Materials Topics

Ablating Material
A material designed to provide thermal protection to a body in a fluid stream through loss of mass.
Abrasion Hardness
Resistance to abrasive wear.
Absolute Powder Density
The mass of powder per unit of absolute volume.
Absolute Powder Volume
The volume of the solid matter after exclusion of all the spaces ie pores and voids.
Absorbent Material
A material which absorbs energy from an incident sound wave.
A durable wood used for palings and posts.
Acid Embrittlement
A form of hydrogen embrittlement that may be induced in some metals by an acid.
Acoustic Material
Any material considered in terms of its acoustical properties.
Adhesive Failure
A rupture of adhesive bond that appears to be a separation at the adhesive-adherend interface.
Aero Metal
A metal used in casting made from aluminium, zinc and copper.
Any phenomenon which includes the mutual interaction between aerodynamic loads and structural deformation.
Air Permeability Test
A procedure for determining the fineness of powdered material.
This wood is very durable in water and not so durable in dry conditions. Historically it was used a lot in pumps, piles and sluices.
Alnico Magnet
A magnet using aluminum, nickel, and cobalt in its construction.
Alpha Rockwell Hardness
Index of the resistance of a plastic to surface penetration by a specified indenter under specified load applied with a Rockwell hardness tester.
Aluminium 1000 series
High purity aluminium with excellent corrosion resistance, high thermal conductivity, high electrical conductivity, excellent workability, but the downside is low mechanical properties

Aluminium 1050
Part of the 1000 series. This particular alloy is 99.5% pure aluminium.

Aluminium 1060
Part of the 1000 series. This particular alloy is 99.6% pure aluminium.

Aluminium 1100
Part of the 1000 series. This particular alloy is 99.0% pure aluminium.

Aluminium 1199
Part of the 1000 series. This particular alloy is 99.99% pure aluminium.

Aluminium 2000 series
The principal alloying element is copper and can be heat treated to achieve mechanical properties that can exceed mild steel. The downsides are: solution heat treatment required to get optimum properties, corrosion resistance not as good as other aluminium alloys, tend to be brittle and exhibit poorer corrosion resistance than other alloy series.

Aluminium 3000 series
The principal alloying element is manganese - up to 1.5%, moderate strength, higher manganese alloys have good machinability, particularly resistant to pitting corrosion.

Aluminium 3003
Commercially pure aluminum with the addition of manganese that increases the strength. 3003 has excellent corrosion resistance and workability.

Aluminium 4000 series
The principal alloying element is silicon, in significant amounts it lowers the melting point. Most alloys non-heat treatable and good casting qualities.

Aluminium 5000 series
The principal alloying element is magnesium, alloys with high magnesium and manganese result in high strength but non-heat treatable, good welding characteristics, anodizes well and good resistance to corrosion even in marine environments. The downsides are: limited cold working and lower safe operating temperatures due to magnesium content.

Aluminium 6000 series
The principal alloys silicon and magnesium. This series is heat treatable, has good formability, good corrosion resistance and medium strength. Relatively easy to roll extrude and forge.

Aluminium 7000 series
The principal alloy is Zinc. The addition of magnesium results in heat-treatable and very high strength and sometimes other elements added such as copper and chromium.

Aluminium 8000 series
This series of aluminium is mainly used for lithium alloys. May contain tin, iron or silicon. Can be rolled into thin sheets.

Aluminium Alloys
Aluminum containing specified quantities of alloying elements added to obtain the necessary mechanical and physical properties.
Aluminium Temper
The heat treatment and coding as applied to aluminium.
Formation of an aluminum or aluminum-alloy coating on a metal by hot dipping, hot spraying or diffusion.
American Society For Testing Material
An open forum for the development of high-quality, market relevant international standards used around the globe.
Anaerobic Adhesive
An adhesive which hardens in the absence of air, such adhesives are often used as a thread locking medium.
The property of a solid in which deformation depends on the time rate of change of stress as well as on the stress itself.
A phenomenon observed in some materials in which complete magnetic moment cancellation occurs as a result of antiparallel coupling of adjacent atoms or ions.
Apparent Particle Density
The mass of a particle divided by its apparent particle volume.
Apparent Particle Volume
The total volume of the particle, excluding open pores, but including closed pores.
Apparent Powder Density
The mass of a powder divided by its apparent volume.
Apparent Powder Volume
The total volume of solid matter, open pores and closed pores and interstices.
A hard and dense wood that when stained is a good substitute for ebony.

