层残余应力钢钛刀具磨损英文文献和中文翻译(3)
ofcoatingresidualstresseswitheveryoccurredwearformisnotusefulwiththementionedinteraction.Withincreasingthermo-chemically based crater wear the coating is nolongerintactandacoherenceofthecoatingresidualstressandperformanceisnotpresent.Thus,influenceofcoatingcompositionandhardnesswiththestabilityofthecraterlipand the resistance of the crater lip against chipping isinvestigated.Abrasiveflankweariscorrelatedwithresid-ual stresses near the surface of the coatings and near thesubstratesincethecoatingstillisintactwithonwardflankwear.Alsotheinfluenceofthecompositionofthecoatingsonflankwearisexamined.AlTiVXNAl O32-1000-2000-3000-4000-5000-6000-7000TiAlSiXNmultilayerTiAlSiXNRi/79920 ©IFWFig.2 Residualstressdepthdistributionsofthecoatingscorrelation of the residual stresses with the cutting per-formanceofcoatings.Thisinformationisusedtofindoutoptimized residual stress states of coatings for differentcuttingapplications.4 ResultsanddiscussionFortheinvestigatedmaterialsandcuttingconditionsvari-
ousdominantandtoollifelimitingwearcriteriaaredefined(Fig.3).Thedominantformsofwearforeachapplicationintheexperimentsare:4.1 Continuouscut••42CrMo4,continuouscut:craterwear,flankwear42CrMo4,interruptedcut:craterwear,chippingduetocraterwearTool life of the used coatings in continuous cut of42CrMo4ispresentedinFig.4.ExceptforthecoatingsofgroupBtheusedcoatingsachievedthetoollifecriterionof••Ti–6Al–4V,continuouscut:flankwearTi–6Al–4V,interruptedcut:chippingtc=10min.TheAlCrNcoatingsfailedduetobreakageofthecraterlip.However,rapidlygrowingcraterwearofallThesewearformscoincidewithliterature[23–26].coatingsofthegroupsA–Dispresent.Therefore,theearly123 Prod.Eng.Res.Devel.(2016)10:147–155151coating groupflank wear VBIABCDE5000204060µm10012min864tc = 1 minAl O320-500AlTiVXN2-1000-1500-2000MPaAlTiN 10tool life critera: t = 10 min, tool failure due to crater wear (X)TiAlSiXNcAlTiN 3process:tool:workpiece: 42CrMo4cut:external turningCNMG 120412 MSprocess parameters:vc = 200 m/minf = 0.2 mmTiAlSiXNmultilayercontinuousap = 1 mmRi/79921 ©IFWAlTiN 2group A-3000Fig.4 Toollifeofthecoatingsincontinuouscutof42CrMo4flank wear VB100II200001000050µm200tool breakage of AlCrN C can be affiliated to high com-pressiveresidualstressnearthesubstrate(cf.Fig.2).Thisrequires a high stress gradient in the interface of coatingand substrate. In comparison to group D the compressiveresidualstressincreasestowardsthesubstrate,ingroupDthe substrate near residual stress decreases. Thus, theadhesion between coating and substrate decreases andleadstoanearlybreakageofthecraterlip,whichcoincideswithestablishedresultsinliterature[5].Also,theearlytoolbreakage of the AlCrN T coating due to the influence oftensile residual stresses in PVD-coatings is noted in liter-ature[7,27].TheCVD-coatingAl O withtensileresidualtc = 10 minAl O32AlTiN 1-1000-2000-3000-4000-5000MPagroup A and CAlTiVXNAlTiN 2TiAlSiXNmultilayerAlTiN 3TiAlSiXN23coating stress exhibits no crater wear due to the oxide-basedcompositionandchemicalresistanceofthiscoating.The nitride former 42CrMo4 does not lead to chemicallybasedcraterwearatthiscoatingindependentofitsresidualstressstate.Basedondecreasedtoollifeofthecoatingsincontinuous cut of 42CrMo4, group B is not consideredfurther.