Materials Science: Ceramics, Plastics, and Metals

Definition of Ceramics

Inorganic, non-metallic materials generally formed using heat and sometimes pressure.

Ceramic Properties

Hard, brittle, wear-resistant, and electrically insulating.

Glass Ceramic Families

Includes tempered for windshields, commercial for goods, and fiber optic for cables.

Polymer Meaning

Made of many repeating molecules arranged in a line.

Thermoplastic vs. Thermoset Recycling

Thermoplastics can be reheated and recycled; thermosets cannot be reshaped and burn when overheated.

Plastic Recycling Codes

Standard codes categorizing plastics like PET, HDPE, PVC, LDPE, PP, and PS.

Plastic Creep

Phenomenon where thermoplastics slowly deform over time when subjected to prolonged weight.

Metal Grains

Microscopic crystal-like formations that affect the mechanical properties of a metal.

Effect of Grain Size

Smaller grains make metal stronger and harder; larger grains make it softer and more ductile.

Annealing

Heat-treating process that makes metal softer, less strong, and more ductile.

Quenching

Cooling metal quickly to increase its hardness, brittleness, and strength.

Tempering

Reheating quenched steel at a lower temperature to decrease brittleness and increase toughness.

Three Types of Loads

Mechanical, thermal, and processing or manufacturing loads.

Stress Equation

Force divided by cross-sectional area (sigma = F / A).

Strain Equation

Change in length divided by the original length (epsilon = delta length / original length).

Stress-Strain Graph Stages

Includes the elastic region, yield point, ultimate point, and fracture point.

Ferrous Metals

Iron-based metals that are typically, but not always, magnetic.

Non-Ferrous Metals

Metals with little to no iron content that are usually non-magnetic.

Alloys

A mix of a base metal and other elements designed to combine desirable properties.

Metal Production Steps

Mine, refine, make, and shape.

Steel Composition

An MVP alloy composed primarily of iron and carbon.

Low vs. High Carbon Steel

Low carbon is soft and ductile; high carbon is harder, stronger, and more brittle.

Steel Naming Convention

A 4-digit code where the last two digits represent carbon content as a percentage of 1.

Rockwell Hardness Testing

Uses a pointy indentor across scales A, B, and C based on varying test pressures.

Brinell Hardness Testing

Uses a rounded ball indentor and measures the diameter of the resulting crater.