AlCoCrFeNi_(2.1)高熵合金电子束焊接接头耐蚀性

Corrosion resistance of AlCoCrFeNi_(2.1) high entropy alloy welded joint by electron beam welding

为明确高熵合金焊接接头耐腐蚀行为,采用电子束方法对共晶双相AlCoCrFeNi_(2.1)高熵合金进行焊接,并运用电化学腐蚀方法研究了接头耐蚀性.结果表明,焊缝区域(FZ)自腐蚀电位相比母材(BM)提高0.16 V左右,耐蚀性增强,自腐蚀电流减小了一个数量级,腐蚀速率明显降低.焊接接头母材区域腐蚀坑呈纵深扩展趋势,而焊缝区域腐蚀坑呈横向扩展,并表现出明显的相选择性腐蚀现象.焊缝区域的晶粒细化显著,硬度升高,两相分布呈现密集的“网络”状,元素分布更加均匀,大角度晶界增加,这都增强了焊接接头的耐点蚀穿孔的能力.

To clarify the corrosion resistance of high entropy alloy welded joint,the eutectic dual-phase high entropy alloy AlCoCrFeNi_(2.1) was welded by electron beam welding(EBW),and the corrosion resistance of the joint was studied by electrochemical corrosion method.The results show that the self-corrosion potential of weld zone(FZ)is about 0.16 V higher than the one of base metal(BM),the corrosion resistance is enhanced,and the self-corrosion current is reduced by one order of magnitude,and the corrosion rate is greatly reduced.The corrosion pits in the base metal area of the welded joint are expanding in depth,while the corrosion pits in the weld area are expanding horizontally,showing obvious phase selective corrosion.The grains in the weld area are obviously refined,the hardness is stable and slightly increased,and the two-phase distribution presents a dense"network"trend,which is more uniform than the macro distribution of elements in the base metal.These contributes for enhancing the corrosion resistance and penetration of welded joints.