Carburization of Hastelloy alloy X

The carburization of Hastelloy alloy X has been studied by the standard tracer techniques using ¹⁴C over the temperature range 700 to 1100°C in vacuo and helium environment. The ¹⁴C activity in the specimen decreases exponentially with the depth of penetration and increases with carburization time. It is observed that carbon diffusion in the alloy is dominated by grain-boundary diffusion. The effect of oxygen in helium gas on carburization is observed. Oxygen has two opposite types of action on carburization of the alloy. One is inhibitive action and the other is accelerative action.