Design of Mechanical Elements

2Material Selection

2.1 Introduction

In this chapter, we describe the considerations related to selecting a material for the design of a mechanical element. Selecting a material is often one of the most important decisions during the design process because it immediately determines and limits some of the functionality of the mechanical element. For instance, if the mechanical element will operate at high temperature in a corrosive environment, then it is important to consider the melting point of the material as well as its resistance to corrosion. If the mechanical element must conduct electricity or heat, then we have to consider electrical and thermal properties of the material. Many other material properties may be important and require consideration depending on the mechanical design, the intended function of the mechanical element, and the environment in which it will operate. Table 2.1 illustrates a few examples of different categories of material properties we might consider during the design of a mechanical element.

2.2 Material Classification

We can classify or categorize materials in different ways, according to, e.g. physical, chemical, or mechanical properties. We refer to materials science textbooks for an overview of material classification systems using different metrics. However, a common way to classify materials is according to their microstructure.¹ Figure 2.1 illustrates this classification and identifies five independent material categories, and a hybrid ...