Introduction: Classification and Properties of Materials Lecture 1

Classification List the Major Types of MATERIALS That You Know: METALS CERAMICS POLYMERS COMPOSITES ADVANCED MATERIALS

Classification of Materials Polymers Plastics, Wood, Cotton (rayon, nylon), “glue” Composites Glass Fiber-reinforced polymers, Carbon Fiber-reinforced polymers, Metal Matrix Composites, etc. Metals Steel, Cast Iron, Aluminum, Copper, Titanium, many others Ceramics Glass,Cement,Concrete, Brick, Alumina, Zirconia, SiN, SiC.

Classification of Materials Metals and alloys: Composed of one or more metallic elements (such as iron, aluminum, copper, titanium, gold, and nickel), and often also nonmetallic elements (for example, carbon, nitrogen and oxygen) relatively dense relatively stiff and strong, yet are ductile (i.e., capable of large amounts of deformation without fracture), and are resistant to fracture high thermal & electrical conductivity good magnetic properties opaque, reflective Metals have high thermal & electrical conductivity because valence electrons are free to roam

Classification of Materials Ceramics: Ceramics are compounds between metallic and nonmetallic elements; they are most frequently oxides, nitrides, and carbides. For example, some of the common ceramics: Aluminum oxide (or alumina,Al2O3) Silicon dioxide (or silica, SiO2) Silicon carbide (SiC) cement and glass Metals have high thermal & electrical conductivity because valence electrons are free to roam relatively stiff and strong—stiffnesses and strengths are comparable to those of the metals typically very hard but they are extremely brittle (lack ductility), and are highly susceptible to fracture They are insulative to the passage of heat and electricity but can be made electrically conductive resistant to high temperatures and harsh environments than metals Magnetic Property( Fe2O3);

Classification of Materials Polymers: Polymers include the familiar plastic and rubber materials. Many of them are organic compounds that are chemically based on carbon, hydrogen, and other nonmetallic elements (viz. O, N, and Si). Metals have high thermal & electrical conductivity because valence electrons are free to roam low densities not as stiff nor as strong as other material types are extremely ductile soften and/or decompose at modest temperatures, they have low electrical conductivities and are nonmagnetic

Classification of Materials Composites: A composite is composed of two (or more) individual materials, which come from the categories discussed above— viz., metals, ceramics, and polymers One of the most common and familiar composites is fiberglass, Small glass fibers are embedded within a polymeric material (normally an epoxy or polyester) The glass fibers are relatively strong and stiff (but also brittle), whereas the polymer is more flexible. Thus, fiberglass is relatively stiff, strong (Figures 1.4 and 1.5) and flexible. In addition, it has a low density (Figure 1.3). Metals have high thermal & electrical conductivity because valence electrons are free to roam

Comparison of Properties

Comparison of Properties

Comparison of Properties

Comparison of Properties

Comparison of Properties

Classification of Materials Advanced Materials: Semiconductor Materials Biomaterials Materials For Future -Smart Materials ---- Nano-engineered Materials Metals have high thermal & electrical conductivity because valence electrons are free to roam

Semiconductors Solar Cells OLED Technology

Biomaterials Example – Hip Implant With age or certain illnesses joints deteriorate. Particularly those with large loads (such as hip).

Smart Materials Actuators Sensors Four types of materials are commonly used for actuators: 1. shape memory alloys, 2. piezoelectric ceramics, 3. magnetostrictive materials, and 4. electrorheological/magnetorheological fluids. Materials/devices employed as sensors include optical fibers , piezoelectric materials (including some polymers), and micro-electromechanical devices (MEMS) Sensors

Nano Materials Size Comparisons The diameter of your hair is approximately 50,000-100,000 nanometers Your finger nail grows 1 nanometer in 1 second A line of ten hydrogen atoms lined up side by side is 1 nanometer long

COMPUTING Nanotechnology enhancements provide: Faster processing speeds: miniaturization allows more transistors to be packed on a computer chip More memory: nanosized features on memory chips allow more information to be stored Thermal management solutions for electronics: novel carbon-based nanomaterials carry away heat generated by sensitive electronics

BATTERIES Nanotechnology enhancements provide: Higher energy storage capacity and quicker recharge: nanoparticles or nanotubes on electrodes provide high surface area and allow more current to flow Longer life: nanoparticles on electrodes prevent electrolytes from degrading so batteries can be recharged over and over

SENSORS Nanotechnology enhancements will provide: Higher sensitivity: high surface area of nanostructures that allows for easier detection of chemicals, biological toxins, radiation, disease, etc. Miniaturization: nanoscale fabrication methods that can be used to make smaller sensors that can be hidden and integrated into various objects

The Materials Selection Process 1. Pick Application Determine required Properties Properties: mechanical, electrical, thermal, magnetic, optical, deteriorative. 2. Properties Identify candidate Material(s) Material: structure, composition. 3. Material Identify required Processing Processing: changes structure and overall shape ex: casting, sintering, vapor deposition, doping forming, joining, annealing.