Aramid Fibres
A class of heat-resistant and strong synthetic fibres.
A very tough and elastic timber used for oars, blocks and pulleys, spokes of wheels and milk-pails.
Ash Frame
On some old cars the bodywork was built with a wooden frame, normally made from Ash, with panels attached to the wooden frame.
Atom Percent
Concentration specification on the basis of the number of moles or atoms of a particular element relative to the total number of moles or atoms of all elements within an alloy.
Atomic Vibration
The vibration of an atom about its normal position in a substance.
Hot deformation of metastable austenite within controlled ranges of temperature and time that avoids formation of non-martensitic transformation products.
Quenching a ferrous alloy from a temperature above the transformation range.
Face-centered cubic iron; also iron and steel alloys that have the FCC crystal structure.
Austenitic Stainless Steel
The common stainless steel, where the primary microstructure is austenite and the composition primarily iron but also includes both chromium and nickel.
Forming austenite by heating a ferrous alloy above its upper critical temperature to within the austenite phase region from the phase diagram.
An airtight vessel constructed of thick-walled steel alloy for carrying out chemical reactions under pressure and high temperatures.
Autoclave Moulding
A moulding technique in which an entire assembly is placed into an autoclave at 50 to 100 psi, in order to consolidate layers of the part by removing entrapped air and volatiles.
Bag Moulding
A technique in which the composite material is placed in a rigid mould and covered with a flexible bag, with pressure applied by vacuum, autoclave, press, or by inflating the bag.
Balsa Wood
The wood from Ochroma Lagopus.
A very hard wood almost unaffected when exposed to water. Therefore, it is used for keels of ships and flood gates. On account of its hardness it was used for wheels and railway sleepers.
Bias Fabric
A fabric in which warp and fill fibres are at an angle to the length.
Bidirectional Laminate
A reinforced plastic laminate in which the fibres are oriented in more than one direction in the plane of the laminate.
Bimetallic Couple
A joint or union of two dissimilar metals.
Biological Corrosion
Deterioration of metals as a result of the metabolic action of micro-organisms.
Strong flexible wood that has many uses. Amongst the uses are furniture making, building as well as being used for agricultural implements in the past.
Black Oxide
Black finish on a metal produced by immersing it in hot oxidizing salts or salt solutions.
A hardwood from East Africa.
Blue Brittleness
Brittleness exhibited by some steels after being heated to some temperature within the range of 150 to 350C.
Very compact hard wood suitable for machining small parts from.
Brinell Hardness
Characterizes the indentation hardness of materials through the scale of penetration of an indenter.
Brinell Hardness Test
A test for determining the hardness of a material by forcing a hard steel or carbide ball of specified diameter into it under a specified load.
The tendency of a material to fracture without first undergoing significant plastic deformation.
Bulk Powder Density
The mass of a powder divided by its apparent volume.
Carbon Fibre
Material that has small fibres of carbon added for strength.
Cast Alloys
Alloys cast from the molten state.
Cast Iron
An alloy of iron and carbon (2.5%). Distinguished from steel by large amounts of graphite.
Cast Iron BS1452 Grade 220
A continuous cast iron bar, it has a fine grain structure combined with the fine graphite flake size and dense homogeneous structure.

Cast Iron BS1452 Grade 250
Good combination of wear resistance and strength, reasonable machinability and excellent surface finishes.

Cast Iron BS1452 Grade 260
A fine grain structure, combined with the fine graphite flake size and dense homogeneous structure. Good wearing characteristics and when components require a combination of strength and wear resistance superior to those of other softer cast iron grades.

