Precipitation-Strengthened and Microlayered Bulk Copper- and Molybdenum-Based Nanocrystalline Materials Produced by High-Speed Electron-Beam Evaporation-Condensation in Vacuum: Structure and Phase Composition

摘要

The phase composition and structurization of three types of copper and molybdenum composite materials, 0.8 to 5 mm thick, which were condensed from the vapor phase at substrate temperatures 700 and 900A degrees C, are considered: precipitation-strengthened composites, microlayered composites with alternating copper and molybdenum layers 1 to 10 mu m thick, and bulk nanocrystalline composites with alternating layers thinner than 0.5 mu m. Standard precipitation-strengthened Cu- and Mo-based materials condensed from the vapor phase at substrate temperatures 700-900A degrees C can be produced over a relatively narrow composition range of the strengthening phase (0.1-3 wt.% Mo). When Mo content is 3-5 wt.%, the molybdenum particles change their shape from round to acicular and become discontinuous chains oriented perpendicularly to the vapor flow. If there is more than 5 wt.% of the second phase, the condensed composite materials (CCMs) show a layered structure. The layered structure can be observed in other CCM types (Cu-W, Cu-Cr, NiCrAlTi-Al2O3). Layered copper and molybdenum CCMs, 6 mm thick, produced on a rotating substrate heated to 700 +/- 30A degrees C have been experimentally confirmed to belong to bulk nanocrystalline materials.