ASTM E821-16(2023)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E821 − 16 (Reapproved 2023)
Standard Practice for
Measurement of Mechanical Properties During Charged-
Particle Irradiation
This standard is issued under the fixed designation E821; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
PART I—EXPERIMENTAL PROCEDURE mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1. Scope
2. Referenced Documents
1.1 This practice covers the performance of mechanical
2.1 ASTM Standards:
testsonmaterialsbeingirradiatedwithchargedparticles.These
E170Terminology Relating to Radiation Measurements and
tests are designed to provide an understanding of the effects of
Dosimetry
neutron irradiation on the mechanical behavior of materials.
E521Practice for Investigating the Effects of Neutron Ra-
Practices are described that govern the test material, the
diation Damage Using Charged-Particle Irradiation
particle beam, the experimental technique, and the damage
calculations. Reference should be made to other ASTM
3. Terminology
standards, especially Practice E521. Procedures are described
that are applicable to creep and creep rupture tests made in 3.1 Definitions:
tension and torsion test modes. 3.1.1 Descriptions of relevant terms are found in Terminol-
ogy E170.
1.2 The word simulation is used here in a broad sense to
imply an approximation of the relevant neutron irradiation
4. Specimen Characterization
environment.Thedegreeofconformitycanrangefrompoorto
4.1 Source Material Characterization:
nearly exact. The intent is to produce a correspondence
4.1.1 The source of the material shall be identified. The
between one or more aspects of the neutron and charged-
chemicalcompositionofthesourcematerial,assuppliedbythe
particle irradiations such that fundamental relationships are
vendor or of independent determination, or both, shall be
established between irradiation or material parameters and the
stated. The analysis shall state the quantity of trace impurities.
material response.
Thematerial,heat,lot,orbatch,etc.,numbershallbestatedfor
1.3 The values stated in SI units are to be regarded as
commercial material. The analytical technique and composi-
standard. No other units of measurement are included in this
tional uncertainties should be stated.
standard.
4.1.2 The material form and history supplied by the vendor
1.4 This standard does not purport to address all of the
shall be stated. The history shall include the deformation
safety concerns, if any, associated with its use. It is the
process (rolling, swaging, etc.), rate, temperature, and total
responsibility of the user of this standard to establish appro-
extentofdeformation(givenasstraincomponentsorgeometri-
priate safety, health, and environmental practices and deter-
cal shape changes). The use of intermediate anneals during
mine the applicability of regulatory limitations prior to use.
processing shall be described, including temperature, time,
1.5 This international standard was developed in accor-
environment, and cooling rate.
dance with internationally recognized principles on standard-
4.2 Specimen Preparation and Evaluation:
ization established in the Decision on Principles for the
4.2.1 The properties of the test specimen shall represent the
Development of International Standards, Guides and Recom-
properties of bulk material. Since thin specimens usually will
be experimentally desirable, a specimen thickness that yields
bulk properties or information relatable to bulk properties
This practice is under the jurisdiction of ASTM Committee E10 on Nuclear
should be selected. This can be approached through either of
Technology and Applications and is the direct responsibility of Subcommittee
E10.02 on Behavior and Use of Nuclear Structural Materials.
Current edition approved Jan. 1, 2023. Published January 2023. Originally
approved in 1981. Last previous edition approved in 2016 as E821–16. DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/E0821-16R23. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
These practices can be expanded to include mechanical tests other than those Standards volume information, refer to the standard’s Document Summary page on
specified as such experiments are proposed to Subcommittee E10.02. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E821 − 16 (2023)
two techniques: (1) where the test specimen properties exactly ex-reactor neutron irradiation the accelerator, neutron flux and
equalbulkmaterialproperties;and(2)wherethetestspecimen spectrum, temperature, environment, and stress shall be stated,
properties are directly relatable to bulk properties in terms of including descriptions of the measurement techniques. The
deformation mechanisms, but a size effect (surface, texture, dpa/s and dpa should be calculated (see Sections7–10). For
etc.) is present. For the latter case, the experimental justifica- heliumimplantationusinganaccelerator,theaccelerator,beam
tion shall be reported. energy and current density, beam uniformity, degrader system,
temperature, environment, stress, helium content, and helium
4.2.2 The specimen shape and nominal dimensions shall be
stated and illustrated by a drawing. Deviations from ASTM measurement technique and any post-implantation annealing
shall be stated. The helium distribution shall be calculated as
standards shall be stated. The dimensional measurement tech-
niquesandtheexperimentaluncertaintyofeachshallbestated. shalltheresultingdpa(orshowntobenegligible);seeSections
7 and 8 and Practice E521 for assistance. If another helium
Themethodofspecimenpreparation,suchasmilling,grinding,
etc.,shallbestated.Thedegreeofstraightness,flatness,surface implantation technique is used, a description shall be given of
thetechnique.Itisrecommendedthatchemicalanalysisfollow
condition,edges,fillets,etc.,shallbedescribed.Themethodof
gripping the specimen during the test shall be stated and, any of the above preconditioning procedures.
