Metallic glasses attract considerable interest due to their unique combination of superb properties and processability. Predicting their formation from known alloy parameters remains the major hindrance to the discovery of new systems. Here, we propose a descriptor based on the heuristics that structural and energetic ‘confusion' obstructs crystalline growth, and demonstrate its validity by experiments on two well-known glass-forming alloy systems. We then develop a robust model for predicting glass formation ability based on the geometrical and energetic features of crystalline phases calculated ab initio in the AFLOW framework. Our findings indicate that the formation of metallic glass phases could be much more common than currently thought, with more than 17% of binary alloy systems potential glass formers. Our approach pinpoints favourable compositions and demonstrates that smart descriptors, based solely on alloy properties available in online repositories, offer the sought-after key for accelerated discovery of metallic glasses.

Annexins are a multigene, multifunctional family of calcium-dependent, membrane-binding proteins found in animal and plant cells. In plants, annexins have been localized in the cytoplasm and at the cell periphery of highly secretory cell types, and in the tip region of polarly growing cells. Consequently, one proposed function for annexins in plant cells is participation in the Golgi-mediated secretion of new wall materials. In Arabidopsis, there are eight different annexin cDNAs, which share between 30% and 81% deduced amino acid sequence identity. We have used two monospecific Arabidopsis anti-annexin antibodies, raised against divergent 31-mer peptides from AnnAt1 and AnnAt2 and a previously characterized pea anti-annexin p35 antibody, for Western blot and immunolocalization studies in Arabidopsis. Western blot analyses of various Arabidopsis protein fractions showed that the two Arabidopsis antibodies are able to specifically recognize annexins in both soluble and membrane fractions. Immunofluorescence results with the three annexin antibodies show staining of secretory cells, especially at the cell periphery in developing sieve tubes, outer root cap cells, and in root hairs, consistent with previous results. In developmentally different stages some staining was also seen near the apical meristem, in some leaf cells, and in phloem-associated cells. Autoradiography following 3H-galactose incorporation was used to more clearly correlate active secretion of wall materials with the localization patterns of a specific individual annexin protein in the same cells at the same developmental stage. The results obtained in this study provide further support for the hypothesis that these two Arabidopsis annexins function in Golgi-mediated secretion during early seedling growth and development.

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We demonstrate a route to synthesize ultra high-temperature ceramic coatings of ZrB 2 at temperatures below 1,300 K using Zr/B reactive multilayers. Highly textured crystalline ZrB 2 is formed at modest temperatures, because of the absence of any oxide at the interface between Zr and B, and the very short diffusion distance that is inherent to the multilayer geometry. The kinetics of the ZrB 2 formation reaction is analyzed using high-temperature scanning nano-calorimetry, and the microstructural evolution of the multilayer is revealed using transmission electron microscopy. We show that the Zr/B reaction proceeds in two stages: (1) inter-diffusion between the nano-crystalline Zr and the amorphous B layers, forming an amorphous Zr/B alloy; and (2) crystallization of the amorphous alloy to form ZrB 2 . Scanning nano-calorimetry measurements performed at heating rates ranging from 3,100 to 10,000 K/s allow determination of the kinetic parameters of the multilayer reaction, yielding activation energies of 0.47 eV and 2.4 eV for Zr/B inter-diffusion and ZrB 2 crystallization, respectively.

We measure stresses that develop in sputter-deposited amorphous Ge thin films during electrochemical lithiation and delithiation. Amorphous Li x Ge electrodes are found to flow plastically at stresses that are significantly smaller than those of their amorphous Li x Si counterparts. The stress measurements allow for quantification of the elastic modulus of amorphous Li x Ge as a function of lithium concentration, indicating a much-reduced stiffness compared to pure Ge. Additionally, we observe that thinner films of Ge survive a cycle of lithiation and delithiation, whereas thicker films fracture. By monitoring the critical conditions for crack formation, the fracture energy is calculated using an analysis from fracture mechanics. The fracture energies are determined to be   2 8.0 J m for a-Li 0.3 Ge and   2 5.6 J m for a-Li 1.6 Ge. These values are similar to the fracture energy of pure Ge and are typical for brittle fracture. Despite being brittle, the ability of amorphous Li x Ge to flow at relatively small stresses during lithiation results in an enhanced ability of Ge electrodes to endure electrochemical cycling without fracture.