ASTM E821-96(2003)

Standard Practice for Measurement of Mechanical Properties During Charged-Particle Irradiation

ABSTRACT
This practice covers the measurement of the mechanical properties of materials during charged-particle irradiation, with the test materials designed to simulate or provide understanding of, or both, the mechanical behavior of materials when exposed to neutron irradiation. This practice includes requirements for test material and particle beam characterization (such as for strain, load, temperature monitoring and control, and specimen environment monitoring), and recommended procedures for measuring mechanical properties and for calculating radiation damage (such as particle ranges, damage energy, damage rates, and damage gradients). Methods for comparing ion damage with neutron damage are also recommended.
SCOPE
1.1 This practice covers the performance of mechanical tests on materials being irradiated with charged particles. These tests are designed to simulate or provide understanding of, or both, the mechanical behavior of materials during exposure to neutron irradiation. Practices are described that govern the test material, the particle beam, the experimental technique, and the damage calculations. Reference should be made to other ASTM standards, especially Practice E 521. Procedures are described that are applicable to creep and creep rupture tests made in tension and torsion test modes.
1.2 The word simulation is used here in a broad sense to imply an approximation of the relevant neutron irradiation environment. The degree of conformity can range from poor to nearly exact. The intent is to produce a correspondence between one or more aspects of the neutron and charged particle irradiations such that fundamental relationships are established between irradiation or material parameters and the material response.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Jan-1996
• Technical Committee: E10 - Nuclear Technology and Applications

Relations

• Replaces: ASTM E821-96 - Standard Practice for Measurement of Mechanical Properties During Charged-Particle Irradiation
• Effective Date: 10-Jan-1996
• Replaced By: ASTM E821-96(2009) - Standard Practice for Measurement of Mechanical Properties During Charged-Particle Irradiation
• Effective Date: 01-Aug-2009
• Referred By: ASTM E521-23 - Standard Practice for Investigating the Effects of Neutron Radiation Damage Using Charged-Particle Irradiation
• Effective Date: 10-Jan-1996
• Referred By: ASTM E693-23 - Standard Practice for Characterizing Neutron Exposures in Iron and Low Alloy Steels in Terms of Displacements Per Atom (DPA)
• Effective Date: 10-Jan-1996

