Electromechanical Materials - EME 205 - Lecture 1

Metals are materials composed primarily of metallic elements, often with small amounts of non-metallic elements. They are characterized by a highly ordered atomic arrangement and relatively high density compared to ceramics and polymers.

Metals are generally strong, stiff, and ductile, meaning they can deform significantly before breaking. These properties make them excellent for structural applications.

Metals are resistant to fracture, meaning they can withstand significant stress before breaking. This makes them ideal for applications where sudden failure is unacceptable.

Ceramics are inorganic materials composed of metallic and non-metallic elements chemically bonded together, typically in an oxide, nitride, or carbide form.

Ceramics are known for their high hardness, stiffness, and resistance to heat and wear. However, they are also brittle, meaning they fracture easily under impact.

Polymers are organic materials composed of long chains of repeating molecular units called monomers. They are often lightweight and flexible, but their strength varies significantly.

Polymers are typically lightweight, flexible, and relatively unreactive. Their strength can be tailored through different processing techniques and chemical modifications.

Composites are materials made by combining two or more distinct materials with different properties, resulting in a material with enhanced characteristics. This combination often results in a material with unique properties that neither individual material possesses.

Substances that conduct electricity and heat well, are opaque to light, and are often malleable and ductile.

Materials that are created by combining two or more distinct materials, enhancing their properties.

A continuous phase that surrounds and holds together the dispersed phase in a composite material.

The dispersed phase (reinforcement) in a composite material, typically adding specific properties like strength or stability.

Composites used to improve materials' resistance to breaking or cracking under stress.

Materials that respond to changes in their environment by altering their properties.

The ability of a material to stretch or deform under stress.

The ability of a material to be hammered or rolled into thin sheets.

A material that generates an electric charge when mechanically stressed due to its asymmetric crystal structure. This effect is reversible, meaning applying an electrical charge deforms the material.

Materials used as actuators and sensors because they can convert electrical energy into mechanical energy and vice versa.

Materials that change their rheological properties (like viscosity) when exposed to a magnetic field.

Materials that can convert heat energy into electrical energy and vice versa.

The phenomenon where a temperature difference between two dissimilar metals creates an electric current.

The phenomenon where passing a current through two dissimilar metals causes one to become hot and the other cold.

Metals that change their shape in response to a change in temperature, returning to their original shape when the temperature changes back.

These alloys are used in various applications like medical implants, actuators, and self-healing materials due to their ability to change shape and recover their original form.