Introduction to Materials Science - Material Science for Engineers - Lecture Slides, Slides of Material Engineering

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The Science and Engineering of

Materials,

Chapter 1 – Introduction to Materials

Science and Engineering

Objectives of Chapter 1

 Introduce the field of materials science and

engineering (MSE)

 Provide introduction to the classification of

materials

Section 1.

What is Materials Science and

Engineering?

 Materials Science and Engineering

 Composition means the chemical make-up of a

material.

 Structure means a description of the arrangements

of atoms or ions in a material.

 Synthesis is the process by which materials are

made from naturally occurring or other chemicals.

 Processing means different ways for shaping

materials into useful components or changing their

properties.

Section 1.

Classification of Materials

 Metals and Alloys

 Ceramics, Glasses,and Glass-ceramics

 Polymers (plastics), Thermoplastics and Thermosets

 Semiconductors

 Composite Materials

Example of Applications Properties

Semiconductors

Silicon Transistors and integrated Unique electrical

circuits behavior

Composites Carbide cutting tools for High hardness, yet

Tungsten carbide machining good shock resistance

-cobalt (WC-Co)

Table 1.1 Continued

© 2003 Brooks/Cole Publishing / Thomson Learning™

Figure 1.4 Representative strengths of various categories of materials

© 2003 Brooks/Cole Publishing / Thomson Learning™

Figure 1.7 Polymerization occurs when small molecules, represented by the circles, combine to produce larger molecules, or polymers. The polymer molecules can have a structure that consists of many chains that are entangled but not connected (thermoplastics) or can form three-dimensional networks in which chains are cross-linked (thermosets)

Figure 1.8 Polymers are used in a variety of electronic devices, including these computer dip switches, where moisture resistance and low conductivity are required. (Courtesy of CTS Corporation.)

Figure 1. Integrated circuits for computers and other electronic devices rely on the unique electrical behavior of semiconducting materials. (Courtesy of Rogers Corporation.)

Figure 1.10 The X- wing for advanced helicopters relies on a material composed of a carbon-fiber- reinforced polymer. (Courtesy of Sikorsky Aircraft Division— United Technologies Corporation.)

© 2003 Brooks/Cole Publishing / Thomson Learning™

Figure 1. Functional classification of materials. Notice that metals, plastics, and ceramics occur in different categories. A limited number of examples in each category is provided

Section 1.

Classification of Materials-Based on Structure

 Crystalline material is a material comprised of one or

many crystals. In each crystal, atoms or ions show a

long-range periodic arrangement.

 Single crystal is a crystalline material that is made

of only one crystal (there are no grain boundaries).

 Grains are the crystals in a polycrystalline material.

 Polycrystalline material is a material comprised of

many crystals (as opposed to a single-crystal material

that has only one crystal).

 Grain boundaries are regions between grains of a

polycrystalline material.

© 2003 Brooks/Cole Publishing / Thomson Learning™

Figure 1. Increasing temperature normally reduces the strength of a material. Polymers are suitable only at low temperatures. Some composites, special alloys, and ceramics, have excellent properties at high temperatures

© 2003 Brooks/Cole Publishing / Thomson Learning™

Figure 1.13 Skin operating temperatures for aircraft have increased with the development of improved materials. (After M. Steinberg, Scientific American, October, 1986.)

Section 1.

Materials Design and Selection

 Density is mass per unit volume of a material,

usually expressed in units of g/cm 3 or lb/in. 3

 Strength-to-weight ratio is the strength of a material

divided by its density; materials with a high strength-

to-weight ratio are strong but lightweight.