4.3.2 The microstructure of irradiation preconditioned ma-
preferably, illustrated by a drawing.
terial shall be characterized with respect to dislocation loop
4.2.3 The heat treatment conditions such as time,
size and density, total dislocation density, voids, and any
temperature, atmosphere, cooling rate, etc., shall be stated.
microstructural changes from the unirradiated condition.
Because of the small specimen dimensions, it is essential to
Specimen density changes or dimensional changes shall be
anneal in a non-contaminating environment. Reanalysis for O,
reported.Itisrecommendedthatchangesinhardnessortensile
N, C, and other elements that are likely to change in concen-
strength, or both, be reported. Furthermore, any change in
tration during heat treatment is recommended.
surface condition, including coloration, shall be reported.
4.2.4 Specialcareshallbeexercisedduringspecimenprepa-
ration to minimize surface contamination and irregularities
4.4 Analysis After Charged-Particle Irradiation:
because of the possible effect the surface can have on the flow
4.4.1 The physical, mechanical, and chemical properties of
properties of small specimens. Visible surface contamination
the specimen should be characterized prior to irradiation and
during heat treatment shall be reported as a discoloration or,
any irradiation-induced changes reported. Practice E521 pro-
preferably, characterized using surface analysis technique. It is
videsinformationonpost-irradiationspecimenpreparationand
recommended that surface roughness be characterized.
examination.
4.2.5 The pre-irradiation microstructure shall be thoroughly
4.4.2 After charged-particle irradiation, the specimen di-
evaluated and reported, including grain size, grain shape,
mensions and density shall be measured. The microstructure
crystallographic texture, dislocation density and morphology,
and surface conditions shall be reexamined, with changes
precipitate size, density, type, and any other microstructural
being reported. Chemical analysis for those elements likely to
features considered significant. When reporting TEM results,
change during the mechanical test (O, C, N, H) shall be
the foil normal and diffracting conditions shall be stated. The
performed on the test specimen or on a dummy specimen held
specimen preparation steps for optical and transmission elec-
under conditions closely approximating those during irradia-
tron microscopy shall be stated.
tion. It is recommended that changes in hardness, tensile
4.2.6 The pre-irradiation mechanical properties shall be
strength, or creep strength, or both, be measured and reported.
measured and reported to determine deviations from bulk
behavior and to determine baseline properties for irradiation
5. Particle Beam Characterization
measurements.Itisrecommendedthatcreepratesbemeasured
5.1 Beam Composition and Energy:
for each specimen before and after irradiation. The thermal
5.1.1 Most accelerator installations include a calibrated
creep rate shall be obtained under conditions as close as
magnetic analysis system which ensures beam purity and
possible to those existing during irradiation. The temperature,
provides measurement and control of the energy and energy
strain rate, atmosphere, etc., shall be stated.
spread,bothofwhichshouldbereported.Apossibleexception
4.2.7 It is recommended that other material properties
will occur if analog beams are accelerated. For example, a
including microhardness, resistivity ratio, and density be mea-
16 4+
cyclotron can produce simultaneous beams of O (Z/A= ⁄4)
sured and reported to improve interlaboratory comparison.
