Wear Properties of A Shock Consolidated Metallic Glass and Glass-Crystalline Mixtures

Powder flakes prepared from 50 μm thick melt spun ribbons of Markomet 1064 (Ni_(52.5)Mo_(38)Cr_8 B_(1.5) wt%) were shock consolidatedin the unannealed and annealed condition. The unannealed flakes (microhardness 933 kg/mm^2) are amorphous while flakes annealed at 900ºC for 2 hours have an fcc structure with a grain size of 0.3 μm and microhardness of 800 kg/mm^2. The shock consolidated amorphous powder compact (250 kJ/kg shock energy) shows no crystal peaks in an X-ray diffractometer scan. Compacts of annealed powder (400 to 600 kJ/kg shock energies) contain amorphous material (18-21%) which was rapidly quenched from the melt formed at interparticle regions during the consolidation process. The microhardness of the amorphous interparticle material is 1100 kg/mm^2. Wear properties of the compacts measured in low velocity pin on disk tests show low average dynamic friction values (∿0.03). The 60 hour cumulative wear appears to correlate with the energy of shock compaction and surface porosity of the compacts rather than the metallic glass content

Consensus statement: Virus taxonomy in the age of metagenomics

Comment in:A sea change for virology. [Nat Rev Microbiol. 2017]International audienceThe number and diversity of viral sequences that are identified in metagenomic data far exceeds that of experimentally characterized virus isolates. In a recent workshop, a panel of experts discussed the proposal that, with appropriate quality control, viruses that are known only from metagenomic data can, and should be, incorporated into the official classification scheme of the International Committee on Taxonomy of Viruses (ICTV). Although a taxonomy that is based on metagenomic sequence data alone represents a substantial departure from the traditional reliance on phenotypic properties, the development of a robust framework for sequence-based virus taxonomy is indispensable for the comprehensive characterization of the global virome. In this Consensus Statement article, we consider the rationale for why metagenomic sequence data should, and how it can, be incorporated into the ICTV taxonomy, and present proposals that have been endorsed by the Executive Committee of the ICTV