摘要:
电子束焊相较于传统的焊接更适宜于钛合金，但焊接接头的腐蚀行为几乎未见报道，制约了其发展应用。采用金相、电子显微镜和X射线衍射仪分析了焊接接头组织，并采用电化学方法，分别研究了焊接接头整体、焊缝区域、母材区域在1 mol/L HCl介质中的耐蚀性能及腐蚀行为。结果表明：焊接接头母材组织由等轴α相与间隙中的β相组成，热影响区域由原始α相、β相与α’相组成，焊缝组织基本为单一α’相。焊缝耐蚀性能较母材更佳，焊接接头整体的耐蚀性能较母材差。随浸泡时间的增加，所有试样均经过了活性溶解、钝化膜产生和点蚀产生和发展的过程。浸泡后试样表面均产生了蚀孔，耐蚀性能急剧下降。
Abstract:
Electron beam welding is more suitable for titanium alloy than traditional methods,but the corrosion behaviors of the welded joints have been rarely reported for electron beam welding,which restricts its development and applications.In this paper,the microstructure of welded joints was analyzed by metallography,electron microscopy and X-ray diffraction.Meanwhile,the corrosion resistance and corrosive behaviors of the overall welded joint,welding bead and base metal in 1 mol/L HCl medium were investigated by electrochemical method.The results show that the base material of the welded joint consists of the equiaxed α phase and the β phase in the gap,and the heat affected zone is composed of the original α phase,β phase and α’ phase,while the weld bead is under the structure of α’ phase only.The corrosion resistance of the weld bead is better than that of the base metal,and the corrosion resistance of the overall welded joint is worse than that of the base metal.With immersion time increasing,all samples undergo active dissolution,passivation film generation and destruction processes.After immersion,the surface of the samples is etched,the corrosion resistance decreases sharply.
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