1、Designation: E 821 96 (Reapproved 2009)Standard Practice forMeasurement of Mechanical Properties During Charged-Particle Irradiation1This standard is issued under the fixed designation E 821; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.PART IEXPERIMENTAL PROCEDURE1. Scope1.1 This practice covers the performance of mechanicaltests on materials
3、being irradiated with charged particles.Thesetests are designed to simulate or provide understanding of, orboth, the mechanical behavior of materials during exposure toneutron irradiation. Practices are described that govern the testmaterial, the particle beam, the experimental technique, and thedam
4、age calculations. Reference should be made to otherASTM standards, especially Practice E 521. Procedures aredescribed that are applicable to creep and creep rupture testsmade in tension and torsion test modes.21.2 The word simulation is used here in a broad sense toimply an approximation of the rele
5、vant neutron irradiationenvironment. The degree of conformity can range from poor tonearly exact. The intent is to produce a correspondencebetween one or more aspects of the neutron and chargedparticle irradiations such that fundamental relationships areestablished between irradiation or material pa
6、rameters and thematerial response.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user
7、of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3E 170 Terminology Relating to Radiation Measurementsand DosimetryE 521 Practice for Neutron Radiation Damage Simul
8、ationby Charged-Particle Irradiation3. Terminology3.1 Definitions:3.1.1 Descriptions of relevant terms are found in Terminol-ogy E 170.4. Specimen Characterization4.1 Source Material Characterization:4.1.1 The source of the material shall be identified. Thechemical composition of the source material
9、, as supplied by thevendor or of independent determination, or both, shall bestated. The analysis shall state the quantity of trace impurities.The material, heat, lot, or batch, etc., number shall be stated forcommercial material. The analytical technique and composi-tional uncertainties should be s
10、tated.4.1.2 The material form and history supplied by the vendorshall be stated. The history shall include the deformationprocess (rolling, swaging, etc.), rate, temperature, and totalextent of deformation (given as strain components or geometri-cal shape changes). The use of intermediate anneals du
11、ringprocessing shall be described, including temperature, time,environment, and cooling rate.4.2 Specimen Preparation and Evaluation:4.2.1 The properties of the test specimen shall represent theproperties of bulk material. Since thin specimens usually willbe experimentally desirable, a specimen thic
12、kness that yieldsbulk properties or information relatable to bulk propertiesshould be selected. This can be approached through either oftwo techniques: (1) where the test specimen properties exactlyequal bulk material properties; (2) where the test specimenproperties are directly relatable to bulk p
13、roperties in terms ofdeformation mechanisms, but a size effect (surface, texture,etc.) is present. For the latter case, the experimental justifica-tion shall be reported.4.2.2 The specimen shape and nominal dimensions shall bestated and illustrated by a drawing. Deviations from ASTMstandards shall b
14、e stated. The dimensional measurement tech-niques and the experimental uncertainty of each shall be stated.1This practice is under the jurisdiction of ASTM Committee E10 on NuclearTechnology and Applications and is the direct responsibility of SubcommitteeE10.08 on Procedures for Neutron Radiation D
15、amage Simulation.Current edition approved Aug. 1, 2009. Published September 2009. Originallyapproved in 1981. Last previous edition approved in 2003 as E 821 96 (2003).2These practices can be expanded to include mechanical tests other than thosespecified as such experiments are proposed to Subcommit
16、tee E10.08.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Dri
17、ve, PO Box C700, West Conshohocken, PA 19428-2959, United States.The method of specimen preparation, such as milling, grinding,etc., shall be stated.The degree of straightness, flatness, surfacecondition, edges, fillets, etc., shall be described. The method ofgripping the specimen during the test sh
18、all be stated and,preferably, illustrated by a drawing.4.2.3 The heat treatment conditions such as time, tempera-ture, atmosphere, cooling rate, etc., shall be stated. Because ofthe small specimen dimensions, it is essential to anneal in anon-contaminating environment. Reanalysis for O, N, C, andoth
