论文部分内容阅读
为了研究激光熔覆镍基合金涂层显微组织与性能之间的关系,本文选用Ni25、Ni45、Ni60镍基自熔性合金粉末作为熔覆材料,在同一工艺参数下在45#钢基体上制得Ni25、Ni45、Ni60合金激光熔覆涂层。利用扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)、显微硬度计等方法对涂层的显微组织、物相组成、显微硬度等进行了研究。结果表明从Ni25到Ni60合金涂层,随着合金元素含量的提高,涂层微观组织逐渐由亚共晶转变为过共晶,γ-Ni奥氏体枝晶所占体积分数减少,尺寸细化,枝晶间的共晶组织和硬质相所占的体积分数增大,涂层和基体之间结合带的宽度越来越窄,熔覆层的显微硬度越来越高。Ni25、Ni45合金涂层的平均显微硬度分别为250HV和550HV左右,而Ni60合金涂层的平均硬度却高达750HV左右,为Ni25合金涂层的3倍。
In order to study the relationship between microstructure and properties of laser cladding Ni-based alloy coatings, Ni25, Ni45, Ni60 nickel-based self-fluxing alloy powders were selected as cladding materials under the same process parameters on 45 # steel substrate Ni25, Ni45, Ni60 alloy laser cladding coating. The microstructure, phase composition and microhardness of the coatings were investigated by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and microhardness tester. The results show that the coating microstructure changes from hypoeutectic to hypereutectic with Ni-Ni to Ni60 alloy coating. The volume fraction of γ-Ni austenite dendrite decreases and the size of the coating decreases , The volume fraction of the eutectic structure and the hard phase between the dendrites increases, and the width of the bonding zone between the coating and the substrate becomes narrower and narrower, and the microhardness of the cladding layer becomes higher and higher. The average microhardness of Ni25 and Ni45 alloy coating is about 250HV and about 550HV, respectively, while the average hardness of Ni60 alloy coating is as high as about 750HV, which is three times that of Ni25 alloy coating.