Nb55ti plate for a superconducting radio-frequency cavity and preparation method thereof

A preparation method for a Nb55Ti plate for a superconducting radio-frequency cavity, comprising:

• S1, forging, comprising:
• heating a niobium-titanium alloy ingot with a size of Φ×L, a mass fraction of niobium (Nb) of 44% to 46%, and a mass fraction of titanium (Ti) of 54% to 56% to a temperature of 850 Celsius degrees (° C.) to 900° C., followed by holding the niobium-titanium alloy ingot at 850° C. to 900° C. for (0.5 to 0.6)×Φ minutes (min) to obtain a heated ingot;
• performing blooming forging on the heated ingot to obtain a slab blank with a size of H1×B1×L1;
• wherein the blooming forging comprises:
• performing two cycles of axial upsetting and drawing-out on the heated ingot, followed by shaping to obtain the slab blank;
• an upsetting deformation amount is (0.6 to 0.7)×L millimeters (mm);
• a thickness H1 of the slab blank is (0.25 to 0.35)×Φ mm;
• Φ represents a diameter of the niobium-titanium alloy ingot in mm, L represents a length of the niobium-titanium alloy ingot in mm, B1 represents a width of the slab blank in mm, H1 represents a thickness of the slab blank in mm, and L1 represents a length of the slab blank in mm;
• S2, processing a surface of the slab blank, comprising:
• machining the slab blank obtained from step S1 with a computer numerical control (CNC) milling machine to remove surface defects of the slab blank to obtain a machined slab blank;
• S3, rolling, comprising:
• rolling the machined slab blank in step S2 to obtain a plate blank with a size of H2×B2× L2;
• wherein, during the rolling, a heating temperature is in a range of 800° C. to 850° C., and a heating holding time is (0.8 to 1)× H1 min;
• a method of the rolling comprises:
• rolling the machined slab blank along a direction of a width B1 of the slab blank until a thickness of the machined slab blank is H2 to obtain a rolled slab blank, rotating the rolled slab blank by 90°, and rolling the rolled slab blank along a length direction of the rolled slab blank until a thickness of the rolled slab blank is H3;
• and H2 represents a thickness of the plate blank in mm, B2 represents a width of the plate blank in mm, and L2 represents a length of the plate blank in mm;
• S4, processing a surface of the plate blank, comprising:
• sanding the plate blank obtained from step S3 with a sander to obtain a sanded plate blank, placing the sanded plate blank in an acid solution to perform acid pickling for 3 min to 5 min, followed by rinsing with clean water and natural air drying to obtain a processed plate blank, to ensure that a surface roughness Ra of the processed plate blank is smaller than or equal to 1.6 microns (μm);
• S5, performing heat treatment on the processed plate blank, comprising:
• wiping a surface of the processed plate blank in step S4 with ethanol solution to obtain a wiped plate blank, and placing the wiped plate blank in a vacuum heat treatment furnace to perform vacuum heat treatment to obtain a heat-treated plate blank;
• and
• S6, processing the heat-treated plate blank, comprising:
• machining the heat-treated plate blank in step S5 with a CNC machining center to obtain the Nb55Ti plate with the mass fraction of Nb of 44% to 46%, the mass fraction of Ti of 54% to 56%, Vickers Hardness (HV) greater than or equal to 150, and a recrystallization rate of 100%.