Ni-Cr-Mo-Fe-W合金中宏观“黑斑”缺陷特征的形成

On formation of macroscopic “freckle” defect feature in Ni-Cr-Mo-Fe-W alloy

采用晶界萃取碳复型等实验技术，研究了Ｎｉ－ Ｃｒ－ Ｍｏ－ Ｆｅ － Ｗ 合金宏观“黑斑”缺陷特征的微观形成机制．该合金中“黑斑”缺陷的形成归因于钨、钼等元素在这里的富集．富集的钨、钼元素主要以数量较多、尺寸较大的富含钼、钨的Ｍ６Ｃ和Ｐ相的形式存在于晶界上，使“黑斑”区的晶粒细小、晶界易受侵蚀且弱化．

The study on formation of macroscopic “freckle” defect feature in a Ni-Cr-Mo-Fe-W alloy by means of techniques such as extraction of carbon replica from grain surfaces indicates. The “freckle” defects were formed in the alloy because of the enrichment of tungsten and molybdenum in the form of a large number of M 6C and P phases with larger size at grain boundaries, which results in very small grains and active corrosion at brittle grain boundaries in the “freckle” areas.