Environmental Engineering Reference
In-Depth Information
7
Liquid Metal Attack
7.1 INTRODUCTION
The attack of solid metals by liquid metals may be manifested in the following
forms:
1.
Instantaneous failure of a solid metal under applied or residual stresses when
in contact with a liquid metal
2.
Delayed failure of a solid metal in contact with a liquid metal at a static
stress level below the tensile strength of the metal
3.
Stress-independent grain boundary penetration of a solid metal by liquid metal
4.
High-temperature corrosion of a solid metal by a liquid metal
The first two types are generally referred to as
liquid metal embrittlement
(LME) or
liquid metal-induced embrittlement
(LMIE). Liquid metal embrittle-
ment and liquid metal corrosion have been discussed in the following sections.
7.2 LIQUID METAL EMBRITTLEMENT
The catastrophic brittle failure of a solid metal under stress in contact with a
liquid metal is known as liquid metal embrittlement (LME). The loss of ductility
of a normally ductile metal or alloy is manifested as a reduction in fracture stress,
strain, or both. A change in the fracture mode from ductile to brittle intergranular
or brittle transgranular (cleavage) is also normally encountered, though embrittle-
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