Special Processes Institute · sp-i.org

Metallurgy & Materials Science Knowledge Guide

Metallurgy & Materials Science Knowledge App

Understand how composition, atomic bonding, crystal structure, processing, heat treatment, defects and environment combine to determine the performance and failure of engineering metals. Explore interactive diagrams, searchable alloy data, calculations, failure diagnosis and a comprehensive learning test.

Mobile-first learning Interactive diagrams & calculators Engineering guidance

C–P–S–P

Composition → processing → structure → properties

Core crystal systems: BCC, FCC and HCP

30+

Engineering alloys and material families

Best knowledge-test score

The Metallurgical Relationship

The central model

What metallurgy covers

Physical metallurgy

Links atomic and microstructural features to properties. It includes crystal structures, diffusion, phase transformations, heat treatment, strengthening, deformation, fracture and corrosion.

Process metallurgy

Studies casting, forming, welding, machining, powder metallurgy, additive manufacturing, joining, heat treatment and surface engineering, including how each process changes material condition.

Extractive metallurgy

Produces metals from ores and recycled feedstock using mineral processing, pyrometallurgy, hydrometallurgy, electrolysis, refining and remelting.

Core principle: a material designation alone never fully defines performance. The manufacturing route, heat treatment, microstructure, residual stress, defects, surface condition and environment are equally important.

Metallic bonding

Positive ion cores are bound by delocalised electrons. Non-directional metallic bonds allow slip without complete loss of cohesion, explaining conductivity, ductility and formability.

Alloys

Alloying changes phase stability, lattice strain, precipitation, corrosion behaviour, hardenability and high-temperature performance. Small additions can have major effects.

Microstructure

Grain size, phase fraction, morphology, inclusions, porosity, texture and residual stress form the internal architecture controlling properties.

Important alloying elements

Element	Typical metallurgical effects	Examples / cautions
Carbon	Raises steel strength and hardness; forms carbides; controls martensite potential.	Higher carbon reduces weldability and ductility unless carefully processed.
Chromium	Hardenability, carbide formation, oxidation and corrosion resistance.	About 10.5% minimum is associated with stainless behaviour, but local depletion can cause sensitisation.
Nickel	Toughness, austenite stability, corrosion and high-temperature strength.	Important in austenitic stainless and nickel superalloys.
Molybdenum	Hardenability, creep strength, temper resistance and pitting resistance.	Used in Cr-Mo steels, stainless steels and superalloys.
Manganese	Deoxidation, sulphur control, strength and hardenability.	Excess or segregation can influence toughness and cracking.
Silicon	Deoxidiser, solid-solution strength, oxidation resistance and magnetic performance.	Important in spring steels, cast irons and electrical steels.
Vanadium / niobium / titanium	Fine carbides/nitrides, precipitation strengthening and grain control.	Widely used in microalloyed steels and stabilised stainless grades.
Boron	Very small additions strongly increase steel hardenability.	Effect depends on boron remaining in solution rather than tied up as nitrides.
Aluminium	Deoxidation, nitride formation, low density and age-hardening systems.	Central to aluminium alloys and gamma-prime strengthening in nickel alloys.
Copper	Corrosion resistance, conductivity and precipitation strengthening.	Used in weathering steels, aluminium-copper and copper alloys.

Crystal Structures and Slip

Atoms are ordered, but real crystals contain defects

Examples: ferritic iron, chromium, tungsten, molybdenum
Typical behaviour: strong temperature dependence of slip

Examples: aluminium, copper, nickel, austenite
Typical behaviour: twelve easy slip systems and high ductility

Examples: magnesium, α-titanium, zinc, cobalt
Typical behaviour: limited room-temperature slip and anisotropy

BCC

Not close-packed. Slip is temperature and strain-rate sensitive, so many BCC metals show a ductile-to-brittle transition. Ferritic steels can lose toughness at low temperature.

FCC

Twelve easy close-packed slip systems give excellent ductility and toughness across a broad temperature range. Austenitic steels, aluminium, copper and nickel are FCC.

HCP

Fewer easy slip systems at room temperature can restrict ductility and create anisotropy. Twinning and elevated-temperature forming help magnesium and titanium alloys deform.

