一、前言在高温合金中加入微量的镁,可以提高合金的使用性能,特别是持久性能,这已为冶金工作者所熟知。一些工作者研究了镁作为脱硫剂,可以改变硫的分布状况,消除低熔点硫化物共晶体;一些研究者认为添加镁可以减少晶界上的碳化物、硼化物和硫化物的数量。文献都指出,过量的镁形成镍镁相,从而引起合金塑性急剧变坏。本工作通过断口萃取碳复型技术,应用TEM观察研究了不同镁含量的NiCrMoTiNb合金晶界第二相的沉淀特征,发现镁的 First, the preface Adding a trace amount of magnesium in the superalloy, can improve the performance of the alloy, especially the long-lasting performance, which is well known to metallurgical workers. Some workers have studied magnesium as a desulfurization agent, which can change the distribution of sulfur and eliminate low-melting sulfide eutectics. Some researchers think that adding magnesium can reduce the amount of carbides, borides and sulfides on the grain boundaries. The literature points out that excess magnesium forms a nickel-magnesium phase, causing a drastic deterioration of the plasticity of the alloy. This work through the fracture extraction carbon compounding technology, the application of TEM observation of different Mg content NiCrMoTiNb alloy grain boundary precipitation characteristics of the second phase, found that magnesium