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1、江蘇大學(xué)碩士研究生學(xué)位論文摘要本文采用SHS.Casting技術(shù),制各出鋼表面金屬間化合物基復(fù)合材料涂層。采用DSC、XRD、SEM、TEM等分析手段,研究了熱爆反應(yīng)及其產(chǎn)物的形貌、復(fù)合涂層的顯微組織和界面形貌。通過(guò)對(duì)鋼液浸滲的動(dòng)力學(xué)分析和表面復(fù)合涂層形成機(jī)理的探討,總結(jié)了工藝參數(shù)對(duì)涂層組織結(jié)構(gòu)的影響規(guī)律。研究結(jié)果表明:在Ti-C.3Ni.Al體系中,由Ni和觸的放熱反應(yīng)引發(fā)了弧和C的反應(yīng),砸—G3Ni.m體系的起始反應(yīng)溫度與TiC含量無(wú)關(guān)。體系成分和熱爆溫度對(duì)熱爆反應(yīng)及其產(chǎn)物致密度和組織形貌有顯著影響
2、。試驗(yàn)?zāi)艿玫郊儍舻腡iC/Ni3AI復(fù)相表面涂層,涂層端面沒(méi)有出現(xiàn)含鐵相;隨著TiC含量的增加,涂層致密度提高,TiC顆粒略有長(zhǎng)大。界面微觀形貌與涂層中TiC含量有關(guān),當(dāng)mC含量較低時(shí),界面處存在微觀裂紋及孔洞:砸C含量為35%左右時(shí),涂層與鋼基體在界面處實(shí)現(xiàn)了良好冶金結(jié)合;當(dāng)TiC含量耋45%時(shí),涂層出現(xiàn)分層現(xiàn)象。涂層中Ni、Al、面、Fe元素和涂層的顯微硬度沿涂層厚度方向呈梯度變化。涂層的形成過(guò)程是一個(gè)熱力學(xué)作用和動(dòng)力學(xué)作用相互交織、相互影響的過(guò)程,液相Ni3AI的存在大大促進(jìn)了鋼液的浸滲。工藝參數(shù)
3、對(duì)鋼表面蜊i3Al復(fù)合涂層組織結(jié)構(gòu)具有明顯的影響,研究發(fā)現(xiàn):澆注溫度越高,預(yù)制塊密實(shí)度越低,TiC含量越高,涂層與基體結(jié)合越致密。關(guān)鍵詞:佴G3Ni-AI;表面復(fù)合涂層;SHS.Casting.顯微組織;浸滲江蘇大擘碩士研究生學(xué)位論文TiC-reinforcedNi捌matrixcompositeswerefabricated勰coatingsOnsteelthroughSHS-Castingtechnology.Thethermalexplosionanditsproductmicro—topogra
4、phy,microstmctures,interfacesofthecoatingwereanalyzedbyX-raydiffraction(xRD),scanningelectronmicroscopy(SEM),energy-dispersivespectrum(EDS)andtransmissionelectronmicroscopy㈣.Theformationmechanismofthecoatingsaswellasthedynamicprocessofliquidsteelinfiltra
5、tionWasdiscussed.Basedonthis,theaffectsoftechnologicalparametersonthecoatingmicrostructuresWasalsoanalyzed.TheexperimentalresultsshowthatTiCandNi掣AdwerethemoststablephasesinTi-C-3Ni-AIsystem.Theexothermicreactionofnickelandaluminum倒tcdthereactionoftitani
6、umandcarbon.DuringreactionsTiCwasalwaysinsofidststeandNi3AIinliquidstate.Thethermalexplosionstartingtemperatureofthe3Ni-AI-Ti-CsystemisindependentoftheTiCcontent.IngredientsandthermalexplosiontemperaturewerefoundtohaveobviousinfluencesOnthethermalexplosi
7、on,morphologyandraletivedensi哆oftheproducts.TICrNi3AIcoatingWasformed∞steelwithhighpurity.Noironphasecanbefoundinthecoatingsurface.WithincreaseinTiCcontent,TiCparticulateDe魍mleslightlycoar{}efandthecompositedenser.Interfacemorphologyvariedwi血theTiCconten
8、tofthecoating.WithTiCcontentincreasingfrom25wt%to45wt%,thecompositeisdenselyformedwithabsenceofporesandmorphologyoftheinterfacechangesfromintegralformtodetachedform.Ni、AI、Ⅱ、Feandmicrohardncsswererevealedtohavegradeddistrib