Crystal defects

Defect	Description	Engineering significance
Vacancy	Missing atom at a lattice site.	Enables substitutional diffusion; concentration rises strongly with temperature.
Interstitial	Small atom occupies space between lattice sites.	Carbon and nitrogen strongly strengthen iron but may cause strain ageing or embrittlement.
Substitutional atom	Alloy atom replaces a host atom.	Creates lattice strain and solid-solution strengthening.
Dislocation	Line defect that permits incremental slip.	Plastic deformation occurs by dislocation motion; strengthening methods obstruct it.
Grain boundary	Interface between differently oriented grains.	Blocks slip and refines strength, but may support corrosion, segregation and creep damage.
Stacking fault / twin	Local change in stacking sequence or mirrored lattice.	Influences work hardening, deformation mode and transformation behaviour.

Grain size and Hall–Petch

σᵧ = σ₀ + kᵧ d^−1/2

Reducing average grain diameter generally increases yield strength because grain boundaries interrupt slip. Fine grains also improve toughness in many steels, although high-temperature creep resistance can favour larger grains.

Texture and anisotropy

Rolling, extrusion, drawing and additive manufacturing can align grains or crystallographic directions. Properties then depend on test direction. Design allowables, forming limits and fracture behaviour must reflect longitudinal, transverse and short-transverse orientation.

Sampling matters: a tensile result without specimen orientation can be misleading for wrought plate, forgings, extrusions and additively manufactured material.

How to Read a Binary Phase Diagram

Temperature + composition → equilibrium phases

Liquidus boundarySolidus / solvus boundariesTie line and eutectic guide

Liquidus

Above the liquidus the alloy is fully liquid. Crossing it during cooling begins solidification.

Solidus

Below the solidus the alloy is fully solid under equilibrium assumptions. Between liquidus and solidus, liquid and solid coexist.

Tie line and lever rule

A horizontal tie line gives phase compositions. Relative segment lengths give phase fractions.

Iron–carbon system: engineering map

Liquidus boundarySolid-state transformation boundaryCritical reaction / composition guide

This educational diagram is deliberately simplified. Use controlled material specifications and authoritative phase data for engineering decisions.

Steel transformation products

Constituent	Formation	Typical behaviour	Control concerns
Ferrite	BCC iron with low carbon solubility.	Soft, ductile, magnetic below Curie temperature.	Grain size and precipitation strongly affect strength.
Pearlite	Lamellar ferrite + cementite from eutectoid decomposition.	Moderate strength and hardness; finer spacing is stronger.	Cooling rate controls lamellar spacing.
Bainite	Non-lamellar ferrite/carbide aggregate at intermediate temperatures.	Strong with useful toughness.	Upper/lower bainite differ; austempering can target this structure.
Martensite	Diffusionless shear transformation during sufficiently rapid cooling.	Very hard and strong but highly stressed and brittle if untempered.	Carbon content, quench severity, section size and retained austenite.
Tempered martensite	Martensite reheated below A1 to precipitate carbides and relieve stress.	Excellent strength–toughness balance.	Tempering temperature/time and temper embrittlement ranges.
Spheroidite	Rounded carbide particles in ferrite after prolonged treatment.	Soft, machinable and formable.	Used before machining/forming high-carbon steels.

Steel families

Plain carbon steels

Low-carbon grades maximise formability and weldability; medium-carbon grades balance strength and toughness; high-carbon grades support high hardness, springs and wear applications.

Low-alloy steels

Mn, Cr, Ni, Mo, V and B improve hardenability, strength, toughness, wear or creep resistance. Section size and quench response are critical.

Tool steels

High carbon plus carbide-forming elements provides hot hardness, abrasion resistance and dimensional stability. Families include water-, oil- and air-hardening, hot-work, cold-work and high-speed steels.

Maraging steels

Very low carbon martensitic matrix strengthened by age-hardening intermetallic precipitates. High strength and toughness but expensive alloy content.

