Callister - An introduction - 8th edition

WHY STUDY Applications and Processing of Metal Alloys?
Engineers are often involved in materials selection decisions,
which necessitates that they have some familiarity
with the general characteristics of a wide variety of
metals and their alloys (as well as other material types).
In addition, access to databases containing property
values for a large number of materials may be required.
In the processing/structure/properties/performance
scheme, one reason for studying applications and processing
of metal alloys is as follows:
• In Chapter 10, the heat treating of steels was presented
from the perspective of phase transformations;
a processing approach to heat treating is
employed in this chapter. Our discussions here are
devoted to annealing procedures as well as
quenching and tempering to form tempered
martensite.
Learning Objectives
After studying this chapter you should be able to do the following:
1. Name four different types of steels and, for
each, cite compositional differences, distinctive
properties, and typical uses.
2. Name the five cast iron types and, for each,
describe its microstructure and note its general
mechanical characteristics.
3. Name seven different types of nonferrous alloys
and, for each, cite its distinctive physical
and mechanical characteristics. In addition, list
at least three typical applications.
4. Name and describe four forming operations
that are used to shape metal alloys.
5. Name and describe five casting techniques.
6. State the purposes of and describe procedures
for the following heat treatments: process annealing,
stress relief annealing, normalizing, full
annealing, and spheroidizing.
7. Define hardenability.
8. 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 information.
9. Using a phase diagram, describe and explain
the two heat treatments that are used to precipitation
harden a metal alloy.
10. Make a schematic plot of room-temperature
strength (or hardness) versus the logarithm of
time for a precipitation heat treatment at
constant temperature. Explain the shape of
this curve in terms of the mechanism of
precipitation hardening.
11.1 INTRODUCTION
Often a materials problem is really one of selecting the material that has the right
combination of characteristics for a specific application. Therefore, the people who
are involved in the decision making should have some knowledge of the available
options. The first portion of this chapter provides an abbreviated overview of some
of the commercial alloys and their general properties and limitations.
Materials selection decisions may also be influenced by the ease with which
metal alloys may be formed or manufactured into useful components. Alloy properties
are altered by fabrication processes, and, in addition, further property alterations
may be induced by the employment of appropriate heat treatments.
Therefore, in the latter sections of this chapter we consider the details of some of
these treatments, including annealing procedures, the heat treating of steels, and
precipitation hardening.
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