matsci flashcards

Materials Science: investigates the relationships that exist between the structure and properties of materials

Materials Engineering: involves designing or engineering the structure of a material to produce a predetermined set of properties

Materials Scientist: the role is to develop or synthesize new materials

Structure – refers to the arrangement of a materials internal component

Subatomic, atomic, microstructure, macrostructure – 4 types of structure

in-service condition – 1st criteria

Deterioration – 2^nd criteria

Economics – 3^rd criteria

MATERIAL PROPERTY - While in use a material is subjected to an external stimulus that results in a particular response

Mechanical properties - express the relationship of deformation to the applied load or force

Electrical properties - express the response of a material to an electric field

Thermal properties - express the response of the material to heat

Magnetic properties - express the response to a magnetic field

Optical properties - response of the material to electromagnetic or light radiation

Deteriorative (chemical) properties - refers to the chemical reactivity of the material

Processing, Structure, Properties, Performance - FOUR(4) COMPONENTS INVOLVE IN THE SCIENCE & ENGINEERING OF MATERIALS

Metals, Ceramics, Polymers, Composites, Advance materials – Major groups of metals

Metals - made up of one or more metallic elements (Fe, Al, Cu, Au) and often also non-metallic elements (C, Ni, O) in small amounts

Metals - arranged in an orderly manner

Ceramics - are compounds between metallic and non-metallic elements

Ceramics - extremely brittle and susceptible to fracture

Polymers - many are organic compounds that are chemically based on carbon, hydrogen, and other non-metallic elements (e.g. O, N, Si)

Composites - the objective is to have a combination of properties not available in any single material

CFRP (Carbon fiber reinforced polymer) - carbon is stiff and stronger than glass; more expensive than fiberglass

Advanced Materials - materials used in high technology applications

High Technology - a device or product that uses intricate and sophisticated principles

Semiconductors - have electrical properties that are intermediate between conductors (metals, metal alloys) and insulators (ceramics, polymers)

Biomaterials - materials used to replace deceased or damaged body parts

Smart materials - materials that are able to sense changes in their environment and respond to the changes in a predetermined manner

shape-memory alloys – are metals that after being deformed revert back their original shape when temp. is changed

piezoelectric ceramics – expand and contract when exposed to an electric field; they also generate an electric field when their dimensions are changed

magnetostrictive materials – has the same behavior as piezoelectric ceramics when exposed to a magnetic field

electrorheological/magnetorheological fluids – experience changes in viscosity when exposed to electric or magnetic fields

Nanomaterial - The dimensions of this material are in the order of nanometer (10⁻ 9 ), even less than 100 nanometers.

Atomic number (Z) – refers to the number of protons in the nucleus

Atomic Mass (A) – refers to the sum of the masses of the protons & neutrons

Isotopes – elements that have different number of neutrons

Atomic mass unit (amu) – used to compute atomic mass/weight

Bohr Atomic Model – created by Niels Bohr

Wave-mechanical model – assumes that electrons behave not only as particles but also as waves

Quantum Mechanics – a set of principles or laws that govern systems of atomic and subatomic entities

Valence electrons – those in unfilled shells

Ionic Bonding - always found in compounds that are composed of metallic and non-metallic elements.

Ionic Bonding - Occurs between + and - ions, Requires electron transfer.

Covalent bonding - stable electron configurations are assumed by the sharing of electrons between atoms

Metallic Bonding - valence electrons are not bound to any particular atom in the solid and are free to drift; also known as an electron cloud

electric dipole – there is a separation of the positive and negative portions of an atom or molecule

polar molecules – have permanent dipoles

Fluctuating Induced Dipole Bonds - occurs when a normally electrically symmetric atom or molecule undergo temporary distortions in its electron cloud resulting in the creation of a small electrical dipole

Polar molecule-Induce dipole bonds - exist by virtue of an asymmetrical arrangement of positively and negatively charged regions.

Permanent Dipole Bonds - exist between adjacent polar molecules. Are the strongest type of secondary bonds.

CATALYTIC CONVERTER - Is a pollutant-reducing device that is located in a car’s exhaust system

Point defects, Line defects, Area defects - TYPES OF IMPERFECTIONS

Vacancies, Self-interstitial, Substitutional – Types of point defects

W. Hume – Rothery rule

Dislocations- slip between crystal planes result when dislocations move, produce permanent (plastic) deformation.

Linear defects (dislocations) - Are one-dimensional defects around which atoms are misaligned

Edge dislocation - extra half-plane of atoms inserted in a crystal structure. Perpendicular (⊥) to dislocation line

Screw dislocation - spiral planar ramp resulting from shear deformation. Parallel (||) to dislocation line

Burger’s vector (b) - measure of lattice distortion

Interfacial defects - are boundaries that have two dimensions and normally separate regions of the materials that have different crystal structures and/or crystallographic orientations.

Grain Boundaries, Phase Boundaries, Twin Boundaries – External Surfaces

Catalyst - increases the rate of a chemical reaction without being consumed