Stainless steel families

Family	Structure	Strengths	Limitations
Austenitic	FCC	Corrosion resistance, formability, cryogenic toughness.	Not conventionally hardenable by heat treatment; SCC and galling may occur.
Ferritic	BCC	Cost-effective oxidation/corrosion resistance, magnetic.	Lower toughness in thick sections; weld grain growth.
Martensitic	Martensitic after quench	Heat-treatable hardness and wear resistance.	Lower corrosion resistance; tempering and cracking control.
Duplex	Ferrite + austenite	High strength and chloride SCC resistance.	Phase balance, heat input and intermetallic precipitation control.
Precipitation-hardening	Martensitic/semi-austenitic/austenitic	High strength with useful corrosion resistance.	Condition and ageing route must be controlled.

Cast irons

Grey iron

Graphite flakes give excellent damping and machinability but act as stress concentrators, reducing tensile ductility.

Ductile iron

Nodular graphite dramatically improves toughness and strength. Matrix can be ferritic, pearlitic or austempered.

White iron

Carbon retained as carbide produces extreme abrasion resistance and brittleness.

Compacted graphite iron

Intermediate graphite morphology gives strength, thermal conductivity and fatigue performance useful in engine blocks.

Steel selection considerations

Need	Metallurgical consideration	Typical approach
Weldability	Carbon equivalent, hardenable HAZ, hydrogen and restraint.	Lower carbon/CE, preheat, controlled consumables, heat input and PWHT where required.
Through-hardness	Hardenability versus section size and quench severity.	Cr-Mo-Ni alloy steel with validated austenitise/quench/temper route.
Surface wear + tough core	Case depth, carbon/nitrogen potential and retained core toughness.	Carburising, carbonitriding, nitriding or induction hardening.
Low-temperature toughness	DBTT, grain size, impurities and weld HAZ.	Fine-grain, nickel-alloyed or austenitic material with impact qualification.
High-temperature creep	Stable carbides/precipitates and oxidation resistance.	Cr-Mo steels, stainless heat-resistant grades or nickel alloys.

Aluminium alloys

Low density and natural oxide. 2xxx, 6xxx and 7xxx are heat treatable; 1xxx, 3xxx and 5xxx rely mainly on strain hardening. Quench sensitivity, corrosion, exfoliation and SCC matter.

Titanium alloys

High specific strength and corrosion resistance. Alpha, alpha-beta and beta families offer different formability, strength, creep and heat-treatment response. Oxygen and hydrogen pickup must be controlled.

Nickel superalloys

Gamma matrix strengthened by gamma-prime/gamma-double-prime precipitates, solid solution and carbides. Designed for creep, fatigue, hot corrosion and oxidation resistance.

Copper alloys

Excellent conductivity and corrosion behaviour. Brass, bronze, Cu-Ni, precipitation-hardened Cu-Be and Cu-Cr-Zr serve electrical, bearing, marine and tooling roles.

Magnesium alloys

Very low density with good castability and damping. HCP structure limits room-temperature formability; galvanic corrosion and flammability controls require attention.

Cobalt, refractory and precious metals

Cobalt alloys resist wear and heat; W, Mo, Ta and Nb retain strength at extreme temperature; noble metals provide chemical stability and electrical performance.

Aluminium designation and temper guide

Series	Main alloying system	General characteristics	Typical concerns
1xxx	Commercially pure Al	Conductivity, corrosion resistance, formability.	Low strength.
2xxx	Al-Cu	High strength and fatigue performance.	Lower corrosion resistance; often clad/protected.
3xxx	Al-Mn	Formability and moderate strength.	Not heat treatable.
4xxx	Al-Si	Low melting range; welding filler and castings.	Property depends strongly on silicon morphology.
5xxx	Al-Mg	Marine corrosion resistance and weldability.	Sensitisation in high-Mg grades at sustained temperature.
6xxx	Al-Mg-Si	Extrudability, corrosion resistance and moderate strength.	Quench and ageing response; weld HAZ softening.
7xxx	Al-Zn-Mg(-Cu)	Very high strength.	SCC, exfoliation and quench sensitivity; temper selection critical.

Temper examples: O = annealed; H = strain hardened; T4 = solution treated and naturally aged; T6 = solution treated and artificially aged; T7 = overaged/stabilised for improved dimensional or corrosion performance.

