Phase Diagrams

· The lead-tin binary system is an example of a eutectic alloy.
· For this system the eutectic invariant temperature is 183 C, and the composition of the eutectic alloy is Pb-61.9 wt % Sn.

· Two regions exist in which substitutional alloys occur. These are designated α and β on the phase diagram.
· Three two-phase zones also exist: a + L, β + L, and α + β.
· In the liquid phase the full range of compositions may be realized above 327 C.

From: Callister, "Materials Science and Engineering," Wiley (1994)