Materials Engineering 7 Materials Engineering

Objectives Define materials engineering. Identify different types of materials. Describe a range of material properties. List examples of material tests. Describe nanotechnology.

Materials Engineering The understanding and modification of structure and properties of materials to improve the performance and processing of material. Example- they may work in manufacturing to find the best ways to produce products using specific materials. An engineer may develop a better way to use plastics to make toys.

About Materials Engineering Historical time periods based on materials Stone Age Bronze Age Iron Age Information Age (silicon and plastics) Understanding of science is important Design and development of new materials Production using specific materials

Education Typically Required High school courses Upper-level math (calculus and statistics) Upper-level science (chemistry and physics) College courses Engineering design Thermodynamics of materials Structures of materials Metallurgy Internships

Professional Organizations ASTM-American Society for Testing and Materials Develops material testing standards Over 30,000 members worldwide Materials Information Society Materials Research Society NACE International(National Assoc. For Corrosion Engineers) Other organizations for ceramics, plastics, and metals

Principles of Materials Engineering Broad field Materials are used in every engineering field All engineers must understand basic principles Types of materials Properties of materials

Material Types Metals Ceramics Polymers Composites

The Four Types of Materials ARENA Creative/Shutterstock.com; kubais/Shutterstock.com; Evgeny Korshenkov/Shutterstock.com; noppharat/Shutterstock.com

Metals Have crystalline atomic structure Inorganic material High material strength Good conductors of heat and electricity Malleable Inorganic material Most pure metals are natural Many are found in ore Commonly used in alloys

Atomic Structure of Crystalline Materials Goodheart-Willcox Publisher

Properties of Various Forms of Alloys Goodheart-Willcox Publisher

Ceramics Most have crystalline structure Brittle Good insulators Strong in compression High melting temperature Can retain heat well Brittle Good insulators Include clay, cement, many types of abrasives Some can become magnets

Polymers Organic materials Noncrystalline Can be natural or synthetic Plastics are most common type Lightweight but strong Easy and fairly inexpensive to process Have some negative environmental impacts Thermoplastics and thermosets

Atomic Structure of Noncrystalline Materials Goodheart-Willcox Publisher

Thermoplastics and Thermosets Picsfive/Shutterstock.com; Barghest/Shutterstock.com; Claudio Divizia/Shutterstock.com; Big Pants Production/Shutterstock.com; Kletr/Shutterstock.com; Santhosh Kumar/Shutterstock.com

Going Green Recycling Plastics Saves use of oil and natural gas Less plastics take up space in landfills Society of Plastics Industry created codes Include recycling symbol, number, and abbreviation Useful to consumers who recycle Over 82 million tons of materials are recycled per year in U.S.

Composites Utilize advantages of several materials Each material can be identified Can be natural or synthetic Most consist of matrix and fiber Matrix is main material Fiber is strengthening material Include wood, concrete, plywood, and fiberglass

Other Materials Fluids Semiconductors Biomaterials Air and water Many products rely on their use Semiconductors Can act as insulators or conductors Used to create electronic components Biomaterials Can interact safely with human body Used in medical applications

Design Materials Symbols Used in architectural design Symbols for common building materials Brick Concrete Cinder block Symbols for insulation, glass, and metal Allow designers and architects to include graphics of types of materials to be used

Examples of Materials Symbols Goodheart-Willcox Publisher

Material Properties Physical Chemical Mechanical Thermal Electrical Magnetic Chemical Thermal Optical Acoustical

Physical Properties Can often be obtained using senses Include size, shape, look, feel, taste, and smell Some cannot be determined by senses Most commonly used is density Mass per unit of volume Often used to compare materials

Mechanical Properties How material behaves when force or load is applied Understanding of stress is important Can be applied through axis of material Shear stress is not applied through axis Causes strain on material Compression strength and tensile strength Elasticity Plasticity

A Stress/Strain Diagram Goodheart-Willcox Publisher

Electrical Properties How a material behaves when electrically charged Materials fall into one of three categories Conductors Insulators Semiconductors Conductivity Resistivity

Magnetic Properties How a material behaves when within a magnetic field Magnetic permeability Measured in Henrys per meter Impacted by temperature and distance from magnetic field If it is high, material will allow magnetic flow

Chemical Properties Changed by a chemical reaction Include flammability Include corrosion Often need to be controlled because they can be damaging to material

Thermal Properties How the material responds to heat Thermal conductivity Thermal resistance Thermal expansion Melting point

Optical Properties How light waves interact with material How well material absorbs light How well material reflects light How well material transmits light Reflected light gives material color Transmission occurs when light is absorbed and reflected by transparent materials but still passes through materials

Acoustical Properties How sound waves interact with material How well material absorbs sound How well material reflects sound How well material transmits vibration Porous materials usually absorb sound Smooth materials reflect sound in one direction Rough materials reflect sound in many directions

Material Engineering Applications Material testing Many companies specialize in specific materials ASTM develops standards for testing Nanotechnology One nanometer is one billionth of meter Has potentially exciting impacts

Material Testing Used for new materials when creating new products or improving existing products Designer might try different formulation of existing material Large industry Categories of material tests Destructive material tests Nondestructive material tests

Destructive Tests Often used to test mechanical properties Exert a force on material until it fails Tensile tests Compression tests Fatigue tests Often used to test chemical properties Test material’s reaction to corrosion Material exposed to saltwater

Nondestructive Tests Used to inspect materials Used to look for flaws and defects Visual examinations, sometimes with dyes Some use waves Radiography tests Ultrasonic tests Some use currents Eddy current testing Magnetic particle testing

Potential Uses of Nanotechnology For delivery of medicines directly to cancerous tumors For creating microscopic computer chips For manufacturing materials that repair and clean themselves

Nanoparticles Most basic components at nanoscale Some materials demonstrate properties at nanoscale that are not present at larger scales Products are being designed that utilize these properties

Nanostructures Nanowires Nanotubes Buckyballs Designed to transmit light or electricity Might be useful in computer circuits and lighting Nanotubes Cylindrical fullerenes with honeycomb pattern Useful in electronics and structural applications Buckyballs Most perfectly round molecules Useful as lubricants

Nanotubes Tyler Boyes/Shutterstock.com

Buckyballs Mark Lorch/Shutterstock.com

Materials Engineering in Action Used to select or create most appropriate materials for engineered solution Engineers must consider several key elements Material function Manufacturability Cost Safety