Titanium and nickel alloy comparison

Family	Microstructural basis	Strengths	Manufacturing controls
Commercially pure titanium	Alpha HCP	Corrosion resistance and formability.	Surface contamination, oxygen pickup and galling.
Ti-6Al-4V type	Alpha + beta	Broad strength, fatigue and temperature capability.	Forging temperature, alpha case, heat treatment and texture.
Beta titanium	Metastable beta, age hardenable	High strength and formability in solution-treated state.	Transformation kinetics and ageing uniformity.
Solid-solution nickel alloy	FCC gamma strengthened by Cr, Mo, W etc.	Corrosion and high-temperature stability.	Work hardening, hot cracking and segregation.
Precipitation-strengthened superalloy	Gamma + coherent γ′/γ″	Creep, fatigue and rupture strength.	Solution/age cycles, forging grain structure and weldability.

Heat Treatment as Controlled Microstructure Engineering

Time · temperature · atmosphere · cooling rate

Define starting condition

Composition, prior deformation, grain size, segregation, residual stress and existing phases determine response.

Heat at a controlled rate

Avoid excessive thermal gradients, distortion and cracking. Verify furnace uniformity and sensor placement.

Soak sufficiently

Allow temperature equalisation and required dissolution/transformation without excessive grain growth, oxidation or decarburisation.

Cool using the validated route

Furnace, air, gas, polymer, oil, salt or water cooling controls phase transformation and residual stress.

Verify output

Hardness alone may be insufficient. Check microstructure, case depth, decarburisation, conductivity, distortion or mechanical properties as required.

Heat-treatment processes

Process	Purpose	Typical metallurgical result	Main risks
Annealing	Soften, recover ductility, relieve stress or homogenise.	Recovery, recrystallisation, grain growth, spheroidisation or phase equilibration.	Excess grain growth, oxidation, distortion.
Normalising	Refine steel structure and produce consistent condition.	Air-cooled fine ferrite/pearlite.	Section-dependent structure and distortion.
Quench and temper	High strength with controlled toughness.	Martensite followed by tempered martensite.	Quench cracks, distortion, retained austenite and temper embrittlement.
Stress relief	Reduce residual stress without major property change.	Recovery and stress redistribution.	Over-tempering, dimensional movement or sensitisation.
Solution treatment	Dissolve soluble phases before quench/age.	Supersaturated solid solution after rapid cooling.	Incipient melting, grain growth and quench distortion.
Age hardening	Form controlled fine precipitates.	GP zones / coherent or semi-coherent strengthening precipitates.	Underage, overage, non-uniform temperature and prior natural ageing.
Carburising / carbonitriding	Hard wear-resistant case with tough core.	High-carbon martensitic case after quench.	Case depth variation, retained austenite, intergranular oxidation and distortion.
Nitriding	Hard diffusion layer with low distortion.	Nitrides and diffusion zone, often without quench.	White-layer brittleness, poor prior core condition and dimensional growth.
Induction/flame hardening	Local transformation hardening.	Martensitic surface over tough core.	Pattern non-uniformity, cracks and insufficient case depth.

TTT and CCT thinking

Time–temperature–transformation diagrams show isothermal transformation. Continuous-cooling-transformation diagrams better represent real cooling. Alloying shifts transformation curves, allowing martensite to form at slower cooling rates and increasing hardenability.

Hardness ≠ hardenability. Hardness is resistance to indentation; hardenability is the ability to develop hardness through a section during quenching.

Furnace and atmosphere control

Temperature uniformity surveys and calibrated instrumentation.
Load thermocouples where specified.
Atmosphere carbon potential, dew point and oxygen potential.
Prevention of oxidation, decarburisation, alpha case and contamination.
Quench-medium temperature, agitation, concentration and contamination.
Traceable recipe, delay limits and load configuration.

How metals are strengthened

Grain refinement

More grain boundaries impede slip and often improve toughness. Controlled rolling, normalising, inoculation and recrystallisation are common routes.

Solid-solution strengthening

Substitutional or interstitial atoms strain the lattice and interact with dislocations. Carbon in ferrite is especially powerful.

Work hardening

Plastic deformation multiplies and entangles dislocations, increasing strength and reducing ductility.

