The study found that β21s titanium alloy not only has excellent oxidation resistance, but also the corrosion resistance of this alloy is 1 to 2 orders of magnitude higher than that of ordinary titanium alloys. The alloy has good room temperature plasticity in the solution state, so it has good hot and cold processing performance, and can be used for the processing of aerospace sheet metal products. The main β-stabilizing elements of the alloy are high melting point molybdenum and niobium, which make the alloy have good oxidation resistance, and can be used to manufacture parts that are used for a long time in the environment of 500 ℃ high temperature. At present, the United States has used β21s titanium alloy sheet to manufacture Boeing 777 aircraft engine pod components and titanium-based composite high-temperature components for space shuttles, but the solid solution treatment system for its sheet forming and the aging system for the use status of parts have not been reported.
In view of this, researchers have studied the effect of different solution temperatures on the microstructure and mechanical properties of β21s titanium alloy sheets, and at the same time selected different aging temperatures to study the effect of aging temperature on the mechanical properties of β21s titanium alloy sheets at room temperature and high temperature. .
The selected first-class sponge titanium, aluminum bean, aluminum-niobium intermediate alloy, titanium-molybdenum intermediate alloy and other raw materials are evenly mixed, pressed and welded into a consumable electrode, and smelted in a 1000kg vacuum consumable electric arc furnace to produce β21s The finished ingot of titanium alloy, the chemical composition of the ingot meets the requirements of the American ASTMB265 standard. The ingot is selected to be heated in the beta phase area, and then heated and forged in the (α + β) phase area to form a 60mm × 400mm × 600mm slab, and then heated in the (α + β) phase area to hot-roll it to a thickness of 6mm The slab is finally cold rolled into a 2mm thick plate, and the surface is tested by pickling and cleaning. In the study, 4 kinds of solution temperature (800, 815, 830, 845 ℃ × 10min, air cooling) and 3 kinds of aging temperatures (550, 600, 680 ℃ × 8h, air cooling) were selected for the experiment to study the solution temperature and aging The effect of temperature on the microstructure and mechanical properties of β21s titanium alloy sheet. The test results are as follows:
(1) When β21s titanium alloy plate is solid-solution at high temperature, as the solution temperature increases, the solid-solution strength of the alloy decreases and the plasticity increases.
(2) β21s titanium alloy plate solid solution + aging state mechanical properties have a great relationship with the choice of aging temperature. As the aging temperature increases, the strength of the aging state of the alloy decreases and the plasticity increases.
(3) β21s titanium alloy sheet can obtain ideal room temperature processing plasticity after solid solution at 845 ℃, after aging at 600 ℃, its room temperature tensile strength can reach more than 1200MPa, elongation remains at more than 10%, and its 500 The tensile strength at ℃ high temperature can reach more than 700MPa.