The Microstructure Domain Ontology is intended to be a domain ontology for physical metallurgy. The intension is to cover all relevant aspect of metallic microstructures, including: - composition - particles, both stable (primary) and metastable (precipitates) - grains - subgrains - grain boundaries & particle free zones (PFZs) - texture - dislocations - alloy systems The aim is to support both microstructure modelling as well as characterisation. For modelling, we will distinguish between - evolution models (that changes the microstructure through a succession of states) and - property models (that relates a microstructure state to a property). It should support describing same concept at different spatial resolutions, like mean field, 1D, 2D and 3D. For mean field descriptions (what about spatially resolved), it should be possible describe quantities at different statistical levels, like mean size, normalised size distribution (mean + standard deviation) and full size distribution. There should be a common way to connect a state to external conditions, like temperature, volume/shape and pressure (essential for describing a process).
A domain ontology for microstructures focusing on physical metallurgy.
Microstructure domain ontology
Particle containing one PhaseOfMatter
In the physical sciences, a particle (or corpuscule in older texts) is a small localized object to which can be ascribed several physical or chemical properties, such as volume, density, or mass. [Wikipedia]
SinglePhaseParticle
A language entity used in the domain of physical metallurgy.
PhysicalMetallurgy
Diameter of an equivalent sphere with the same volume as the grain
EquivalentSphericalGrainSize
EquivalentSphericalGrainDiameter
the measure of a quantity of any characteristic value per unit of area.
SurfaceDensity
The surface of some different substance, such as a dust particle or the wall of the container, acts as the centre upon which the first atoms, ions, or molecules of the crystal become properly oriented.
Most common nucleation process.
HeterogeneousNucleation
Continuous phase in which a composite or multi-phase alloy is formed in a microstructure of metals and completely surrounds the other (dispersed) phases.
MicrostructureMatrix
HostMatrix
A function that provides the possible values for a variable and how often they occur.
DistributionFunction
A grain boundary with a high oritation angle between the grains.
In aluminium are high angle grain boundaries typically defined with as grain boundaries with a grain boundary angle larger than 15 degree.
HighAngleGrainBoundary
The orientation of a real world object relative to a main reference frame. It can be expressed as the transformation from the main reference frame to a local reference frame.
Three independent values are needed to describe the orientation of the local reference frame.
Orientation
For texture is the local reference frame typically connected to the crystal directions and the main reference frame to the rolling, transverse and normal directions.
A boundary related to a discontinous change in a physical property.
SharpBoundary
The initial process that occurs in the formation of a crystal from a solution, a liquid, or a vapour, in which a small number of ions, atoms, or molecules become arranged in a pattern characteristic of a crystalline solid, forming a site upon which additional particles are deposited as the crystal grows.
Nucleation processes are classed as heterogeneous or homogeneous.
Nucleation
A composite material, who's components are in general so small that they require a microscope to be observed.
A microstructure is also a holistic system (a complex whole with interconnected parts). However, since its parts (collectively called microstructure components) are of a different type than the microstructure itself, it also a fundamental whole.
Being nominalistic, the microstructure is the material itself, not just a description of its structure.
Microstructure
This is consistent with the definition of a microstructure in Oxford Languages: "The fine structure (in a metal or other material) which can be made visible and examined with a microscope".
A microstructure model that predicts the value of a property from a given microstructure.
PropertyModel
Area of parts divided by the total area of the whole (domain under consideration).
AreaFraction
The stress corresponding to the yield point at which the material begins to deform plastically.
The yield strength is often used to determine the maximum allowable load in a mechanical component, since it represents the upper limit to forces that can be applied without producing permanent deformation. In some materials, such as aluminium, there is a gradual onset of non-linear behavior, and no precise yield point. In such a case, the offset yield point (or proof stress) is taken as the stress at which 0.2% plastic deformation occurs. Yielding is a gradual failure mode which is normally not catastrophic, unlike ultimate failure.
