Abstract:The thermodynamic requirements of internal oxidation of Cu-Al alloy were systematically analyzed, and a zone chart of internal oxidation thermodynamics was drawn. The results indicate that the preferential oxidation zone is quite large in the zone chart, and is determined by the maximum and minimum partial pressure of oxygen, where=(max)O2lgP(17 611/T)+12.91,=(min)O2lgP (55 830/T)(4/3)lg[%Al]+19.95. In fact the practical internal oxidation zone is a small part of the preferential oxidation zone near the maximum partial pressure of oxygen. The volume concentration product Ksp and concentration of residual aluminum are so low that the internal oxidation can procede completely. The temperature and partial pressure of oxygen should be adjusted synchronously during the control of internal oxidation. The optimum conditions for internal oxidation are heat treatment at a high temperature of about 1 223 K, and a high oxygen partial pressure approaching or even equal to the upper limit. Rapid cooling with hydrogen is used to prevent oxidation of the copper.