Chemistry, bonding and fracture of grain boundaries in Ni3Si

Studies of local bonding and chemistry at internal interfaces using electron energy loss spectroscopy

“…This shifts states away from the main d-band to the tails resulting in a decrease in the DOS at the Fermi level leading to a decrease in the white line intensity at the peak onset. EELS and X-ray absorption spectra recorded from bulk Ni 2 Si and Ni 3 Si show that the white line intensity is reduced in bulk Ni 2 Si with respect to Ni [5,36,40], consistent with the above model. In the work by Muller et al [32], the Ni L 3 edge at the grain boundary is compared to that recorded from the bulk.…”

“…A similar study was conducted on grain boundaries in Ni 3 Si (Ni-23 %Si) [40]. The boundaries were found to be Ni-rich using ADF imaging and EDX analysis.…”

“…This method places stringent requirements on the performance of the microscope and detector system with regard to stability, detector efficiency and energy resolution. The study on grain boundaries in Ni 3 Al and Ni 3 Si was done using this method [32,39,40]. (B) In the spatial difference method [28], a spectrum is obtained with the beam scanning over an area containing the interface or with a probe placed at the interface, of a size such that it includes the bulk as well as the interface.…”

“…Recently, this technique has been used to study the effect of segregated elements on the local electronic structure at grain boundaries in a few systems. This paper reviews the relationship between the near edge fine structure in EELS and local electronic structure and illustrates the application of the technique with examples from a study conducted on the effect of boron on grain boundaries in Ni3Al and Ni 3 Si [32,39,40] from the authors' work, and one by Bruley et al [9] on the effect of Bi on grain boundaries in Cu. The paper also briefly discusses fine structure studies at metal-ceramic interfaces.…”

Nanoresolution profiling of metal-metal interfaces from x-ray Fraunhofer diffraction data

“…It will, in future, be necessary to combine the atomic-scale spatial resolution of the techniques of high-resolution analytical transmission electron microscopy and atom probe field ion microscopy, which require destructive preparation of thin sections for analysis, and the rapidly improving spatial resolution, the high energy resolution, and statistically averaged accuracy of high-resolution two-dimensional ͑2D͒ and threedimensional ͑3D͒ x-ray diffraction microscopy techniques 6,7 using high intensity ͑synchrotron͒ x-ray sources, which potentially permit nondestructive characterization of interfaces embedded in macroscopic sections. Unlike early synchrotron x-ray scattering studies of embedded interfaces 8,9 which were limited to quantitative intensity measurements, the present work uses a highly coherent x-ray source and phase retrieval x-ray diffractometry ͑PRXRD͒ to map the complex refractive index variation in such interfaces. In this initial phase of the work, we focus on artificial and macroscopic interfaces created by simple mechanical abutment of dissimilar metals/alloys, in order to demonstrate the hitherto untested extension of this approach into synthesis of the real and imaginary components of the complex refractive index of a material, and the potential of the technique to contribute to the characterization of interfaces between dissimilar metals.…”