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E821–96 (Reapproved 2003)
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 3.1.1 Descriptions of relevant terms are found in Terminol-
ogy E170.
1. Scope
4. Specimen Characterization
1.1 This practice covers the performance of mechanical
testsonmaterialsbeingirradiatedwithchargedparticles.These 4.1 Source Material Characterization:
tests are designed to simulate or provide understanding of, or 4.1.1 The source of the material shall be identified. The
both, the mechanical behavior of materials during exposure to chemicalcompositionofthesourcematerial,assuppliedbythe
neutron irradiation. Practices are described that govern the test vendor or of independent determination, or both, shall be
material,theparticlebeam,theexperimentaltechnique,andthe stated. The analysis shall state the quantity of trace impurities.
damage calculations. Reference should be made to other Thematerial,heat,lot,orbatch,etc.,numbershallbestatedfor
ASTM standards, especially Practice E521. Procedures are commercial material. The analytical technique and composi-
described that are applicable to creep and creep rupture tests tional uncertainties should be stated.
made in tension and torsion test modes. 4.1.2 The material form and history supplied by the vendor
1.2 The word simulation is used here in a broad sense to shall be stated. The history shall include the deformation
imply an approximation of the relevant neutron irradiation process (rolling, swaging, etc.), rate, temperature, and total
environment.Thedegreeofconformitycanrangefrompoorto extentofdeformation(givenasstraincomponentsorgeometri-
nearly exact. The intent is to produce a correspondence cal shape changes). The use of intermediate anneals during
between one or more aspects of the neutron and charged processing shall be described, including temperature, time,
particle irradiations such that fundamental relationships are environment, and cooling rate.
established between irradiation or material parameters and the 4.2 Specimen Preparation and Evaluation:
material response. 4.2.1 The properties of the test specimen shall represent the
1.3 This standard does not purport to address all of the properties of bulk material. Since thin specimens usually will
safety concerns, if any, associated with its use. It is the be experimentally desirable, a specimen thickness that yields
responsibility of the user of this standard to establish appro- bulk properties or information relatable to bulk properties
priate safety and health practices and determine the applica- should be selected. This can be approached through either of
bility of regulatory limitations prior to use. two techniques: (1) where the test specimen properties exactly
equal bulk material properties; (2) where the test specimen
2. Referenced Documents
properties are directly relatable to bulk properties in terms of
2.1 ASTM Standards:
deformation mechanisms, but a size effect (surface, texture,
E170 Terminology Relating to Radiation Measurements etc.) is present. For the latter case, the experimental justifica-
and Dosimetry
tion shall be reported.
E521 Practice for Neutron Radiation Damage Simulation 4.2.2 The specimen shape and nominal dimensions shall be
by Charged-Particle Irradiation
stated and illustrated by a drawing. Deviations from ASTM
standards shall be stated. The dimensional measurement tech-
3. Terminology
niquesandtheexperimentaluncertaintyofeachshallbestated.
3.1 Definitions:
Themethodofspecimenpreparation,suchasmilling,grinding,
etc.,shallbestated.Thedegreeofstraightness,flatness,surface
condition,edges,fillets,etc.,shallbedescribed.Themethodof
This practice is under the jurisdiction of ASTM Committee E10 on Nuclear
Technology and Applications and is the direct responsibility of Subcommittee
gripping the specimen during the test shall be stated and,
E10.08 on Procedures for Neutron Radiation Damage Simulation.
preferably, illustrated by a drawing.
Current edition approved July 10, 2003. Published March 1996. Originally
4.2.3 The heat treatment conditions such as time, tempera-
published as E821–81. Last previous edition E821–89.
ture, atmosphere, cooling rate, etc., shall be stated. Because of
These practices can be expanded to include mechanical tests other than those
specified as such experiments are proposed to Subcommittee E10.08.
the small specimen dimensions, it is essential to anneal in a
Annual Book of ASTM Standards, Vol 12.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E821–96 (2003)
non-contaminating environment. Reanalysis for O, N, C, and Specimen density changes or dimensional changes shall be
otherelementsthatarelikelytochangeinconcentrationduring reported.Itisrecommendedthatchangesinhardnessortensile
heat treatment is recommended. strength, or both, be reported. Furthermore, any change in
surface condition, including coloration, shall be reported.
4.2.4 Specialcareshallbeexercisedduringspecimenprepa-
4.4 Analysis After Charged-Particle Irradiation:
ration to minimize surface contamination and irregularities
4.4.1 The physical, mechanical, and chemical properties of
because of the possible effect the surface can have on the flow
the specimen should be characterized prior to irradiation and
properties of small specimens. Visible surface contamination
any irradiation-induced changes reported. Practice E521 pro-
during heat treatment shall be reported as a discoloration or,
videsinformationonpost-irradiationspecimenpreparationand
preferably, characterized using surface analysis technique. It is
examination.
recommended that surface roughness be characterized.
4.4.2 After charged-particle irradiation, the specimen di-
4.2.5 The preirradiation microstructure shall be thoroughly
mensions and density shall be measured. The microstructure
evaluated and reported, including grain size, grain shape,
and surface conditions shall be reexamined, with changes
crystallographic texture, dislocation density and morphology,
being reported. Chemical analysis for those elements likely to
precipitate size, density, type, and any other microstructural
change during the mechanical test (O, C, N, H) shall be
features considered significant. When reporting TEM results,
performed on the test specimen or on a dummy specimen held
the foil normal and diffracting conditions shall be stated. The
under conditions closely approximating those during irradia-
specimen preparation steps for optical and transmission elec-
tion. It is recommended that changes in hardness, tensile
tron microscopy shall be stated.
strength, or creep strength, or both, be measured and reported.
