宽带激光熔覆铸造WC_p/Ni基合金复合涂层结合界面组织特征

Microstructure Characteristics of Bonding Interface of Cast WC_P /Ni Based Alloy Composite Coating by Wide-Band Laser Cladding

研究了宽带激光熔覆铸造WCp /Ni基合金复合涂层结合界面组织特征。结果表明结合界面微区组织特征为细小的共晶体组织、过渡层组织以及白亮带组织。白亮带及过渡层中主要含有Fe ,Cr,Ni,Si等元素。白亮带主要是单相的γ - (Fe ,Cr ,Ni,Si)固溶体组织。从熔覆区→过渡层→白亮带的平均显微硬度值呈梯度分布。复合涂层结合界面主要元素、微观组织结构和显微硬度呈梯度分布的特征 ,提高了涂层与基材之间的匹配性 ,缓解应力集中 ,避免裂纹形成 ,实现了基材与涂层良好的冶金结合。

Microstructure characteristics of bonding interface of Cast WC P/Ni based alloy composite coating by wide band laser cladding were studied.The experimental results indicate that microstructure characteristics near bonding interface are composed of small eutectic structure ,transition layer and white bright band. The chemical elements such as Fe, Cr, Si, Ni are included in the white bright band and transition layer.The white bright band is mainly single phase solidation γ (Ni,Fe,Cr,Si). The average microhardness value from cladding coating transition layer white bright band gradiently distributes.The gradient distributions of main elements, microstructure and microhardness near bonding interface raise matching between coating and substrate, release stress concentration, avoid the form of cracks and realize better metallurgical bonding between coating and substrate.