الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
l Lattice Imperi’ections in Metals •
It becar~>e properly re8.lized thac perfect crystal model
in which the regulax· arrangement. of the ”’toms extends
everywhere, do not really exist. This perfect crystal
model is adequate, however for explaining these so-called
structure insensitive properties, such as melting point,
density, and specific heat •. On the other hand there are
many other properties of metals ~cJuch as mechanical as well
as phisical properties which are sensitive to the material
past-history and cannot be accounted for on the basis of
the perfect crystal theory (Elastic, plastic and electric
properties of metal).
Actual ,crystal lattices are de via ted from ideality by
the presence of physical lattice imperfections, possibly
classified as point defects (vacancies and interstitials),
line imperfections (dislocations), surface defects (grain
boundaries) and volume defects (voids and. microcracks).
I.l.l- Point dei’ects, (l, 2 )
point defects:
there are three types of
(a) vacanay, which exists when an atom is missing from a
normal lattice position as shown in Fig. (l.a).
VacEJ.ncies are usually found in thermodynamic equilibriwn,
so at a given tempera tur<:e: