Investigation of the conditions required for the formation of (Ti,W)(CN) during carburization of titanium under nitrogen

Abstract

Phase stability diagrams for a Ti-W-C-N system were constructed as a function of carbon activity and nitrogen pressure. It was found that the stability domains of titanium carbonitride (Ti(CN)) and W disappeared due to the high stability of the (Ti, W)(CN) phase when the Ti: W molar ratio was 3:1. When the Ti: W molar ratio was changed to 1:1, the phase stability domain of (Ti, W)(CN) reduced and the phase stability diagram consisted of Ti, W, Ti(CN), and (Ti, W)(CN). Finally, when the Ti: W molar ratio was 1:3, the stable region of (Ti, W)(CN) phase disappeared due to the low affinity between W and N. The results of this study can be used as a practical guideline for preparing a toughened (Ti, W)(CN) phase using Ti/W mixtures. (C) 2017 Elsevier B.V. All rights reserved.