Experimental study of phase equilibria in the system Cu-Al-Sn

Chakrabarty, AK and Jacob, KT (2013) Experimental study of phase equilibria in the system Cu-Al-Sn. In: Journal of Phase Equilibria and Diffusion, 34 (4). pp. 267-276.

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Abstract

Phase equilibria in the Cu-rich corner of the ternary system Cu-Al-Sn have been re-investigated. Final equilibrium microstructures of 20 ternary alloy compositions near Cu3Al were used to refine the ternary phase diagram. The microstructures were characterized using optical microscopy (OM), x-ray diffraction (XRD), electron probe microanalysis and transmission electron microscopy. Isothermal sections at 853, 845, 833, 818, 808, 803 and 773 K have been composed. Vertical sections have been drawn at 2 and 3 at% Sn, showing beta(1) as a stable phase. Three-phase fields (alpha + beta + beta(1)) and (beta + beta(1) + gamma(1)) result from beta -> alpha + beta(1) eutectoid and beta + gamma(1) -> beta(1) peritectoid reactions forming metastable beta(1) in the binary Cu-Al. With the lowering of temperature from 853 to 818 K, these three-phase fields are shifted to lower Sn concentrations, with simultaneous shrinkage and shifting of (beta + beta(1)) two-phase field. The three-phase field (alpha + beta + gamma(1)) resulting from the binary reaction beta -> alpha + gamma(1) shifts to higher Sn contents, with associated shrinkage of the beta field, with decreasing temperature. With further reduction of temperature, a new ternary invariant reaction beta + beta(1) -> alpha + gamma(1) is observed at similar to 813 K. The beta disappears completely at 803 K, giving rise to the three-phase field (alpha + beta(1) + gamma(1)). Some general guidelines on the role of ternary additions (M) on the stability of the ordered beta(1) phase are obtained by comparing the results of this study with data in the literature on other systems in the systems group Cu-Al-M.

Item Type:	Journal Article
Publication:	Journal of Phase Equilibria and Diffusion
Publisher:	Springer
Additional Information:	Copyright of this article belongs to Springer.
Keywords:	Four-Phase Equilibrium; Invariant Reaction; Isothermal Section; Phase Diagram; System Cu-Al-Sn; Three-Phase Equilibria
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	02 Sep 2013 06:21
Last Modified:	02 Sep 2013 06:21
URI:	http://eprints.iisc.ac.in/id/eprint/46947

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