Producing composite single-crystal molybdenum mirrors by diffusion welding in the hot isostatic pressing conditions

Experience in HIP Diffusion Welding of Dissimilar Metals and Alloys

“…Single-crystal molybdenum (Mo single ) is material of choice for producing the first mirrors of 200 mm x100 mm to be used in a diagnostics system for ITER Hydrogen Lines Spectroscopy [7]. Both the severe quality requirements and the complicated 250 mm-diameter blank technology determine very high price of the molybdenum single crystals.…”

“…and servicing. The HIP diffusion bonding between single-crystal molybdenum and polycrystalline molybdenum was achieved by the titanium foil interlayer of 0.1 mm thickness (Ti 0.1 ) [7]. The titanium and molybdenum form a continuous number of the solid solutions and therefore there is no danger of forming any embrittlement phases in the contact zone.…”

“…8a). The composite single-crystal molybdenum mirrors with working surface area of 5000 mm 2 and 8000 mm 2 (Fig.8b) [7] Titanium alloy / aluminum alloy HIP Diffusion Bonding The fusion welding of bimetallic titanium alloy/aluminum alloy is impossible because intermetallic TiAl 3 and TiAl are formed in alloying zone at 1340 0 C and 1460 0 C, respectively. Ultimate solubility of titanium in aluminum is as low as 0.26-0.28 wt% and 0.07 wt% at 665 0 C and at the room temperature, respectively.…”