The relative stability of Al11Sm3 (Al4Sm) intermetallic phases was experimentally investigated through a series of heat treatments followed by microstructural, microchemical, and X-ray diffraction (XRD) analyses. The principal findings are that the high-temperature tetragonal phase is stable from 1655 to 1333 K and that the low-temperature orthorhombic phases, α and γ, have no range of full stability but are metastable with respect to the crystalline Al and Sm reference states down to 0 K. Thermodynamic modeling is used to describe the relative energetics of stable and metastable phases along with the associated two-phase mixtures. Issues regarding transition energetics and kinetics are discussed.
Copyright 2007 ASM International. This paper was published in Metallurgical and Materials Transactions A, Vol. 38, Issue 6, pp. 1145-1151 and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.
Shihuai Zhou and Ralph E. Napolitano. "The Stability of Al11Sm3 (Al4Sm) Phases in the Al-Sm Binary System" Metallurgical and Materials Transactions A
Vol. 38 Iss. 6 (2007) p. 1145 - 1151
Available at: http://works.bepress.com/ralph_napolitano/14/