1. Lecture 22 – Glasses Prescribed Text:
Ref 1: Higgins RA & Bolton, Materials for Engineers and Technicians, 5th edition, Butterworth Heinemann. ISBN:
Readings:
Callister: Callister, W. Jr. and Rethwisch, D., 2210, Materials Science and Engineering: An Introduction, 8th Edition, Wiley, New York. ISBN
Ashby 1: Ashby, M. & Jones, D., 2211, Engineering Materials 1: An Introduction to Properties, Applications and Design, 4th edition, Butterworth-Heinemann, Oxford UK. IBSN:
Ashby 2: Ashby, M. & Jones, D., 2211, Engineering Materials 2: An Introduction to Microstructures and Processing, 4th edition, Butterworth-Heinemann, Oxford UK. IBSN:
Lecture (2 hrs):
Ref 1, Ch 1: Engineering materials;
Ref 1 Ch 2: Properties of materials.
Laboratory 1 (2 hrs): Hardness test
Callister: Ch 1, 2, 22-22
Ashby 1: Ch 1, 2
Ashby 2: Ch 1 1

2. Glasses Reference Text Section
Higgins RA & Bolton, Materials for Engineers and Technicians, 5th ed, Butterworth Heinemann
Ch 22
Reference Text
Section
Callister, W. Jr. and Rethwisch, D., 2210, Materials Science and Engineering: An Introduction, 8th Ed, Wiley, New York.
Ch 3 (part)
Engineering Materials and Processes

3. Glasses (Higgins 22) High quality glass goes back to ancient times.
The engineering definition of glass includes a whole range of substances that are not true crystalline solids. Hence terms like “glassy metals” means metal atoms in a glass-like structure.
Moldavite, a natural glass formed by meteorite impact, from Besednice, Bohemia
A modern greenhouse in Wisley Garden, England, made from float glass
Roman Cage Cup from the 4th century CE
Engineering Materials and Processes

4. 22.2 Composition and structure of glass (Higgins 22.2)
Engineering Materials and Processes

5. 22.3 Glass-transition temperature (Higgins 22.3)
Engineering Materials and Processes

6. 22.3 Glass-transition temperature (Higgins 22.3)
Devitrification
Glass ceramics
Higgins
Engineering Materials and Processes

7. 22.4 Glass manufacture (Higgins 22.4)
Devitrification
Glass ceramics
Higgins
Engineering Materials and Processes

8. 22.4 Glass manufacture (Higgins 22.4)
Float process
Higgins
Engineering Materials and Processes

9. 22.4 Glass manufacture (Additional)
Toughened or tempered glass is heat treated to created a surface compression. This increases the strength of the glass but makes it impossible to cut by any process (scoring, sawing, drilling, water jet cutting etc). The glass must be annealed before it can be processed and then re-tempered. When broken, the glass breaks into small granular chunks instead of splintering into jagged shards.
Wikipedia
Wikipedia
Engineering Materials and Processes

10. 22.4 Glass manufacture (Higgins 22.4)
Glass blowing
Higgins
Engineering Materials and Processes

11. 22.5 The properties of glass (Higgins 22.5)
However a 'glass' is, by definition, a substance existing below the glass transition temperature so that very little movement of molecules is possible. This means that a glass at ambient temperature is extremely brittle.
Higgins
Engineering Materials and Processes

12. 22.6 Glasses and their uses (Higgins 22.6)
Pyrex
Glass ceramics
Higgins
Engineering Materials and Processes

13. 22.7 Metallic glasses (Higgins 22.7)
Engineering Materials and Processes

14. Glassy Metal
'Melt Spinning' or 'Splat quenching' to produce metallic glass ribbon. Molten tin alloy is fed through several nozzles onto a rotating metal drum, resulting in extremely high cooling rates (approx. 1 million Kelvin per second).
High speed photography at 4000 fps.
You Tube
Offline
From TLP: Casting,
DoITPoMS, The University of Cambridge.
Engineering Materials and Processes 14

15. Resources. Wikipedia: Glass Engineering Materials and Processes
h ttp://
S how this website on screen. Will be using this later.
Engineering Materials and Processes 15

16. Glossary Amorphous Crystalline Toughened glass Annealed glass
Laminated glass
Tempered glass
Safety glass
Refractive index
Transmittance
Absorptance
Reflectance
Dispersion
Glass transition temperature
Engineering Materials and Processes

17. Engineering Materials and Processes
QUESTIONS
Higgins Ch22, Newell, Timmings
Define all glossary terms
How do network modifiers affect the properties of glasses?
Compare and contrast the glass transition temperature of glasses with those of polymers.
Explain why molten SiO2 forms glass instead of cooling back into a crystalline form.
Compare and contrast the properties of silica glass and Portland cement.
(a) Select two types of glass and describe their composition, properties and typical applications. (b) Describe the heat-treatment processes available for making glass less susceptible to fracture. (c) Describe a chemical treatment process available for making glass less susceptible to fracture.
Describe the optical properties of glass with respect to optical lenses. Name a surface treatment process used in high quality camera lenses. What does it do?
Obsidian is a naturally occurring (usually dark) volcanic rock. Granite has large visible crystals and forms deep underground. Which one is more likely to be a glassy structure? Explain.
Discuss silicon based solar cell technology: mono, poly crystalline and amorphous
Engineering Materials and Processes 17