Materials Science

Materials Science tests knowledge of the properties and characteristics of metals, ceramics, polymers and composite materials, with a focus on material characterization techniques, intermolecular forces, and surface chemistry.

Event Format
Teams are allowed to bring one nonprogrammable calcualator and one three-ring binder of notes.

Event supervisors will provide a periodic table and any needed materials and constants.

Students must wear closed-toed shoes, chemical splash goggles, full length pants or skirts, and a lab coat or chemical apron & long-sleeved shirt. Gloves are optional.

The Material Performance section and the Intermolecular Forces section will both be weighted 50% in this event.

Materials Science
Materials science is an interdisciplinary field applying the properties of matter to various areas of science and engineering. This scientific field investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties. It incorporates elements of applied physics and chemistry.

Classes of Materials

 * Metals -
 * Ceramics -
 * Polymers -
 * Composites -

Basic Terms
Stress - Force per unit area.

Strain - The amount of deformation an object experiences compared to its original size and shape.

Young's Modulus - A measure of the stiffness of an elastic material.It is equal to the stress over the strain.

Plastic Deformation- Irreversible deformation, as opposed to the reversible elastic deformation.

Yield Strength - The stress at which a material begins to deform plastically.

Creep Rate - The slow permanent deformation under the influence of stresses. It occurs as a result of long term exposure to high levels of stress that are below the yield strength of the material.

Viscosity - A measure of a fluid's resistance to gradual deformation by stress.

Surface Tension - The tendency of liquids to resist external force, caused by cohesion.

Contact Angle - The angle where a liquid/vapor interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid via the Young equation.

Ionic Bond - The bonding between a non-metal and a metal that occurs when charged atoms (ions) attract after one loses one or more of its electrons.

Covalent Bond - The chemical bond that involves the sharing of pairs of electrons between atoms.

Crystalline - A solid material whose constituent atoms, molecules, or ions are arranged in an ordered pattern extending in all three spatial dimensions.

Semi-Crystalline - A material composed partially of crystalline and partially of amorphous matter.

Amorphous - Also known as a non-crystalline solid, they lack the long-range order characteristic of a crystalline material.

Atomic Packing Factor - The fraction of volume in a crystal structure that is occupied by atoms.

Young's Modulus
$$E &= \frac{A_0\Delta\L}}$$ $$E$$ is the Young's modulus (modulus of elasticity)

$$F$$ is the force exerted on an object under tension;

$$A_0$$ is the original cross-sectional area through which the force is applied;

$$\Delta\L$$ is the amount by which the length of the object changes;

$$L_0$$ is the original length of the object.

The force may be found using Hooke's Law, $$F=-kx$$ where

$$x$$ is the displacement of the spring's end from its equilibrium position.

$$F$$ is the restoring force exerted by the spring on that end.

$$k$$ is a constant called the rate or spring constant.

Yield Strength
The Yield Strength of a material is the force at which the material begins to deform plastically, or the force at which changes are not fully reversible.It is determined through a Stress-Strain curve, such as the one below.




 * 1) True elastic limit
 * 2) Proportionality limit
 * 3) Elastic limit
 * 4) Offset yield strength

Creep Rate
Creep Rate is "the permanent deformation of material under constant load."

Viscosity
Viscosity is "the resistance to flow."

State and National Topics
The following are advanced topics that should only be found on state and national tests.