UNIT 2

Engineering Materials

https://www.youtube.com/watch?v=xOKr462HLc0 (A2 may be fun for B1,2)

https://www.youtube.com/watch?v=lVbqKn-VuQ0 (B1,B2)

Answer the questions:

• What does material science study?

• What are the main groups of engineering materials?

• In what industries is Material Science Engineering used?

• What are the main applications of engineering materials in medicine, energy industry, sports, transportation, communications, aerospace, nanotechnology? What other applications of engineering materials may you suggest?

• Why is it prestigious to work in the field of engineering material science?

Engineering materials are classified into the following broad groups:

What do you know about each of these categories? What do they have in common? How are they different from each other? What is important to know to use the materials properly? What different properties do different materials possess? What do you know about different applications of materials in industry?

Classification of Engineering Materials:

Metals Ferrous metals and alloys (irons, carbon steels, alloy steels, stainless steels, tool and die steels) Nonferrous metals and alloys (aluminum, copper, magnesium, nickel, titanium, precious metals, refractory metals, superalloys)	Polymeric Thermoplastics plastics Thermoset plastics Elastomers
Ceramics Glasses Glass ceramics Graphite Diamond	Composites Reinforced plastics Metal-matrix composites Ceramic-matrix composites Sandwich structures Concrete

Metals

Metals account for about two thirds of all the elements and about 24% of the mass of the planet. Metals have useful properties including metallic luster, hardness, strength, ductility, high melting points, thermal and electrical conductivity, toughness and malleability.

A few of the common metals and their typical uses are presented below. Metals are usually characterized by a well-defined crystal structure. They are bonded together by means of metallic bonds which maintain an electron cloud. This electron cloud is crucial for the high electrical and thermal conductivity characteristic to metals.

Common Metallic Materials

• Iron/Steel - Steel alloys are used for strength critical applications

• Aluminum - Aluminum and its alloys are used because they are easy to form, readily available, inexpensive, and recyclable.

• Copper - Copper and copper alloys have a number of properties that make them useful, including high electrical and thermal conductivity, high ductility, and good corrosion resistance.

• Titanium - Titanium alloys are used for strength in higher temperature (~1000° F) application, when component weight is a concern, or when good corrosion resistance is required

• Nickel - Nickel alloys are used for still higher temperatures (~1500-2000° F) applications or when good corrosion resistance is required.

• Refractory materials are used for the highest temperature (> 2000° F) applications.