Incubation Behavior Of Hg-Lme In Aluminum

When high strength aluminum alloys are subjected to liquid metals, physical and chemical reactions ensue resulting in what is known as liquid metal embrittlement (LME). A subset of environmentally-assisted cracking, LME is exhibited when a liquid metal, e.g. Hg or Ga, comes into intimate contact with a solid metal having significant susceptibility. As mechanical loads are applied, the interaction between the two metals results in a reduction in the flow properties of the solid metal. Several theories have been proposed to identify the underlying microstructural failure mechanism; however, none have been widely accepted. Crack growth experiments on Al 7075-T651 in liquid mercury have been conducted to extend these physically-based theories. Through constant initial stress intensity factor (SIF) tests, incubation periods were analyzed, providing data for a load-based theory of LME. These mechanical test data, along with metallographic analysis, show that the phenomena of LME are both time- and SIF-dependent