A eutectic system or eutectic mixture is a homogeneous mixture that has a melting point lower than those of the constituents. The lowest possible melting point over all of the mixing ratios of the constituents is called the eutectic temperature. On a phase diagram, the eutectic temperature is seen as the eutectic point (see plot above). [ref]

InBsSn alloy, often called Field's Metal, is a fusible alloy that becomes liquid at approximately 62 °C. It is a eutectic alloy of bismuth, indium, and tin, with the following mass fractions: 32.5% Bi, 51% In, 16.5% Sn. When prepared, Field's metal can be melted in hot water.  [ref]

The ingot is a mass of metal cast into a convenient shape for storage or transportation to be later processed, while the particle is a minute quantity or fragment. In many cases, ingots are processed to become particles and the processing parameters determine the size and shape of the particles.