Unit 1 Engineering Materials, Processes and Techniques
What do you already know? For most engineering applications the most important criteria for the selection of materials is that they do the job properly (i.e. that they perform according to the specification that has been agreed) and that they do it as cheaply as possible. Whether a material does its job depends on its properties, which are a measure of how the material reacts to the various influences to which it is exposed. For example, loads, atmospheric environment, electromotive forces, heat, light, chemicals, and so on. To aid our understanding of the different types of materials and their properties I have divided them into four categories; metals, polymers, ceramics, and composites. Strictly speaking, composites are not really a separate group since they are made up from the other categories of material. However, because they display unique properties and are a very important engineering group, they are treated separately here.