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L E S S O N 15
I. Translate the following text into Russian.
METALS AND ALLOYS
In the last thirty years or so, due to the fast development of industry, the need for new metallic materials
has enormously increased. Metals practically unheard of before, such as germanium, plutonium, and than um
have come to light, taking their place in the electronic and atomic industries. There have also been developed
high-temperature alloys for power plants capable of withstanding oxidation and erosion, new ferro-magnetic
materials, constructional steels, etc., intended for operating under severe stresses, or/and at extremely high or
low temperatures.
Practically speaking, each metal possesses certain distinct combinations of properties that may be varied for
specific engineering applications by alloying it with relatively small amounts of other metals.
Before starting to study the basic phenomena, which determine the performance of metallic materials, it is
advisable to get an idea of what the terms "metal", "alloy" and "element" mean.
The term "alloy" is commonly used to describe a material containing more than one chemical element, the
properties of the alloy being determined by the properties of the elements it consists of. The term "pure metal",
on the other hand, is used for materials in which almost all chemical elements but one are eliminated.
The distinction between metals and alloys is immaterial for describing the effects of their chemical compo-
sition on forming, such as rolling, forging, pressing, etc. But even small amounts of chemical elements, or im-
purities, in pure metals used in electronics may affect their performance in the same way as the comparatively
large quantities of alloying elements in pure metals used in other fields of engineering. The designation "metal" is
sometimes applied in metallurgy to metallic materials without making distinction between pure metal and alloy,
the first definition of the word "metal" having been formulated by M.V. Lomonosov in the following way: "A
metal is a bright solid that can be forged." This definition is still true, metallic lustre and the ability for plastic de-
formation being, in fact, characteristic features of metals. The most important feature of metals, however, is their
high electrical conductivity which decreases as the temperature is raised.
As to the term "element", it is frequently used not only for commercially pure metals but also for some al-
loys containing a considerable amount of other metals, the most common but rather misleading term of this na-
ture being "iron", when used in English-speaking countries for designation of cast iron containing a large quan-
tity of carbon.
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