PRECIPITATION-STRENGTHENED AND MICROLAYER BULK COPPER- AND MOLYBDENUM-BASED NANOCRYSTALLINE MATERIALS PRODUCED BY HIGH-SPEED ELECTRON-BEAM EVAPORATION–CONDENSATION IN VACUUM: STRUCTURE AND PHASE COMPOSITION

Abstract

The phase composition and structurization of three types of copper- and molybdenum-based composite materials from 0.8 to 5 mm thick that were condensed from the vapor phase at substrate temperatures 700 and 900 °С are considered: precipitation-strengthened, microlayer with alternative layers of copper and molybdenum from 1 to 10 μm in thickness, and bulk nanocrystalline with alternating layers less than 0.5 μm in thickness. Typical precipitation-strengthened Cu- and Mo-based materials condensed from the vapor phase at substrate temperatures 700–900 °C can be obtained in a relatively narrow concentration range of the strengthening phase (0.1–3 wt.% Mo). When Mo content is 3–5 wt.%, the shape of molybdenum particles changes from round to needle one located in the materials as intermittent chains, perpendicular to the vapor flow. In the content of the other phase is more than 5 wt.%, the condensed composite materials (CCМs) show a layered structure. The layered structure can be observed in other CCM types (Cu–W, Cu–Cr, NiCrAlTi–Al₂O₃). It is experimentally confirmed that layered copper- and molybdenum-based CCМs of 6 mm thickness produced on a rotating substrate heated to 700 ± 300 °С belong to bulk nanocrystalline materials.