AM.II.A.K1

From the FAA library

• Aviation Maintenance Technician Handbook - Generalp. 7-13
  Chapter 7: Aircraft Materials, Hardware, & Processes › Aircraft Metals › Internal Structure of Metals

  Heat-treating can also make a metal softer and more ductile. No one heat-treating operation can produce all these characteristics. In fact, some properties are often improved at the expense of others. In being hardened, for example, a metal ... become brittle. The various heat-treating processes are similar in that they all involve the heating and cooling of metals. They differ, however, in the temperatures to which the metal is heated, the rate at which it is cooled…

• Aviation Maintenance Technician Handbook - Airframep. 4-89
  Chapter 4: Aircraft Metal Structural Repair › Basic Principles of Sheet Metal Repair › Types of Damage & Defects

  metal, usually to an appreciable depth over a relatively long and narrow area, by mechanical means, as would occur with the use of a saw blade, chisel, or sharp-edged stone striking a glancing blow. • Dent—indentation in a metal ... produced by an object striking with force. The surface surrounding the indentation is usually slightly upset. • Erosion—loss of metal from the surface by mechanical action of foreign objects, such as grit or fine sand. The eroded area is rough…

• Aviation Maintenance Technician Handbook - Airframep. 4-1
  Chapter 4: Aircraft Metal Structural Repair

  create stress risers that may cause cracks in other locations. As discussed in Chapter 3, Aircraft Fabric Covering, sheet metal aircraft construction dominates modern aviation. Generally, sheet metal made of aluminum alloys is used in airframe sections that serve ... both the structure and outer aircraft covering, with the metal parts joined with rivets or other types of fasteners. Sheet metal is used extensively in many types of aircraft from airliners to single engine airplanes, but it may also appear…