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利用 5kWCO2 激光器在Ni基铸造高温合金 4 5 #钢基体上宽带、窄带激光熔覆了H¨ogan¨as钴基合金 ,制备了无缺陷的涂层。用金相显微镜、扫描电镜和X射线衍射仪对比分析了熔覆层的显微组织特征和相结构。结果显示 ,熔覆层均为由初生相γ Co枝晶和γ Co +Cr2 3C6 共晶组成。宽带熔覆层界面为垂直于界面生长 ,窄带熔覆层界面结晶方向受热流控制 ,为多方向结晶。 4 5 #钢熔覆层界面具有明显的白亮过渡层且宽带熔覆比窄带宽 ;Ni基合金熔覆层界面区很宽且不规则 ,无白亮色过渡层。沿熔覆层中心线的纵截面取样可见平行生长的枝晶
Using a 5kWCO2 laser on a Ni-based cast superalloy 4 5 # steel substrate, a narrow-band laser cladding Höogan¨¨as cobalt-based alloy prepared defect-free coatings. The microstructure and phase structure of the cladding layer were analyzed by metallographic microscope, scanning electron microscopy and X-ray diffraction. The results show that the coatings consist of γ Co dendrites and γ Co + Cr2 3C6 eutectic phases. The interface of the broadband cladding layer grows perpendicular to the interface, and the crystallization direction of the interface of the narrowband cladding layer is controlled by heat flow, which is multi-directional crystallization. 4 5 # steel cladding layer has obvious white-bright transition layer and wide-band cladding than narrow-band width; Ni-based alloy cladding layer interface area is wide and irregular, no white bright transition layer. Dendrites grown parallel to the sample were taken along the longitudinal section of the cladding centerline