Unravelling LME

Why does a solid metal that is engineered for ductility become brittle, often suddenly and with dramatic consequences, in the presence of certain liquid metal impurities? The phenomenon, known as liquid metal embrittlement, or LME, has baffled metallurgists for a century. Now, a team of Lehigh ceramics researchers has shed light on LME by obtaining atomic-scale images of unprecedented resolution of the grain boundaries, or internal interfaces, where LME occurs. In doing so, says Martin Harmer, professor of materials science and engineering, the researchers have achieved the first direct observation in a metal system of a bilayer grain boundary phase transition. The findings were covered by several nanoscience media outlets including Nanowerk, Nanotechnology Now, Science Daily, and Red Orbit.

Unravelling LME

The aberration-corrected scanning transmission electron microscope (STEM) reveals a bilayer of bismuth atoms at a grain boundary in the nickel-bismuth alloy.