Specificity in liquid metal induced embrittlement

Abstract

One of the most intriguing features of liquid metal induced embrittlement (LMIE) is the observation that some liquid metal-solid metal couples are susceptible to embrittlement, while others appear to be immune. This is referred to as the specificity of LMIE. A number of theories have been developed in an attempt to predict the occurrence of LMIE in untested liquid metal-solid metal couples based on two observations of embrittling couples, namely the low mutual solubility and the lack of intermetallic compounds between the solid and liquid metals. To study the embrittlement of two brass alloys by molten gallium (Tm = 29.8 °C), Tensile tests on smooth, unnotched specimens were used. The alloys used were CZ106, a 70/30 alpha-brass, and CZ109, a 60/40 alpha-beta brass. Both alloys were in the annealed condition. Tests were conducted over a range of temperatures and strain rates, both with and without molten gallium. These results indicate clearly that CZ106 brass is, in fact, susceptible to LMIE given the appropriate testing conditions. Furthermore, subsequent tests on pre-cracked, fracture mechanics type specimens of CZ106 brass confirm that this material is susceptible to embrittlement in molten gallium.