Deformation and Fracture Mechanisms in Thin Films and Beryllium Intermetallics

摘要

The overall goal of this program was to investigate the mechanical properties ofseveral Be intermetallics for the purpose of evaluating their suitability for high temperature structural applications. This program enabled the completion of research on the fracture toughness of thin films and the deformation behavior of Be12X compounds. The grant enabled the extension of previous thin film work to include tests of thin brittle films on elastic-plastic substrates in order to measure the fracture toughness of the film and the film substrate interface. The atomistic modeling had been focused on a study of the atomic arrangement in the core of several different types of dislocations in Be12X. This work was extended to examine the energetics of the transformation of the bct Be12X phase to the rhombohedral Be17X2 phase by the repeated faulting. There is the potential that this deformation operation could produce a structure with enhanced plasticity.