Caul Sheet
Plate or sheet the same size and shape used in contact with a composite layup to transmit normal pressure and temperature during cure.
Cavitation Corrosion
A process involving conjoint corrosion and cavitation.
A durable wood used in ancient buildings. Easy to work and strongly scented.
Ceramic Matrix Composite
A composite that uses a ceramic as the matrix phase.
Chain Folded Model
A model that describes the structure of platelet crystallites for crystalline polymers.
Chemical Vapour Deposition
A method of depositing thin semiconductor films.
A reddish hardwood that can be stained to make a good imitation of mahogany.
Very durable and much like oak. Comparitavely easy to work and does not shrink much when drying.
Chrome Plating
A technique of electroplating a thin layer of chromium onto a metal or plastic object.
Climbing Drum Peel Test
Method for determining peel resistance of adhesive bond between a relatively flexible and a rigid material.
Abbreviation of Ceramic Matrix Composite.
Coarse Pearlite
Pearlite for which the alternating ferrite and cementite layers are relatively thick.
Cured and simultaneously bonded to another prepared surface.
Coefficient of Elasticity
An alternate term for modulus of elasticity or Young′s Modulus.
Coefficient of Thermal Expansion
The constant value or factor of expansion of a material for a given increase in temperature, divided by the length of the material. This is different for each material.
Cold Rolled Steel
Steel that has been rolled to accurate size and smooth finish when made. In contrast, hot-rolled steel may have a rough, pitted surface and slag inclusion.
Complex Modulus
Measure of dynamic mechanical properties of a material, taking into account energy dissipated as heat during deformation and recovery.
A material brought about by combining materials differing in composition or form on a macroscale for the purpose of obtaining specific characteristics and properties.
Composite Materials
Structural materials of metals, ceramics, or plastics with built-in strengthening which may be in the form of filaments, foils, powders, or flakes of a different compatible material.
Compressibility and Recovery Test
Method for measuring behaviour of gasket materials under short time compressive loading at room temperature.
Compression Deflection Test
Nondestructive method for determining relationship between compressive load and deflection under load for vulcanized rubber.
Compression Fatigue
Ability of a material to sustain repeated fluctuating compressive loads.
Compression Moulding
Moulding technique using heat and pressure.
Compression Set
The extent to which a material is permanently deformed by a prolonged compressive load.
Compression Test
Method for determining behaviour of materials under crushing loads.
Compressive Yield Strength
Stress which causes a material to exhibit a specified deformation.
Conduction Band
Lowest empty or partially filled band in a semiconductor.
Contact Moulding
A technique in which reinforcement and resin are placed in a mould, with cure taking place at room temperature with a catalyst/promoter system, or in a heated oven.
Continuous Filament
An individual, small-diameter reinforcement that is flexible and indefinite in length.
Continuous Filament Yarn
Yarn that is formed by twisting two or more continuous filaments into a single continuous strand.
Deteriorative loss of a metal as a result of dissolution environmental reactions.
Corrosion Current Density
The current flowing in a corrosion "local" cell.
Corrosion Inhibitor
A lubricant additive for protecting surfaces against chemical attack from contaminants in the lubricant.
Corrosion Protection
Modification of a corrosion system so that corrosion damage is mitigated.
Corrosion Resistance
The ability of a material to resist deterioration by chemical or electrochemical reaction with its environment.
Corrosive Wear
A material deterioration due to the co-joint action of corrosion and mechanical action.
Cure Temperatur
The temperature at which a material attains final cure.
Curing Agent
A catalytic or reactive agent that brings about polymerization when it is added to a resin.
Casehardening method that introduces carbon and nitrogen to the workpiece simultaneously.
A change in the shape of an object or material.
Deformation Under Load
Measure of the ability of rigid plastics to withstand permanent deformation and the ability of nonrigid plastics to return to original shape after deformation.
Occurs when a composite material formed from a number of layers is stressed, thermally or otherwise, such that the layers begin to separate.
Delamination Strength
Measure of the node-to-node bond strength of honeycomb core materials.
A unit used in measuring the thickness (fineness) of yarn. It is the mass in grams of 9000m of yarn.
The derived SI unit of density is kgm-3
Deposit Corrosion
Corrosion occurring under or around a deposit on a metallic surface. Also called Poultice Corrosion.
Diffusion Furnace
Furnace used to make junctions in semiconductors by diffusing dopant atoms into the surface of the material.
