How do the solidification processes of alloys differ from pure metals?

The solidification processes of alloys differ from pure metals primarily in that most alloys begin solidifying at the liquidus temperature. In the context of alloy solidification, the liquidus temperature refers to the temperature at which the first solid phase begins to form as the alloy cools. This is a critical concept because alloys, which consist of two or more elements, do not have a uniform melting point like pure metals. Instead, the presence of multiple components in an alloy leads to a range of solidification temperatures, typically characterized by the existence of both solid and liquid phases during cooling.

In contrast, pure metals have a definitive melting point, solidifying at a sharp temperature rather than through a range. This marked temperature difference is due to the different atomic structures and bonding characteristics in pure metals compared to the complex interactions within alloys.

As an additional point, while solidification of alloys may occur at lower temperatures compared to pure metals, it is not a universal rule and depends on the specific types of alloys and pure metals being compared. Hence, this makes the notion that most alloys begin solidifying at the liquidus temperature a fundamental aspect of their solidification process.