Precipitation hardening

Fine particles obstruct dislocations by cutting or bypass mechanisms. Size, spacing and coherency determine strength.

Transformation hardening

Martensitic transformation creates a hard supersaturated structure with high dislocation density and lattice strain.

Dispersion strengthening

Stable oxide or carbide particles resist coarsening and retain strength at high temperature.

Strength versus toughness

Increasing strength may reduce ductility, fracture toughness, fatigue crack-growth resistance or stress-corrosion tolerance. Material and heat-treatment selection must optimise the complete property set rather than maximise hardness alone.

Residual stress

Source	Typical residual stress	Potential impact	Controls
Quenching	Tensile/compressive gradients from thermal and transformation mismatch.	Distortion, cracking, fatigue sensitivity.	Quench design, agitation, fixturing, temper/stress relief.
Welding	High tensile stress around weld and HAZ.	Fatigue, SCC, distortion and brittle fracture.	Sequence, heat input, restraint control, PWHT, peening where approved.
Machining/grinding	Mechanical or thermal surface stress.	Grinding burns, reduced fatigue, stress-corrosion initiation.	Coolant, wheel condition, feeds/speeds, nital etch or Barkhausen inspection.
Shot peening	Beneficial compressive surface stress.	Improved fatigue and SCC resistance.	Coverage, intensity, media, masking and saturation curve.
Cold forming	Directional work-hardening and residual stress.	Springback, distortion, cracking and anisotropy.	Forming route, intermediate anneal, stress relief.

Manufacturing process → metallurgical effect

Process	Beneficial effects	Typical risks / defects	Verification
Casting	Near-net shape and alloy flexibility.	Shrinkage, gas porosity, inclusions, hot tears, segregation, coarse grains.	Radiography/UT, chemistry, metallography, heat-treatment records.
Forging	Grain refinement, pore closure and directional grain flow.	Laps, bursts, underfill, overheating, undesirable grain flow.	Macroetch, UT, mechanical tests and process qualification.
Rolling/extrusion	Shape control, work hardening and refined structure.	Texture, laminations, edge cracks, centreline segregation and anisotropy.	Directional testing, UT and dimensional/process controls.
Welding	Efficient structural joining.	Solidification cracking, hydrogen cracking, HAZ softening/hardening, porosity and sensitisation.	Procedure qualification, NDT, hardness/macro, ferrite or mechanical tests.
Machining	Precision and surface generation.	Residual stress, smearing, tearing, white layer and grinding burn.	Surface integrity inspection, roughness, etch and dimensional checks.
Additive manufacturing	Complex geometry and local material efficiency.	Porosity, lack of fusion, anisotropy, residual stress, texture and powder contamination.	Build monitoring, CT/UT, density, witness coupons, HIP and heat-treatment verification.
Powder metallurgy	Controlled composition and low waste.	Residual porosity, contamination, incomplete sintering and density gradients.	Density, chemistry, metallography and mechanical tests.
Surface engineering	Tailored corrosion, wear, friction and fatigue behaviour.	Adhesion failure, hydrogen embrittlement, thermal mismatch and coating defects.	Thickness, adhesion, hardness, porosity and process validation.

Welding metallurgy essentials

Fusion-zone solidification structure and segregation.
Heat-affected-zone grain growth and phase transformations.
Carbon equivalent and hardenability of steel HAZ.
Hydrogen level, restraint and cooling rate.
Hot cracking from low-melting films or segregation.
Sensitisation and sigma/intermetallic formation in stainless/duplex materials.
Preheat, interpass, heat input and PWHT control.

Additive manufacturing essentials

Rapid solidification creates fine, non-equilibrium structures.
Layer-wise thermal cycling produces texture and anisotropy.
Residual stress can be severe without stress relief.
Lack-of-fusion defects are often more damaging than spherical gas pores.
Powder reuse, oxygen/nitrogen pickup and contamination must be controlled.
HIP may close internal pores but cannot automatically repair oxide-lined lack-of-fusion defects.

