Manufacturing Technology: Engineering Material

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• Engineering Materials

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• Material Properties

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• Metals 3 basic atomic arrangements

• Body-centered cubic (bcc)o Iron(Fe)o Tungsten(W) …

• Face-centered cubic (fcc)o Aluminum(Al)o Copper(Cu)o Gold(Au) …

• Hexagonal close-packed (hcp)

o Magnesium(Mg)

o Titanium(Ti)

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• Metal Crystalline and non-crystalline structure

Grains and grain boundaries

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• Material Properties Determined by its structure

Mechanical properties• Stress and strain• Hardness• Fatigue and creep• Fluid property

Physical properties• Volumetric property• Thermal property• Mass diffusion• Electronic property• Electrochemical property

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• Mechanical property 1: stress and strain Stress

Strain

Hooke’s law

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• Mechanical property 1: stress and strain Stress-strain relationship

Tensile test

Compressive test

Shear test

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• Mechanical property 2: Hardness

• Mechanical property 3: Fatigue and Creep

• Mechanical property 4: Fluid property

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• Exercise 1

How many atoms are in a single repeating cell of an fcc crystal structure? How many in a repeating cell of an hcp structure?

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• Exercise 1

How many atoms are in a single repeating cell of an fcc crystal structure? How many in a repeating cell of an hcp structure?

1 18 6 48 2fccN

1 112 2 3 66 2hcpN

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• Exercise 2

Show that, for the fcc unit cell, the radius r of the largest hole is given by r = 0.414R.

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• Exercise 2

Show that, for the fcc unit cell, the radius r of the largest hole is given by r = 0.414R.

For a face centered cubic unit :2 2 2(4 )a a R 2 2a R

The side length:2 2R r a 0.414r R

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• Exercise 3

A paper clip is made of wire that is 120mm long and 0.75mm in diameter. If the ASTM grain size is 9, how many grains are there in the paper clip.

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• Exercise 3

A paper clip is made of wire that is 120mm long and 0.75mm in diameter. If the ASTM grain size is 9, how many grains are there in the paper clip.

Volume of the paper clip :2 2 3120 3.14 (0.75 / 2) 52.9875 (mm )V l r

Grains number:652.9875 185,000 9.8 10N V