MELTS

Melts, in general, refers to substances that have transitioned from a solid to a liquid state, or to the liquids themselves produced by melting. The term appears in science, industry, and culinary contexts.

In physics and materials science, melting is an endothermic phase transition at a characteristic temperature known as the melting point. For pure crystalline substances, solid to liquid occurs at a single temperature; impure materials melt over a range due to different components. Latent heat of fusion accompanies melting, and pressure can influence the melting temperature according to phase diagrams.

Industrial and metallurgical contexts use melting to produce molds, alloys, and glass. Metal and glass melts are heated in furnaces and then poured into molds, alloyed with other elements, or formed by casting. The term melt describes the liquid state before solidification, and cooling rate and composition determine the resulting microstructure and mechanical properties.

Geology and planetary science describe melting of rocks to form magma. Partial melting produces melts enriched in volatile elements and incompatible elements. Melting temperatures vary by mineral and pressure; subsequent crystallization and mixing create diverse igneous rocks.

Culinary usage uses melts to describe hot sandwiches with melted cheese, such as patty melts and tuna melts. The name emphasizes the cheese becoming fluid as the sandwich is heated.

Some scientific software and studies use the term MELTS to denote thermodynamic models that simulate melt compositions and phase relations in magmatic systems.