中文摘要：

利用强流脉冲电子束（High current pulsed electron beam,HCPEB）技术对镍基高温合金GH4169进行表面处理,利用X射线衍射仪（X-ray diffraction,XRD）、扫描电子显微镜（Scanning electron microscope,SEM）和透射电子显微镜（Transmission electron microscopy,TEM）对HCPEB诱发的微观结构进行详细的表征,并考察HCPEB辐照处理后样品表面的腐蚀性能。试验结果表明,HCPEB辐照后GH4169合金表面发生熔化并形成熔坑,熔坑密度随辐照次数的增加而降低,尺寸较大的第二相颗粒等可随着熔坑的喷发而清除,进而实现表面净化。HCPEB辐照后GH4169合金表面形成3~5μm厚的重熔层,重熔层内部以尺寸在100 nm左右的纳米晶为主,HCPEB辐照还可在表层诱发强烈的塑性变形,形成高密度的位错及变形孪晶等变形结构。HCPEB辐照显著地改善了GH4169合金的耐蚀性能,腐蚀性能的改善主要归因于表面净化效应以及表层纳米重熔层和高密度的晶体缺陷的形成,这些微观结构促进了表层钝化膜的形成,起到保护基体的作用。

英文摘要：

High-current pulsed electron beam（HCPEB） treatment is applied on a nickel-based superalloy GH4169. The microstructural changes induced by the pulsed electron beam irradiation are investigated in detail by X-ray diffraction, scanning electron microscopy（SEM） and transmission electron microscopy（TEM） together with their corrosion property. The experimental results indicate that the irradiated surfaces are melted and many craters are formed, while the density of craters shows a significant reduction with the increasing number of HCPEB irradiation. The second phase particles are eliminated with the eruption of the craters, leading to the surafce purification. After the HCPEB irradiation, the formation of a melted layer with depth of about 3-5 μm on the irradiated surface is observed. Furthermore, nanocrystals with the size of 100 nm are also formed in the melted region. Microstructural analysis shows the severe plastic deformationtion, high density of dislocations, as well as large quantities of deformation twins in the irradiated surface. Consequently, the corrosion resistance of the nickel-based superalloy GH4169 is significantly improved by HCPEB treatments. The surface purification effect induced by the HCPEB treatment, nanostructured surface melted layer along with high density of crystal defects which promote the formation of surface passivation layer, are responsible for the improvement in corrosion resistance.