19、er elements that are likely to change in concentration duringheat treatment is recommended.4.2.4 Special care shall be exercised during specimen prepa-ration to minimize surface contamination and irregularitiesbecause of the possible effect the surface can have on the flowproperties of small specime
20、ns. Visible surface contaminationduring heat treatment shall be reported as a discoloration or,preferably, characterized using surface analysis technique. It isrecommended that surface roughness be characterized.4.2.5 The preirradiation microstructure shall be thoroughlyevaluated and reported, inclu
21、ding grain size, grain shape,crystallographic texture, dislocation density and morphology,precipitate size, density, type, and any other microstructuralfeatures considered significant. When reporting TEM results,the foil normal and diffracting conditions shall be stated. Thespecimen preparation step
22、s for optical and transmission elec-tron microscopy shall be stated.4.2.6 The preirradiation mechanical properties shall be mea-sured and reported to determine deviations from bulk behaviorand to determine baseline properties for irradiation measure-ments. It is recommended that creep rates be measu
23、red for eachspecimen before and after irradiation (see section 3.4 for moredetail). The thermal creep rate shall be obtained under condi-tions as close as possible to those existing during irradiation.The temperature, strain rate, atmosphere, etc., shall be stated.4.2.7 It is recommended that other
24、material propertiesincluding microhardness, resistivity ratio, and density be mea-sured and reported to improve interlaboratory comparison.4.3 Irradiation Preconditioning:4.3.1 Frequently the experimental step preceding charged-particle irradiation will involve neutron irradiation or heliumimplantat
25、ion. This section contains procedures that character-ize the environment and the effects of this irradiation precon-ditioning. For reactor irradiations the reactor, location inreactor, neutron flux, flux history and spectrum, temperature,environment, and stress shall be reported. The methods ofdeter
26、mining these quantities shall also be reported. The dis-placement rate (dpa/s) and total displacement (dpa) shall becalculated; see Practice E 521 for directions. For ex-reactorneutron irradiation the accelerator, neutron flux and spectrum,temperature, environment, and stress shall be stated, includ
27、ingdescriptions of the measurement techniques. The dpa/s and dpashould be calculated (see Sections 7-10). For helium implan-tation using an accelerator, the accelerator, beam energy andcurrent density, beam uniformity, degrader system, tempera-ture, environment, stress, helium content, and helium me
28、asure-ment technique and any post-implantation annealing shall bestated. The helium distribution shall be calculated as shall theresulting dpa (or shown to be negligible); see Sections 7 and 8and Practice E 521 for assistance. If another helium implanta-tion technique is used, a description shall be
29、 given of thetechnique. It is recommended that chemical analysis followany of the above preconditioning procedures.4.3.2 The microstructure of irradiation preconditioned ma-terial shall be characterized with respect to dislocation loopsize and density, total dislocation density, voids, and anymicros
30、tructural changes from the unirradiated condition.Specimen density changes or dimensional changes shall bereported. It is recommended that changes in hardness or tensilestrength, or both, be reported. Furthermore, any change insurface condition, including coloration, shall be reported.4.4 Analysis A
31、fter Charged-Particle Irradiation:4.4.1 The physical, mechanical, and chemical properties ofthe specimen should be characterized prior to irradiation andany irradiation-induced changes reported. Practice E 521 pro-vides information on post-irradiation specimen preparation andexamination.4.4.2 After
32、charged-particle irradiation, the specimen di-mensions and density shall be measured. The microstructureand surface conditions shall be reexamined, with changesbeing reported. Chemical analysis for those elements likely tochange during the mechanical test (O, C, N, H) shall beperformed on the test s
33、pecimen or on a dummy specimen heldunder conditions closely approximating those during irradia-tion. It is recommended that changes in hardness, tensilestrength, or creep strength, or both, be measured and reported.5. Particle Beam Characterization5.1 Beam Composition and Energy:5.1.1 Most accelerat
34、or installations include a calibratedmagnetic analysis system which ensures beam purity andprovides measurement and control of the energy and energyspread, both of which should be reported.Apossible exceptionwill occur if analogue beams are accelerated. For example, acyclotron can produce simultaneo
