Y2O3含量对激光熔覆0.3C-18Cr合金涂层组织和性能的影响

在3Cr14不锈钢基体上激光熔覆制备不同Y₂O₃含量的0.3C-18Cr复合涂层。采用金相显微镜(OM)、扫描电子显微镜(SEM)、X射线衍射(XRD)、显微硬度仪等设备研究了不同Y₂O₃含量对熔覆层的微观结构、相组成及硬度的影响。结果表明,未添加Y₂O₃试样熔覆层有较多孔洞,熔覆层组织由晶内铁素体、晶界分布的上贝氏体及少量马氏体组成；加入在3Cr14不锈钢基体上激光熔覆制备不同Y2O3含量的0.3C-18Cr复合涂层。采用金相显微镜（OM）、扫描电子显微镜（SEM）、X射线衍射（XRD）、显微硬度仪等设备研究了不同Y2O3含量对熔覆层的微观结构、相组成及硬度的影响。结果表明，未添加Y2O3试样熔覆层有较多孔洞，熔覆层组织由晶内铁素体、晶界分布的上贝氏体及少量马氏体组成；加入Y2O3后熔覆层枝晶长度减小且数量减少，枝晶尖端钝化且径向粗化，长径比减小，同时熔覆层气孔减少，熔覆层得到净化；熔覆层组织由板条马氏体+晶界少量贝氏体构成；且随Y2O3含量增加，板条马氏体略有粗化，贝氏体数量明显减少，贝氏体碳化物的碳浓度增大，碳化物类型由低碳型碳化物向高碳型碳化物转变。加入Y2O3后，熔覆层显微硬度显著提高，添加2% Y2O3时熔覆层的硬化效果最佳，比未添加Y2O3时增加160 HV0.2。

Influence of Y2O3 Content on Microstructure and Properties of Laser Cladding 0.3C-18Cr Alloy Coating

PreparationSofS0.3C18CrScompositeScoatingsSwithSdifferentSY₂O₃ contentsSonS3Cr14 stainlessSsteelSsubstrateSbySlaserScladdig. The effects of different Y₂O₃ contents on the microstructure, phase composition and hardness of the cladding layer were studied by metallographic microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD) and microhardness tester. The results show that there are many porous holes in the cladding layer without adding Y₂O₃, and the microstructure of the cladding layer consists of intragranular ferrite, bainite with grain boundary distributed and a small amount of martensite; After adding Y₂O₃, the dendrite length of the cladding layer is reduced and the number decreases, the dendrite tip is passivated and radially coarsening, the length to diameter ratio decreases, meanwhile the pores of the cladding layer decrease, and the cladding layer is purified. The microstructure of the cladding layer is composed of lath martensite and a small amount of bainite in the grain boundary. With the increase of Y₂O₃, the lath martensite is slightly coarsened, the number of bainite decreases obviously, the carbon concentration of bainite carbide increases, and the type of lamellar carbides transforms from low carbon carbide to high carbon carbide. After adding Y2O3, the microhardness of the clad layer is significantly improved,; When added 2% Y₂O₃, the hardening effect of the cladding layer comes up to the best, which was 160 HV0.2 higher than that without adding Y₂O₃.