Glass-to-metal seal absorb the stresses from thermal expansion mismatches. Due to its very low vapor pressure, indium finds use in glass-metal seals used in vacuum technology. Gallium is a soft metal with melting point at 30 °C. It readily wets glasses and most metals and can be used for seals that can be assembled/disassembled by just slight heating. It can be used as a liquid seal up to high temperatures or even at lower temperatures when alloyed with other metals (e.g. as galinstan). Mercury is a metal liquid at normal temperature. It was used as the earliest glass-to-metal seal and is still
Liquid metal embrittlement rate sensitive. Temperature also affects the kinetics of LME. An increase in strain rate increases the upper limit temperature as well as the crack propagation rate. In most metal couples LME does not occur below a threshold stress level. Testing typically involves tensile specimens but more sophisticated testing using fracture mechanics specimens is also performed. Many theories have been proposed for LME. The major ones are listed below; All of these models, with the exception of Robertson, utilize the concept of an adsorption-induced surface energy lowering of the solid metal as the central cause of LME. They have succeeded in