Ductile-to-Brittle Transition
The transition from ductile to brittle behaviour with a decrease in temperature.
Lists all Durability topics in the Encyclopaedia
A very dark, hard and smooth wood used for ornamental work.
Edge Tearing Strength
Measure of the resistance of paper to tearing when folded over a V-notch beam and loaded in a tensile testing machine.
Effective Particle Density
The mass of a particle divided by its volume including open pores and closed pores.
Elastic Deformation
A non-permanent deformation that totally recovers upon release of an applied stress.
A material is elastic if it returns to it's original shape after being deformed.
Electroless Nickel Plating
An auto-catalytic chemical technique used to deposit a layer of nickel-phosphorus or nickel-boron alloy on a solid workpiece, such as metal or plastic.
A hard, durable and coarse grained wood. Used for ship building.
Reduction in ductility due to physical or chemical changes.
Endurance Limit
In fatigue testing, the number of cycles which may be withstood without failure at a particular level of stress.
Energy Dispersive Spectroscopy
Technique based on the characteristic X-ray peaks that are generated when an energetic electron beam interacts with the specimen.
Engine Oil
Liquid that reduces friction or wear, or both, between the moving parts within an engine; removes heat, particularly from the underside of pistons; and serves as a combustion gas sealant for the piston rings.
Envelope Volume
The external volume of a particle, powder, or monolith such as would be obtained by tightly shrinking a film to contain it.
Environmental Tests
A set of tests used to establish that a piece of equipment can withstand a lifetime of exposure to the environment it will have to survive.
Powder or grain shapes with approximately equal dimensions.
Material made from natural or man-made fibres.
Fatigue Corrosion
The process in which a metal fractures prematurely under conditions of simultaneous corrosion and repeated cyclic loading at lower stress levels or fewer cycles than would be required in the absence of the corrosive environment.
Material that has populations of atoms with opposing magnetic moments, the opposing moments are unequal and a spontaneous magnetization remains.
Spontaneous alignment of electric dipoles within a material under the influence of an electric field, resulting in a hysteresis loop when the direction of electric field is switched.
Ferromagnetic Material
A highly magnetic material, such as iron, cobalt, nickel, or their alloys.
Fibre Reinforcement
A fibrous material used to reinforce a material.
File Hardness
Hardness as determined by the use of a file.
Filiform Corrosion
Corrosion that occurs under organic coatings on metals as fine wavy hairlines.
A light coloured and soft wood. Needs to be dried very well before use.
Fire Resistance
The resistance of an object or system to fire. Fire resistance may be applied as a coating or as a methodology in a particular construction design.
Flex Resistance
Ability of foam rubber to sustain repeated compressive loads without damage to cell structure.
Flexural Strength
A property of a solid that indicates its ability to withstand bending.
Flexure Test
Behaviour of materials subjected to simple beam loading.
Free Machining Steels
A group of steels designated as being easy to machine. Contain one or more additives, which enhance machining characteristics and lower machining cost.
Fretting Corrosion
Can take place when two metals are held in contact and subjected to repeated small sliding, relative motions.
Full Annealing
Imprecise term that denotes an annealing cycle designed to produce minimum strength and hardness.
Galvanic Corrosion
Corrosion associated with the current of a galvanic cell consisting of two dissimilar conductors in an electrolyte or two similar conductors in dissimilar electrolytes.
Geometric Volume
The volumes of a material calculated from measurements of its physical dimensions.
Guiner-Preston Zone
A small precipitation domain in a supersaturated metallic solid solution.
Hand Layup
A fabrication method in which reinforcement layers, preimpregnated or coated afterwards, are placed in a mould by hand.
A substance used to promote or control curing action by taking part in it; as opposed to catalyst.
Resistance of metal to plastic deformation usually by indentation.
The fully developed wood which surrounds the pith.
Heat Affected Zone
That part of the base metal which has been altered by the heat from the welding, brazing, or cutting operation.
Heat Cracking
A pattern of small, irregular cracks, that result from local heating of an object.
Heat Treating Cast Iron
Cast iron has plenty of carbon available and is easy to heat treat.
High Carbon Steel
Steel with a carbon content greater than 0.85%.
High Current Arc Ignition Test
Required testing for a material that is in contact with or in close proximity to uninsulated live parts (typically 0.80 mm for non-arcing parts or 12.5 mm for arcing parts).
High Speed Steel
About 6 times harder than carbon steel and used extensively for machine tools.

