In your first job, you are working for a large aerospace firm that is constructing a new regional...


In your first job, you are working for a large aerospace firm that is constructing a new regional jetliner. You are assigned the task of performing a process audit on a small heat treat company in Pennsylvania that has had several precipitation hardened spars and wing struts rejected for low hardness. During your audit, you observe that they are not properly monitoring the time that they are holding the parts at temperature. What is the condition of the aluminum alloy called?

A. Austenizing

B. Solutionizing

C. Normalizing

D. Embrittlement

E. Overaging


It is a process of heat treatment of ferrite material to increase the ductility and toughness of the alloy steel. In this process, steel is heated a temperature that is above recrystallization temperature and then cooled down slowly to the room temperature.

Answer and Explanation:

The company has had some precipitation hardened wing struts and spares that are rejected for their low value of hardness; the time of holding the parts at a particular temperature is not monitored properly by the company. This condition for aluminum alloy is called overaging. By putting an aluminum object on an elevated temperature for a specific time for the precipitation so that it can restrict the movement of location and generate fine grains to strengthen the object. This time duration is an essential factor; if it is not monitored correctly, it can cause the problem in diffusion and can reduce hardness; this is named as overaging.

Thus, (E) is the correct option.

Learn more about this topic:

Phase Changes and Heating Curves

from Chemistry 101: General Chemistry

Chapter 6 / Lesson 3

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