Material Science

Unit cell

a mixture of two or more metals

Screw dislocation

A deffect formed by distortion of the lattice as may be produced by a simple shear stress.

Alloy

A metallic substance that is composed of two or more elements.

Network Polymer

A polymer produced from multifunctional monomers having three or more active covalent bonds, resulting in the formation of three-dimensional molecules.

Bragg's law

A relationship that stipulate the condition for diffraction by a set of crystallographic planes.

Monomer

A stable molecule from which a polymer is synthesized.

Lattice

A structure consisting of strips of wood or metal crossed and fastened together with square or diamond-shaped spaces left between.

Noncrystalline

Amorphous, lacking three-dimensional order. Amorphous materials are either rubbers or glasses. normal stress The force divided by the area normal to the force.

Self-diffusion

Atomic migration in pure metals. Or when atoms change position in pure metals.

Single Crystal

For a crystalline solid, when the periodic and repeated arrangement of atoms is perfect or extends throughout the entirety of the specimen without interruption, the result is a ........

Miller Indices

Indices used to define crystallographic planes. The indices are specified as the lowest common denominator of the reciprocals of the intercepts made by a crystal face on the crystallographic axes.

Grain boundary

Interfacial defect, boundary that seperating two small grains or crystals having different crystallographic orientations in polycrystalline materials. or defect between adjacent crystals having different crystallographic orientations.

Edge dislocation

It is a linear defect that centers around the line that is defined along the end of the extra half-plane of an atom.

Cations

Metallic ions or ..... are positively charged

Crystalline

One in which the atoms are situated in a repeating or periodic array ( 3D array )over large atomic distances. Typical of : Metals, many ceramics, some polymers.

Isotropic

Substances in which measured properties are independent of the direction of measurement.

Isotropic material

Substances in which measured properties are independent of the direction of measurement. or when the mechanical properties of a material are independent of the direction in which measurement are taken.

Anisotopy

The directionality of properties is termed ...... and is associated with the variance of atomic or ionic spacing with crystallographic direction.

Crystal Structure

The manner in which atoms, ions, or molecules are spatially arranged.

Anions

The nonmetallic ions or ..... are negatively charged

Diffusion

The phenomenon of material transport by atomic motion.

Polymorphism

The phenomenon that some metals as well as non metals , may have more than one crystal structure

Linear polymers

are those in which the repeat units are joined together end to end in single chains. These long chains are flexible and may be thought of as a mass of a spaghetti.

Copolymer

composed of two or more mer units arranged as : random, graft, block, and alternating copolymer.

Weight-average molecular weight

considers weight percent of each range of molecular weights in determing the molecular weight of a polymer.

Fick's second law

equations representing the time-dependent change in diffusion. or the law governing the dependence of diffusion on time.

Lattice

it is the three-dimensional array of points coinciding with atom positions ( or sphere centers )

Diffraction

it occurs when a wave encounters a series of regurlarly spaced obstacles that 1) are capable of scattering the wave and 2) have spaciings that are comparable in magnitude to the wavelength. Futhermore, diffraction is a consequence of specific phase relationships established between two or more waves that have been scattered by obstacles.

Allotropy

polymorphism in elemental solids

Crystal structure

the manner in which atoms, ions, or molecules are spatially arranged.

Crystal system

the seven different possible combinations of the lattice parameters.

Lattice parameter

the six parameters of a unit cell. the three edge lengths (a, b,c ) and the three interaxial angles ( alpha, beta and gamma)

Schottky Defect

type of defect found in AX materials ( ceramics ) is a catio vacancy-anion vacancy pair. Or in ceramics,Schottky defect are missing a cation and an anion.