The high temperature oxidation behavior of a superalloy prepared by vacuum induction melting and electron beam smelting: A comparative study

Abstract

In this paper, the high temperature oxidation behavior of superalloys prepared by the electron beam smelting (EBS) and vacuum induction melting (VIM) at 900 °C and 1000 °C is investigated. Experimental results indicate that EBS alloys show better oxidation resistance and oxide layer integrity. The relationship between the growth rates of Al2O3 and Ta2O5 and the oxygen partial pressure at the oxide/substrate interface is explained by the growth model of n-type semiconductor oxides. Lower oxygen partial pressure can be achieved at the oxide/substrate interface due to the higher purity of the EBS alloys. This effectively slows down the growth rate of the n-type semiconductor oxides such as Al2O3 and Ta2O5 and the thickening rates of the other n-type oxides, which ultimately leads to better oxidation resistance.