Mechanical and physical properties

Property	Meaning	Typical test / evidence	Design significance
Elastic modulus	Stiffness in elastic range.	Tensile/extensometer, dynamic methods.	Deflection and vibration; little changed by ordinary heat treatment.
Yield strength	Stress where defined permanent strain begins.	Tensile test, often 0.2% proof.	Static load and permanent deformation.
UTS	Maximum engineering stress in tensile test.	Tensile test.	Useful descriptor but not generally the design limit.
Ductility	Plastic deformation before fracture.	Elongation and reduction of area.	Formability, overload tolerance and defect sensitivity.
Toughness	Energy absorption before fracture.	Charpy, fracture toughness, tensile area.	Damage tolerance and brittle-fracture resistance.
Hardness	Resistance to indentation.	Rockwell, Vickers, Brinell, Knoop.	Quick proxy for strength/condition; not a complete property assessment.
Fatigue strength	Resistance to cyclic crack initiation and growth.	S–N, strain-life, crack-growth testing.	Most rotating, vibrating and repeatedly loaded parts.
Creep strength	Resistance to time-dependent deformation at temperature.	Creep and stress-rupture tests.	Turbines, boilers, engines and hot structures.
Fracture toughness	Resistance to crack extension.	KIC, JIC, CTOD.	Damage-tolerant design and critical flaw assessment.
Thermal expansion	Dimensional change with temperature.	Dilatometry.	Thermal stress, fits, coatings and dissimilar joints.

Hardness methods

Rockwell

Depth-based, rapid production test. Scale selection depends on material and thickness. Surface condition, curvature and support affect results.

Brinell

Large ball impression averages heterogeneous structures, making it useful for castings and forgings.

Vickers / micro-Vickers

Diamond pyramid and optical measurement. Broad force range supports weld traverses, case-depth profiles and thin sections.

Knoop

Elongated micro-indenter suited to very thin coatings, brittle phases and closely spaced measurements.

Fatigue fundamentals

Initiation often starts at a notch, inclusion, pore, corrosion pit or damaged surface.
Crack propagation leaves striations or beach marks under suitable conditions.
Mean stress, stress ratio, spectrum loading and residual stress alter life.
Surface finish and compressive stress can dominate performance.
Variable-amplitude service loads cannot always be represented by a single S–N point.

Fatigue can occur below yield strength. A dimensionally conforming component can still fail after many cycles if local stress or surface integrity is poor.

Failure Mechanisms

Identify mechanism before assigning root cause

Corrosion mechanisms

Mechanism	Characteristics	Common controls
Uniform corrosion	Relatively even section loss.	Material selection, coatings, inhibitors and corrosion allowance.
Galvanic corrosion	Dissimilar metals electrically connected in an electrolyte.	Compatible couples, isolation, area-ratio control and sealing.
Pitting	Local passive-film breakdown producing deep cavities.	More resistant alloy, chloride control, surface quality and cathodic protection where suitable.
Crevice corrosion	Occluded chemistry under joints, deposits or seals.	Eliminate crevices, seal/weld correctly, drainage and alloy selection.
Intergranular corrosion	Preferential boundary attack from segregation or precipitate depletion.	Stabilised/low-carbon grades, controlled heat treatment and weld practice.
Stress-corrosion cracking	Specific environment + tensile stress + susceptible microstructure.	Material/environment change, compressive stress, stress relief and coating.
Hydrogen embrittlement	Hydrogen reduces ductility/toughness in susceptible high-strength material.	Minimise charging, controlled cleaning/plating, prompt bake, alternative process and material limits.
High-temperature oxidation/hot corrosion	Scale growth or accelerated attack from deposits/molten salts.	Cr/Al-rich alloys, coatings, temperature/environment management.
MIC	Microorganisms alter local chemistry and accelerate attack.	Design, cleanliness, biocide strategy, water chemistry and monitoring.

Structured failure investigation

Preserve evidence

Do not clean, force open or alter fracture surfaces before documentation.

Collect service history

Loads, cycles, temperature, environment, maintenance, anomalies, batch and manufacturing route.

Visual and NDT examination

Map crack origin, secondary damage, corrosion, wear and defect distribution.

Fractography and sectioning

Examine origin, crack path, microstructure, inclusions, case condition and heat-affected regions.

Verify material and properties

Chemistry, hardness, mechanical properties and heat-treatment condition.