-7000process:tool:workpiece: 42CrMo4cut:external turningCNMG 120412 MSprocess parameters:vc = 200 m/minf = 0.2 mmcontinuousap = 1 mmRi/79923 ©IFWAftert =1minwearwasmeasuredforthecorrelationcwith residual stresses near the surface of the coatingsFig.5 Flankweardependingontheresidualstressesnearthesurfaceandthesubstratersurface (Fig.5, I). After t =10min flank wear was cor-crelated with residual stress near the substrate rsubstrate(Fig.5, II). Related to the residual stress rsurface , flankwear of group A with AlTiN-coatings exhibits a minimalwidth of flank wear land VB. Hence the level of theresidual stress state near the surface of group A does nothave any influence of the width of flank wear land. Incorrelation of the width of flank wear land VB aftertc=10minwiththeresidualstressrsubstrate groupAalsoreveals a minimal flank wear. Decreasing flank wear wasfurther observed for the compressive residual stress levelnearthesubstrateabout-1500MPa.Forlessflankwearincontinuous cut of 42CrMo4 AlTiN-coatings and AlTiN-basedcoatings(AlTiVXN)withdecreasing residualstres-ses from the surface of the coating to the substrate aresuitable.Figure6summarizesthetoollifeoftheusedcoatingsincontinuous cut of Ti–6Al–4V. The short tool life of thenitride coating with tensile residual stresses AlCrN T issignificant compared to the other coatings. This can beexplainedbytheloadstressesinthecuttingwedgewhicharetensileduetothechipformation[28,29].In Fig.7 the ratio of the cutting force F to the thrustcforce F for both used materials is exemplary shown forD123 152Prod.Eng.Res.Devel.(2016)10:147–155coating groupIflank wear VBABCDE0020406080µm12025mintc = 1 min-50015105AlCrN C-1000-1500-2000MPaAlTiVXNAlTiN 3TiAlSiXNAlTiN 10tool life critera: t = 20 min, VB > 200 µm (X)process:tool:workpiece: Ti-6Al-4Vcut:cexternal turningCNMG 120412 MSprocess parameters:vc = 60 m/minf = 0.1 mmTiAlSiXNmultilayercontinuousap = 1 mmRi/79922 ©IFWAlTiN 2-3000Fig.6 ToollifeofthecoatingsincontinuouscutofTi–6Al–4VIIflank wear VB0050100150µm2502.5tc = 10 min AlTiN 2-AlTiN 1-1000-2000-3000-4000-5000MPa42CrMo41.51.0AlTiVXNAlTiN 30.5Ti-6Al-4V002468min12TiAlSiXNmultilayercutting time tcprocess:tool:coating:cut:external turningCNMG 120412 MSAlTiN 1process parameters:vc = 60 / 200 m/minf = 0.1 / 0.2 mmap = 1 mmAlCrN CcontinuousRi/79931 ©IFWTiAlSiXN-7000Fig.7 RatioofcuttingforceF andthrustforceFDcprocess:tool:external turningCNMG 120412 MSworkpiece: Ti-6Al-4Vcontinuousprocess parameters:vc = 60 m/mincoating 1. The material properties of 42CrMo4 and Ti–6Al–4Vrequiredifferentprocessparametersinmachining,butwithallusedcoatingstheratioofF toF decreasesforf = 0.1 mmcut:ap = 1 mmRi/79924 ©IFWcDtitanium up to factor two compared to 42CrMo4. Due tothisfactthetensileresidualstressesofthecoatingandtheadditional tensile load in the rake face lead to decreasedtoollifeinmachiningtitanium.TheoxidecoatingAl O isFig.8 Flankweardependingontheresidualstressesnearthesurfaceandthesubstrate23with residual stresses of the coatings near the substratersubstrate (Fig.8, II). The cutting experiments show nosignificant relation between residual stresses and perfor-manceofthecoatings.However,aslightwearprogresscanbe identified with decreasing residual stresses from thesurface of the coatings to the substrate, similar to theresultsincontinuouscutof42CrMo4.notusefulforcuttingoftitaniumalloysduetothechemicalinteractions between material and coating.