A furnace for removing a molybdenum-alloy refractory metal core through sublimation comprising a retort furnace having an interior; a sublimation fixture insertable within the interior of the retort furnace, the sublimation fixture configured to receive at least one turbine blade having the molybdenum-alloy refractory metal core; a flow passage thermally coupled to the retort furnace configured to heat a fluid flowing through the flow passage and deliver the fluid to the molybdenum-alloy refractory metal core causing sublimation of the molybdenum-alloy refractory metal core.