It was found that the β21s titanium alloy not only has excellent oxidation resistance, but also the corrosion resistance of the alloy is 1 to 2 orders of magnitude higher than that of ordinary titanium alloys. The alloy has good room-temperature plasticity in the solid solution state, so it has good hot and cold processing performance and can be used for processing aerospace sheet metal products. The main β-stabilizing elements of the alloy are high-melting molybdenum and rhenium, which makes the alloy have good oxidation resistance and can be used to manufacture parts that have been used for service in high temperature environments of 500°C for a long time. At present, the United States has used beta21s titanium alloy plates to make Boeing 777 aircraft engine nacelle parts and high-temperature components for space shuttles and titanium composites. However, there are no reports on the solution treatment system for plate forming and the aging system for the use of parts.
In view of this, the researchers studied the effect of different solution temperature on the microstructure and room temperature mechanical properties of β21s titanium alloy sheet, and selected different aging temperatures, studied the effect of aging temperature on the room temperature and high temperature mechanical properties of β21s titanium alloy sheet. .
The primary grade sponge titanium, aluminum bean, aluminum germanium master alloy, titanium molybdenum master alloy and other raw materials are uniformly mixed and pressed and welded into consumable electrodes, and β21s is produced through three meltings on a 1000kg vacuum consumable arc furnace. Titanium alloy finished ingots, ingot chemical composition in line with the United States ASTM B265 standard requirements. The ingot is heated in the β-phase zone and then forged in the (α+β) phase zone to form a slab of 60 mm×400 mm×600 mm in size. It is then hot rolled in the (α+β) phase zone to a thickness of 6 mm. The slabs were finally cold-rolled to 2 mm thickness plates and tested after pickling and cleaning the surfaces. Four kinds of solution temperature (800, 815, 830, 845°C × 10min, air cooling) and three aging temperatures (550, 600, 680°C × 8h, air cooling) were selected for the study to study the solution temperature and aging. Effect of Temperature on Microstructure and Mechanical Properties of β21s Titanium Alloy Plates . The test results are as follows:
(1) When the β21s titanium alloy sheet is in solution at high temperature, the solid solution strength decreases and the plasticity increases as the solution temperature increases.
(2) The mechanical properties of solution and aging of β21s titanium alloy sheet are greatly related to the choice of aging temperature. With aging temperature increasing, the alloy's aging strength decreased and its plasticity increased.
(3) After the β21s titanium alloy sheet is solid-dissolved at 845°C, the desired room temperature processing plasticity can be obtained. After aging at 600°C, the tensile strength at room temperature can reach 1200 MPa or more and the elongation can be maintained at more than 10%. At the same time, its 500 °C high temperature tensile strength up to 700MPa or more.