YieldStress
ElasticLimit
YieldStrength
The arithmetic mean position vector of all the position vectors in the object
defined the position of an extended object
Centroid
The zone of transition of a physical property between two regions of a material.
Boundary
A boundary between at least two grains.
GrainBoundary
Number of objects per volume
NumberDensity
A physical field who’s values are vectors.
PhysicalVectorField
Distance from a point inside a material to the surface.
DistanceFromSurface
Field values assigned to each voxel (VoxelGrid cell)
VoxelField
tomography image
A material process that is categorised to be long to the field of physical metallurgy.
PhysicalMetallurgicalProcess
Rate of cooling.
CoolingRate
Ratio between the maximum and minimum length of an object
AspectRatio
The minor component in a solution, dissolved in a solvent.
Solute
Short-range ordered fluctuations of the spatial distribution of solutes in a non-random solid solution.
OrderedCluster
Cluster
A planar defect is a discontinuity of the perfect crystal structure across a plane.
PlanarDefect
The average size of a set of particles.
AverageParticleSize
Boundray between two crystalline solid phases - incoherent lattices
IncoherentPhaseBoundary
The process by which a solute separates from a solution and forms solid particles.
This can occur either from a liquid solution or a solid solution.
Precipitation
A name identifying a material.
MaterialName
A region of a grain with (almost) the same crystal orientation.
A common definition is that subgrains are separated from their neighbours by subgrain boundaries with a misorientation angle between 5 and 15 degrees.
Subgrain
Boundary between two (or more) phases.
PhaseBoundary
A pore filled with gas.
GasPore
A database containing mobilities of a range of species.
A mobility database is typically combined with a thermodynamic database for predicting diffusivities and other kinetic properties.
MobilityDatabase
metallurgicalReference
Imperfection in the regular geometrical arrangement of the atoms in a crystalline solid.
CrystallographicDefect
Nucleation because to atoms coming into a enegetically beneficial configuration due to random movement of through the bulk of the medium.
HomogenousNucleation
A conventional global reference frame.
GlobalReferenceFrame
the measure of a quantity of any characteristic value per unit of length, area or volume
GeneralisedDensity
A model that either predict a microstructure property or the evolution of the microstructure.
MicrostructureModel
A distribution of the Sizes of multiple particles.
ParticleSizeDistribution
Small solid self-connected part of a microstructure that is separated from its sourroundings and has a different phase(s) across all its borders.
Everything a metallurgist calls a "particle" in a microstructure.
MicrostructureParticle
Innoculant
Precipates
Alpha particles
Representative length of a subgrain measured according to a specified procedure (experimentally or theoretically).
SubgrainSize
A grain boundary with a low oritation angle between the grains.
In aluminium are high angle grain boundaries typically defined with as grain boundaries with a grain boundary angle less than 5 degree.
LowAngleGrainBoundary
Ratio between the maximum and minimum length of a box
Also a method to characterize object by finding the smallest box that fully comprise the object
BoxAspectRatio
The smallest volume over which a measurement can be made that will provide a value representative for the whole.
RepresentativeElementaryVolume
REV
RVE
RepresentativeVolumeElement
A physical quantity that is determined from a statistical analysis the value of a set of determinations/observations/measurements of another physical quantity.
StatisticalQuantity
A boundary consisting of exactly two phase of matter.
DualBoundary
Local deviation from a regular pattern.
Defect
A physical phenomenon where deformed grains within a metal reduce their stored energy by removing or rearranging defects in their crystal structure, primarily dislocations.
Dislocations are introduced by plastic deformation and contribute to increasing the yield strength of the material. The recovery process reduces dislocation density, leading to a decrease in material strength but an increase in ductility. This is why recovery can be seen as either beneficial or detrimental depending on the application.
