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als. 3. The most widely used non-ferrous metals are aluminium and copper. 4.
The most common engineering thermoplastics are ABS and PVC. 5. The most
common engineering thermosets are epoxy resins and polyamides.
Model B:
Materials science encompasses various classes of materials.
What does materials science encompass?
1. This alloy contains copper. 2. Large amount of carbon in cast iron in-
creases its brittleness. 3. Stainless steel contains nickel or chromium. 4. A com-
pound consists of two or more elements. 5. A mixture includes two or more
elements or compounds.
Exercise 24. Ask questions and use the words in italics in your answers. The
words in brackets will help you.
1. Fiberglass is
correctly called
glass-reinforced plastic
(how). 2.
Cast iron
has a wide range of applications
in machines and automotive industry parts
(where). 3. At present some car manufacturers are switching from steel to alu-
minium
to save weight of a car
(why). 4. Car makers try
to make vehicles lighter
(what). 5. Thermosets can be moulded
only once
(how many times).
Exercise 25. Read the following dialogue, sum up the information and act out a
similar dialogue.
APPLICATION OF ENGINEERING MATERIALS
A.: We have been discussing the classification of engineering materials during
the English classes. Have you memorized the
groups of engineering mate-
rials?
B.: Sure. They are metallic and non-metallic materials.
A.: Yes, you are right! There is such a wide variety of materials. And I’d like to
know where they are all used in mechanical engineering. It seems to me
that cast irons tend to have a declining usage.
B.: Nothing of the kind. Cast iron has a wide range of applications in machines
and automotive industry parts.
A.: Is that really so? But as for the cars, steel but not cast iron makes up by far
the single largest percentage of materials.
B.: I agree with you on this point. If I am not mistaken,
an average car has
about 55 per cent of steel.
A.: But materials technology is constantly changing and at present some car
manufacturers are switching from steel to aluminium to save weight of
a car. I wonder if aluminium can fully substitute steel.
B.: New alloys mean that aluminium is now as rigid as steel. Moreover, it is
corrosion-resistant.
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A.: It’s going to be interesting to see if the popularity of aluminium continues
to increase in the future.
B.: Not only of aluminium but plastics too. As car
makers try to make vehicles
lighter the plastics percentage is increasing all the time.
A.: I see. Thanks a lot for your comments.
B.: You are welcome.
Достарыңызбен бөлісу: 
