Определить функцию инфинитива в предложениях. дать возможные варианты перевода предложений.

1. above certain critical temperature, changes begin to take place in the molecular structure of a metal.
2. to prepare metals for practical use requires much knowledge and experenсe.
3. the aim of any research is to enlarge the possibilities which areoffered by modem science.
4. in order to prevent сorosion, metals to be used in industry must bе covered with special paint.
5. it is difficult to define what an amorphous material is. it may be composed of crystals which are too small to be detected.
6. this metal is too brittle to be hammered.
7. dissimilar metals and alloys are joined to get the final product with qualities of each component. metals and alloys to be joined are placed close together and are subjected to pressure and shock waves.
8. to strengthen metals is to reinforce them with fibres.
9. to produce changes in physical state а considerable amount of thermal energy must be supplied to metal.
10. а very good practice is to introduce the best scientific inventions into industry.
11. toughness is the ability of а material to absorb mechanical energy by permanent deformation without breakage.
12. steam engines were the first to be tried in aeroplanes but they were too heavy to be of аnу real use.
13. steel is the metal to be formed from iron with a definite amount of carbon.
14. if steel is heated above critical temperature, it becomes softer and much easier to be machined.
15. this alloy is not tough enough to be used in this process.
16. these exists a large number of mefals to be found free in nature