Recovery
Doherty et al. (1997) defined recovery as All annealing processes occurring in deformed materials that occur without the migration of a high-angle grain boundary. This definition allows to differentiated recovery from recrystallization and grain growth as both feature extensive movement of high-angle grain boundaries. -- RD Doherty; DA Hughes; FJ Humphreys; JJ Jonas; D Juul Jenson; ME Kassner; WE King; TR McNelley; HJ McQueen; AD Rollett (1997). "Current Issues In Recrystallisation: A Review". Materials Science and Engineering. A238: 219–274.
Recovery differs from recrystallization and grain growth, which involve significant movement of high-angle grain boundaries. In contrast, recovery occurs without this migration. If recovery happens during deformation (common in high-temperature processing), it is known as dynamic recovery. When it happens after processing, it is called static recovery.
A microstructure model that predicts the evolution of a microstructure given a starting point and some boundary conditions.
An evilution model is a formal description of one or more physical phenomena.
EvolutionModel
A set of critically evaluated parameter values for a range of thermodynamic functions.
For metallic systems is CALPHAD a popular approach for calculating thermodynamic properties. In this approach are the thermodynamic properties defived from parametrised expressions of the Gibb free energy (and possible other basic quantities) of each phase. It is the parameters of these expressions that are stored in the thermodynamic database.
ThermodynamicDatabase
Area of one phase divided by the total area.
AreaPhaseFraction
A physical field who’s values are scalars.
PhysicalScalarField
Length of a pixel.
A pixel is the smallest unit of a digital image. In the common case where the pixels are 2D squares, the pixel size is length of one of the sides.
PixelSize
A line defect is a line along which whole rows of atoms in a solid are arranged anomalously.
LineDefect
Stacking fault, dislocation
Phase with uniform crystalline structure with a defined composition range (or stoichiometry)
CrystallinePhase
Grid with cubic elements of exactly the same size composing a box.
VoxelGrid
An alloy designation is a system of numbers, letters, and sometimes chemical symbols used to identify the composition and properties of a metal alloy. These designations often indicate the primary alloying elements, their percentages.
Common systems include the four-digit numerical system for wrought aluminum and the Unified Numbering System (UNS), which uses a prefix letter followed by five digits.
alloyDesignation
- 6061 (four-digit aluminium alloy designation) - S31008 (UNS)
A language within physical metallurgy with which alloys are categorised.
AlloySystem
AA6082 Inconel 625
A substance that dissolves a solute, resulting in a solution.
A solvent can be in many state of matter.
Solvent
Alphanumeric code that identify the chemical composition and temper (heat treatment) of a metal alloy.
The four-digit numerical portion represents the alloy chemistry, while the temper designation, added after the four-digit code, indicates the specific heat treatment applied.
AlloyDesignation
For example, "6061-T6" indicates a 6061 alloy that has been solution heat treated and then artificially aged.
finely divided particles of one substance [PhaseOfMatter] dispersed in another [Merriam-Webster]
clarify difference from precipitate
Dispersoid
The movement of individual atoms, ions and molecules relative to the remainder of the material.
The movements of individual atoms is random but where there is a concentration gradient and a large number of movement occur, there will be a net effect for atoms to move down the gradient.
Diffusion
A physical field who’s values are tensors.
PhysicalTensorField
Numbers of counts for a number of intervals for the value of some property.
Distribution
Histogram
the measure of a quantity of any characteristic value per unit of volume.
VolumeDensity
A physical field that is only defined on a set of volume elements in space and time.
PhysicalDiscretisedField
Rate at which the temperature is changed.
Since ISO 80000 does not define a temperature change rate, this quantity should not be included in EMMO. We therefore add it here.
TemperatureChangeRate
An element whos concentration is given from the remaining concentration after the concentration of all other elements has been given.
DependentElement
BalanceElement
Number of grains in a control volume.
NumberOfGrains
Generic discretisation of a volume. It covers completely (an approximation of) the volume with no overlapping elements.
A mesh does not put any restructiction on the type of vomume elements that are used.
Mesh
Number of phases in a control volume.
