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Unformatted text preview: ses (i.e.,the regionsleft missingthe periodic table), lattice site, a
to take on some defect characteristics.haveincrease in covalent characteristic of the
point covalent is said to The been formed. with
intermetallics Stoichiometric compounds
bonds in metals is part of the reason the density of metals generally decreases as one
rials property that relates the moves to characteristic metal atom given row.
the right in ratio
in a ratios such as of the 3 Al,
Poisson’sthe periodic tableThe negative ratioAlLi, Nitransverse
magnetic ﬁeld strength H.
When Al V, AlSb, CuZn, Ti Al, and Mg S.
some metals are mixed together, they form stoichiometric compounds with
strain divided by the longitudinal 2strain in a tensile test.
characteristic metal atom ratios. Examples include AlLi, Ni3 Al, Al3 V, AlSb, CuZn, Ti3 Al,
and Mg2polarization Thereferred to as intermetallics. Mostthat are deﬁned
Si. These compounds are regions between atoms of these compounds
Separation of positive and negative
exhibit either mixed metallic/covalent oror ions. Interstices in crystals are
mixed metallic/ionic bond characteristics, deby at least four atoms usually by an electric ﬁeld. The
ation that provides the
pending chargeEin values of the elements involved. Although brittle, these materials
N a material,
usually tetrahedral or octahedral.
in size and the yield stress. often have good high-temperaturethe dipoles ain a strength-to-weight unit As a
vector sum of all resistance and high material per ratio.
result, Ni3 Al and Ti3 Al are ﬁnding usage in the aerospace industry.an atom or ion
ith decreasing grain size
volume is the A point defect consisting of
In previous examplesthe term mixed bonding referred to the intermediate characterisequation.
tics of an that is located in the intersticesbonding occurs in materials having
individual bond. Another type of “mixed” of the structure under
polycrystallineInterstitials mayabethe previo...
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