CN-117583449-B - Ultrasonic vibration assisted titanium alloy superplastic forming method and device

CN117583449BCN 117583449 BCN117583449 BCN 117583449BCN-117583449-B

Abstract

The invention relates to the field of superplastic forming, in particular to a method and a device for superplastic forming of a titanium alloy by ultrasonic vibration, wherein the step S1 is to select the vibration frequency of ultrasonic vibration generated by an ultrasonic generator according to the types, thickness, size and forming shape of different titanium alloy plates, adjust the vibration amplitude of the ultrasonic vibration, generate a proper ultrasonic vibration mode by changing a transducer or an amplitude transformer, adjust the heating temperature, heating time and output pressure of an air source system of a heating electric furnace, and add ultrasonic vibration to assist forming in the process of superplastic forming of the titanium alloy, so that the high-temperature yield strength and flow stress of the titanium alloy plates heated to superplastic are reduced under the combined action of high-pressure argon and ultrasonic vibration, the superplastic forming period is shortened, the ultrasonic vibration is applied in the forming process, the die pasting performance is better, and the contour precision of a formed part and the qualification rate of a finished product are improved.

Inventors

Zhao tianzhang
SHAO JINYANG
HAN YINGJIE
DAI QUN
QI YINGWEI
ZHENG HUI

Assignees

沈阳航空航天大学

Dates

Publication Date: 20260505
Application Date: 20231206

Claims (9)

1. The ultrasonic vibration assisted titanium alloy superplastic forming method is characterized by comprising the following steps of: Step S1, selecting the vibration frequency of ultrasonic vibration generated by an ultrasonic generator according to different titanium alloy plate types, thicknesses, sizes and forming shapes, adjusting the vibration amplitude of the ultrasonic vibration, and generating a proper ultrasonic vibration mode by replacing a transducer or an amplitude transformer; S2, putting the titanium alloy plate to be processed into a forming die of a heating furnace, starting an air source system to pump out air in the forming die and filling argon; S3, controlling the heating temperature of the heating electric furnace, heating the titanium alloy plate to reach the superplastic temperature and preserving heat; S4, introducing argon with pressure into the forming die by the air source system, starting the ultrasonic generator at the same time, driving the high Wen Gangzhu to output stable circulating ultrasonic load to be transferred to the forming die by the amplitude transformer, applying ultrasonic vibration to the titanium alloy plate to be processed until the titanium alloy plate is completely attached to the forming die, preserving heat for a period of time, and ensuring the dimensional accuracy of formed parts; S5, cooling the heating electric furnace, opening the furnace door, taking out the formed titanium alloy part, and cleaning the forming die; In the step S1, the frequency range of ultrasonic vibration generated by the ultrasonic generator is 18-60 KHz, the amplitude range of the ultrasonic vibration is 8-20 um, and the vibration mode adopted by the ultrasonic vibration in the superplastic forming process is longitudinal vibration.
2. The method for ultrasonic vibration assisted titanium alloy superplastic forming according to claim 1, wherein in step S2, the vacuum degree in the forming die is not more than 2 x 10 -4 MPa, and the cleanliness of the argon gas is 99.99% for preventing oxidation of the formed part.
3. The method for ultrasonic vibration assisted titanium alloy superplastic forming according to claim 2, wherein in step S3, the heating temperature and the holding time are determined according to the temperature and the holding time required for the forming process of the selected formed titanium alloy, and the temperature and the holding time required for different titanium alloy plates are different.
4. The method for ultrasonic vibration assisted titanium alloy superplastic forming according to claim 3, wherein in step S4, when the titanium alloy sheet is heated to a superplastic state, an air source system introduces argon into a forming die to blow-mold the titanium alloy sheet, and the pressure of the introduced argon is 2mpa to 4mpa.
5. The method for ultrasonic vibration assisted titanium alloy superplastic forming according to claim 4, wherein in step S4, the forming time of the titanium alloy sheet under the action of argon is 1.5-2 h, and in step S1, the forming time of the titanium alloy sheet decreases with the increase of the ultrasonic vibration frequency and amplitude.
6. The method of ultrasonic vibration assisted titanium alloy superplastic forming according to claim 5, wherein in step 5, ultrasonic vibration is continuously applied during the temperature reduction of the heating device for improving the precision of the formed part.
7. An ultrasonic vibration assisted titanium alloy superplastic forming device is applied to the ultrasonic vibration assisted titanium alloy superplastic forming method of any one of claims 1-6, and is characterized by comprising a heating electric furnace, a forming die, a forming gas circuit and an ultrasonic vibration mechanism; the heating electric furnace is a heating device of titanium alloy plates, and is internally provided with a heat insulation layer and a heating block; The forming die is arranged in the heating electric furnace, and a heat insulation layer and a heating block are arranged around the forming die; The output end of the forming gas circuit is communicated with the lower die, and the input end of the forming gas circuit is connected with an external gas source system; the ultrasonic vibration mechanism is used for generating and transmitting ultrasonic vibration and comprises an ultrasonic generator, a transducer, an amplitude transformer and a high Wen Gangzhu, wherein the ultrasonic generator is connected with the transducer through a wire, the transducer and the amplitude transformer are arranged outside the heating furnace and are in threaded connection with the amplitude transformer through a stud, one end of the high-temperature steel column is in threaded connection with the amplitude transformer through the stud, and the other end of the high-temperature steel column is in threaded connection with the upper die through the stud.
8. The ultrasonic vibration-assisted titanium alloy superplastic forming device of claim 7, further comprising a water cooling system disposed inside the height Wen Gangzhu.
9. The ultrasonic vibration-assisted titanium alloy superplastic forming apparatus of claim 7, wherein the external gas source system is used to pump out the forming die interior air and to feed argon into the forming die interior.

