1、Designation: F1801 97 (Reapproved 2014)Standard Practice forCorrosion Fatigue Testing of Metallic Implant Materials1This standard is issued under the fixed designation F1801; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 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.1. Scope1.1 This practice covers the procedure for performing cor-rosion fatigue tests to obtain S-N fatigue curves or statist
3、icallyderived fatigue strength values, or both, for metallic implantmaterials. This practice describes the testing of axially loadedfatigue specimens subjected to a constant amplitude, periodicforcing function in saline solution at 37C and in air at roomtemperature. The environmental test method for
4、 implant mate-rials may be adapted to other modes of fatigue loading such asbending or torsion. While this practice is not intended to applyto fatigue tests on implantable components or devices, it doesprovide guidelines for fatigue tests with standard specimens inan environment related to physiolog
5、ical conditions.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-
6、conformancewith the standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations
7、 prior to use.2. Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesE466 Practice for Conducting Force Controlled ConstantAmplitude Axial Fatigue Tests of Metallic MaterialsE467 Practice for Verification of Constant Amplitude Dy-namic Forces in an Axial Fa
8、tigue Testing SystemE468 Practice for Presentation of Constant Amplitude Fa-tigue Test Results for Metallic MaterialsE739 Practice for StatisticalAnalysis of Linear or LinearizedStress-Life (S-N) and Strain-Life (-N) Fatigue DataE1012 Practice for Verification of Testing Frame and Speci-men Alignmen
9、t Under Tensile and Compressive AxialForce ApplicationE1150 Definitions of Terms Relating to Fatigue (Withdrawn1996)3F86 Practice for Surface Preparation and Marking of Metal-lic Surgical ImplantsF601 Practice for Fluorescent Penetrant Inspection of Me-tallic Surgical ImplantsG15 Terminology Relatin
10、g to Corrosion and Corrosion Test-ing (Withdrawn 2010)32.2 ANSI Standard:ANSI B46.1 Surface Texture43. Terminology3.1 Definitions:3.1.1 The terminology used in conjunction with this practicecomplies to Terminology E1150 and Terminology G15.3.2 Definitions of Terms Specific to This Standard:3.2.1 S-N
11、 curvesS-N curves (also known as Whler-curves) show the correlation between the applied stress (S) andthe counted number (N) of cycles to failure.4. Significance and Use4.1 Implants, particularly orthopedic devices, are usuallyexposed to dynamic forces. Thus, implant materials must havehigh fatigue
12、resistance in the physiological environment.4.1.1 This practice provides a procedure for fatigue testingin a simulated physiological environment. Axial tension-tension fatigue tests in an environmental test chamber arerecommended as a standard procedure. The axial fatigueloading shall comply with Pr
13、actice E466 and Practice E467.4.1.1.1 Bending and rotating bending beam fatigue tests ortorsion tests may be performed in a similar environmental cell.4.1.2 This practice is intended to assess the fatigue andcorrosion fatigue properties of materials that are employed or1This practice is under the ju
14、risdiction ofASTM Committee F04 on Medical andSurgical Materials and Devices and is the direct responsibility of SubcommitteeF04.15 on Material Test Methods.Current edition approved Oct. 1, 2014. Published November 2014. Originallyapproved in 1997. Last previous edition approved in 2009 as F1801 97(
15、2009)1.DOI: 10.1520/F1801-97R14.2For 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.3The last approved version of
16、 this historical standard is referenced onwww.astm.org.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1proj
17、ected to be employed for implants. This practice is suitablefor studying the effects of different material treatments andsurface conditions on the fatigue behavior of implant materials.The loading mode of the actual implants may be different fromthat of this practice. Determining the fatigue behavio
18、r ofimplants and implant components may require separate teststhat consider the specific design and loading mode.4.1.3 As a substitute for body fluid, 0.9 % saline solution isrecommended as a standard environment. One of the variousRingers solutions or another substitute for body fluid may alsobe su
19、itable for particular tests. However, these various solu-tions may not give equal fatigue endurance results. Thechloride ions are the most critical constituent in these solutionsfor initiating corrosion fatigue.4.1.4 Because implants are manufactured from highlycorrosion-resistant materials, no visi
