Any clay, but chiefly kaolinite, which, when mixed with water, is easily
shaped and retains this shape until fired.
a. Permanent deformation of the shape or volume of a substance, without
rupture. It is mainly accompanied by crystal gliding and/or
recrystallization. Syn:plastic flow; thixotropy. CF:plastic strain
AGI
b. Deformation by one or both of two grain-scale mechanisms: slip, and
twinning. This is a metallurgical definition, increasingly used by
geologists. Sometimes called crystal plasticity. AGI
c. Rheological term for deformation characterized by a yield stress, which
must be exceeded before flow begins. AGI
d. An elastic deformation of brittle minerals--such as olivine under
mantle conditions, or quartz, during metamorphism; deformation occurs
along well-defined crystallographic planes in specific directions, which
may be preserved as thin deformation lamellae or as deformation twinning.
It may be annealed out by recrystallization. CF:elastic deformation
e. Irreversible deformation of metallic minerals, such as gold or copper.
See also:malleability
The design of steel or reinforced-concrete structural frames which is
based on the assumption that plastic hinges form at points of maximum
bending moment. See also:elastic design; plastic modulus.
Hammond
See:plastic and semiplastic explosive
A common term for both high duty and super-duty fire clay plastic
refractories.
The breakage of a solid material under load when being permanently
deformed. Hammond
A corklike device for lighting a safety fuse. When the cord is ignited an
intense flame passes along its length at a uniform rate and ignites the
blackpowder core of an ordinary safety fuse. Two types are made: the fast
has a nominal burning speed of 1 s/ft (3.3 s/m); the other is about 10
times as slow. Nelson
The property of a material that enables it to undergo permanent
deformation without appreciable volume change, elastic rebound, or
rupture. See also:plastic deformation; plastic flow; plastic limit;
plastic soil; plastic state; plasticity index. ASCE
The water-content range of a material at which it is plastic, defined
numerically as the liquid limit minus the plastic limit.
CF:Atterberg limits; plastic limit.
A material, usually organic, capable of imparting plastic properties to
nonplastics or improving the plasticity of ceramic mixtures.
Syn:wetting agent
a. The water-content boundary beyond which a soil can be rolled into a
thread approx. 3 mm in diameter without crumbling, i.e., beyond which it
is plastic.
b. The water content of a soil or clay material corresponding to an
arbitrarily defined boundary between a plastic and a semisolid state.
CF:Atterberg limits; plasticity index.
A factor used in the plastic design of steel structures. It is a constant
for each particular shape of section. See also:plastic design
Hammond
a. A soil that can be rolled into 1/8-in (1.6-mm) diameter strings without
crumbling. Nichols, 1
b. A soft, rubbery soil. Nichols, 1
c. A soil that exhibits plasticity. ASCE
A solid that undergoes change of shape continuously and indefinitely after
the stress applied to it passes its elastic limit.
The range of consistency within which a soil exhibits plastic properties.
Also called plastic range. ASCE
In rocks, which are composed of many crystals commonly belonging to
several mineral species, the term applies to any permanent deformation
throughout which the rock maintains essential cohesion and strength
regardless of the extent to which local microfracturing and displacement
of individual grains may have entered into the process.
CF:plastic deformation
A tamping rod or stemmer, of a rigid nature, made from plastic possessing
suitable dielectric properties. A plastic conducive to the building up of
heavy charges of static electricity is unsuitable. Nelson
Dies, jigs, and fixtures for metal forming, boring, assembly, and
checking; made at a saving of time and labor, of laminated and cast
components, and cemented into highly stable industrial tools, chiefly with
epoxy and some with polyester resins. Epoxies are strong adhesive resins,
particularly useful because of their low shrinkage factor. Polyesters have
a cost advantage and are easy to handle. Crispin
The term commonly applied to plastic deformation. Hammond
In explosion-formed-crater nomenclature, this zone differs from the
rupture zone by having less fracturing and only small permanent
deformations. There is no distinct boundary between the rupture and
plastic zones. Min. Miner. Eng., 2