the vibration of an atom about its normal position in a substance,
these atomic vibrations may be thought of as imperfections or defects.
At any instant not
all atoms vibrate at the same frequency, amplitude, or energy, but as temperature
increases the average energy increases. –pg. 96
Boltzmann’s Constant (k)
– a thermal energy constant. –pg. 82
k = 1.38 x 10
k = 8.62 x 10
Burgers vector (b)
– a vector that denotes the magnitude and direction of lattice
distortion associated with a edge, screw, or mixed dislocation.
For an edge dislocation,
they are perpendicular.
Screw, they are parallel, and neither for mixed. –pg. 89, Figures
– the relative content of a particular element or constituent within an alloy,
usually expressed in weight percent or atom percent. –pg. 85
– the line that extends along the end of the extra half-plane of atoms for
an edge dislocation, and along the center of the spiral of a screw dislocation. –pg. 88
– an extra portion of plane atoms, or half-plane, the edge of which
terminates within the crystal
A linear crystal-line defect associated with the lattice distortion produced in the vicinity
of the end of an extra half-plane of atoms within a crystal.
The Burgers vector is
perpendicular to the dislocation line. –pg. 88
– the average grain diameter as determined from a random cross section.
– a deviation from atomic/ molecular order and or continuity, this could be
a different kind of atom or a hole. –pg. 81
Interstitial solid solution
– Impurity atoms fill the voids or interstices among the host
For metallic materials that have relatively high atomic packing factors, these
interstitial positions are relatively small.
Therefore, the atomic diameter of an interstitial
impurity must be substantially smaller than that of the host atoms. –pg. 84
– the investigation of micro-structural elements using some type of
microscope (optical, electron, scanning probe microscopes). –pg. 97
– the structural feartures of an alloy (grain, phase structure…) that are
subject to observation under a microscope. –pg. 97
– a dislocation that has both edge and screw components. –pg. 89,
The photo made with a microscope, which records a microstructural
image. –pg. 97
Point defect –
Defects associated with one or two atomic positions.
self-interstitials, and impurities in solids. –pg. 81