Liquid metal embrittlement in failure analysis

Liquid metal embrittlement (LME) is one of the least studied forms of environmental fracture. The phenomenon has been recognised for over a century, but although industrially important, it has not received the same attention as other forms of environmental cracking such as stress corrosion cracking or hydrogen embrittlement. The characteristics of how LME behaves are less well understood and there are several conflicting models for the micromechanics of LME. While LME is not fully understood, it is readily recognized as a mode of failure. In the first part of this paper, are view of some of the instances where LME has been observed is presented. While this is not comprehensive, the aim of the work is to identify some of the common areas where LME has been a problem and to try to examine some of the methods frequently used to avoid its future occurrence. The paper is written from the perspective of the authors` experiences as failure investigators and is a representation of past experience in the investigation of LME failures. In the second part of this paper, some of the work currently being carried out at the CUED on the behavior of LME cracks is described. A great deal of previous work was carried out on the LME behavior of plain cylindrical tensile tests and a considerable amount of information is currently available on the effects of various experimental parameters on the behavior of these specimens. 19 refs.