Termelt

Termelt is a term used in materials science to describe non-equilibrium, thermally induced melting processes in crystalline solids. It denotes a regime where melting proceeds under conditions of rapid heating or high thermal gradients, so that the observed transition temperature differs from the equilibrium melting point and the process is strongly influenced by microstructural state, defects, and grain boundaries. The concept was introduced to distinguish rapid, non-equilibrium melting from classic equilibrium melting and to emphasize kinetic control in phase-change materials and laser-assisted processing.

The termelt framework considers both thermodynamic driving forces and kinetic barriers. Key quantities include the non-equilibrium onset temperature, the apparent melting range, and the rate of latent heat absorption under fast heating. It is studied with techniques such as differential scanning calorimetry, high-speed infrared thermography, and in-situ X-ray diffraction or electron diffraction during rapid heating.

Applications include additive manufacturing, laser-assisted alloy refinement, and thermal energy storage materials, where controlling the onset and progression of melting affects microstructure and performance. In practice, termelt remains a topic of discussion, as researchers debate definition, measurement conditions, and its relationship to conventional melting points and phase transitions.

Etymology: termelt is formed from combinations of "thermal" and "melt," and is sometimes used informally to refer to non-equilibrium melting phenomena; not universally standardized.