In situ investigation of Al bicrystal embrittlement by liquid Ga using synchrotron imaging

The penetration behaviour of liquid Ga along two different types of symmetrical tilt Al bicrystals is analysed as a function of tensile load applied normal to the boundary plane by means of synchrotron radiation X-ray micro-radiography. A direct relation between the grain boundary energy and the applied load required to promote liquid metal embrittlement is evidenced. Analysis of the in situ penetration experiments allows us to establish a link between crack velocity and the stress intensity factor. The thickness of the intergranular liquid Ga film is compared to the expected crack opening which accompanies crack propagation in mode I loading conditions.