The effect of the structural inhomogeneity and oxygen defects on the thermal conductivity of polycrystalline aluminum nitride (AlN) thin films deposited on single-crystal silicon substrates is experimentally and theoretically investigated. The influence of the evolution of crystal structure, grain size, and out-of plane disorientation along the cross plane of the films on their thermal conducti...

The grain structure of an Al-0.3 wt%Mn alloy deformed to 1% strain was reconstructed using diffraction contrast tomography (DCT) and high-energy diffraction microscopy (HEDM). 14 equally spaced HEDM layers were acquired and their exact location within the DCT volume was determined using a generic algorithm minimizing a function of the local disorientations between the two data sets. The microst...

The birth of a crystal is initiated by a nucleus from which the crystal grows--a dust grain in a snowflake is a familiar example. These nuclei can be heterogeneous defects, like the dust grain, or homogeneous nuclei which are intrinsic to the material. Here we study homogeneous nucleation in nanoscale polymer droplets on a substrate which itself can be crystalline or amorphous. We observe a lar...

The effect of the initial nitridation of the sapphire substrate on the GaN crystal quality as a function of substrate temperature was studied. GaN layers were grown by plasma-assisted molecular beam epitaxy (MBE) on sapphire substrates nitridated at different substrate temperatures. A strong improvement in the GaN crystal quality was observed at 100 °C nitridation temperature. Symmetric (0004) ...

Polar organic nonlinear optical material, L-tartaric acid single crystals have been grown from slow evaporation solution growth technique. Single crystal X-ray diffraction study indicates that the grown crystal crystallized in monoclinic system with space group P21. Crystalline perfection of the crystal has been evaluated by high resolution X-ray diffraction technique and it reveals that the cr...

Aluminum single crystal with 99.999% purity was deformed at room temperature by equal channel angular pressing (ECAP) up to 16 passes. Grain size and misorientation of processed samples were quantitatively characterized by TEM and EBSD. The results show that the refinement efficiency of high purity aluminum single crystal was poor in the initial stage. Extrusion by fewer ECAP passes (n ≤ 8) res...

Bismuth sodium zirconate titanate ceramics with the formula Bi0.5Na0.5Zr1-xTixO3 [BNZT], where x = 0.3, 0.4, 0.5, and 0.6, were prepared by a conventional solid-state sintering method. Phase identification was investigated using an X-ray diffraction technique. All compositions exhibited complete solubility of Ti4+ at the Zr4+ site. Both a decrease of unit cell size and phase transition from an ...

Mesoscale models are used to study dynamic deformation and failure in silicon carbide (SiC) and aluminum oxynitride (AlON) polycrystals. Elastic and anisotropic elastic-plastic crystal models represent mechanical behavior of SiC and AlON and grains, respectively. Cohesive zone models represent intergranular fracture. Failure data that can be used to inform macroscopic continuum models of cerami...

Crack initiation in Ti-6242 has been observed to occur in a grain with a hard orientation for basal slip neighbouring a grain with a soft orientation. Because there is significant variability in microstructural features and crack initiation life, it is useful to explore the effects of the variability of the microstructural components through a probabilistic sensitivity analysis. In this paper, ...

The aim of this paper is to study the effect of Mn concentration on the structural, magneticand optical properties of TiO2 nanoparticles. TiO2 nanopowders with Mn concentration of 0%,0.2%, 1% and 5% were synthesized by the sol-gel method. The structural, surface morphologyand average crystal grain size, optical, magnetic properties and chemical compounds of thesamples are studied using XRD, FE-...