Embrittlement of Zinc Monocrystals and Bicrystals by Mercury and Gallium

摘要

A study was made of the fracture behavior of zinc monocrystals and asymmetric bicrystals tested in tension at room temperature while coated with liquid mercury or gallium. The results are consistent with the view that adsorption of the active liquid metal specifically at some stable obstacle to slip is a prerequisite for embrittlement. Thus, carefully prepared and handled monocrystals, oriented for single slip and tested in tension, are not embrittled by mercury or gallium unless these liquid metals are adsorbed specifically at kink bands formed during deformation in the vicinity of the grips. The data from the bicrystal studies provide experimental support for the theoretical criteria for fracture in zinc proposed by Likhtman-Shchukin and Gilman. From this data, a value of 48 = 3 ergs/sq cm was deduced for the fracture surface energy of zinc in the presence of mercury, in good agreement with an earlier determination of this quantity by the present authors. The results of the investigation are discussed with regard to earlier work by Shchukin and others. (Author)