unstableryan
CGN Ultra frequent flyer
- Location
- Beautiful Okanagan Valley
On the inside... I was hoping someone would bust out a phase diagram 
Alloys always melt at lower temperatures than their constituent metals. This is due to atomic size mismatch which makes the resultant crystal less stable thermodynamically. This difference can be substantial, as this phase diagram for lead-antimony shows:
You can see that pure lead on the left melts at 327.5°C, pure antimony on the right at 630.8°C. In between the various blends all have declining melting points until you hit the minimum at Pb-12%Sb, with a melting point of 252.2°C. This composition that yields the lowest melting point is called the eutectic composition. There are some alloys that will actually melt in the palm of your hand, notably the bismuth-tin eutectics.