20、ble corrosion may bedetectable by optical or electron-optical (SEM) means. Only adecrease of fatigue strength in the high cyclic life range may benoticeable. Therefore, S-N curves covering a broad fatigueloading range should be generated in 0.9 % saline solution(Ringers solutions) and air. Compariso
21、n of fatigue curvesgenerated in air and saline solution may be the only way toassess the effect of the saline environment.4.1.5 Where the fatigue behavior of a material system isalready established, it may suffice to test modifications of thematerial properties or surface condition in only a selecte
22、d stressrange.4.1.6 The recommended loading frequency of one hertzcorresponds to the frequency of weight-bearing during walk-ing. For screening tests, higher test frequencies may be used;but it must be realized that higher frequencies may affect theresults.4.1.7 Summary of Standard ConditionsFor int
23、er-laboratory comparisons the following conditions are consid-ered as the standard test. Axial tension-tension tests withcylindrical specimens in 37C 0.9 % saline solution and airunder a loading frequency of 1 Hz.5. Testing Equipment5.1 The mechanics of the testing machine should be ana-lyzed to ens
24、ure that the machine is capable of maintaining thedesired form and magnitude of loading for the duration of thetest (see Practices E4).5.2 Axial Fatigue Testing:5.2.1 Tension-tension fatigue tests may be performed on oneof the following types of axial fatigue testing machines:5.2.1.1 Mechanical,5.2.
25、1.2 Electromechanical or magnetically driven, and5.2.1.3 Hydraulic or electrohydraulic.5.2.2 The machine shall have a load-monitoring system,such as a transducer mounted in series with the specimen. Thetest loads shall be monitored continuously in the early stage ofthe test and periodically thereaft
26、er, to ensure that the desiredload is maintained. The magnitude of the varying loads,measured dynamically as described in Practice E467, shall bemaintained within an accuracy of less than or equal to 2 % ofthe extreme loads applied during testing.5.3 Non Axial Fatigue TestingCorrosion fatigue tests
27、un-der loading conditions different from axial tension-tension maybe requested. In such cases established experimental arrange-ments for bending, rotating bending beam, or torsional testingmay replace the axial tension-tension mode. An environmentaltest chamber is attached to the equipment and the e
28、nvironmen-tal tests are carried out under conditions as described in thisstandard. Except for the mechanical testing arrangements theconditions of this standard practice apply where possible.Reporting should follow Section 9 and should include alldetails where the testing deviates from the standard
29、procedure.5.4 Environmental Chamber:5.4.1 For corrosion fatigue testing, the machine shall befitted with an environmental test cell surrounding the specimengauge section as shown in Fig. 1. A heated solution reservoir,a solution pump, and connecting lines for circulating the testsolution to the spec
30、imen surface are required. The solutionshould be pumped from the reservoir through the system at arate that will maintain the temperature at 37 6 1C in the testcell, but with flow rates low enough to avoid flow-dependentphenomena like erosion-corrosion. The reservoir should have aminimum capacity of
31、 1000 mL per square centimeter ofspecimen surface exposed to the electrolyte. The reservoir shallbe vented to the atmosphere. If the solution volume decreases,the reservoir shall be replenished with distilled water tomaintain the saline concentration, or the solution should beexchanged. During long
32、testing periods exchange of thesolution is recommended. A typical environmental test cell foraxial fatigue testing is shown in Fig. 1.5.4.2 The test equipment should be manufactured of mate-rials or should be protected in such a manner that corrosion isavoided. In particular galvanic corrosion in co
33、njunction withthe test specimen and loosening of the specimen grips due tocorrosion must be avoided.6. Test Solution6.1 To prepare the saline solution, dissolve9gofreagent-grade sodium chloride in distilled water and make up to 1000mL. If other typical Ringers solutions are used, note thesolution in
34、 the report.7. Test Specimen7.1 Specimen Design:7.1.1 Axial Fatigue Testing:7.1.1.1 The design of the axial load fatigue test specimensshould comply to Practice E466 (see Fig. 2, Fig. 3, Fig. 4 andFig. 5). For the dimensional proportions of flat specimens referto the drawing in Practice E468. The ra
35、tio of the test sectionarea to end section area will depend on the specimen geometryand should comply to those standards. The test specimensspecified in Practice E466 and Practice E468 are designed sothat fatigue failure should occur in the section with reduceddiameter and not at the grip section.7.
