Mechanical Behavior of Titanium Based Metal Matrix Composites Reinforced with TiC or TiB Particles under Quasi-Static and High Strain-Rate Compression.

The mechanical behavior of titanium alloys has been mostly studied in quasi-static conditions when the strain rate does not exceed 10 s, while the studies performed in dynamic settings specifically for Ti-based composites are limited. Such data are critical to prevent the "strength margin" approach, which is used to assure the part performance under dynamic conditions in the absence of relevant data. The purpose of this study was to obtain data on the mechanical behavior of Ti-based composites under dynamic condition.

Improving the imaging capability of an on-axis transmission Kikuchi detector.

Transmission Kikuchi Diffraction (TKD) in the scanning electron microscope has been developing at a fast pace since its introduction less than a decade ago. The recently presented on-axis detector configuration, with its optimized geometry, has significantly increased the signal yield and facilitated the acquisition of STEM images in bright field (BF) and dark field (DF) mode, in addition to the automated orientation mapping of nanocrystalline electron transparent samples. However, the physical position of the integrated imaging system, located outside the detector screen, requires its movement in order to combine high resolution STEM images with high resolution orientation measurements.

Advancing FIB assisted 3D EBSD using a static sample setup.

A new setup for automatic 3D EBSD data collection in static mode has been developed using a conventional FIB-SEM system. This setup requires no stage or sample movements between the FIB milling and EBSD mapping. Its capabilities were tested experimentally on a coherent twin boundary of an INCONEL sample.

Structure and phase stability of nanocrystalline Ce(1-x)Ln(x)O(2-x/2-delta) (Ln = Yb, Lu) in oxidizing and reducing atmosphere.

The structure and phase evolution of nanocrystalline Ce(1-x)Ln(x)O(2-x/2-delta) (Ln = Yb, Lu, x = 0 - 1) oxides upon heating in H(2) was studied for the first time. Up to 950 degrees C the samples were single-phase, with structure changing smoothly with x from fluorite type (F) to bixbyite type (C). For the Lu-doped samples heated at 1100 degrees C in the air and H(2), phase separation into coexisting F- and C-type structures was observed for ~0.