High temperature phase decomposition in TixZryAlzN
2014 (English)In: AIP Advances, ISSN 2158-3226, E-ISSN 2158-3226, Vol. 4, no 12, 127147-1-127147-9 p.Article in journal (Refereed) Published
Through a combination of theoretical and experimental observations we study the high temperature decomposition behavior of c-(TixZryAlzN) alloys. We show that for most concentrations the high formation energy of (ZrAl)N causes a strong tendency for spinodal decomposition between ZrN and AlN while other decompositions tendencies are suppressed. In addition we observe that entropic effects due to configurational disorder favor a formation of a stable Zr-rich (TiZr)N phase with increasing temperature. Our calculations also predict that at high temperatures a Zr rich (TiZrAl)N disordered phase should become more resistant against the spinodal decomposition despite its high and positive formation energy due to the specific topology of the free energy surface at the relevant concentrations. Our experimental observations confirm this prediction by showing strong tendency towards decomposition in a Zr-poor sample while a Zr-rich alloy shows a greatly reduced decomposition rate, which is mostly attributable to binodal decomposition processes. This result highlights the importance of considering the second derivative of the free energy, in addition to its absolute value in predicting decomposition trends of thermodynamically unstable alloys.
Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2014. Vol. 4, no 12, 127147-1-127147-9 p.
IdentifiersURN: urn:nbn:se:liu:diva-110682DOI: 10.1063/1.4905138ISI: 000347170100078OAI: oai:DiVA.org:liu-110682DiVA: diva2:748114
On the day of the defence date the status of this article was Manuscript.2014-09-182014-09-182015-06-01Bibliographically approved