4.2.6 Thepreirradiationmechanicalpropertiesshallbemea-
sured and reported to determine deviations from bulk behavior
5. Particle Beam Characterization
and to determine baseline properties for irradiation measure-
5.1 Beam Composition and Energy:
ments.Itisrecommendedthatcreepratesbemeasuredforeach
5.1.1 Most accelerator installations include a calibrated
specimen before and after irradiation (see section 3.4 for more
magnetic analysis system which ensures beam purity and
detail). The thermal creep rate shall be obtained under condi-
provides measurement and control of the energy and energy
tions as close as possible to those existing during irradiation.
spread, both of which should be reported.Apossible exception
The temperature, strain rate, atmosphere, etc., shall be stated.
will occur if analogue beams are accelerated. For example, a
4.2.7 It is recommended that other material properties 16 4+
cyclotron can produce simultaneous beams of O (Z/A= ⁄4)
including microhardness, resistivity ratio, and density be mea- 12 3+ 2
and C (Z/A= ⁄4) at different energies (E+ E Z /A) which
o
sured and reported to improve interlaboratory comparison.
cannot easily be separated magnetically or electrostatically.
4.3 Irradiation Preconditioning:
This situation, normally only significant for heavy ion beams,
4.3.1 Frequently the experimental step preceding charged-
can be avoided by judicious choice of charge state and energy.
particle irradiation will involve neutron irradiation or helium
For Van de Graaff accelerators analogue beams of light ions,
+ ++
implantation. This section contains procedures that character-
such as D and He , can be generated, and under certain
ize the environment and the effects of this irradiation precon-
circumstances involving two stage acceleration and further
+ + ++
ditioning. For reactor irradiations the reactor, location in
ionization (for example, He→ 5 MeV He→ 5 MeV He ),
reactor, neutron flux, flux history and spectrum, temperature,
beams of impurity ions can be produced that may not be easily
+
environment, and stress shall be reported. The methods of
separated from the primary beam (for example, 5 MeV H ).
determining these quantities shall also be reported. The dis-
5.1.2 For most cases, ion sources are sufficiently pure to
placement rate (dpa/s) and total displacement (dpa) shall be
remove any concern of significant beam impurity, but this
calculated; see Practice E521 for directions. For ex-reactor
problem should be considered. Beam energy attenuation and
neutron irradiation the accelerator, neutron flux and spectrum,
changes in the divergence of the beam passing through
temperature, environment, and stress shall be stated, including
windows and any gaseous medium shall be estimated and
descriptionsofthemeasurementtechniques.Thedpa/sanddpa
reported.
should be calculated (see Sections 7-10). For helium implan-
5.2 Spatial Variation in Beam Intensity:
tation using an accelerator, the accelerator, beam energy and
5.2.1 The quantity of interest is beam intensity/unit area at
current density, beam uniformity, degrader system, tempera-
thespecimen.Itisusuallydesirabletoproduceauniformbeam
ture,environment,stress,heliumcontent,andheliummeasure-
density over the specimen area so that this quantity can be
ment technique and any post-implantation annealing shall be
inferred from a measurement of the total beam intensity and
stated. The helium distribution shall be calculated as shall the
area.
resulting dpa (or shown to be negligible); see Sections 7 and 8
5.2.2 Total beam intensity should be measured using a
and Practice E521 for assistance. If another helium implanta-
Faraday cup whenever possible; however, this may not be
tion technique is used, a description shall be given of the
possible on a continuous basis during irradiation. The Faraday
−5
technique. It is recommended that chemical analysis follow
cup shall be evacuated to P<10 and shall be electron-
any of the above preconditioning procedures.
suppressed; otherwise, spurious results may be generated.
4.3.2 The microstructure of irradiation preconditioned ma- Various secondary beam monitors may then be used, such as
terial shall be characterized with respect to dislocation loop ionization chambers, secondary emission monitors, transform-
size and density, total dislocation density, voids, and any ers or other induction devices (for pulsed beams), beam
microstructural changes from the unirradiated condition. scanners, or particles scattered from a foil. All such devices
E821–96 (2003)
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-
tion should be imposed on individual elements of the strain
NOTE 1—Non-uniform specimen cross section may give rise to dis-
measuring system while the strain signal is monitored. It is
placement rate variations in the x- and y-directions, even under a
recommendedthatthestrainsensitivitytoambienttemperature
spatially-uniform beam.
fluctuations be recorded. It is recommended that the strain
5.2.3.1 Displacement rate ratios of 1.2 to 2.5 (ratio of
sensitivity to vibrations and coolant flow rates be monitored
displacement rate at exit surface to rate at entrance surface of
and reported. The strainmeasuring resolution, linearity, and
specimen in the Z direction) are common, but it is recom-
reproducibilityshouldbeexaminedatseveraltesttemperatures
mended that this ratio be minimized. In the case of foil
on a regular basis using calibrated standards developed for
specimens it is also recommended that the variations in beam
such a purpose.
intensity in the X direction be minimized, since a gradient in
6.1.3 The sensitivity of the strain measurement shall be
this direction will affect both the temperature and the creep
considered with respect to large magnetic or electrostatic
compliance so as to maximize the stress gradient from speci-
fields, both of which may be present in these experiments.The
men center to edge.
effect of stray ion currents caused by secondary radiation
5.2.4 The beam may be rastered over the specimen to
should also be considered. The effect of lead length and
improve uniformity. The frequency of rastering shall be re-
shielding between the strain transducer(s) and the indicating
ported. The beam profile shall be measured regularly during
device should be considered. Grounding may give rise to
the irradiation experiments, if possible. If this is not possible,
problems, especially with long lead lengths and associated
some secondary measurement, such as temperature gradient,
ground potential differences.
should be made.Analysis of the variation in specimen activity
6.1.4 The means of defining the deforming gage length
...