36、1.1.2 For bending tests one may refer to the specimenconfiguration suggested in Practice E466.7.1.1.3 To calculate the load necessary to obtain the re-quired stress, the cross-sectional area of the specimen test-section must be measured accurately. The dimensions shouldF1801 97 (2014)2be measured to
37、 the nearest 0.03 mm 0.001 in. for specimensless than 5.00 mm thick 0.197 in., and to the nearest 0.05 mm0.002 in. for specimens more than 5.00 mm thick 0.197 in.Surfaces intended to be parallel and straight should be carefullyaligned.7.2 Specimen DimensionsConsult Practice E466 andPractice E468 for
38、 the dimensions of fatigue specimens for axialtension-tension loading (Fig. 2, Fig. 3, Fig. 4, and Fig. 5). Ifbending specimens corresponding to the example of PracticeF466 are used, observe the suggested dimensions.FIG. 1 Example for Environmental Chamber for Axial Corrosion Fatigue TestingFIG. 2 S
39、pecimens With Tangentially Blending Fillets Between the Test Section and the EndsFIG. 3 Specimens With a Continuous Radius Between EndsF1801 97 (2014)37.3 Specimen Preparation:7.3.1 The method of surface preparation and the resultingsurface condition of the test specimens are of great importancebeca
40、use they influence the test results strongly. Standardpreparation shall consist of machining, grinding, or polishing,or all of these. A final mechanical polish is suggested to give afinish of 16 Min RA or less in accordance with ANSI B46.1.Alternatively, a finish with 600 grit paper in the longitudi
41、naldirection may be used. However, specimens that are to becompared should be prepared the same way. Mechanicallyfinished specimens shall then be degreased in acetone, flushedfirst with ethyl alcohol, then with distilled water, and finallyblown dry with warm air.7.3.1.1 Surface passivation may be ca
42、rried out where ap-propriate (compare Practice F86).7.3.1.2 The surface preparation may be also exactly as usedor intended to be used for surgical implants. A full account ofthe surface preparation should be given in the test protocol.7.3.2 All specimens used in any given series of experiments,inclu
43、ding comparison between the air and liquid environments,should be prepared with the same geometry and by the samemethod to ensure comparable and reproducible results. Regard-less of the machining, grinding or polishing method used, thefinal mechanical working direction should be approximatelyparalle
44、l to the long axis of the specimen to avoid notch effectsof surface grooves.7.3.3 Fillet undercutting and the introduction of residualstresses into the specimen must be avoided. Both effects can becaused by poor machining practice. Fillet undercutting can beidentified by visual inspection. The intro
45、duction of unwantedresidual stresses can be avoided by careful control of themachining process.7.3.4 Specimens that are subject to surface alterations underambient conditions shall be protected appropriately, preferablyin an inert medium or exsiccator, to prevent surface changeuntil the beginning of
46、 the test.7.3.5 Visual inspections at a magnification of approximately20 shall be performed on all specimens. When such inspec-tions reveal potential defects, nondestructive dye penetrant,ultrasonic methods, or other suitable tests may be employed.Dimensional inspection should be conducted without a
47、lteringor damaging the specimens surface. Specimens with surfacedefects should not be used for testing. Inspection should takeplace prior to final surface cleaning.7.3.6 Immediately prior to testing, the specimens may besteam sterilized at a temperature of 120 6 10C and a pressureof 0.10 MPa 14.5 ps
48、i to simulate the actual implant surfaceconditions. Specimens shall be allowed to cool to roomtemperature prior to testing. This sterilizing procedure is notmandatory. If it is used, it should be employed consistently intest series that are related and should be reported in the testprotocol.7.3.7 In
49、 the liquid environmental testing, the time elapsedbetween surface preparation and testing can influence theresults due to the growth of a passive film. The elapsed timeshould thus be reported.8. Procedure8.1 Test Set-Up:8.1.1 Specimen grips shall be designed so that alignment isconsistently good from one specimen to the next. Every effortshould be made to prevent misalignment, due either to twisting(rotation of the grips) or to displacement in their axes ofsymmetry.8.1.2 For axial fatigue testing, alignment should be verifiedaccording to Practice E4, P