NumberOfPhases
Length of a gas pore measured according to a specified procedure (and/or model)
GasPoreSize
Regular mesh with one type of volume elements.
Grid
Boundray between two crystalline solid phases - epitaxial layer
CoherentPhaseBoundary
Physical quantities categorised according to the microstructure domain ontology.
MicrostructureQuantity
MicrostructureProperty
Length or thickness of a grain who's shape can be approximated with a cylinder.
CylinderShapedGrainLength
Diameter of a grain who's shape can be approximated with a cylinder.
CylinderShapedGrainDiameter
An entity with a spatial variation of its properties.
SpatialContrast
SpatialPattern
SpatialVariation
Smooth and continuation change in a physical property.
DiffuseBoundary
Finely dispersed particles containing one PhaseOfMatter forming from solid phaseOfMatter by precipitation.
A precipitate can not live without its sourounding microstructure
Precipitate
Reduction of dislocation mobility in a material as a response to an external thermomechanical treatment.
Hardening typically involves the alteration of the metal's microstructure through heat treatment, mechanical work, or the addition of alloying elements.
Hardening
Here are some common hardening techniques: 1. Work Hardening (Cold Working): This process involves deforming the metal at temperatures below its recrystallization point, which introduces defects into the crystal structure. These defects impede the movement of dislocations, making the metal harder and stronger. Common methods include rolling, hammering, and drawing. 2. Heat Treatment: This broad category includes several specific processes: Quenching and Tempering: The metal is heated to a high temperature and then rapidly cooled (quenched) in water or oil. This results in a hard but brittle structure. The metal is then reheated to a lower temperature (tempered) to achieve a balance between hardness and toughness. Precipitation Hardening (Age Hardening): This involves heating the alloy to a high temperature to form a solid solution and then cooling it rapidly. Subsequent aging at lower temperatures allows the formation of fine precipitates within the metal matrix, which hinder dislocation movement and increase hardness 3. Case Hardening: This method is used to harden the surface of a metal while maintaining a softer, ductile core. Techniques include carburizing, nitriding, and carbonitriding, where the surface of the metal is enriched with carbon or nitrogen through exposure to a reactive gas or liquid at high temperatures 4. Solid Solution Strengthening: Alloying elements are added to the metal to create a solid solution, where the atoms of the alloying element distort the metal’s crystal lattice and hinder dislocation movement, thereby increasing hardness and strength.
In metallurgy, hardening refers to a variety of processes used to increase the hardness and strength of a metal or alloy.
A distribution of the Sizes of multiple pores
PoreSizeDistribution
A distribution that gives the probabilities of the occurence of different possible outcomes (of a measurement).
ProbabilityDistribution
A length that represent the size of an object measured according to a given procedure (experimental or theoretical).
RepresentativeLength
Mass of one phase divided by the total mass.
MassPhaseFraction
Ratio between the major axis and minor axis length of an ellipsoid
Also a method to characterize object by finding the smallest ellipsoid that fully comprise the object
EllipsoidAspectRatio
A small openings in a solid substance.
Pores are typically filled with other material, like air or water.
Pore
Size of a particle measured according to a specified procedure (and/or model).
Common representations of a particle size are the particle volume or the diameter of a (hypothetical) sphere with the same volume as the particle.
ParticleSize
a PhysicalField where
ConcentrationField
Point defects are lattice defects of zero dimensionality, i.e., they do not possess lattice structure in any dimension.
PointDefect
vacancy, interstitial atom, substitutional atom
SinglePhaseParticle forming during solidification
PrimaryParticle
Length of a voxel.
VoxelSize
A name identifying a sample.
sampleName
Average total composition of a microstructure.
NominalComposition
An interstitial defect is an atom that occupies a site in the crystal structure at which there is usually not an atom
InterstitialDefect
A distribution of the Sizes of multiple grains
GrainSizeDistribution
A Guinier–Preston zone, or GP-zone, is a fine-scale metallurgical phenomenon, involving early stage precipitation.
