Intro to Materials Science and Engineering

• Materials Science and Materials Engineering are sometimes referred to as Engineering Materials.

Why Materials?

• Materials influence virtually every aspect of daily life, including transportation, housing, communication, clothing, recreation, and food production.
• Early civilizations are categorized by their level of materials development, such as the Stone Age and Bronze Age.
• Early humans had limited access to materials like stone, wood, clay, and skins.
• There are now newly developed materials, processes and knowledge to learn.
• With tens of thousands of materials now available, selection is becoming a challenge.

Materials Science and Materials Engineering Defined

• Materials Science investigates the relationship between the structures and properties of materials.
• Materials Engineering involves processing material to produce a predetermined set of properties for better performance.
• Materials Science and Engineering encompasses a relationship between processing, structure, properties, and performance.
• Structure relates to the arrangement of a material's internal components at subatomic, atomic, microscopic, and macroscopic levels.
• Properties is a material trait in terms of response to a specific stimulus.

Why Study Engineering Materials?

• The best combination of properties in a single material is seldom found. Rather, the optimum balance involves trading characteristics.
• When needing a packaging material for soft drinks, a material other than glass may have other beneficial properties that better suit a need.
• Deterioration of material properties during performance can occur if desired application is at an elevated temperature, or in a corrosive environment
• The ideal set of properties for a given application may result in costs that are too high.

Classification of Engineering Materials

• Solid materials were grouped into metals, ceramics, and polymers prior to the 1980s, based on chemical makeup and atomic structure.
• Composites, semiconductors, and biomaterials were added as new emerging classifications beginning in the 1990s due to heightened impact to society.

Metals

• Metals are pure or combinations of metallic elements, also known as alloys
• Electrons are free, not bound to particular atoms and are responsible for the conductivity, heat conductivity, strength, and deformability.
• Metals are mature materials with limited potential for major breakthroughs.
• Development areas include higher operating temperature engines/turbines and powder metallurgy.

Ceramics

• Ceramics are solid compounds formed via heat and sometimes pressure.
• They comprise at least one of the following: a) metallic + non metallic elements or Non metallic elemental solid (NMES), b) at least two NMES and c) at least two NMES + non metal.
• Common examples of ceramics are oxides, nitrides, carbides, and borides, such as clay materials, cement, and glass.
• Ceramics are generally insulative of electricity and heat.
• Ceramics are resistant to high temperatures and harsh environments.
• Ceramics are hard but brittle.
• Development areas for ceramics include ceramics engines
• Development areas for ceramics include superconductors
• Development areas for ceramics include electro-optic components

Polymers

• Polymers constitute a special branch of organic chemistry, also known as plastics
• The term “Plastics” describes the formability of many polymers during fabrication.
• Polymers are lightweight, low cost, low strength, and have low melting points and higher chemical reactivity.
• Polymer development areas include biodegradable polymers, liquid crystal polymers, electrically conducting polymers, and in recycling.

Composites

• Composites are combinations of two or more different materials intended utilize the best characteristics of each component.
• Fiber Reinforced Plastics (FRP), fiberglass, and concrete are examples of composites.

Semiconductors

• Properties are intermediate between conductors and insulators
• Their advent made integrated circuitry possible, revolutionizing electronics and computers over past two decades
• Applications include optical computing, micromachining, and memory chip size scaling from 1 million to 100 million.

Biomaterials

• Biomaterials are materials implanted into the human body, replacing bones.
• They must be inert or biocompatible, bioactive, or resorbable.
• Stainless steels, ceramics, glass, polymers and composites are all examples of biomaterials.

Advanced Materials

• These materials are used primarily in high-tech applications.
• Lasers, ICs, LCDs, and fiber optics all can use advanced materials.
• SMART materials are new, state-of-the-art materials being developed.
• SMART materials are now used as sensors and actuators.