Unformatted text preview: 31:511.] . .
— substances of which something is composed or made. The term engmeermg
Walls is sometimes used to refer speciﬁcally to materials used to produce technical products. However, there is no clear demarcation line between the two terms, and they are
used interchangeably. -"S-er. 1.2 a scientiﬁc discipline that is primarily concerned with the search for. basic knowledge about the internal structure, properties, and processing of materials. ‘
an engineering discipline that is primarily concerned Wlth the use of fundamental and applied knowledge of materials so that they can be converted into
products needed or desired by society. .1 : the equivalent number of atoms whose centers are intersected by a selected
area divided by the selected area. the number of atoms whose centers lie on a speciﬁc direction on a speciﬁc
length ofTine in a unit cube. Sec. 3.10 (as pertains to metals): the abiiity of a metal to exist in two or more crystal structures. For example, iron can have a ECG or an FCC crystal structure, depending on
the temperature. Sec. 3.12 materials with regions of crystalline structure dispersed in the surrounding,
amorphous region; for instance some polymers. metals with an amorphous atomic structure. a glass coating applied to a ceramic substrate. a glass coating applied to a metal substrate.
a glass coating applied to a glass substrate. Sec. 11.10 a condition in which the applied implant is carrying a signiﬁcant portion of
load carried by a fractured bone. It has negative side effects. 'Sec. 2.6 a primary bond resulting from the sharing of electrons. In most cases the
covalent bond involves the overlapping of half-ﬁlled orbitals of two atoms. It is a
directional bond. An example of a covalently bonded material is diamond. an atomic orbital obtained when two or more noneqmiralent‘ orbitals of an
atom combine. The process of the rearrangement of the orbital: i: (‘91le humidity-anon.
electrons in the outermost shells that are most often involved in bonding. an atom without its valence electrons. '
a primary bond resulting from the sharing of delocallzed outer electrons in the Immectron charge cloud by an aggregate of metal atoms. It is a nondirectional bond.
An example of a metallicallybonded material is elemental sodium. a seQndaiy bond created by the attraction of molecules that have permanent dipoles. That is, each molecule has positive and negative charge centers
se arated b I a distance. a Special type of intermolecular permanent dipole attraction that occurs
[Wdrogen atom bonded to a highly electronegative element (F, O, N, or Cl) and another atom of a highly electronegative element. ...
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- Spring '09