Materials Technology

Materials technology comprises the selection, production, and processing of materials to ensure that they ultimately have the desired shape and specified properties for optimum performance. Materials include plastic, glass, ceramics, metals, and semiconductors; they may be used alone or in combinations.

Engineering of Materials
To specify the required properties, a materials engineer must work with other engineer to anticipate the functional and service requirements of the final product. The materials engineer must be familiar with many field of technology; chemistry, physics, metallurgy, ceramics, and so on. The guiding principle of materials technology is that:

1. Properties depend directly on the internal structure of the materials.
2. Any desired change in properties required an appropriate change in the internal structure.

Conversely, if service condition changes the internal structure, a corresponding change must be expected in the properties.

Properties of Materials
The engineer who design machines, electrical products, buildings, refineries, nuclear reactors, and ships has to know whether the chosen materials will perform as required, and whether they will resist failure in service. Key properties include mechanical behavior, electrical and magnetic responses, thermal characteristics, and chemical stability.

Mechanical properties involve the response of materials to applied forces, or loads. Stress is the amount of load per unit of area. Materials respond to a stress with a strain, which is deformation per unit length. Typically the initial stress is elastic; that is, the material resumes its original shape when the stress is removed. The amount of elastic stress is proportional to the applied stress. The ratio of stress to strain is characteristic property of a material and is called the modulus of elasticity. Its value is high for a rigid material such as steel, and much lower for flexible materials.