Measurement of panar fault energies in Ni_3Ge-Fe_3Ge intermetallic alloys

摘要

a combination of transmission electron microscopy (TEM) and image simulations has facilitated a highly quantitative measure of superdisolocation dissociations. The experimental observations have been corrected for images shifts within the framework of anisotropic elasticity by comparison with simulated images. This allows experimental quantification of planar fault energies, thus providing a benchmark for first principles the atomistic simulations and fundamental insight towards alloy modeling and design. Such measurements of superdislocation dissociations on the order of 1-15 nm have been receorded for the pseudobinary Ni_3Ge-=Fe_3Ge alloy system. These detailed measurements of fault widths obtained by weak-beam TEM observationsd of deformation structures will be presented and discussed as a function of alloy composition. The transition from anomalous to normal temperature dependence of yielding behavior in these alloys will also be discussed in terms of observed dislocation structures and planar fault energies calculated using the above measurements.