Materials Characterization and Testing: test plan development; test management; data analysis

Whether you are designing a new product, maintaining an existing product or developing a quality control procedure, accurate materials characterization and testing data is critical. Materials are commonly referred to by their name, e.g., AISI 321 stainless steel, or AA7075 aluminum. However, these names do not control or specify design critical properties. For design, it is vital to evaluate the specific product form, manufacturing method, heat treatment, and operational environmental influence to develop the design database on which your product relies. The table lists our materials testing protocol experience. We have applied these methods and others to characterise a wide range of metals, ceramics, and composites.

We can help you develop a test plan and analysis plan that includes the properties critical to your product. This is a diverse field which includes mechanical, thermal, electrical, corrosion, and wear. We have extensive experience preparing test procedures, managing testing, and analyzing test results. Where possible, national and international standards such as those issued by ASTM form the basis for testing. A list of selected publications is given at the bottom of this page. Working with outside laboratories, we have experience in the areas given in the table below. We can also help you with developing a materials selection strategy, where our broad materials experience shown in the second table below, forms only a beginning basis.

 
Materials science and metallurgical consulting. Stress vs. strain curve for continuous fiber reinforced carbon-carbon composite during the second load cycle. Digital image correlation (DIC) shows strain localization and fatigue damage. This article was published in Carbon, 126, P. Chowdhury, H. Sehitoglu, and R. Rateick, "Damage tolerance of carbon-carbon composites in aerospace application", 1-12, Copyright Elsevier (2018).
Stress vs. strain curve for continuous fiber reinforced carbon-carbon composite during the second load cycle. Digital image correlation (DIC) shows strain localization and fatigue damage. [2]

Sometimes it is prudent to augment or deviate from the standard test methods in order to extract additional information from the test or to adjust the test to better represent the real loading and operating environment of the product. An example of augmenting a standard test is the use of digital image correlation (DIC) to extract strain field data around the crack tip during tensile, fracture toughness or fatigue crack growth testing. The illustration above shows damage accumulation during tensile cycling of a carbon-carbon composite (low cycle fatigue) which would not be evident simply by using extensometers to measure net section strain. DIC is effectively a high resolution spacial strain gage. As another example, consider the ASTM cavitation (ASTM G32) or thrust washer wear tests (ASTM D3702). In their standard forms, these tests are designed to measure steady state wear by cavitation or sliding. However, sometimes a design requires a material which will not show damage even during the transient phases of material removal. 

Relevant blog postings:

Anodizing aluminum and magnesium causes fatigue strength reduction in many alloys. This posting discusses fatigue debit and the underlying mechanism in aluminum-copper alloys AA2219 and AA2024. It includes additional information on AA6061 and magnesium alloy WE43A-T6.

Electron micrograph of anodic coating on aluminum alloy AA2219-T851 (between arrows) and in a pit caused by dissolution of Al2Cu which explains why anodizing aluminum causes fatigue.
AA2219-T851 plate after anodizing showing pits which cause fatigue strength loss. [1]

Materials characterization techniques experience base

MechanicalThermal/ElectricalCorrosion & oxidationWear and frictionChemical
Tensile (ASTM E8, ASTM B557)Thermal conductivity and diffusivitySalt fog (ASTM B117)Bearing life (Weibull)X-Ray diffraction (Phase analysis, residual stress, crystallite size for graphite)
Low cycle fatigue (ASTM E606)Electrical conductivity of solidsTafel extrapolationThrust washer (ASTM D3702), 3-ball, 4-ball, pin on disk, pin on plate)Spectroscopy (ICP-OES, ICP-MS, MS, UV/VIS, NMR)
High cycle fatigue (axial: ASTM E466, wire: E2948, rotary bending: ISO 1143)Thermal expansionElectrochemical impedance spectroscopy (EIS)Friction coefficientSurface analysis (Auger, XPS (ESCA), RBS)
Fracture toughness (KIC: ASTM E399, JIC: ASTM E813)Heat capacity (specific heat)Component level exposure testingLubricant analysis and life predictionThermal: TGA/DSC/DTA/DMA
Fatigue crack growth (ASTM E647)Electrical conductivity of solutionsHigh temperature oxidationTribometer designRheology
Stress corrosionSolid state diffusion coefficientCyclic voltammetry
Cavitation erosion (ASTM G32)Surface tension/wettability (tensiometer: Du Noüy ring, Wilhelmy plate, sessile drop)
Bending (flexure strength), uniaxial (ceramics: ASTM C1161), biaxialDilatometry (thermal expansion, cereamic and powder metal sintering)Temperature programed oxidation (TPO)Particulate erosionPolarimetry
Creep (ASTM E139)Refractometry, refractive index
X-Ray residual stressDilatometry (thermal expansion)
Component testingCarbon/sulfur and oxygen/hydrogen/nitrogen analysis
Spring fatigue, set, shear modulusBHT/BJS (surface area, pore size distribution)
Nano-indentation
Digital image correlation (strain)

Materials selection and characterization experience base

FerrousStainless steelAluminumNickel/CobaltTitaniumCeramics/glassMisc.Coatings
AISI 1010AISI 304LAA2014Inconel 718Ti-6-4Silicon nitrideCarbon-CarbonAnodized aluminum
AISI 1045AISI 304AA2024Inconel 625Ti-24-11Silicon carbideGraphiteAnodized magnesium
AISI 4340AISI 321AA2219Haynes 25Ti-25-10-3-1Zirconia toughened aluminaPitch polymers and carbonCarburizing
AISI 3130AISI 347AA6061Haynes 230Ti-6242AluminaParticle reinforce AA8009Nitriding
AISI 52100AISI 410AA7075WaspaloyBeta-CBoron nitrideRheniumBoriding
Aermet 100AISI 416AA8090Mar-M-247Phosphate glassTungstenCase hardening
InvarAISI 430AA8009Stellite alloysLanthanide glassMolybdenumParylene
Controlled expansion alloysAISI 440CC355Ni-Co electroformedTitanium nitrideFuran polymersSpark anodizing
BG4217-4 PHA357Nickel 200ParyleneChrome plating
Kronodor-3017-7 PHUdimet 700Photo polymersTungsten-cobalt plating
AISI M5015-15 PHHastelloy X750Fluoro-silicone polymersTungsten-nickel plating
AISI H11Greek AscoloyHastelloy XCDA 630Rhenium-nickel plating
CPM-10VNitronic 60Hastelloy CCDA 544Stellite coatings
A286Spinodal bronze ToughMet®

Selected Publications (external links):

Citations for illustrations used with permission

[1] R. G. Rateick, R. J. Griffith, D. A. Hall, and K. A. Thompson, “Relationship of microstructure to fatigue strength loss in anodised aluminium-copper alloys,” Materials Science & Technology, vol. 21, no. 10, pp. 1227–1235, 2005. Copyright © 2005 Institute of Materials, Minerals and Mining, figures reprinted by permission of Taylor & Francis Ltd, http://www.tandfonline.com on behalf of Institute of Materials, Minerals and Mining

[2] This article was published in Carbon, 126, P. Chowdhury, H. Sehitoglu, and R. Rateick, “Damage tolerance of carbon-carbon composites in aerospace application”, 1-12, Copyright Elsevier (2018).

Contact us to see how REXP2 Research can help your organization with materials characterization and testing.