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MATERIALS ENGINEERING

SEMINAR

“Liquid Metal Embrittlement Induced by Gallium-based Liquid Metal”

By

Yifan Wu

Purdue MSE Preliminary Exam

Advisors: Professor Carol A. Handwerker and Professor John E. Blendell

ABSTRACT

Liquid metal embrittlement (LME) is a phenomenon in which a normally ductile metal or alloy experiences loss of ductility when stressed while in contact with a liquid metal. Ga is of particular interest in the study of LME due to its relatively low melting point. Although LME has been discovered for over a century, the mechanism behind is yet fully understood. Current consensus on the occurrence of LME is decrease in interatomic bond strength induced by the adsorption of liquid metal. Recent progress in nanoscale characterization techniques, such as synchrotron X-ray radiography and in situ TEM shows that the Ga penetration-induced dislocation movement and localized plasticity at the penetration front of gallium. Advanced synchrotron X-ray tomography reveals the dependence of Ga liquid metal penetration on grain boundary energy. Computational methods provide an alternative approach in studying LME at an atomic scale. Atomistic simulation results show the effect of applied stress on grain boundary penetration at an atomistic scale as well as dislocation movement along the grain boundary. A new model, dislocation climb model, was proposed based on this observation to explain the occurrence and propagation of cracks in LME.

Key words: Liquid metal embrittlement, gallium liquid metal, grain boundary penetration

Date: Wednesday, December 11, 2019

Time: 8:00 A.M.

Place: ARMS 1109

School of Materials Engineering

Purdue University

Neil Armstrong Hall of Engineering

701 West Stadium Ave. Room 2200

West Lafayette, IN 47907

765-494-4105