简介：Asetofcouplingexperimentalinstrumentwasdesignedtostudythetransportpropertiesofchlorideioninconcreteundersimultaneouscouplingactionoffatigueloadandenvironmentalfactors.Firstlythewater-saturatedperformanceofmodernconcretewasinvestigated,thendiffusionperformanceofchlorideionunderdifferentstresslevelsanddifferenttemperaturewerestudiedrespectively;meanwhile,thetime-dependentbehaviorofthechlorideiondiffusioninconcretewasalsoresearched.Theresultsshowedthatthesaturationdegreeofconcretecanreachashighas99%.Besides,diffusioncoefficientofchlorideionincreasedwithincreasingofthestresslevelandtemperature,andwhenthestresslevelandtemperatureareat0.6and60℃respectively,thediffusioncoefficientis6.3×10-14m2/s,moreoverthediffusioncoefficientofchlorideioninconcretedecreasedwithtimeunderthesimultaneouscouplingactionoffatigueloadandenvironmentfactors.

简介：Theeffectofcathodichydrogenchargingonthetensileandconstantloadpropertieswasdeterminedforanausteniticstainlesssteelweldmentcomprisinga304Lsteelinthesolutiontreatedconditionasabasemetalanda308Lfillersteelasaweldmetal.Partofthe304Lsolutiontreatedsteelwasseparatelygivenadditionalsensitizationtreatmenttosimulatethemicrostructurethatwoulddevelopintheheataffectedzone.Testswereperformedatroomtemperatureonnotchedroundbarspecimens.Hydrogenchargingresultedinapronouncedembrittlementofthetestedmaterials.Thiswasmanifestedmainlyasaconsiderablelossinthedluctilityoftensilespecimensandadecreaseinthetimetofailureandthresholdstressofconstantloadspecimens.The308Lweldmetalexhibitedthehighest,andthe304Lsolutiontreatedsteelthelowest,resistancetohydrogenembrittlement.Hydrogenembrittlementwasassociatedwiththeformationofstraininducedmartensiteaswellasatransitionfrombrittletoductilefracturemorphologyonwardsthecentreofthespecimens.

简介：QingdaoJiaozhouBaysubseatunnelisthesecondself-builttunnelinChinawiththedesignedservicelifeover100years.Thedurabilityofliningconcreteareoneofanimportantfactorstodeterminatetheservicelifeoftunnel.Consideringthemainenvironmentalloadsandmechanicalloadsofsubseatunnel,thedurabilitypropertiesofliningconcreteundercombinedactionofcompressiveloadandcarbonationhasbeenstudiedthroughthecriticalcompressiveloadtest,acceleratedcarbonationtest,naturalcarbonationtestandcapillarysuctiontest.Thetestsresultsshowthatcriticalcompressiveloadapparentlyacceleratesthecarbonationanddeterioratestheanti-permeabilityofconcrete.Underthecombinedactionofcriticalcompressiveloadandcarbonation,thedurabilityofliningconcretedecreases.Basedonthecarbonizationlifecriteriaandresearchresults,forthehigh-performanceconcretewithproposedmixratio,thepredictedservicelifeofliningconcreteforJiaozhoubaysubseatunnelisabout80yearswhichfailstoreachtherequiredservicelife.Itisnecessarytoadoptothermeasurementssimultaneouslytoimprovethedurabilityofliningconcrete.

简介：Theeffectofthermalcyclingunderloadingonmartensitictransformationandtwo-wayshapememoryeffectwasinvestigatedforTi-49.8at.pctNialloy.ItisshownthatMsandMftemperatureincreasewithincreasingthenumberofcycles,whileAsandAftemperaturedecreaseduringthermalcycling.Thetotalstrainεtandpermanentstrainεpincreasewithincreasingappliedstressandnumberofcycles.Thetwo-wayshapememoryeffectcanbeimprovedbyproperthermalcyclingtrainingunderloading,whileexcessivelyhighappliedstressresultsinthedeteriorationofTWSME.Thereasonforthechangesinmartensitictransformationcharacteristicsandtwo-wayshapememoryeffectduringthermalcyclingunderloadingisdiscussedbasedontheanalysisofmicrostructurebyTEMobservations.

简介：ConstantloadtestsinNS4solutionpurgedwithN2-5%CO2gasmixturewereconductedonAmericanPetroleumInstitute(API)X80pipelinesteelappliedinthe2ndWest-EastGasPipelineprojectwithandwithoutpreload.TheresultsshowthatcrackscouldinitiateandpropagateinX80pipelinesteelinnear-neutralpHenvironmentunderaconstantloadcondition.Thelifeofcrackinitiationandpropagationincreasedwithdecreasingappliedstress.Preloaddidnotchangeitscorrosionbehaviorobviously.However,preloadreducedthetimeforcrackinitiation.