金属晶界在高温氧化中的作用

扼要阐述了金属材料晶界在纯金属与合金高温氧化中的 作用.指出金属中晶界面积增加(晶粒尺寸减小)有3种效应：改善合金抗氧化性能的有益的正 效应，相反为负效应以及双重效应.讨论了金属晶界扩散动力学基本方程的参数，如Tamman 温度及晶粒尺寸对其影响、晶粒形状因子(q)、晶界偏聚因子(s)、晶界夹角(θ)对晶界 扩散的影响.最后介绍了晶界作为高速扩散通道对合金晶间内氧化的重要作用.

THE ROLE OF METALLIC GRAIN BOUNDARY IN HIGH TEMPERATURE OXIDATION

This paper explains the role of metallic materials grain boundary in high temperature oxidation behaviour of pure metals and alloys in brief.There are three effects concerned of increased metallic materials grain boundary area (e.g.decreased grain size):(1) positive (benefici al) effect,improvement on oxidation resistance of metals,(2) in contradiction,ne gative (deleterious) effect,and (3) dual effect.The influences of parameters of fundamental equation of grain boundary diffusion,such as Tamman tem perature and influence of grain size on it， factor of grain shape (q)、fact or of GB segregation (s)、grain boundary angle (θ) on the grain boundar y diffusion were discussed,Finally,the importance of grain boundary acted as hig h velocity diffusivity pathways in the intergranular internal oxidation was intr oduced.