High Voltage Arc Resistance to Ignition Test
Required by various end-product standards when the material is used in contact with uninsulated live parts.
High Voltage Arc Tracking Rate
Required of the material when it is used in contact with or in close proximity (within 0.80 mm) to uninsulated live parts.
Hot Crack
A crack that forms due to internal stresses developed from shrinkage during solidification of a metal casting.
Hot Dip
To coat metal parts by immersion in molten metal, such as tin or zinc.
Hot Dipped Galvanized
Process to coat steel to offer environmental resistance to corrosion.
Hot Rolled Steel
Steel which is rolled to finished size while hot.
Hot Wire Ignition Test
Required of a material when it is in contact with or in close proximity (typically within 0.8 mm) to uninsulated live parts.
Hybrid Composite
A composite with two or more reinforcing fibres.
Hydrogen Embrittlement
A process which results in a decrease of the toughness or ductility of a metal due to absorption of hydrogen.
A nickel based alloy with good corrosion resistance.

Inconel 600
Inconel is a registered trademark of Special Metals Corporation, referring to a family of nickel-based superalloys. Inconel alloys are oxidation and corrosion resistant materials designed for use in high heat environments.

Inconel 625
Inconel is a registered trademark of Special Metals Corporation, referring to a family of nickel-based superalloys. Inconel alloys are oxidation and corrosion resistant materials designed for use in high heat environments.

Inconel 690
Inconel is a registered trademark of Special Metals Corporation, referring to a family of nickel-based superalloys. Inconel alloys are oxidation and corrosion resistant materials designed for use in high heat environments.

Inconel 718
Inconel is a registered trademark of Special Metals Corporation, referring to a family of nickel-based superalloys. Inconel alloys are oxidation and corrosion resistant materials designed for use in high heat environments.

Inconel 939
Inconel is a registered trademark of Special Metals Corporation, referring to a family of nickel-based superalloys. Inconel alloys are oxidation and corrosion resistant materials designed for use in high heat environments.

Inorganic Material
Substances not derived from living things.
Intergranular Fracture
Fracture of polycrystalline materials by crack propagation along grain boundaries.
Interstitial Void
An opening in a rock or soil that is not occupied by solid matter.
Intumescent Mat
Ceramic fibre mat which irreversibly expands after exposed to high temperature.
Isothermal Annealing
Austenitizing a ferrous alloy and then cooling to and holding at a temperature at which austenite transforms to a relatively soft ferrite carbide aggregate.
Isothermal Transformation
A change in phase at any constant temperature.
Killed Steel
Steel treated with a strong deoxidizing agent.
Knoop Hardness Test
An indentation hardness test.
Laminate Ply
One layer of a laminated product.
An elastic wood suitable where some degree of bending is required.
An extremely durable wood used for rough work. It warps a lot when dried, but can be polished to a fine finish when dry.
Direction of the predominant surface pattern, which is determined by the production method.
The placement of layers of reinforcement in a mould.
Linear Thermal Expansion
Most substances expand when heated and contract when cooled.
Liquid Crystal Polymer
A type of thermoplastic, melt processible, with high orientation in moulding, improved tensile strength, and high-temperature capability.
Lubricating Grease
A semi-fluid to solid product of a dispersion of a thickener in a liquid lubricant.
A pore of diameter greater than about 50 nm.
A very hard wood that is very durable and can be polished to a fine finish with a rich colour.
Malleable Cast Iron
White cast iron that has been heat treated to convert the cementite into graphite clusters; a relatively ductile cast iron.

Maraging Steel
Steels which are known for possessing superior strength and toughness without losing malleability, although they cannot hold a good cutting edge.

Quenching an austenitized ferrous alloy in a medium at a temperature in the upper part of the martensite range.
Martensite is a microconstituent or structure in quenched steel characterized by an acicular or needle-lie pattern on the surface of polish.
Material Safety Data Sheet
Safety information sheet for a particular substance that lists physical properties, hazards, cleanup and disposal procedures, fire and explosion data, and protective equipment required.
Materials Books
Lists all Materials Books in the Encyclopaedia
Materials Calculations
Lists all Materials Calculations in the Encyclopaedia
Materials Conversions
Lists all Materials Conversions in the Encyclopaedia
Materials Weblinks
Lists all Materials Weblinks in the Encyclopaedia
Maximum Fibre Stress
Maximum tensile or compressive stress in a homogeneous flexure or torsion test specimen.
Melt Flow Index
Measure of how many grams of polymer pass through a standardized capillary under a standard load over 10 minutes. The value obtained through the melt flow index test is a single data point.
A pore of diameter from about 2 nm to 50 nm.
Metal Matrix Composite
A composite that uses a metal as the matrix phase.
The hardness of microscopic areas or of the individual microconstituents in a metal.
A pore of diameter less than about 2 nm.
The structural features of an alloy that are subject to observation under a microscope.
Microvoid Coalescence
Occurs due to the nucleation of microvoids, followed by their growth and eventual coalescence.
Mild Steel
A term used for low-carbon machine steel.

