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本文利用分析电子显微术及化学分析方法研究了GH220合金中镁的分布及存在方式,应用蠕变过程的动态观察,研究了含镁及无镁合金的蠕变变形特征。实验分析表明:在最佳镁含量合金中,一部分镁不均匀地填隙于晶界上碳化物与基体(或γ′)的非共格的界面上,形成100 A左右尺寸的Ni_2Mg相;在碳化物颗粒之间有点阵常数为12～14 A的面心立方点阵的含镁相析出。从而降低了晶界空位浓度,减缓了空位扩散型攀移造成的晶界滑动,使得晶内γ′和基体及晶界上的碳化物有时间得以充分变形以与晶界被减缓的滑动协调,降低了稳态蠕变速率。
In this paper, the distribution and existence of magnesium in GH220 alloy were studied by means of analytical electron microscopy and chemical analysis. The creep deformation characteristics of magnesium-containing and magnesium-free alloy were studied by dynamic observation of creep process. The experimental results show that a part of magnesium is interstitially interstitially filled in the non-coherent interface between the grain boundary carbides and the matrix (or γ ’) to form a Ni_2Mg phase of about 100 A in the best magnesium alloy. Carbide particles have a lattice constant of 12 ~ 14 A face-centered cubic lattice of magnesium-containing phase precipitation. Thereby reducing the grain boundary vacancy concentration and slowing the grain boundary sliding caused by the vacancy diffusion type climbing so that the γ ’in the grain and the carbide on the grain boundary and the grain boundary have sufficient time to be coordinated with the slow sliding of grain boundaries, Reduced steady-state creep rate.