12 3+ 2
and C (Z/A= ⁄4) at different energies (E+ E Z /A) which
o
4.3 Irradiation Preconditioning: cannot easily be separated magnetically or electrostatically.
4.3.1 Frequently the experimental step preceding charged- This situation, normally only significant for heavy ion beams,
particle irradiation will involve neutron irradiation or helium can be avoided by judicious choice of charge state and energy.
implantation. This section contains procedures that character- ForVandeGraaffacceleratorsanalogbeamsoflightions,such
+ ++
ize the environment and the effects of this irradiation precon- as D and He , can be generated, and under certain circum-
stances involving two-stage acceleration and further ionization
ditioning. For reactor irradiations the reactor, location in
+ + ++
reactor, neutron flux (fluence rate), flux history and spectrum, (for example, He → 5 MeV He → 5 MeV He ), beams of
impurityionscanbeproducedthatmaynotbeeasilyseparated
temperature, environment, and stress shall be reported. The
+
methods of determining these quantities shall also be reported. from the primary beam (for example, 5 MeV H ).
The displacement rate (dpa/s) and total displacement (dpa) 5.1.2 For most cases, ion sources are sufficiently pure to
shall be calculated; see Practice E521 for directions. For remove any concern of significant beam impurity, but this
E821 − 16 (2023)
problem should be considered. Beam energy attenuation and this should be reported. When scanning a pulsed beam at a
changes in the divergence of the beam passing through subharmonic of its natural frequency, it should be noted that
windows and any gaseous medium shall be estimated and the beam spot will strike the specimen at discrete locations,
reported. rather than be distributed continuously across the specimen.
The raw beam spot must therefore be considerably larger than
5.2 Spatial Variation in Beam Intensity:
the distance between these locations or a very nonuniform
5.2.1 The quantity of interest is beam intensity/unit area at
intensity distribution will result. It is most desirable to use a
thespecimen.Itisusuallydesirabletoproduceauniformbeam
continuous rather than rastered beam. If a rastered beam is
density over the specimen area so that this quantity can be
used, the degree of defect annealing between pulses shall be
inferred from a measurement of the total beam intensity and
considered.
area.
5.2.2 Total beam intensity should be measured using a
6. Mechanical Testing Apparatus
Faraday cup whenever possible; however, this may not be
6.1 Strain Measurement:
possible on a continuous basis during irradiation. The Faraday
−5
6.1.1 The strains measured during light ion irradiation tests,
cup shall be evacuated to P<10 and shall be electron-
for measurement periods ;1 day and for conditions where the
suppressed; otherwise, spurious results may be generated.
irradiation has a significant effect on the elongation rate, are
Various secondary beam monitors may then be used, such as
−3 −5
very small (typically ;10 to 10 ). Therefore, the strain
ionization chambers, secondary emission monitors, transform-
resolutionnormallyrequiredforcontinuousmeasurementsis1
ers or other induction devices (for pulsed beams), beam
−6
to 10×10 . The strain resolution as well as displacement
scanners, or particles scattered from a foil. All such devices
resolution shall be reported.
shall be calibrated through Faraday cup measurements or
6.1.2 Normally for these experiments the limiting factor in
through activation analysis. These calibrations shall be re-
strain measurement is not the resolution of the actual displace-
ported.
ment measuring device (for example, LVDT, LVDC, strain
5.2.3 Displacement rate gradients occur in charged-particle
gage, laser extensometer, etc.); it is the ability of the apparatus
irradiation specimens in the Z (beam) direction because of
to transmit the displacement with fidelity. To minimize these
changes in ion energy and, therefore, displacement cross
displacement measurement errors, it is recommended that the
sectionwithpenetration(see10.5.1),andinthe Xand Y(lateral
temperature be monitored or controlled, or both, on each
and longitudinal specimen axes, respectively) directions be-
critical part of the apparatus and that thermal sensitivity
cause of spatial variations in beam intensity.
experiments be performed; that is, a local temperature fluctua-
NOTE1—Nonuniformspecimencrosssectionmaygiverisetodisplace-
tion should be imposed on individual elements of the strain-
ment rate variations in the x- and y-directions, even under a spatially
measuring system while the st
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