Mill Finish
A surface finish produced on sheet and plate. Characteristic of the ground finish used on the rolls in fabrication.
Abbreviation of Metal Matrix Composite.
Modulus of Elasticity
The modulus of elasticity is the slope of the stress-strain diagram in the linear region.
Modulus of Elasticity in Shear
Another name for Shear Modulus.
The process of manufacturing by shaping pliable raw material using a rigid frame or model called a pattern.
Also known as Polycrystalline.
Nickel Plating
A technique of electroplating a thin layer of nickel onto a metal object.
An alloy consisting of roughly 80% nickel and 20% chromium with additives such as titanium and aluminium.
Nimonic 75
A Nickel-Chromium alloy with good corrosion and heat resistance. Often used for aircraft fasteners.

Nimonic 90
An alloy consisting of roughly 80% nickel and 20% chromium with additives such as titanium and aluminium. The main use is in gas turbine blades. Nimonic is a registered trademark of Special Metals Corporation and is a family of metals.

Introducing nitrogen into the surface layer of a solid ferrous alloy. This is done to increase hardness, wear resistance and fatigue strength.
Several processes in which both nitrogen and carbon are absorbed into the surface layers of a ferrous material and, by diffusion, create a concentration gradient.
Non-Reference Oil
Any oil other than a reference oil; such as a research formulation, commercial oil or candidate oil.
A synthetic polymer used in the manufacture of fibres.
The strongest and most durable wood that lasts for long periods in either wet or dry conditions.
Offset Yield Strength
Arbitrary approximation of elastic limit.
Arrangements in space of the axes of a crystal lattice with respect to a coordinate system.
Gaseous emission or de-aeration of a material.
Paramagnetic Material
A material having a permeability slightly greater than 1.
Parana Pine
A yellowish with red streaks softwood that has good working qualities and can be obtained without knots.

Pentavalent Impurity
A type of impurity that contains five valence electrons and donates one electron to the doped material.
Easily worked and used where moderate strength and durability are required. Turpentine is obtained from the pine.
Pitch Pine
A softwood with a colour similar to Scots pine but with strong marked figure. This wood has a lot of resin.

Plane Wood
A North American wood that resembles beech, durable in water but not in air.

