Insight into the complex ternary phase behavior in Al-Mn-Ce alloys

Autor(es)

Coury, Francisco Gil ^[1] ; Pires, Elcio L. ^[2] ; Wolf, Witor ^[2] ; Paes de Almeida, Fernando H. ^[2] ; Costa e Silva, Andre Luiz ^[3] ; Botta, Walter J. ^[2] ; Kiminami, Claudio S. ^[2] ; Kaufman, Michael J. ^[1]

Afiliação do(s) autor(es)

^[1] Colorado Sch Mines, Dept Met & Mat Engn, 1500 Illinois St, Golden, CO 80401 - USA

^[2] Univ Fed Sao Carlos, Dept Engn Mat, Rodovia Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[3] Univ Fed Fluminense, Escola Engn Ind Met Volta Redonda, Av Trabalhadores 420 Vila Santa Cecilia, 1R-27255125 Volta Redonda, RJ - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Alloys and Compounds; v. 727, p. 460-468, DEC 15 2017.
• Citações Web of Science: 3

Resumo

The subtle change in the space group that occurs in the Al12-xMnxCe tau t phase as the Al/Mn ratio is varied in the Al-Mn-Ce system was characterized using scanning electron microscopy and analytical transmission electron microscopy and the atom positions associated with this change were refined using x-ray diffraction. In addition, the reaction temperatures were identified using differential scanning calorimetry. Understanding the nature of this phase is of particular importance because of its presence in a series of high strength, high temperature alloys that are being pursued in this system. It is shown that there are two distinct space groups for the t phase that are related to one another and depend on the Al/Mn ratio - at lower ratio, the space group is I4//mmm but at higher Al/Mn ratio, the Mn and Al atoms order on one of the Wyckoff sites in the I4/mmm structure and the ordering plus slight distortions away from the symmetry positions causes a loss of the body centering and a change to the P4/nmm space group with a unit cell approximately twice that of the I4/mmm cell. The results provide clarification to the conflicting reports in the literature and lead to a clearer assessment of the phase equilibria in the Al-rich portion of the Al-Mn-Ce system. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 13/24530-9 - Mecanismo de formação de fase quasicristalina em ligas de alumínio sob baixas taxas de resfriamento a partir do líquido
• Beneficiário: Francisco Gil Coury
• Modalidade de apoio: Bolsas no Brasil - Mestrado