ASTM_D_3762_-_03_2010.pdf

Designation:D376203(Reapproved 2010)Standard Test Method forAdhesive-Bonded Surface Durability of Aluminum(WedgeTest)1This standard is issued under the fixed designation D3762;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,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.1.Scope1.1 This test method2,3simulates in a qualitative manner theforces and effects on an adhesive bond joint at metal-adhesive/primer interface.It has proven to be highly reliable in deter-mining and predicting the environmental durability of adher-end surface preparations.The method has proven to becorrelatable with service performance in a manner that is muchmore reliable than conventional lap shear or peel tests(Note 2).NOTE1While this test method is intended for use in aluminum-to-aluminum applications it may be used for determining surface durabilityof other metals and plastics provided consideration is given to thicknessand rigidity of the adherends.NOTE2This test method is not a quantitative fracture strength testmethod.To measure fracture strength see Test Method D3433.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.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 prior to use.2.Referenced Documents2.1 ASTM Standards:4D907 Terminology of AdhesivesD3433 Test Method for Fracture Strength in Cleavage ofAdhesives in Bonded Metal Joints3.Terminology3.1 DefinitionsMany of the terms used in this test methodare defined in Terminology D907.4.Summary of Test Method4.1 A wedge is forced into the bondline of a flat-bondedaluminum specimen,thereby creating a tensile stress in theregion of the resulting crack tip.The stressed specimen isexposed to an aqueous environment,usually at an elevatedtemperature,or to an appropriate environment relative to theuse of the bonded structure.The resulting crack growth withtime and failure modes are then evaluated.Variations inadherend surface quality are easily observable when thespecimens are forcibly,if necessary,opened at the test conclu-sion.5.Significance and Use5.1 The test is primarily qualitative,but is very discriminat-ing in determining variations in adherend surface preparationparameters and adhesive environmental durability.The test hasfound application in controlling surface preparation operationsand in screening surface preparations,primer and adhesivesystems for durability.In addition to determining crack growthrate and assigning a value to it,the adhesivejoint failure isevaluated and reported.For example,adhesion failure;cohe-sion failure;or adherend failure are noted after opening up thespecimen at the conclusion of the test period.6.Apparatus6.1 Magnifier(preferably stereo binocular),5 to 30-power.6.2 Marking Stylus,sharp-pointed,or triangular file.6.3 Wedges,aluminum or stainless steel.NOTE3Wedges are preferably of the same composition as theadherends of the specimen being tested to reduce the possibility ofelectrolytic corrosion.Stainless steel wedges have been found to workwell with many adherends and are very durable and reuseable.6.4 Scale,small,graduated in millimetres or hundredths ofan inch.1This test method is under the jurisdiction of ASTM Committee D14 onAdhesives and is the direct responsibility of Subcommittee D14.80 on MetalBonding Adhesives.Current edition approved Oct.1,2010.Published October 2010.Originallyapproved in 1979.Last previous edition approved in 2003 as D3762 03.DOI:10.1520/D3762-03R10.2Marceau,J.A.,Moji,Y.,and McMillan,J.C.,“A Wedge Test for EvaluatingAdhesive Bonded Surface Durability,”21st SAMPE Symposium,Vol 21,April 68,1976.3Scardino,W.M.,Marceau J.A.,“Comparative Stressed Durability of AdhesiveBonded Aluminum Alloy Joints,”Symposium on Durability of Adhesive BondedStructures,U.S.ArmyArmament Research and Development Command,Dover,N.J.Oct,2729,1976.4For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.Test Specimen7.1 Use a minimum of five 25.4 by 203-mm(1 by 8-in.)specimens from a single assembly for each test(Fig.1).7.2 It is desirable to prevent plastic deformation(yielding)of the test specimen adherends when inserting the wedge intothe bondline.However,some plastic deformation is permis-sible providing it is not excessive.(Fig.2 illustrates data inwhich some plastic deformation of hi