Separate mechanism, cause and contributing factors

For example: fatigue is the mechanism; a machining groove plus overload spectrum may be causal contributors.

Metallographic preparation

Choose representative location and orientation

Section without thermal or mechanical damage

Mount and preserve edges where required

Grind through controlled abrasive sequence

Polish to reveal true microstructure

Etch using material-specific reagent and time

Image, measure and report with scale and orientation

Characterisation methods

Optical microscopy

Grain size, phases, decarburisation, case depth, inclusions, porosity and weld macro/microstructure.

SEM and EDS

High-depth-of-field fractography, fine features and local elemental analysis. EDS is semi-quantitative and has interaction-volume limits.

XRD

Phase identification, lattice parameter, texture and residual stress.

EBSD

Grain orientation, boundary character, phase mapping and local deformation.

OES / combustion / ICP

Bulk chemical composition, including carbon/sulphur or trace elements depending on method.

DSC and dilatometry

Transformation temperatures, precipitation reactions and dimensional change during thermal cycles.

What a good metallurgical report contains

Section	Expected content
Objective and scope	Question being answered, parts/lots, standards and limitations.
Traceability	Material identity, orientation, sampling location, condition and chain of custody.
Methods	Equipment, calibration, preparation, etchants, magnification and test parameters.
Results	Images with scales, tables, measured values, uncertainty where relevant and observed distributions.
Interpretation	Relationship between evidence, expected structure and plausible mechanisms.
Conclusion	Clear findings separated from assumptions; answer to the original question.
Recommendations	Containment, additional testing, process correction and prevention actions.

Searchable Alloy & Material Family Database

Education and preliminary selection

Comparison Table

Material family	Structure / strengthening	Key properties	Applications	Risks / controls

Use limitation: this app supports education and early technical discussion. Final material selection must use current controlled specifications, design allowables, environmental data, processing capability and competent engineering approval.

Carbon Equivalent Calculator

CE_IIW = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15

C %

Mn %

Cr %

Mo %

V %

Ni %

Cu %

Thermal Expansion Calculator

ΔL = α × L₀ × ΔT

Initial length (mm)

CTE (µm/m·°C)

Initial temperature (°C)

Final temperature (°C)

Rule-of-Mixtures Density

Estimate alloy/composite density from mass fractions:

ρ ≈ 1 / Σ(wᵢ / ρᵢ)

Component A mass %

A density g/cm³

Component B mass %

B density g/cm³

Engineering Stress & Strain

σ = F/A₀ ε = ΔL/L₀

Force (kN)

Original area (mm²)

Original gauge length (mm)

Extension (mm)

Metallurgy Learning Test

Ready

Questions

Order

Standards, specifications and controlled data

Area	Examples of commonly used document families	Use guidance
Quality and aerospace	ISO 9001, AS9100, customer quality requirements, Nadcap programme criteria.	Control special processes, competence, traceability, validation and objective evidence.
Material specifications	ASTM, AMS, EN, ISO, BS, defence and customer material specifications.	Use current revision and exact product form/condition; chemistry alone is insufficient.
Mechanical testing	ASTM E8/E8M, ISO 6892, ASTM E18, ASTM E384, ISO 6507 and related methods.	Specimen geometry, orientation, temperature, machine verification and reporting matter.
Metallography	ASTM E3, E407, E112, E45, E1245 and relevant ISO methods.	Preparation, etching, sampling and measurement method must suit the alloy and question.
Heat treatment	AMS 2750, CQI-9 and process/material-specific specifications.	Furnace class, instrumentation type, surveys, load control and atmosphere must match requirements.
Welding	ISO 15614, ISO 9606, ASME IX, AWS codes and customer specifications.	Procedure and personnel qualification must match material, thickness, process and application.
Corrosion and environment	ASTM G-series, ISO 9227 and application-specific test methods.	Accelerated tests are comparative and do not directly equal service life.
Failure and fracture	ASTM E399, E1820, E647 and sector-specific damage-tolerance requirements.	Constraint, thickness, crack geometry and environment determine validity.

Verification requirement: standards and specifications change. Always confirm the current revision, contractual flow-down, product form, material condition, test method and acceptance criteria before use.