CHAPTER 14
SYNTHESIS, FABRICATION, AND PROCESSING OF MATERIALS
LEARNING OBJECTIVES
1.
(a) Name and describe four forming operations that are used to shape metal
alloys.
(b) Cite the general mechanical characteristics of materials that are subjected
to these forming operations.
2.
(a) Name and describe five casting techniques.
(b) Cite three circumstances for which casting is the preferred fabrication
mode.
3.
Describe the powder metallurgical forming process, and note two reasons
why it is used.
4.
(a) Briefly describe the process of welding, and note reasons why it is used.
(b) Cite four potential problems that may be encountered with the formation
of a heat affected zone in the vicinity of a weld junction.
5.
State the purposes of and describe the procedures for the following heat
treatments:
process annealing, stress relief annealing, normalizing, full
annealing, and spheroidizing.
6.
Define hardenability.
7.
Describe the Jominy end-quench test.
8.
Make a schematic sketch of a typical hardenability curve (label both vertical
and horizontal axes), and then briefly explain the shape of the curve.
9.
(a) On the same plot, schematically sketch hardenability curves for two
different alloys--one of which is more hardenable than the other.
(b) Explain the difference in shape of these two curves.
10. For the quenching of a steel specimen, briefly explain why quenching
medium type and degree of medium agitation influence the rate of specimen
cooling.
11. Generate a hardness profile for a cylindrical steel specimen that has been
austenitized and then quenched, given the hardenability curve for the specific
alloy, as well as quenching rate-versus-bar diameter curves at several radial
positions for the quenching medium used.
12. Make a schematic plot of tensile strength versus tempering temperature for a
cylindrical specimen. Now superimpose of this plot a second curve for a
cylindrical specimen having a larger diameter.
13. Make a schematic plot of ductility versus tempering temperature for a
cylindrical specimen. Now superimpose of this plot a second curve for a
cylindrical specimen having a larger diameter.
14. Using a phase diagram, describe the two heat treatments (solution and
precipitation) that are involved in the precipitation hardening of a binary
alloy. Explain why each heat treatment is carried out and what happens to
the microstructure during each heat treatment.
15. (a) Make a schematic plot of room-temperature yield and tensile strengths,
and hardness versus the logarithm of time for a precipitation heat treatment at
constant temperature.
(b) Explain the shapes of these curves in terms of the mechanism of
precipitation hardening (i.e., dislocation-precipitate particle interactions).
16. Cite two necessary requirements for an alloy to be precipitation hardenable.
17. (a) Schematically plot specific volume versus temperature for both
crystalline and noncrystalline ceramics.
(b) On this graph indicate melting and glass-transition temperatures.
18. (a) Schematically sketch a plot of the temperature dependence of the
viscosity of a glass.
(b) Now note how the curve changes with increasing impurity additions.
19. Name and briefly describe four forming methods that are used to fabricate
glass pieces.
20. Briefly explain why thermal stresses are established in glass pieces as they
are cooled.
21. Briefly describe and explain the procedure by which glass pieces are
thermally tempered.
22. Cite the two roles that clay minerals play in the fabrication of ceramic bodies.
23. Name and briefly describe two techniques that are used to fabricate clay
products.
24. Briefly explain those processes that occur during the drying and firing of
clay-based ceramic ware.
25. (a) Define vitrification.
(b) Note the role this process plays in the development of strength of a
ceramic body.
26. Name and briefly describe the three ceramic powder pressing techniques that
were discussed in this chapter.
27. Briefly describe/diagram the sintering process of powder particle aggregates.
28. Describe the tape casting process.
29. Briefly describe addition and condensation polymerization mechanisms.
30. Name the five types of polymer additives, and, for each, how it modifies the
properties.
31. Name and briefly describe five fabrication techniques used for plastic
polymers.
32. Briefly describe forming/processing techniques that are typically employed in
the fabrication of fibers and films.