I. Copy the underlined words and word-combinations, translate them into Ukrainian and learn them.

II. Find the following words and word combinations inEnglish in the text: кількість маси; одиниця об’єму; важкий; співвідношення; сила, яка застосовується; переваги; квадратний корінь; вдале дослідження; двигуни літаків.

III. Answer the following questions.

1. What is density of materials?

2. What are the units of density? Where low density is needed?

3. What are the densities of water, aluminum and steel?

4. A measure of what properties is stiffness? When stiffness is important?

5. What is Young modulus?

6. What is strength?

7. What is yield strength? Why fracture strength is always greater than yield strength?

8. What is ductility? Give the examples of ductile materials. Give the examples of brittle materials.

9. What is toughness?

10. What properties of steel are necessary for the manufacturing of: a) springs, b) car body parts, c) bolts and nuts, d) cutting tools?

11. Where is aluminium mostly used because of its light weight?

Test yourself:

1. Choose the right variant.

1. An important feature of hot working is that it

a) eliminates porosity, directionality, and segregation.

b) provides better ductility and toughness.

c) provides the improvement of mechanical properties of metals.

d) all of the mentioned above.

2. During the forging of a bar

a) the grains of the metal become greatly elongated in the direction of flow.

b) the toughness of the metal is greatly improved in direction of flow.

c) the toughness of the metal is weakened in directions transverse to the flow.

d) all of the mentioned above.

3. Fracture of the workpiece during forming can result from

a) strain.

b) inner flaws.

c) stress.

d) all of the mentioned above.

4. All materials respond to external forces such as

a) compression, tension, fatigue and creep.

b) tension, creep, torsion and shear.

c) compression, shear, bending and tension.

d) tension, compression, torsion, bending and shear.

5. In mechanical working processes the metal is shaped

a) by heat and pressure.

b) by heat only.

c) by pressure.

6. The initial materials for the mechanical working of metals are

a) ingots and billets of certain cross sections and weights.

b) ingots and billets of different cross sections and weights.

c) ingots and billets of various cross sections and weights.

2. Fill in the right words into the sentences.

fatigue; volume; recrystallization temperature; creep; tension; stress; temperature

1. Hot working refers to processes where metals are plastically deformed above their...

2. The resistance of metals to plastic deformation generally falls with...

3. A fracture is the (local) separation of an object or material into two, or more, pieces under the action of...

4. Compression is an increase in pressure of the charge in an engine or compressor obtained by reducing its...

5. … is a force that tends to stretch or elongate something.

6. … is the progressive cracking of a material subjected to alternating stresses, esp. vibrations.

7. … is a slow longitudinal movement or deformation.

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