MaterialsLetters64(2010)1458–1461ContentslistsavailableatScienceDirectMaterialsLettersjournalhomepage:www.elsevier.com/locate/matletTwostepcoatingofahypereutecticPMAl–SialloyM.GurutzePérezArtiedaa,⁎,A.Cortiellab,N.R.Harlanb,F.Zapirainc,F.ZubiricaUniversidadPúblicadeNavarra,CampusdeArrosadía,31006Pamplona,SpainbCEMITEC,PolígonoMocholí,PlazaCeinno.4,31110,Noain,SpaincLORTEKLaserandRapidManufacturing,B°LaGranjas/n20240,Ordizia,SpainarticleinfoabstractArticlehistory:TheaimofthepresentworkwastocombinethehighstrengthofAl–SialloysproducedviaRapidReceived4February2010Solidification(RS)andSprayForming(SF)withawearresistantsurfacecoating,designedforhighAccepted24March2010temperatureuse.Thesurfacecoating,composedmainlyofnickelandchromium,wasappliedinatwostepAvailableonline30March2010process:plasmasprayfollowedbylasersurfacealloyingusingadiodelaser.Themicrostructureandhardnessofthesurfacecoatingwereanalysed.IntheAl–SialloysproducedviaRapidSolidification,gasbubbleKeywords:formationwasobservedduringthelaseralloyingprocess.IntheSprayFormedalloys,globulesofthecoatingLaserCoatingmaterialandaneedle-likemicrostructureformed,indetrimenttothemechanicalpropertiesofthealloyedMicrostructurelayer.HypereutecticAl–Si©2010ElsevierB.V.Allrightsreserved.SprayForming1.Introductionnitrogenanddepositedontoabillet.Dendriteswhichformintheatomizeddropletsarebrokenupuponimpactwiththebillet.TheThesearchforlightweightalloysorcompositematerialsthatsolidificationrateoftheatomizeddropletsisabitslowerthanthatofpossesstherequiredmechanicalpropertiestoreplacesteelshasbeentheRapidlySolidifiedalloys,soaslightlylargersiliconparticleisthesubjectofmuchresearchinrecentyears.Thepotentialweightformed.AsinRapidSolidification,intermetalliccompoundsaresavingoffersanattractiveadvantageintheautomotiveindustry,brokenupduringextrusionofthebillet[10–12].Inbothproductionwherethedemandforincreasedengineefficiencyduetomoremethods,thesizeofthesiliconparticlesisrefined,comparedtoAl–SistringentCO2