1、Designation: F1801 97 (Reapproved 2009)1Standard 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 yea
2、r 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.1NOTEUnits information was editorially corrected in January 2010.1. Scope1.1 This practice covers the procedure for performin
3、g cor-rosion fatigue tests to obtain S-N fatigue curves or statisticallyderived 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 37
4、C and in air at roomtemperature. The environmental test method for 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 t
5、ests with standard specimens inan environment related to physiological 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
6、the other. Combiningvalues from the two systems may result in non-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 pr
7、actices and determine the applica-bility of regulatory limitations 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
8、 Verification of Constant Amplitude Dy-namic Forces in an Axial Fatigue Testing SystemE468 Practice for Presentation of Constant Amplitude Fa-tigue Test Results for Metallic MaterialsE739 Practice for Statistical Analysis of Linear or Linear-ized Stress-Life ( S-N) and Strain-Life (e-N) Fatigue Data
9、E1012 Practice for Verification of Test Frame and SpecimenAlignment Under Tensile and Compressive Axial ForceApplication3E1150 Definitions of Terms Relating to FatigueF86 Practice for Surface Preparation and Marking of Me-tallic Surgical ImplantsF601 Practice for Fluorescent Penetrant Inspection of
10、Me-tallic Surgical ImplantsG15 Terminology Relating to Corrosion and CorrosionTesting2.2 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 Speci
11、fic to This Standard:3.2.1 S-N 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 ma
12、terials must havehigh fatigue 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 fatig
13、ueloading shall comply with Practice 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 or
14、projected to be employed for implants. This practice is suitable1This practice is under the jurisdiction ofASTM Committee F04 on Medical andSurgical Materials and Devices and is the direct responsibility of SubcommitteeF04.15 on Material Test Methods.Current edition approved Aug. 1, 2004. Published
15、January 2010. Originallyapproved in 1997. Last previous edition approved in 2004 as F1801 97(2004).DOI: 10.1520/F1801-97R09E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information
16、, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2
17、959, United States.for 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 behavior ofimplants and implant components may r
18、equire 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 suitable for particular tests. However, the
19、se 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 visible corrosion may bedetectable by optical
20、 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. Comparison of fatigue curvesgenerated in air and s
21、aline 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 selected stressrange.4.1.6 The recommended loadi
22、ng 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 inter-laboratory comparisons the following c
23、onditions 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 ensure that the machine is capable of mainta
24、ining 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,5.2.1.2 Electromechanical or magnetically dri
25、ven, 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 thereafter, to ensure that the desiredload is mai
26、ntained. 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 testsunder loading conditions different from ax
27、ial tension-tensionmay be requested. In such cases established experimentalarrangements for bending, rotating bending beam, or torsionaltesting may replace the axial tension-tension mode. An envi-ronmental test chamber is attached to the equipment and theenvironmental tests are carried out under con
28、ditions as de-scribed in this standard. Except for the mechanical testingarrangements the conditions of this standard practice applywhere possible. Reporting should follow Section 9 and shouldinclude all details where the testing deviates from the standardprocedure.5.4 Environmental Chamber:5.4.1 Fo
29、r 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 specimen surface are required. The solutionshoul
30、d 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 1000 mL per square centimeter ofspecimen su
31、rface 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 testing periods exchange of thesolution is r
32、ecommended. 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 conjunction withthe test specimen and loosenin
33、g 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 the report.7. Test Specimen7.1 Specimen Des
34、ign: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 ratio of the test sectionarea to end section a
35、rea 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.7.1.1.2 For bending tests one may refer to the
36、 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 shouldbe measured to the nearest 0.03 mm 0.001 in. for specimensless than 5.00 m
37、m thick 0.197 in., and to the nearest 0.05 mmF1801 97 (2009)120.002 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 the dimensions of fatigue specimens for ax
38、ialtension-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.7.3 Specimen Preparation:7.3.1 The method of surface preparation and the resultingsurface condition of the test specimens are o
39、f great importancebecause they influence the test results strongly. StandardFIG. 1 Example for Environmental Chamber for Axial Corrosion Fatigue TestingFIG. 2 Specimens With Tangentially Blending Fillets Between the Test Section and the EndsFIG. 3 Specimens With a Continuous Radius Between EndsF1801
40、 97 (2009)13preparation 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 longitudinaldirection may be used. However, specime
41、ns 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 carried out where ap-propriate (compare Prac
42、tice 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,including comparison between the air and liquid
43、 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 approximatelyparallel to the long axis of the specimen to avoi
44、d 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 introduction of unwantedresidual stresses can b
45、e 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 the test.7.3.5 Visual inspections at a ma
46、gnification of approximately203 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 alteringor damaging the specimens surface.
47、 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 psi to simulate the actual implant surfacec
48、onditions. 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 the liquid environmental testing, the ti
49、me 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, Practice E467, and Practice E1012.8.2 Te
