What causes liquid metal cracking? The mechanism of liquid
metal cracking is clearly not electrochemical in nature. It is
most probably an adsorption-induced cracking. The liquid metal
atoms when adsorbed on a susceptible metal or alloy reduces
the metal bond strength within the grain boundary regions of
the susceptible metal. Under tensile stress, crack initiates
and propagates rapidly along the grain boundaries.What is
liquid metal embrittlement? Liquid Metal Embrittlement (LME)
refers to environmental cracking caused by contact with a
liquid metal. It is also known or as Liquid Metal Cracking
(LMC). There is a specific combination of liquid metals and
stressed metals or alloys that can lead to catastrophic
intergranular cracking. For example, carbon steels and
stainless steels are susceptible to liquid metal embrittlement
by zinc and lithium; aluminum and aluminum alloys are
susceptible to liquid metal embrittlement by mercury and zinc;
copper and copper alloys are susceptible to liquid metal
cracking by mercury and lithium. Cracking is frequently
observed to be a single intergranular crack that propagates
rapidly, at a rate of 25 cm/s. Mercury-containing items are
prohibited by all airlines as they pose a real risk to the
structural integrity of the aircraft which is made of aluminum
alloys. Zinc from galvanized steel parts or zinc-rich paints
is frequently found to be responsible for the cracking of
welded steel components in various industries.
