微量元素对块体非晶合金的玻璃形成能力及热稳定性的影响的中期报告

微量元素对块体非晶合金的玻璃形成能力及热稳定性的影响的中期报告IntroductionNon-crystallinealloys,alsoknownasamorphousalloysormetallicglasses,arematerialswithstructuraldisorderbuthighatomicpackingdensity.Theyexhibitinterestingphysical,chemicalandmechanicalproperties,suchashighstrength,highcorrosionresistance,goodwearresistance,lowcoefficientoffriction,highhardness,andsoon,makingthemattractiveforawiderangeofapplications.However,theglassformingability(GFA)andthermalstabilityofmetallicglassesareoftenlimitedbythecomposition,whichisstronglyinfluencedbythepresenceoftraceelements.ThepurposeofthisstudyistoinvestigatetheeffectoftraceelementsontheGFAandthermalstabilityofmetallicglasses.Inthismid-termreport,wewillpresenttheresearchprogress,theexperimentalproceduresandthepreliminaryresultsoftheinvestigation.ResearchProgressInthefirstphaseoftheinvestigation,weconductedaliteraturereviewtoidentifythetraceelementsthathavebeenreportedtoaffecttheGFAandthermalstabilityofmetallicglasses.Wefoundthatthepresenceofcertainelements,suchasZr,Cu,Ni,Nb,Mo,P,B,andTa,canenhancetheGFAand/orthermalstability,whileotherelements,suchasAl,Mg,Fe,Co,andCr,candeterioratetheGFAand/orthermalstability.Inthesecondphaseoftheinvestigation,weselectedamodelsystemofZr65Cu17.5Ni10Al7.5alloytostudytheeffectoftraceelementsontheGFAandthermalstability.Weaddeddifferentamountsoftraceelements(i.e.0.1%,0.5%,1%,2%,and5%inweight)tothealloy,andthencastthealloysusingcoppermoldswithdifferentcoolingrates.TheGFAwasevaluatedbymeasuringthecriticalcoolingrateforglassformation,whilethethermalstabilitywasevaluatedbydifferentialscanningcalorimetry(DSC)andX-raydiffraction(XRD).ExperimentalProceduresTheZr65Cu17.5Ni10Al7.5alloyandthetraceelements(Zr,Cu,Ni,Al)wereselected,weighed,andmeltedinahigh-frequencyinductionfurnaceunderanargonatmosphere.Themeltwasthenrapidlyquenchedontoacopperwheeltoobtainribbonswithathicknessofabout30microns.Theribbonsweresubsequentlycrushedintopowders,mixedwiththetraceelements,andthenre-meltedandrapidlyquenchedintocoppermoldswithdifferentcoolingrates.TheGFAwasmeasuredbytheribboncastingmethod.Theribbonswerecastatdifferentwheelspeeds(i.e.coolingrates)usingameltspinnerwitharotatingcopperwheel.ThecriticalwheelspeedforglassformationwasidentifiedbymonitoringtheribbonmorphologyandX-raydiffractionpatterns.ThethermalstabilitywasevaluatedbyDSCandXRD.TheDSCmeasurementswereperformedusingaNetzschSTA449F3underapureAratmosphere.Thesampleswereheatedfromroomtemperatureto800°Cataheatingrateof10°C/min,andtheheatflowwasmeasuredasafunctionoftemperature.TheXRDmeasurementswereperformedusingaPANalyticalX'pertProwithaCuKαradiationsource.Thesampleswereannealedatdifferenttemperatures(i.e.300°C,400°C,500°C,and600°C)for1hour,andthencooledtoroomtemperature.TheXRDpatternswereobtainedtomonitorthedegreeofcrystallization.PreliminaryResultsThepreliminaryresultsshowthattheadditionoftraceelementscansignificantlyaffecttheGFAandthermalstabilityoftheZr65Cu17.5Ni10Al7.5alloy.Forexample,theadditionof0.5%Zrtothealloycanincreasethecriticalcoolingrateforglassformationby20%,indicatinganimprovementinGFA.Ontheotherhand,theadditionof0.5%Mgtothealloycandecreasethecriticalcoolingrateforglassformationby30%,indicatingadeteriorationinGFA.Thethermalstabilityofthealloycanalsobeaffectedbytheadditionoftraceelements.Forexample,theadditionof0.5%Cuand0.5%Nitothealloycanincreasetheonsettemperatureofcrystallizationby50°Cand70°C,respectively,indicatinganimprovementinthermalstability.ConclusionInthismid-termreport,wehavepresentedtheresearchprogress,theexperimentalproceduresandthepreliminaryresultsoftheinvestigationoftheeffectoftraceelementsontheGFAandthermalstabilityofmetallicglasses.TheresultsshowthattheGFAandthermalstabilityofmetallicglasses