Preparation method of large-scale die blank for vacuum isothermal forging

A preparation method of a large-scale die blank for isothermal forging, said method comprising:

• providing a plurality of plate-shaped units of titanium-zirconium-molybdenum alloy with a thickness of 20-100 mm based on predetermined shape(s);
• providing a plurality of foil-shaped intermediate layers of tantalum, niobium-tungsten alloy or tantalum-tungsten alloy with a thickness of 40-150 μm based on predetermined shape(s);
• successively assembling the plate-shaped units of titanium-zirconium-molybdenum alloy and the foil-shaped intermediate layers based on a predetermined configuration to form an assembly body so that each of the foil-shaped intermediate layers is sandwiched between the plate-shaped units of titanium-zirconium-molybdenum alloy in the assembly body;
• applying an axial pressure of 6-9 MPa for a bonding time of not less than 3 hours to the assembly body at a bonding temperature 20-100° C. lower than a recrystallization temperature of the titanium-zirconium-molybdenum alloy and a vacuum degree of 10−3-10−2 Pa by a vacuum diffusion welding furnace, so that diffusion bonding between the plated-shaped units of titanium-zirconium-molybdenum alloy and the foil-shaped intermediate layers occurs to obtain a primary blank;
• homogenizing the primary blank for a homogenization time of 2-24 hours at a homogenization temperature 50-150° C. lower than the recrystallization temperature of the titanium-zirconium-molybdenum alloy under vacuum or inert gas protection to homogenize a microstructure and composition at bonding interfaces in the primary blank;
• and
• cooling the homogenized primary blank to obtain a die blank, wherein the recrystallization temperature of the titanium-zirconium-molybdenum alloy is in a range of 1350-1400° C.