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The oxidation process of Ti 2 AlC ceramics in dry synthetic air at 1200 C was monitored with thermogravimetry. The microstructural evolution of the oxide scale with time was characterised by Xray diffractometry, scanning electron microscopy, X-ray microanalysis and electron back scattering diffraction. The oxide scale is comprised of a continuous a-Al 2 O 3 inner layer with isolated coarse TiO 2 particles on top. At the early oxidation stage (roughly less than 0.5 h), a-Al 2 O 3 and TiO 2 are the main reaction products, while at longer reaction times the oxidation only leads to the formation of a-Al 2 O 3 . The a-Al 2 O 3 grains in the oxide scale grow in size upon high-temperature oxidation with the grain size being uniform throughout the thickness of the scale. As diffusion of oxygen along the grain boundaries dominates the oxide scale growth, the change in grain size affects the oxide scale growth kinetics. A simple oxide scale growth model, that takes into account this change in fast diffusion paths, describes the experimentally observed oxide scale growth kinetics perfectly.

a b s t r a c tWe have studied the bonding and elastic properties of amorphous AlYB 14 using theoretical and experimental means. Based on pair distribution functions and Voronoi tessellation, the icosahedral bonding is expected. A rather large Young's modulus of 365 GPa is predicted for amorphous AlYB 14 .To verify these predictions, we have measured density, pair distribution functions, binding energy and elastic properties of Al-Y-B thin films synthesized by magnetron sputtering. The calculated and measured densities are with a deviation of 3.5% in good agreement. The measured binding energy and pair distribution functions are also consistent with icosahedral bonding. The measured Young's modulus is 305 719 GPa, which is 16% smaller than the theoretical value and hence in good agreement. Overall consistency between theory and experiments was obtained indicating that the computational strategy employed here is useful to describe correlations between bonding, elasticity, density as well as (chemical) short range order and may hence enable future knowledge-based design of these ternary borides which show great potential for surface protection applications.

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A paramount challenge in materials science is to design damage-tolerant glasses. Poisson’s ratio is commonly used as a criterion to gauge the brittle-ductile transition in glasses. However, our data, as well as results in the literature, are in conflict with the concept of Poisson’s ratio serving as a universal parameter for fracture energy. Here, we identify the electronic structure fingerprint associated with damage tolerance in thin film metallic glasses. Our correlative theoretical and experimental data reveal that the fraction of bonds stemming from hybridised states compared to the overall bonding can be associated with damage tolerance in thin film metallic glasses.