Final answer:
The eutectic transformation occurs at the eutectic point, involving the change from a liquid phase to typically two solid phases with fixed compositions. The enthalpy changes during this transformation, such as the enthalpy of fusion, signify the energy involved in the phase change at that temperature.
Step-by-step explanation:
The temperature at which the eutectic transformation occurs is specific to the substances involved in the alloy or mixture. This transformation takes place at a fixed temperature where the liquid phase becomes two or more distinct solid phases at equilibrium; this temperature is known as the eutectic point. The phases involved in eutectic transformation include a liquid phase and usually two solid phases, which have specific chemical compositions dependent on the system being observed. These compositions are represented by points on the phase diagram of the alloy or mixture.
For example, in a simple binary alloy system, the eutectic transformation might involve the change from a liquid phase to two solid phases, α and β, each with a different composition. The enthalpy changes associated with this transformation, which include the enthalpy of fusion, reflect the energy required to change from one phase to another at the eutectic temperature which is isothermal.