简介:TakingTi-6Al-4Vspecimensintoconsideration,thecoupledthermal-electricalfiniteelementmodelhasbeendevelopedinAbaqus/ExplicittosimulatetheheatingprocessinGleeble3800andtostudythetemperaturehistoryanddistributioninthespecimen.Inordertoverifythefiniteelement(FE)results,thermaltestsarecarriedoutonGleeble3800foraTi-6Al-4Vspecimenwithaslottointhecentreofthespecimen.Theeffectsofthespecimensize,heatingrate,andairconvectiononthetemperaturedistributionoverthespecimenhavebeeninvestigated.Theconclusionscanbedrawnas:thetemperaturegradientofthespecimendecreasesasthespecimensize,heatingrate,andvacuumingdecrease.
简介:GaNmicrocrystallinegrainsweregrownbyhot-wallchemicalvapordepositiononSi(111)substrate.Thesegrainswithdiametersof2-4μmweredetectedbyscanningelectronmicroscopy.X-raydiffraction,Fouriertransformationinfraredtransmissionspectroscopyandphotoluminescencewereusedtoanalyzethestructure,compositionandtheopticalpropertiesofthesamples.TheresultsshowthatthemicrocrystallinegrainsarehexagonalwurtziteGaN,andthepropertyofthegrainswasgreatlyaffectedbythegrowthtime.