Description

Ultrasonic vibration assisted titanium alloy superplastic forming method and device Technical Field The invention relates to the field of superplastic forming, in particular to a method and a device for ultrasonic vibration assisted titanium alloy superplastic forming. Background Titanium alloy is used as a material with light weight, high strength and corrosion resistance, and is widely applied to the fields of aerospace, automobiles, medical appliances and the like. However, conventional forming methods such as forging or machining have certain limitations due to the high melting point and difficult workability of titanium alloys. At this time, the titanium alloy superplastic forming technology can play an important role. The superplastic forming of titanium alloy is a forming technique in which a titanium alloy material is subjected to high-temperature heating treatment to form a complex shape under a superplastic state by pressure and a die. Advantages of superplastic forming of titanium alloys include the ability to manufacture complex geometries, improved material utilization, reduced processing steps, improved production efficiency, and the like. However, the process complexity of the titanium alloy superplastic forming is high, and parameters such as temperature, pressure, time and the like need to be strictly controlled so as to ensure the quality of the finished product. Some common problems and challenges may be encountered during the superplastic forming of titanium alloys, including: defects and cracks due to the high temperature deformation characteristics and the tissue structure sensitivity of the titanium alloy, improper forming conditions or excessive deformation stress can cause defects, cracks or fractures of the parts. The thickness distribution is uneven, namely, the thickness of a part area can be changed due to the flowability and deformability of the material in the superplastic forming process, so that the thickness distribution of the part is uneven. Surface quality and precision requirements the surface quality and dimensional precision of titanium alloy superplastic formed parts are critical for many applications. Due to high temperature deformation and fluidity, problems such as surface smoothness, air holes, protrusions or shrinkage may occur, and further post-treatment or finishing operations are required. The invention provides a method and a device for ultrasonic vibration assisted titanium alloy superplastic forming, which use an ultrasonic vibration mechanism to generate ultrasonic vibration to be transmitted to a titanium alloy plate through a high Wen Gangzhu so as to improve the high-temperature plastic deformation capacity of the titanium alloy, improve the friction condition between the plate and a die and achieve the purposes of improving the die sticking property of parts and reducing the occurrence of defects of the parts. The method and the device have the advantages of wide applicability, capability of remarkably improving the forming performance and the like. Disclosure of Invention According to the problems, the ultrasonic vibration auxiliary forming is added in the titanium alloy superplastic forming process, so that the high-temperature yield strength and the flow stress of the titanium alloy plate are reduced under the combined action of high-pressure gas and ultrasonic vibration when the plate heated to achieve superplastic, the superplastic forming period is shortened, the ultrasonic vibration is applied in the pressure-maintaining forming process, the die pasting performance is better, and the contour precision of a formed part and the qualification rate of a finished product part are improved. In order to achieve the purpose, the invention adopts the following specific technical scheme that the ultrasonic vibration assisted titanium alloy superplastic forming method comprises the following steps: Step S1, selecting the vibration frequency of ultrasonic vibration generated by an ultrasonic generator according to different titanium alloy plate types, thicknesses, sizes and forming shapes, adjusting the vibration amplitude of the ultrasonic vibration, and generating a proper ultrasonic vibration mode by replacing a transducer or an amplitude transformer; S2, putting the titanium alloy plate to be processed into a forming die of a heating furnace, starting an air source system to pump out air in the forming die and filling argon; S3, controlling the heating temperature of the heating electric furnace, heating the titanium alloy plate to reach the superplastic temperature and preserving heat; S4, introducing argon with pressure into the forming die by the air source system, starting the ultrasonic generator at the same time, driving the high Wen Gangzhu to output stable circulating ultrasonic load to be transferred to the forming die by the amplitude transformer, applying ultrasonic vibration to the titanium alloy plate to be processed until the titanium all