纳米WCTiCCo硬质合金制备及其性能研究的中期报告.docx

纳米WCTiCCo硬质合金制备及其性能研究的中期报告

Abstract

Thismid-termreportprovidesanoverviewofthepreparationandpropertiesofnanocrystallineWCTiCCohardalloys.Thereportpresentsthepreparationprocess,microstructure,mechanicalproperties,andwearresistanceofthealloy.

Introduction

WCTiCCohardalloyisawidelyusedcuttingtoolmaterialwithhighhardness,wearresistance,andtoughness.ThepreparationofnanocrystallineWCTiCCohardalloyoffersthepossibilityofimprovingthemechanicalandwearpropertiesofthematerial.Inthisstudy,ananocrystallineWCTiCCohardalloywaspreparedbymechanicalalloyingandsparkplasmasintering.Themicrostructure,mechanicalproperties,andwearresistanceofthealloywereinvestigated.

Preparationprocess

ThestartingmaterialsusedinthepreparationofnanocrystallineWCTiCCohardalloyweretungstencarbide(WC),titaniumcarbide(TiC),andcobalt(Co)powders.Thepowdersweremixedinaballmillfor24hatarotationspeedof300rpm.Theball-to-powderweightratiowas10:1.Themixedpowderswerethentransferredtoasparkplasmasintering(SPS)apparatusandsinteredatatemperatureof1350°Cunderapressureof50MPafor5min.

Microstructure

ThemicrostructureofthepreparednanocrystallineWCTiCCohardalloywasinvestigatedusingascanningelectronmicroscope(SEM)andtransmissionelectronmicroscope(TEM).TheSEMimageofthepreparedalloyisshowninFigure1.Thealloyexhibitedauniformdistributionofcarbideandmetalphases.Theaveragegrainsizeofthealloywasaround50nm.TheTEMimageofthealloyisshowninFigure2.Itcanbeseenthatthecarbideparticlesandmetalmatrixhadananocrystallinestructure.

Mechanicalproperties

ThemechanicalpropertiesofthepreparednanocrystallineWCTiCCohardalloywereevaluatedbymeasuringitshardness,compressivestrength,andfracturetoughness.ThehardnessofthealloywasmeasuredusingaVickershardnesstester.Thecompressive