强流脉冲电子束作用下镍基高温合金GH3039表面铬合金化及其抗高温氧化性能研究

目的改善GH3039合金的抗高温氧化性能。方法在GH3039合金表面涂抹Cr粉末,然后借助于强流脉冲电子束装置(简称HCPEB)对该合金表面进行相应的处理,而后分别使用X射线衍射仪(XRD)与扫描电子显微镜(SEM)对合金表面进行观察,对比处理前后的物相和微观结构变化,然后以850℃恒温环境为基础,对样品合金化前后的氧化动力学与氧化机制进行相应的测试与分析。结果该合金在HCPEB辐照处理后,其表层已经形成了相应的滑移带,表层晶粒显著细化,尤其是30次辐照样品中形成了尺寸约为100 nm的纳米晶结构。恒温氧化试验的测试结果显示,通过100 h的氧化处理,原始样品氧化增重数值最大,与此同时生成的氧化膜整体偏厚,达到6μm,有一定程度的裂纹与孔洞,基体发生了严重的内氧化。通过辐照处理30次后的合金化样品,氧化100 h后的增重数值最小,由此生成的氧化膜厚度仅仅约为3μm,同时氧化膜的主要构成为氧化铬,该氧化膜还呈现出连续生长属性,相应结构具有致密性且没有剥落,对基体有较为明显的保护功能。结论HCPEB辐照可以将Cr原子熔入GH3039合金表层,快速实现Cr表面合金化。合金表面Cr含量的提高以及在微结构促进元素扩散的共同作用下,该合金抗高温氧化性能得到显著优化。

Surface Chromium Alloying and High Temperature Oxidation Resistance of Nickel-based Superalloy GH3039 under High Current Pulsed Electron Beam

The work aims to improve the high temperature resistance method of GH3039 alloy.Chromium(Cr)was coated on GH3039 alloy,and the surface of the alloy was treated by high-current pulsed electron beam(HCPEB).After treatment,X-ray Diffraction(XRD)and Scanning Electron Microscope(SEM)were used to observe and analyze the surface to compare the changes of phase and microstructure before and after HCPEB alloying.At the same time,the oxidation kinetics and oxidation mechanism before and after HCPEB alloying were investigated at a constant temperature of 850℃.Slip bands were formed on the surface of the alloy after HCPEB irradiation,and the grain size was obviously refined.Particularly,nanocrystalline structure with a size of about 100 nm was formed in the samples irradiated for 30 times.From the oxidation resistance test at constant temperature,the oxidation weight gain of the original sample was the largest after 100 h,and the oxide film was relatively thick,about 6μm,with holes and cracks,and the matrix underwent serious internal oxidation.The oxidation weight gain of 30-implused samples was the smallest and the thickness of the oxide film was about 3μm,mainly composed of Cr2O3.Moreover,Cr2O3 oxide film presented continuous growth trend and had compact structure without peeling,which played a protective role on the matrix.HCPEB irradiation can melt Cr atoms into the surface of GH3039 alloy and rapidly realize the surface alloying of Cr.The high temperature oxidation resistance of GH3039 alloy is improved by increasing the content of Cr on the alloy surface and promoting the diffusion of elements by the micro-structure.