Liquid metal Liquid metal Liquid metal consists of alloys with very low melting points which form a eutectic that is liquid at room temperature. The standard metal used to be mercury, but gallium-based alloys, which are lower both in their vapor pressure at room temperature and toxicity, are being used as a replacement in various applications. A few elemental metals are liquid at or near room temperature. The most well known is mercury(Hg), which is molten above −38.8 °C (234.3 K, −37.9 °F). Others include caesium(Cs), which has a melting point of 28.5 °C (83.3 °F), rubidium (Rb)(39 °C [102 °F]), francium
Transient liquid phase diffusion bonding diffusion occurs when a melting point repressant element from an interlayer moves into lattice and grain boundaries of the substrates at the bonding temperature. Solid state diffusional processes lead to a change of composition at the bond interface and the dissimilar interlayer melts at a lower temperature than the parent materials. Thus a thin layer of liquid spreads along the interface to form a joint at a lower temperature than the melting point of either of the parent materials. This method differs from brazing in that it is "isothermally solidifying". While holding the temperature above the filler metal melting point,