Ab initio calculation of the BCC Fe-Al-Mo (Iron-Aluminum-Molybdenum) phase diagram: Implications for the nature of the tau(2) phase

Author(s)

Sodre, Ney ^[1] ; Gonzales-Ormeno, Pablo Guillermo ^[2] ; Petrilli, Helena Maria ^[1] ; Schoen, Claudio Geraldo ^[3]

Affiliation

^[1] Univ Sao Paulo, Inst Fis, Dept Fis Mat & Mecan, BR-05315970 Sao Paulo - Brazil

^[2] Univ Nacl Callao, Fac Ciencias Nat & Matemat, Bellavista, Callao - Peru

^[3] Univ Sao Paulo, Escola Politecn, Dept Met & Mat Engn, Computat Mat Sci Lab, BR-05508900 Sao Paulo - Brazil

• Document type: Journal article
• Source: CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY; v. 33, n. 3, p. 576-583, SEP 2009.
• Web of Science Citations: 10

Abstract

The metastable phase diagram of the BCC-based ordering equilibria in the Fe-Al-Mo system has been calculated via a truncated cluster expansion, through the combination of Full-Potential-Linear augmented Plane Wave (FP-LAPW) electronic structure calculations and of Cluster Variation Method (CVM) thermodynamic calculations in the irregular tetrahedron approximation. Four isothermal sections at 1750 K, 2000 K, 2250 K and 2500 K are calculated and correlated with recently published experimental data on the system. The results confirm that the critical temperature for the order-disorder equilibrium between Fe(3)Al-D0(3) and FeAl-B2 is increased by Mo additions, while the critical temperature for the FeAl-B2/A2 equilibrium is kept approximately invariant with increasing Mo contents. The stabilization of the Al-rich A2 phase in equilibrium with overstoichiometric B2-(Fe,Mo)Al is also consistent with the attribution of the A2 structure to the tau(2) phase, stable at high temperatures in overstoichiometric B2-FeAl. (C) 2009 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 06/02470-0 - Monte Carlo modeling of the interaction between configurational order and point defects in iron aluminides
• Grantee: Claudio Geraldo Schon
• Support Opportunities: Regular Research Grants