  Many systems where a liquid metal is in contact with a polycrystalline solid
exhibit deep liquid grooves where the grain boundary meets the solid-liquid
interface. For example, liquid Ga quickly penetrates deep into grain boundaries
in Al, leading to intergranular fracture under very small stresses. We report
on a series of molecular dynamics simulations of liquid Ga in contact with an
Al bicrystal. We identify the mechanism for liquid metal embrittlement, develop
a new model for it, and show that is in excellent agreement with both
simulation and experimental data.
