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对一种镍基高温合金进行电场和脉冲电流处理,研究了电效应对合金组织及腐蚀行为的影响。结果表明,在保证力学性能基本不变的前提下,合金的抗晶间腐蚀能力均得到改善。电场作用下,合金中退火孪晶比例增加,使得大量原始大角度晶界被低能晶界取代,连续分布的原始大角度晶界被分割,降低了晶界Cr、Mo等合金元素的贫化程度,从而导致沿晶腐蚀沟的形成与生长被抑制。而脉冲电流对抗腐蚀性能的贡献,主要是由于电效应能够促进合金元素的扩散(尤其是界面扩散速度),使M23C6型碳化物在晶界处呈不连续析出,从而大幅度降低了大角度晶界处合金元素的贫化现象。因此,在保证力学性能不变的前提下,合金的抗晶间腐蚀能力得到大幅度提高。
A nickel-based superalloy was subjected to electric field and pulsed current processing to study the effect of electrical effects on the microstructure and corrosion behavior of the alloy. The results show that under the premise of ensuring the mechanical properties remain unchanged, the intergranular corrosion resistance of the alloy is improved. Under the action of electric field, the ratio of annealing twins in the alloy increases, so that a large number of original large-angle grain boundaries are replaced by low-energy grain boundaries. The continuously distributed original large-angle grain boundaries are segmented, reducing the degree of depletion of alloying elements such as Cr and Mo , Resulting in the formation of intergranular corrosion groove and growth is inhibited. The contribution of pulse current to corrosion resistance is mainly due to the fact that the electrical effect can promote the diffusion of alloying elements (especially the interfacial diffusion rate), causing the M23C6 carbides to be discontinuously precipitated at the grain boundaries, thereby greatly reducing the large angle crystal Boundary Department of the depletion of alloying elements. Therefore, to ensure the same mechanical properties under the premise of the alloy’s resistance to intergranular corrosion has been greatly improved.