Arrangement of Materials on categories for practical engineering.

Современное материаловедение

1. Arrangement of Materials on categories for practical engineering.

2. Metals, Semiconductors and insulators. Main properties and examples.

3. Processing and Selection of materials according to further application.

4. The Planetary model of Atomic structure.

5. The ionic bond: characteristics and examples.

6. What is the difference between covalent and metallic bonds.

7. The mechanism of secondary bonding (Van der Waals force).

8. Crystalline structure: Systems and Lattices.

9. The solid solution – chemical imperfection.

10. Explain Hume – Rothery rules.

11. Point defects as zero – dimensional imperfection.

12. Linear defects, or dislocations as one – dimensional imperfection.

13. Planar defects as two – dimensional imperfection.

14. Noncrystalline solids as three – dimensional imperfections.

15. The main work principles of Atomic Force Microscopy.

16. The main work principles of Scanning Electron Microscopy.

17. Solid state diffusion. Thermally activated processes.

18. Thermal production of point defects.

19. Exhibit relation between Point defects and solid – state diffusion.

20. Mechanical behavior. Stress versus strain. Elastic deformation.

21. Unique Mechanical behavior of Ceramics and Glasses.

22. Mechanical behavior. Polymers. Tensile strength and modulus of elasticity.

23. Viscoelastic deformation. The glass transition temperature.

24. Give definition of Heat capacity and Debye temperature.

25. Thermal behavior. Thermal conductivity.

26. Thermal behavior. Thermal expansion.

27. Thermal behavior. Thermal shock.

28. Ferrous alloys. Carbon and low-alloy steels.

29. Ferrous alloys. Stainless steel. Tool steel.

30. Ferrous alloys. Super-alloy.

31. Aluminum alloys as an example of Non-ferrous alloys.

32. Titanium Copper alloys as an example of Non-ferrous alloys.

33. Ferrous alloys. Cast iron.

34. Nickel alloys. Non-ferrous alloys.

35. Metals. Zinc, Lead and other alloys.

36. Consider Ceramics as crystalline materials.

37. Glasses as non-crystalline materials.

38. What are the main Structural features of polymers?

39. Compare Thermoplastic and Thermosetting polymers.

40. Intrinsic, elemental Semiconductors. The electrons and holes.

41. Extrinsic, elemental Semiconductors: donors and acceptors.

42. The temperature Variation of Conductivity and Carrier Concentration.

43. Compound and Amorphous Semiconductors: features and examples.

44. Processing of Semiconductors.

45. Application of Semiconductors as a base of electronic devices.

46. Nanomaterials, devices and technologies.

47. What synthesis methods of nanostructural materials do you know?

48. Explain the Hall effect.

49. Magnesium alloys as an example of Non-ferrous alloys.

50. Copper alloys as an example of Non-ferrous alloys

Modern Material Science

Exam

William d callister book

Arrangement of Materials on categories for practical engineering.

Types of Materials

We consider 5 categories for practical engineers:

• metals;

• ceramics and glasses;

• polymers;

• composites;

• semiconductors.

Metals

Metallic properties:

1) strong and be formed into practical shapes;

2) permanent deformability or ductility;

3) characteristic metallic luster;

4) good conductor of electrical current

This is a large family indeed. But so many compounds based on the various alloys, including the iron and steels (from Fe); aluminum alloys (Al); magnesium alloys (Mg); titanium alloys (Ti); copper alloys (Cu) and etc.

Ceramics and glasses

Al₂O₃ Aluminum is a common metal, but aluminum oxide Al2O3is typical of a fundamentally different family – ceramics.

Advantages ceramics over metallic compound:

1) chemically stablein a wide variety of severe environment;

2) has a significantly higher melting point(2020 ⁰C for Al₂O₃ and for Al only 660 ⁰C)

Conclusion: this makes oxides a popular refractory and a high-temperature resistant material of wide use in industrial furnace construction.

Disadvantages: Brittleness(so ceramics are eliminated from many structural application because they are brittle). SiO₂ is typical example of the traditional ceramics and SiO2is another good example. SiO₂ is the basis of a large and complex family of silicates, which includes clay sand claylike minerals. Si₃N₄ is an important nonoxide ceramic used in a variety of structural applications. You can see in the Periodic table only 5 nonmetallic elements (C,N,O,P,S).

Properties:

1) Metals and ceramics may be crystalline structure.

2) Many ceramics can be made in noncrystalline form (glasses).

Most common glasses are silicates. Glasses are important engineering materials because of other properties, such as their ability to transmit visible light; chemical inertness. Certain glass composition can be fully devitrified by special thermal treatment.

Polymers

The main part of the polymer is a single hydrocarbon molecule such as ethylene (C₂H₄). Polymers are long-chain molecules composed of many mers bonded together. The most common commercial polymer is polyethylene (-C2H4-)_n, where n can range from approximately 100 to 1000.

· Many important polymers including polyethelene are simple compounds of hydrogen and carbon.

· Others contain oxygen, nitrogen, fluorine and silicon.

Properties:

1) ductility;

2) lightweight;

3) low cost alternatives to metals instructural design applications;

4) lower strength compared with metals;

5) lower melting point and higher chemical reactivity compared with ceramics and glasses.

Composites

Composites– combinations of individual materials from the previous categories. The best example – fiberglass. This is composite of glass fibers embedded in a polymer matrix.

Properties (the best properties of each component):

1) high strength of the small-diameter glass fibers is combined with

2) ductility of the polymer matrix = result is

3) strong material capable of withstanding the normal loading required of a structural material.

· Wood-excellent example of a natural material with useful mechanical properties because of a fiber- reinforced structure.

· Concrete is a common example of an aggregate composite.

· Rock and sand reinforce a complex silicate cement matrix.

Semiconductors

Polymer materials we can see every day and everywhere. But semiconductors are relatively invisible for us. A relatively small group of elements and compounds has an important electrical property – semiconduction– in which they are neither good electrical conductor (as metals) nor good electrical insulators (as polymers or ceramics). Their ability to conduct electricity is intermediate and we call them semiconductors. Three important compound Si, Ge (germanium) – widely used compounds, Sn – serve as a kind of boundary between metallic and nonmetallic elements.

Solid materials have been conveniently grouped into three basic categories: metals, ceramics, and polymers. This scheme is based primarily on chemical makeup and atomic structure, and most materials fall into one distinct grouping or another. In addition, there are the composites, which are engineered combinations of two or more different materials. A brief explanation of these material classifications and representative characteristics is offered next. Another category is advanced materials—those used in high-technology applications, such as semiconductors, bio materials, smart materials, and nanoengineered materials.

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