Materials Final

Ionic and Covalent

Cations (+)

Anion (-)

ionic

covalent

Ax (NaCl)

AmXp (CaFl2)

AmBnZp (BaTiO3)

size of A, B and x and electrically neutral. Charged ions make it difficult to pack close

Traditional & Modern

Pro: Very high specific properties, corrosion resistant, high use temper, the hardest, formable

Con: no toughness, lowest Kic, porosity, $$$, low impact resistance, difficult to machine

2

ax2

AmBnXf

Point, Line, Surface, Volume

vacancy, interstitial, substitutional

Edge, screw

desire small grains, increase grain boundary

porosity

Heat Engine, Optical Fiber, Ceramic Ball Bearings, Microelectromechanical Systems (MEMS)

High purity silica, very clean, no scattering of light

Large organic chains or molecules

Examples: rubber, wood, oild

Many

repeating unit

Same compound but with a different structure

Linear: covalent & vander waal

Branched: covalent & vander waal

Crosslinked: covalent

joining mers via current, heat, pressure, etc

Thermoplastics, same mers,sequential linear, fast, spontaneous

Thermosets, different mers, slow, by product, cross-linked polymers

average # of mers in a chain n=Molecular weight (given)/total molecular weight of atoms

True

chain alignment "ribbons" or crystals

Chains become closer together and vander wall bond strength is increased, easiest for long chains, linear to form crystals, slow cooling from melt

Pro: low density, cheap, strong eough, low tmp, recycle

Con: poor mechanical properties, weak, creep, embrittle, low Tmp, low impact resistance, temp sensitive, UV sensitive

liquify/melt, linear chains, copoymer, addition polymerization, viscoelastic

Properties: melt, ductile, low Sy and E, formable

permanently set, do not melt, char or burn, network, covalent bonds, retationally rigit, brittle, condensation plymerization, elastomers

Properties: brittle, high Sy, E, low Kic

Clay based, brick, tile, glasses, silicate, High temper, abrasives

High purity powder, controlled micro structure, C, graphite, diamond, strengthening mech? sw, sss, gs, ds

Size, Shape, Structure

Uses up all bonding

Double bonds or greater were used

Double unsaturated structure

Crosslinked

Linear and Branched

isotactic, syndiotactic and atactic

same side of chain

alternate sides

randomly positioned

brittle behavior, chain have no time to slide

ductile behavior

Temp where the material goes from rubber to brittle

Pigments, stabilizers, plasticize, reinforcement, antistatic, flame retardants

degree of polymerization, bond type, chain structure, e, temp, environment, additives

two or more monomers polymerized together

The amorphous region is unkinking, elongation of the chains, crystallites thicken due bonding and stretching

Necking, tilting of crystallites/chain folds, crystalline region aligning, vander waals breaking

Crystalline blcok segments separate from lamellae, vander waals breaking

Continued block sliding and separation, tie chains are aligned with load, fibrillar structure, vander waals and covalent bonds break

large particle, dispersion strengthened

continuous(aligned) and discontinuous (short), fiber types whiskers, fibers, wires

Laminates, sandwich panels

two or more materials that synergistically combine to give optimum properties that neither material count provide alone

soft, ductile, adhere to fiber/ppt, transfer shear stress

Hard, tough, strong, stiff, corrosion resistant, low density, $$

Pros: low density, high E, the highest specific properties, fatigue resistance, tailorable

Cons: low damage tolerance, toxic, moisture absorption, $$$, difficult to process,

stopping of slowing dislocation motion

dislocation motion

bond stretching

Solution treat: heat up allow to 100% alpha

Quench: rapidly cool below solidus

Age: at room temp or below solidus

decreasing solubility with temp

is a chemical process for converting natural rubber or related polymers into more durable materials by the addition of sulfur or other equivalent curatives or accelerators