COST 507 - Repositório Aberto da Universidade do Porto

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^ Cu8Zr3
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MOLE FRACTION MG
Figure 5. The assessed Cu­Mg­Zr phase diagram at 500 °C with the τ phase.
3 The Al­Li­Cu­Mg system
3.1 Introduction
The experimental study of the Al­Li­Cu­Mg system was carried out by the Baikov
Institute of Metallurgy [94Rok].
3.2 Experimental part
The phase relations in the Al­rich alloys containing up to 7 wt.% Li, 7 wt.% Mg, and
10 wt.% Cu were investigated. Microscopy analysis, quality local X­ray spectral
analysis, and X­ray phase analysis were applied. The alloys were prepared by melting
in alumina crucibles in electrical resistivity furnace under flux containing 80 wt.%
LiCl + 20 wt.% LiF preserving from Li burning out. The alloys were poured into
copper mould with round cavity of 15 mm in diameter. The ingots were squeezed by
50% reduction of their height and cut into pieces. One part the pieces was placed into
silica ampoules which were evacuated and then filled by Ar up to 0.5 bar. The
ampoules were annealed at 500 °C for 50 hours or at 400 C C for 100 hours followed
by quenching into cold water. These samples were used for construction of the
isothermal sections. The other part of pieces were used for differential thermal
analysis needed for construction of the polythermal sections [96Rok].
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