35、us beams of16O4+(Z/A =14)and12C3+(Z/A =14) at different energies (E + EoZ2/A) whichcannot easily be separated magnetically or electrostatically.This situation, normally only significant for heavy ion beams,can be avoided by judicious choice of charge state and energy.For Van de Graaff accelerators a
36、nalogue beams of light ions,such as D+and He+, can be generated, and under certaincircumstances involving two stage acceleration and furtherionization (for example, He+ 5 MeV He+ 5 MeV He+),beams of impurity ions can be produced that may not be easilyseparated from the primary beam (for example, 5 M
37、eV H+).5.1.2 For most cases, ion sources are sufficiently pure toremove any concern of significant beam impurity, but thisproblem should be considered. Beam energy attenuation andchanges in the divergence of the beam passing throughwindows and any gaseous medium shall be estimated andreported.5.2 Sp
38、atial Variation in Beam Intensity:5.2.1 The quantity of interest is beam intensity/unit area atthe specimen. It is usually desirable to produce a uniform beamdensity over the specimen area so that this quantity can beinferred from a measurement of the total beam intensity andarea.E 821 96 (2009)25.2
39、.2 Total beam intensity should be measured using aFaraday cup whenever possible; however, this may not bepossible on a continuous basis during irradiation. The Faradaycup shall be evacuated to P RpE/4! (2)RdE! 2RpE/2!. (3)Since these expressions are derived from an electronicstopping power equation
40、(11) (that is, Bethe Bloch formulism),they are valid to the extent the electronic stopping powerapproximates the total stopping power.Agreement with tabularvalues is within 5 % for deuteron energies greater than 2 MeVand alpha particle energies above 8 MeV and improves withenergy. Generally, these e
41、rrors will be tolerable in view of thefact that end of range is usually avoided in mechanical propertytesting. It is near end of range that the stopping power isvarying most rapidly and the energy and range straggling isgreatest. Furthermore, it is near end of range that the influenceof foreign atom
42、s introduced by ions coming to rest will begreatest.10. Damage Calculations10.1 In calculations involving light ion radiation damage, itis recommended that models consistent with those recom-mended for use in calculating neutron damage be used wher-ever practical. Therefore, consistency in the choic
43、e of energypartition theory and secondary displacement models will berecommended and discussed in this section. More detail incertain areas can be obtained by consulting Practice E 521.10.1.1 It is likely that mechanical property testing may beconducted at some future date using energetic electrons,
44、 lightions with E 100 MeV, or very energetic heavy ions (A 4).It is anticipated that as experimental techniques using theseparticles evolve, the standards will be amended to includedamage calculations covering them.10.2 Damage Regimes:10.2.1 The interaction between an energetic light ion (E 1MeV) an
45、d target nuclei has generally been assumed to be dueto pure Coulomb scattering, leading to the Rutherford scatter-ing cross section for purposes of calculating displacementdamage. This is only true, however, over a limited region ofparticle energy and energy transfer where the limits of validityare
46、determined by both the incident light ion and targetmaterial. For small energy transfers or low energies, or both,the electronic screening of the nuclei becomes important. Asufficient criteria for the neglect of screening corresponds to(12):E . Es; 0.4A1/A2!Z12Z22Z12/31 Z22/3! 3 leV/Ed!MeV (4)Recomm
47、ended values of Edhave been tabulated in PracticeE 521, Table 1. Representative values of Esfor several mate-rials are listed in Table 1 of this practice. In practice, theinfluence of screening may be neglected at somewhat lowerenergies depending upon accuracy desired. As an approximaterule, the scr
48、eening correction to the damage is less than 5 % ifE Es/5. For large energy transfers or high energy, or both,nuclear forces may cause deviations from Rutherford scatter-ing. The energy, in megaelectronvolts, where nuclear forcesbecome significant is approximated by the coulomb barrier andis of the
49、order of:EcZ1Z2A11/31 A21/3(5)Representative values of Ecare given in Table 2.TABLE 1 Values of the Screening Energy, Es, MeVMaterial 1p11d22He32He4Al 0.82 1.6 11 14Cu 2.9 5.8 37 49Ag 5.5 11 68 91Au 7.0 14 87 120E 821 96 (2009)6Therefore, the expression:Es, E , Ec(6)establishes a criterion for the use of Rutherford scattering. Insome cases Es Ec(for example, alpha particles on copper) inwhich case there are deviations from Rutherford scattering forsmall and large energy transfers. In general, however, there isa limited energy range over which Rutherford scattering may
