激光比能对Fe2B激光熔覆涂层微观组织与性能的影响

Effects of Laser Specific Energy on Microstructure and Properties of FeB Laser Cladding Coating

利用粉末喷射激光熔覆以球形硼铁粉末为原材料成功制备了Fe2B金属间化合物涂层。采用金相显微镜(OM)、X射线衍射仪(XRD)、扫描电镜(SEM)、电子探针(EPMA)、显微维氏硬度计及摩擦磨损试验机对涂层/m2左右时,采用粉末喷射激光熔覆能制备较为理想的Fe2B金属间化合物涂层。制备的单层涂层的物相为Fe2B与Fe,显微硬度峰值达1360HV0.05,涂层组织中大量弥散分布的Fe2B相的生成是涂层具有高硬度的原因。制备的多层涂层与基体具有良好的冶金结合,从基体到涂层,组织经历了一个由平面外延生长组织到胞状晶再到等轴晶的演变过程,涂层稳定摩擦因数为0.385,磨损率为5.67×10-15m3/N·m,表现出良好的耐磨性能,磨损机制为磨粒磨损与疲劳磨损。

With spherical ferroboron alloy powder as raw material,the Fe2B intermetallic coatings were successfully prepared by powder injection laser cladding.Microstructure and properties of the coatings were analyzed by employing metallographic microscope(OM),X-ray diffracton(XRD),scanning electron microscopy(SEM),electron probe microanalysis(EPMA),micro Vickers hardness tester and friction wear tester.Results show that when the laser specific energy was controlled at about 3.00×108 k J/m2,a more desirable Fe2B intermetallic compound coating could be prepared.The phases of the prepared monolayer coating were Fe2B and Fe,and the peak microhardness reached 1360 HV0.05.The formation of a large number of dispersed Fe2B phases in the coating microstructure contributed to the high hardness of the coating.The metallurgical bond between the prepared multilayer coating and substrate was well realized.From substrate to coating,the microstructure had experienced an evolution process from planar epitaxial growth microstructure to cellular-like crystal and then to equiaxed crystal.The coating had good wear-resisting property,with stable friction coefficient of 0.385 and wear rate of 5.67×10-15 m3/Nm.And its wear mechanism was abrasive wear and fatigue wear.