GP-zones are associated with the phenomenon of age hardening, whereby room-temperature reactions continue to occur within a material through time, resulting in changing physical properties.
GPZone
GuinierPrestonZone
A part of a microstructure with (almost) the same crystal orientation.
A common definition is that grains are separated from their neighbour grains by grain boundaries with a misorientation angle higher than 15 degrees.
Grain
Grain, in metallurgy, any of the crystallites (small crystals or grains) of varying, randomly distributed, small sizes that compose a solid metal. Randomly oriented, the grains contact each other at surfaces called grain boundaries. The structure and size of the grains determine important physical properties of the solid metal. Grains of a metal ingot can be elongated and locked together by rolling to improve the mechanical properties in the direction of grain length. Internal stresses at grain boundaries may be relieved by annealing to restore exhausted ductility in certain alloys or to harden other alloys. -- britannica.com (https://www.britannica.com/science/grain-solid)
Grains (and subgrains) are in general not (single) crystals since they may include small particles (e.g. precipitates) with another crystal structure.
Note, since grains are defined as being a (holistic) component of a microstructure, we cannot speak about a single grain without it being a part of a microstucture.
Part of a crystalline material consituted primarily of one crystalline phase.
Grid with square elements of exactly the same size composing a rectangular shape.
PixelGrid
Self-similar object at different length scale
FractalObject
A mathematical operator producing a single number that represents a set of numbers.
An average operator can be defined in several ways, like as an median, arithmetic mean or geometrical mean.
Average
AverageValue
Number of precipitates in a control volume.
NumberOfPrecipitates
Length of the dislocation per volume. Usually counted by pits in an etched area section
DislocationDensity
Three angles describing the orientation of a real world object with respect to a main reference frame.
EulerAngles
Time duration for heating.
HeatingTime
The attainment of an increase in matrix strength through addition of different soluble elements, which are likely to include chromium, tungsten, cobalt, molybdenum, rhenium and ruthenium. The distortion of atomic lattice caused by the misfit of atomic radius inhibits dislocation movement.
SolidSolutionHardening
Time duration for cooling.
CoolingTime
materialName
The process involves deforming the metal at temperatures below its recrystallization point, which introduces defects into the crystal structure. These defects impede the movement of dislocations, making the metal harder and stronger. Common methods include rolling, hammering, and drawing.
WorkHardening
ColdWorking
Unordered fluctuations of the spatial configuration of solutes in a solid solution.
The size distribution of solute clusters are assumed to follow Maxwell-Boltzmann statistics.
SoluteCluster
NMer
UnorderedCluster
Field values assigned to each pixel (PixelGrid cell)
PixelField
Pixelated image.
Rate of heating.
HeatingRate
A linear crystallographic defect or irregularity within a crystal structure.
NEED TO CLARIFY LINE OR PLANAR
Dislocation
Number of specifiying chemical compounds or atoms in a volume
VolumetricConcentration
the measure of a quantity of any characteristic value per unit of length.
LengthDensity
LineDensity
Boundary with at least one solid
SolidPhaseBoundary
A boundary volume , where tree things collocate.
A triple junction is a line in space.
TripleJunction
Number of particles that are nucleated per time unit.
NucleationRate
The average volume of atoms in a given phase.
AtomVolume
The difference between two orientations.
The misorientation depends only on the two local reference frames, but not on the main reference frame.
Misorientation
Misorientation between two grains.
A physical quantity that has a value in each point in space and time.
PhysicalField
A representative length of a grain measured according to a specified procedure (experimentally or theoretically).
Note the asymmetry with the definition of the more general particle size, which can be measured with any quantity (e.g. volume, average cross-section diameter, etc) the grain size is always a length. This is to be consistent with the common jargon in metallurgy where grain size always refer to a length.
GrainSize
A boundary volume , where four things collocate.
A quadruple junction is a point in space.