A solid material in the primary ingredient of which is an organic polymer of high molecular weight.
Modelling Clay.
Forming an adherent layer of metal on an object; often used as a shop term for electroplating.
Thin sheets of wood glued together with the grains running in different directions to improve the strength of the resultant board.
Abbreviation of Polymer Matrix Composite.
A macromolecule with repeating units linked by amide bonds.
Polymer Matrix Composite
A composite that uses a polymer as the matrix phase.
A light wood, but not very strong and or very good wear resistance.
An additional elevated temperature exposure that is performed often without tooling or pressure to improve elevated temperature mechanical properties.
Pot Life
The length of time a catalyzed thermosetting resin system retains a viscosity low enough for it to be suitable for processing.
Poultice Corrosion
Corrosion occurring under or around a deposit on a metallic surface.
Precipitation Hardening
Increase the hardness of a supersaturated solid solution by heat treating it to cause a second phase to precipitate out.
The full or partial setting of a resin or adhesive before the clamping operation is complete or before pressure is applied.
Pressure Bag Moulding
A moulding technique in which a flexible bag is placed over the contact layup in the mould, sealed, and clamped in place, and pressure applied by compressed air, which forces the bag against the part while the part cures.
Process Engineered Fuel
A processed solid fuel, made from segregated plastic and paper, derived from industrial, commercial, and residential sources, for use by utilities and industry.
A continuous process for manufacturing composites in rods, tubes, and structural shapes having a constant cross-section.
Radiant Panel Test
Used to measure and compare the surface flammability of materials when exposed to a prescribed level of radiant heat energy.
Non-destructive method of internal examination in which metal objects are exposed to a beam of X-ray or gamma radiation. Differences in thickness, density, or absorption caused by internal defects or inclusions are apparent in the shadow image produced on a fluorescent screen or photographic film placed behind the object.
Rapid Solidification Technology
Process in which molten metals such as titanium and aluminum are transformed into a very fine powder, which is then solidified.
A material, generally a polymer, that has an indefinite and often high molecular weight and a softening or melting range and exhibits a tendency to flow when it is subjected to stress.
Resin Transfer Moulding
A moulding process in which catalyzed resin is transferred into an enclosed mould into which the fibre reinforcement has been placed, cure normally is accomplished without external heat.
Rockwell Hardness
Hardness determined from size of indentation using a diamond or steel ball and given load.
A collection of bundles of continuous filaments either as untwisted strands or as twisted yarns.
Rust Remover
Any chemical substance which removes rust.
Rust Sealer
A rust converter that provides a coat on metal surfaces to protect them against air exposure and thus to prevent continued corrosion.
SAE Steel
Steel manufactured under the specifications by the Society of Automotive Engineers.
Safety Data Sheet
OSHA has replaced MSDS with SDS in 2013 under 29CFR Part 1910.1200.
Salt Spray Test
A test method used to check corrosion resistance of coated samples.
Sandwich Construction
A composite construction of alloys, plastics, and other materials consisting of a foam or honeycomb layer and glued between two hard outer sheets.
Lighter coloured wood on the outside of a log, this wood is more susceptable to rot than heartwood.
Abbreviation of Safety Data Sheet.
Secant Modulus of Elasticity
Ratio of stress to strain at any point on curve in a stress-strain diagram.
Secondary Electron Imaging
Production of secondary electrons is very topography related. Any changes in topography in the sample that are larger than this sampling depth will change the yield of secondaries due to collection efficiencies.
Self Extinguishing
A material which will not support combustion when external source of flame is removed.
Lists all Semiconductors topics in the Encyclopaedia
Also known as Polycrystalline.
Sheet Steel
Either hot or cold rolled sheets produced on continuous sheet mill.
Shore Hardness
A hardness measure determined by a Shore durometer.
Silica Fabric
A high performance textile fabric designed for use where severe temperature conditions exist.
Skeletal Density
The ratio of the mass of discrete pieces of solid material to the sum of the volumes of: the solid material in the pieces and closed or blind pores within the pieces.
Skeletal Volume
The sum of the volumes of the solid material and closed (or blind) pores within the pieces.
Smoke Developed
Measure of smoke density developed by a material when compared with red oak, which has a smoke density index of 100 in accordance with ASTM E 84.
Solder Paste
Mixture of minute spherical solder particles, activators, solvent, and a gelling or suspension agent.
Solid Solution
A single solid homogeneous crystalline phase containing two or more chemical species.
Solidification Shrinkage Crack
A crack that forms due to internal stresses developed from shrinkage during solidification of a metal casting; also called a hot crack.
Specific Volume
The volume of a unit mass of substance, the reciprocal of density.
Splitting Resistance
Measure of the ability of felt to withstand tearing.
A white softwood that can attain a lustrous surface when finished.

A process used to apply semiconductor material to a substrate by a physical vapour deposition process where high-energy ions are used to bombard elemental sources of semiconductor material, which eject vapours of atoms that are then deposited in thin layers on a substrate.
Stainless Steel
Any steel containing at least 10.5% Cr as the principal alloying element.
An iron-based alloy containing manganese, usually carbon, and other alloying elements.
Steel EN16T
Manganese molybdenum steel with good ductile and mechanical strength and the ability to withstand shock loading.

Steel EN19T
A steel that is suitable for higher strength applications where resistance to shock is required. Typically 1% chromium molybdenum with good ductile and mechanical strength.

Steel EN1A
Low carbon free cutting mild steel. Good machining qualities.

Steel EN24T
A nickel chrome molybdenum steel with good ductile and tensile strength with good shock and wear resistance properties.

Steel EN36
A nickel chrome case hardening steel that can be hardened to provide a very hard surface with a strong, tough core.

Steel EN8
A medium tensile strength steel with a carbon content of 0.4 to 0.45%. The mechanical properties are just above those of mild steel. Can be heat treated to improve surface hardness.

