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1、学兔兔www.xuetutu.com第19卷第1期粉末冶金材料科学与工程2014年2月Vol.19No.1MaterialsScienceandEngineeringofPowderMetallurgyFeb.2014核阀密封面FCo-5合金粉末激光熔覆层的组织与性能1,21,22李必文，张春良，金坤文(1.南华大学核科学技术学院，衡阳421001；2.南华大学机械工程学院，衡阳421001)摘要：以FCo-5自熔性钴基合金粉末为堆焊材料，在0Cr18Ni12Mo3Ti核阀试样表面制备厚度为2.04mm、横截面单圆弧拟合半径为2.69mm的密封面激光熔覆
2、层。利用SEM和XRD分析熔覆层的微观结构和物相，测试熔覆层的显微硬度及最小厚度处的高温硬度。结果表明：熔覆层从界面到表层的结晶形态依次由平面晶向胞状树枝晶、多方向生长树枝晶、细小树枝晶过渡；中、上部组织主要由γ-Co奥氏体枝晶、枝晶间层片状共晶组织以及弥散分布的Cr23C6硬质颗粒组成；在距界面1.52~1.60mm的区域，密封带宽度为2.95～3.18mm，常温硬度阈值为44.3～45HRC；在650℃以下时，熔覆层最小厚度处具有优异的抗蠕变性能和高温硬度特性，经720℃以上回火处理后有较强的二次硬化效应。关键词：FCo-5钴基合金粉末；核阀密封面；
3、激光熔覆层；组织；硬度中图分类号：TG174.44文献标识码：A文章编号：1673-0224(2014)1-159-06MicrostructureandperformanceoflasercladdinglayerofFCo-5alloypowderonnuclearvalvesealingsurface1,21,22LIBi-wen,ZHANGChun-liang,JINKun-wen(1.SchoolofNuclearScienceandTechnology,UniversityofSouthChina,Hengyang421001,China;2
4、.SchoolofMechanicalEngineering,UniversityofSouthChina,Hengyang421001,China)Abstract:Asealingsurfacelasercladdinglayerwiththicknessof2.04mmandcrosssectionofcirculararchavingafittingradiusof2.69mmwaspreparedona0Cr18Ni12Mo3TinuclearvalvesamplesurfaceusingFCo-5fluxedcobalt-basealloyp
5、owderasoverlayingweldingmaterial.ThemicrostructureandphasecompositionofthecladdinglayerwereanalyzedusingSEMandXRD.Themicrohardnessofthecladdinglayerandhightemperaturehardnessatthepositionwithminimumthicknessweremeasured.Theresultsshowthatthecrystalmorphologyofcoatingalteredinturn
6、asplanecrystalcellulardendrites,multi-directionalgrowthdendritesandfinedendritesfromtheinterfacetosurface.Themidanduppermicrostructuremainlyconsistsofγ-Coaustenitedendrite,interdendriticlayerlamellareutecticorganizationanddispersedCr23C6hardparticlephase.Thesealbeltwidthvariesfro
7、m2.95mmto3.18mm,hardnessthresholdundernormaltemperatureis44.3~45HRCintheregionawayfromtheinterface1.52~1.60mm.Theminimumthicknesslocalizedcladdinglayerhasthecharacteristicofgoodcreepresistanceandhightemperaturehardnessbelow650℃,aswellascangeneratestrongsecondaryhardeningeffectaft
8、ertemperingabove720℃.Keywords:FCo-5cobal
