CHAPTER 6
MECHANICAL PROPERTIES OF METALS- Revision
Theory
1. List three factors that should be considered in designing laboratory tests to assess the
mechanical characteristics of materials for service use.
2. Distinguish between elastic and plastic deformations, both by definition, and in terms of behavior
on a stress-strain plot.
3. State what is occurring on an atomic level as a material is elastically deformed.
4. Briefly explain how the shape of a material's force versus interatomic separation curve influences its
modulus of elasticity.
5. Define anelasticity.
6. Cite the typical value range of Poisson's ratio for metallic materials.
7. Schematically sketch the stress-strain behavior for a metal that displays distinct upper and lower
yield points, and then explain how the yield strength is determined.
8. For the tensile deformation of a ductile cylindrical specimen, describe changes in specimen profile
to the point of fracture.
9. Explain why engineering stress decreases with increasing engineering strain past the tensile strength
point.
10. Cite typical yield and tensile strength ranges for metal alloys.
11. Give a brief definition of ductility, and schematically sketch the engineering stress-strain behaviors
for both ductile and brittle metals.
12. For metallic materials cite which tensile parameters are sensitive (and also insensitive) to any prior
deformation, the presence of impurities, and/or any heat treatment.
13. For metallic materials cite how elastic modulus, tensile and yield strengths, and ductility change
with increasing temperature.
14. Give brief definitions of and the units for modulus of resilience and toughness (static).
15. Describe the phenomenon of elastic recovery using a stress-strain plot.
1
16. Define hardness in a one- or two-sentence statement and state three reasons why hardness tests are
performed more frequently than any other mechanical test on metals.
17. Name the two most common hardness-testing techniques; note two differences between them.
18. Name and briefly describe the two different microindentation hardness testing techniques. Now
cite situations for which these techniques are generally used.
19. Provide three precautions that should be taken when performing hardness tests in order to insure
accurate readings.
20. Schematically diagram tensile strength versus hardness for a typical metal.
21. Provide five factors that can lead to scatter in measured data of tensile tests.
22. List two reasons why is ductility important information for design engineers?
Calculations : Textbook Questions
6.4-6.5
6.7-6.8
6.16-6.21
6.24
6.27-6.28
6.37
6.44-6.47
6.49
6.54
6.56-6.57
6.60
Submit
All the design questions:6.D1-6-D4 in groups.
2