Storage Life
The amount of time a material can be stored and remain suitable for use.
Strain Hardening Exponent
Measure of increase in hardness and strength caused by plastic deformation. It is related to true stress and true strain.
Stray Current Corrosion
A form of attack caused by electrical currents going through an unintentional path.
Stress Concentration Factor
Ratio of the greatest stress in the area of a notch or other stress raiser to the corresponding nominal stress.
Stress Corrosion
Preferential attack of areas under stress in a corrosive environment, where such an environment alone would not have caused corrosion.
Stress Corrosion Cracking
Material deterioration due to cracking, by being under static stress either applied or residual.
Structural Adhesive
An adhesive used for transferring loads between adherends.
Structural Bond
A bond joining load-bearing components of an assembly.
Superficial Rockwell Hardness Test
Form of Rockwell hardness test using relatively light loads which produce minimum penetration.
Synthetic Oil
A non-petroleum based oil.
Synthetic Rubber
A man-made elastomer.
Tangent Modulus of Elasticity
The instantaneous rate of change of stress as a function of strain.
Tap Density
The apparent powder density obtained under stated conditions of tapping.
A strong and durable wood that doesn't shrink much and is comparatively easy to work.
Tear Length
Measure of the drawability of sheet metal.
Reheating a quench-hardened or normalized ferrous alloy to a temperature below the transformation range and then cooling at any rate desired.
Tensile Modulus of Elasticity
Tangent or secant modulus of elasticity of a material subjected to tensile loading.
Tensile Test
Method for determining behaviour of materials under axial stretch loading.
Terminal Solid Solution
A solid solution that exists over a composition range extending to either composition extremity of a binary phase diagram.
Thermal Cycling
Subjecting a product to pre-determined temperature changes, between hot and cold extremes.
Thermal Electromotive Force
The electromotive force generated in a circuit containing two dissimilar metals when one junction is at temperature different from that of the other.
Thermal Fatigue
A type of fatigue failure that introduces the cyclic stresses by fluctuating thermal stresses.
Thermal Shock
Stresses induced in a material because of a rapid temperature change or a thermal gradient.
Thermal Stress
A residual stress introduced within a body resulting from a change in temperature.
A polymer that softens or melts on heating, and becomes rigid again on cooling.
Thermosetting Plastic
A polymer that solidifies on heating and cannot be remelted.
Thickener for Lubricating Grease
A substance composed of finely divided particles dispersed in a liquid lubricant to form the product′s structure.
Titanium Aluminium Nitride
A group of metastable hard coatings consisting of the metallic elements aluminium and titanium, and nitrogen.
Tool Steel
Any steel used o make tools for cutting, forming, or otherwise shaping a material into a final part.
Torsional Modulus of Elasticity
Modulus of elasticity of material subjected to twist loading.
An untwisted bundle of continuous filaments.
Transgranular Fracture
Fracture of polycrystalline materials by crack propagation through the grains.
Transition Temperature
An arbitrarily defined temperature that lies within the temperature range where metal fracture characteristics change rapidly.
True Density
The mass of a particle divided by its volume, excluding open pores and closed pores.
True Volume
Volume excluding open and closed pores.
Uniform Corrosion
Corrosion that is uniform across the surface of the object.
Vacuum Bag Moulding
A moulding technique in which the part is cured inside a layer of film, from which entrapped air is removed by vacuum.
Vicker′s Hardness
Determined by indenting the material with a diamond pyramid under a specific load and then measuring the size of the impression.
A type of deformation exhibiting the mechanical characteristics of viscous flow and elastic deformation.
Viseoelastic Material
A material which can behave as an elastic solid on a short-time scale and as a viscous fluid on a long-time scale.
During firing of a ceramic body, the formation of a liquid phase that becomes a glass-bonding matrix upon cooling.
Space between particles or material.
Cross grained wood used for ornamental work.
Wet Layup
The application of resin to dry reinforcement in the mould.
A very thin, single crystal of high perfection which has an extremely large length-to-diameter ratio.
A hard substance which forms the branches and trunks of trees and which can be used as a building material, for making things, or as a fuel.
Woods Metal
A fusible bismuth based low melting point alloy. 50 percent bismuth, 25 percent lead, 12.5 percent tin, and 12.5 percent cadmium

Woven Roving
A heavy, coarse fabric produced by the weaving of continuous roving bundles.
Continuously twisted fibres or strands suitable for use in weaving into fabrics.
The onset of plastic deformation.
Zinc Spraying
A process for applying zinc coatings to iron and steel.
Any group of crystal planes that are all parallel to one line, called the zone axis.
Zone Melting
Highly localized melting, usually by induction heating.
Zone Refining
A technique used to reduce the level of impurities in certain metals, alloys, semiconductors, and other materials.

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Subjects: Chemistry Civil Engineering Mechanical Engineering Physics