QuadrupleJunction
Ratio of the quantity of a phase over the total quantity of all the phases over the domain considered. Quantity is usually mass, mole, area, or volume.
PhaseFraction
An abstract coordinate system with an origin, oritation and scale specified by a set of reference points.
ReferenceFrame
FrameOfReference
A characterisation measurement process where the composition of a material is measured.
CompositionMeasurement
Number of VolumeElements in a mesh (or grid)
NumberOfCells
Diameter of an equivalent sphere with the same volume as the object
EquivalentSphericalDiameter
The distribution of orientations of the constituents of a whole.
OrientationDistribution
Mixture with metallic character composed of two or more elements of which at least one is a metal.
Alloys may have very different properties compared to the pure substances it is composed of.
Alloy
Averaging the distance between adjacent side branches on the longitudinal section of a primary dendrite.
SecondaryDendriteArmSpacing
DAS
SDAS
Number of moles of one phase divided by the total number of moles.
AmountPhaseFraction
MolePhaseFraction
The volume of a grain.
GrainVolume
Volume of one phase divided by the total volume.
VolumePhaseFraction
Reference frame that is local to (follows) a real world object.
LocalReferenceFrame
A physical quantity that is determined from averinging the value of a set of determinations/observations/measurements of another physical quantity.
AverageQuantity
AverageGrainSize
Cooling rate during solidification.
Typically an average value is referred to.
SolidificationCoolingRate
The surface area of a grain.
GrainSurfaceArea
A distribution of the sizes of multiple objects. It is measured in as the number of items of a given size class per volume.
SizeDistribution
Size distribution of precipitates.
An alloy can have multiple precipitate size distributions, one for each type of precipitates. For example GP zones, β'', β', U1 and U2 in an aluminium 6xxx alloy.
PrecipitateSizeDistribution
An alphanumeric designation appended to the alloy designation that describes the thermomecanical treatment of the alloy.
Temper designations tell both the producer and the user how the alloy has been mechanically and/or thermally treated to achieve the properties desired. The first character in the temper designation (a capital letter, F, O, H, W, or T) indicates the general class of treatment. - F, as fabricated. Most F-temper products are “semi-finished” products. They will be used in shaping, finishing or thermal processes to achieve other finished forms or tempers. - O, annealed. Annealing treatments are used to achieve the lowest-strength condition for the alloy. The main reason is to maximize workability or increase toughness and ductility. - H, strain-hardened. This is for non-heat-treatable alloys that have had their strength increased by strain hardening, usually at room temperature. - W, solution heat-treated. This designation applies only to alloys that age naturally and spontaneously after solution heat treating. It is rarely a finished temper. - T, thermally treated. This applies to any product form of any heat-treatable alloy that has been given a solution heat treatment followed by quenching and aging.
temperDesignation
T6 (peak aged)
The composition in the matrix.
The effective composition is different from the nominal composition, since it only considers the composition of the matrix, excluding all other phases.
EffectiveComposition
The process where particles increase in size and mass over time. particle growth can be understood as the manifestation of various physical processes that lead to the enlargement of particles in a system.
Particle growth occurs through several mechanisms: * Diffusion: Atoms, molecules, or ions move randomly and attach to the surface of a growing particle. * Aggregation: Smaller particles collide and stick together, forming larger particles. * Coalescence: Two or more smaller particles merge to form a single larger particle. * Condensation: A vapor or gas transforms into solid or liquid particles under supersaturated conditions. * Ostwald Ripening: Larger particles grow at the expense of smaller ones, driven by differences in solubility.
ParticleGrowth
A part (component) of a microstructure that contributes to the overall properties of the microstructure itself.
Microstructure components are defined as holistic spatial parts of a microstructure. Hence, single microstructure components does not exists - their definition depends on being a part of a microstructure.
MicrostructureComponent
Grain, precipitate
Centre for Sustainable and Competitive Metallurgical and Manufacturing Industry