[Originally posted to material science forum but no reply] It's no surprise that if I take a particular metal and 'add' atoms of a second metal that has a lower melting point that the Tmelt of the combination is usually lower than that of the pure metal. This is hypoeutectic composition. But it seems surprising that if a reverse this, take a low Tmelt metal and add atoms of a higher Tmelt the Tmelt of the combination is even lower. This is hypereutectic composition. In fact there is a minimum of Tmelt at the Eutectic composition. Any insight into why adding a few percent of a higher Tmelt metal can lower the Tmelt of the combination?