Thickness uniformity control of large-sized super-alloy sheet in electron beam physical vapor deposition

The large-sized (1.0 m in diameter) super-alloy sheets were synthesized by electron beam physical vapor deposition (EBPVD). The influence of the growth conditions, including but not limited to the crucible/substrate separations, effective evaporation rates of ingots and pressure, on the thickness uniformity of the super-alloy sheets was theoretically analyzed and experimentally investigated. The results show that the crucible/substrate distances have a major impact on the uniformity of thickness distribution and effective evaporation efficiency. For example, an increasing distance resulted in a decreased effective evaporation-efficiency and an improved uniformity. Under the compromised conditions: in a distance of 50 cm and the effective evaporation efficiencies of No.2 and No.4 crucibles were 83% and 17%, respectively, the most uniform super-alloy sheet was deposited with the uniformity of thickness distribution, in a ≤450 mm area, better than the national standards for thickness tolerances of sheet. In addition, the calculated and experimental results were found to be in good agreement.