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

• Published in: Powder metallurgy and metal ceramics 2018-03, Vol.56 (11-12), p.633-646
• Main Authors: Grechanyuk, N. I., Grechanyuk, V. G.
• Format: Article
• Language: English
• Subjects: Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Glass; Materials Science; Metallic Materials; Molybdenum; Nanostructured Materials; Natural Materials; Precipitation (Meteorology)
• ISSN: 1068-1302; 1573-9066
• DOI: 10.1007/s11106-018-9938-4

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 900°C, are considered: precipitation-strengthened composites, microlayered composites with alternating copper and molybdenum layers 1 to 10 μm thick, and bulk nanocrystalline composites with alternating layers thinner than 0.5 μm. Standard precipitation-strengthened Cu- and Mo-based materials condensed from the vapor phase at substrate temperatures 700–900°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–Al 2 O 3 ). Layered copper and molybdenum CCMs, 6 mm thick, produced on a rotating substrate heated to 700 ± 30°C have been experimentally confirmed to belong to bulk nanocrystalline materials.