Phase Equilibria in the System Ag-Cu-Si

Hans Flandorfer,Hongwei Yang,Klaus W Richter,Gabriel Reisinger

doi:10.1007/s11669-020-00781-w

Abstract

The ternary alloy system Ag-Cu-Si was investigated in detail for the first time. The phase diagram was analysed by means of light optical microscopy, powder x-ray diffraction, differential thermal analysis (DTA) and scanning electron microscopy in combination with energy dispersive x-ray spectroscopy. The complete isothermal section at 650 °C was studied experimentally, and several additional samples were studied in order to obtain insight into phase equilibria with the high-temperature phases of the binary Cu-Si system. DTA studies in two vertical sections were used to determine ternary invariant phase reactions and to construct the ternary reaction scheme (Scheil diagram). A liquidus surface projection was constructed by combining these data with microstructure analysis of selected as-cast samples.

Highlights

Introduction and Literature ReviewPhase equilibria of the ternary system Ag-Cu-Si L ? (Cu)-Si was not studied in detail up to now, alloys containing these metals have been studied for their potential as filler materials in brazing applications
Phase equilibria of the ternary system Ag-Cu-Si was not studied in detail up to now, alloys containing these metals have been studied for their potential as filler materials in brazing applications
A total number of approximately 30 samples was prepared and annealed at 650 °C for 14 days. These samples were organized in sections at 5, 10, 20 and 25 at.% Ag in order to have a sufficient basis for the analysis of the ternary phase reactions in these vertical sections doing differential thermal analysis (DTA), see sections 3.2 and 3.3

Summary

Introduction and Literature Review

Phase equilibria of the ternary system Ag-Cu-Si was not studied in detail up to now, alloys containing these metals have been studied for their potential as filler materials in brazing applications. A critical assessment including all literature up to 1982 was given by Olesinski and Abbaschian.[3] A more recent thermodynamic assessment of the system has been given by Yan and Chang.[4] New experimental investigations with focus on the Cu-rich part have been performed in 2011 by Sufryd et al.[5] The binary compounds are all situated in the Cu-rich part of the phase diagram, starting with Cu3Si, being the compound richest in silicon This phase shows three different modifications: the high-temperature g-phase, an intermediate phase g0 and the low.

Experimental

Results and Discussion

Samples Annealed at Higher Temperatures

U4 E2 U3 U6 Invariant other Non-invariant Liquidus heating