1. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 1 Chapter 1: Introduction to Materials Science and Engineering Chapter 1: Introduction to Materials Science and Engineering

2. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 2 Learning Objectives 1.What is materials science and engineering? 2.Classification of materials. 3.Functional classification of materials. 4.Classification of materials based on structure. 5.Environmental and other effects. 6.Materials design and selection. Chapter 1: Introduction to Materials Science and Engineering

3. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 3 CompositionChemical makeup of a material StructureDescription of the arrangement of atoms, as seen at different levels of detail Materials scienceUnderlines the relationships between the synthesis and processing, structure, and properties of materials Materials engineering Focuses on how to translate or transform materials into useful devices or structures MicrostructureStructure of the material at the microscopic scale What is Materials Science and Engineering? Chapter 1: Introduction to Materials Science and Engineering

4. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 4 Figure 1.1 - Application of the Tetrahedron of Materials Science and Engineering to Sheet Steels for Automotive Chassis Chapter 1: Introduction to Materials Science and Engineering

5. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 5 Figure 1.2 - Application of the Tetrahedron of Materials Science and Engineering to Semiconducting Polymers for Microelectronics Chapter 1: Introduction to Materials Science and Engineering

6. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 6 Table 1.1 - Representative Examples, Applications, and Properties for Each Category of Materials Chapter 1: Introduction to Materials Science and Engineering

7. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 7 Polymers PolymerizationProcess by which polymers are produced Strength-to-weight ratio Is high for polymers Thermoplastic polymers Contain long polymer chains that are not rigidly connected, have good ductility and formability Thermosetting polymers Strong polymers but more brittle because the molecular chains are tightly linked PlasticsContain additives that enhance the properties of polymers CompositesFormed from two or more materials, producing properties not found in any single material Chapter 1: Introduction to Materials Science and Engineering

8. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 8 Figure 1.3 - Representative strengths of various categories of materials Chapter 1: Introduction to Materials Science and Engineering

9. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 9 Figure 1.6 - Functional Classification of Materials Chapter 1: Introduction to Materials Science and Engineering

10. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 10 Classification of Materials Based on Structure CrystallineThe material’s atoms are arranged in a periodic fashion AmorphousThe arrangement of the material’s atoms does not have a long-range order Single crystalsCrystalline materials in the form of one crystal PolycrystallineCrystalline materials with many crystals or grains Grain boundariesRegions between individual crystals in a polycrystalline material Chapter 1: Introduction to Materials Science and Engineering

11. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 11 Figure 1.7 - Increasing Temperature Normally Reduces the Strength of a Material Chapter 1: Introduction to Materials Science and Engineering

12. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 12 Figure 1.8 - Skin Operating Temperatures for Aircraft Have Increased With the Development of Improved Materials Chapter 1: Introduction to Materials Science and Engineering

13. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 13 Environmental and Other Effects  Corrosion  Metals and polymers react with oxygen or other gases, particularly at elevated temperatures.  Metals and ceramics — Disintegrate.  Polymers and non-oxide ceramics — Oxidize.  Materials are attacked by corrosive liquids which leads to premature failure. Chapter 1: Introduction to Materials Science and Engineering

14. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 14 Environmental and Other Effects  Fatigue  Components must be designed such that the load on the material may not be enough to cause permanent deformation.  Fatigue failure: When the material is loaded and unloaded thousands of times small cracks may begin to develop and materials fail as these cracks grow.  Strain rate  Metallic materials:  Can be stretched significantly if pulled slowly — Small rate of strain.  Can snap if pulled fast — High rate of strain. Chapter 1: Introduction to Materials Science and Engineering

15. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 15 Materials Design and Selection  The material must:  Acquire the desired physical and mechanical properties.  Be capable of being processed or manufactured into the desired shape.  Provide an economical solution to the design problem.  Material cost is calculated on a cost-per-kilogram basis.  Density of the material or its weight per unit volume should be considered. Chapter 1: Introduction to Materials Science and Engineering

16. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 16 Table 1.2 - Strength-to-Weight Ratios of Various Materials Chapter 1: Introduction to Materials Science and Engineering

17. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 17 Key Terms  Composition  Composites  Crystalline  Density  Fatigue failure  Grains  Grain boundaries  Materials science and engineering  Materials science Chapter 1: Introduction to Materials Science and Engineering

18. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 18 Key Terms  Mechanical properties  Materials engineering  Microstructure  Materials science and engineering tetrahedron  Polymerization  Plastics  Polycrystalline  Physical properties  Processing Chapter 1: Introduction to Materials Science and Engineering

19. © 2011 Cengage Learning Engineering. All Rights Reserved. 1 - 19 Key Terms  Structure  Synthesis  Strength-to-weight ratio  Semiconductors  Smart material  Single crystals  Thermoplastic  Thermosetting Chapter 1: Introduction to Materials Science and Engineering