CN-122013084-A - Method for improving mechanical properties of titanium alloy through low-temperature high-speed pre-impact

Abstract

The invention relates to a method for improving mechanical properties of a titanium alloy through low-temperature high-speed pre-impact, and belongs to the technical field of titanium alloy development. The invention utilizes low-temperature environment to carry out small-deformation high-speed pre-impact of specific parameters on the titanium alloy sample, thereby deliberately introducing a high-density flaky FCC titanium phase and an L-C lock into the microstructure thereof, and the special defect structures are used as 'prefabricated strengthening phases', and can effectively pin dislocation and block crack expansion in the subsequent dynamic loading process, thereby cooperatively improving the final mechanical property of the material. The invention has simple and controllable treatment, and the obtained product has excellent performance and is convenient for industrialized application.

Inventors

• SONG YUFENG
• DENG XIWANG
• LI ZHIXIN
• DING XUEFENG
• HUANG HAO
• LI CHAO
• ZHOU HONGGANG
• CAI CHENG
• CHEN YUQIANG
• LI LEIFENG

Assignees

• 湖南科技大学

Dates

Publication Date

20260512

Application Date

20260302

Claims (9)

1. 1. A method for improving mechanical properties of a titanium alloy through low-temperature high-speed pre-impact is characterized in that a low-temperature environment is utilized to pre-impact a titanium alloy sample with small deformation of specific parameters, so that a flaky FCC titanium phase and an L-C lock are introduced into a microstructure of the titanium alloy sample, the temperature of the low-temperature environment is between 20 ℃ below zero and 196 ℃ below zero, and the deformation of the small deformation pre-impact is between 0.5% and 8%.
2. 2. The method for improving the mechanical properties of the titanium alloy through low-temperature high-speed pre-impact according to claim 1, wherein the impact force with the strain rate of 100-2000s -1 is applied to the titanium alloy at the temperature of-70 ℃ to-196 ℃ so that the titanium alloy generates plastic deformation with small deformation amount of 1% -5%.
3. 3. The method for improving the mechanical properties of the titanium alloy by low-temperature high-speed pre-impact according to claim 1, wherein the impact force with the strain rate of 700-1200s -1 is applied to the titanium alloy at-80 ℃ to-196 ℃ so that the titanium alloy generates plastic deformation with small deformation amount of 1.5% -3.5%.
4. 4. The method for improving mechanical properties of a titanium alloy by low-temperature high-speed pre-impact according to claim 1, wherein the titanium alloy is selected from one of TA15, TC4 and TA 0.
5. 5. The method for improving mechanical properties of a titanium alloy by low-temperature high-speed pre-impact according to claim 4, wherein the titanium alloy is at least one selected from an as-cast state, a rolled state, a printed state and an annealed state.
6. 6. The method for improving mechanical properties of titanium alloy by low-temperature high-speed pre-impact according to claim 1, wherein the wire-cut electric discharge machining is used for cutting out samples with required shapes from titanium alloy plates or bars.
7. 7. The method for improving mechanical properties of a titanium alloy through low-temperature high-speed pre-impact according to claim 1, wherein when the titanium alloy is a printing-state titanium alloy or a titanium alloy after annealing of a printing blank, impact force is applied to the titanium alloy at-120 ℃ to-196 ℃ to enable the titanium alloy to generate plastic deformation with small deformation of 1.5% -3.5%, and preferably, impact force with a strain rate of 800-1200s -1 is applied to the titanium alloy at-140 ℃ to-196 ℃ to enable the titanium alloy to generate plastic deformation with small deformation of 2% -3%.
8. 8. The method for improving mechanical properties of the titanium alloy through low-temperature high-speed pre-impact according to claim 7, wherein printing parameters of the printing-state titanium alloy are 400-700W of laser power, 300-400 mm/s of scanning speed, 0.2-0.4 mm of scanning interval, 0.3-0.5 mm of powder paving layer thickness and 10-15 g/min of powder feeding rate.
9. 9. The method for improving the mechanical properties of the titanium alloy through low-temperature high-speed pre-impact according to claim 1, wherein the method is characterized in that a sample is placed in an incubator of forming equipment and cooled to a low-temperature environment of-20 ℃ to-196 ℃, and liquid nitrogen medium is adopted to realize cooling and keep the temperature stable.

Description

Method for improving mechanical properties of titanium alloy through low-temperature high-speed pre-impact Technical Field The invention relates to a method for improving mechanical properties of a titanium alloy through low-temperature high-speed pre-impact, and belongs to the technical field of titanium alloy development. Background In the prior art, the method for improving the mechanical properties of the titanium alloy mainly comprises the steps of heat treatment regulation and control such as solid solution, aging and the like, plastic processing strengthening such as rolling, forging and the like, alloying and composite strengthening by adding alloy elements or introducing reinforcing phases, and additive manufacturing process optimization such as selective laser melting, electron beam melting and the like, and the method realizes the mechanical property improvement by adjusting the microstructure or components of the titanium alloy. According to the search, the prior art has few reports on improvement of the mechanical properties of titanium alloy through low-temperature high-speed pre-impact. Disclosure of Invention The invention provides a method for generating a strengthening phase and an L-C lock by inducing titanium alloy through low-temperature pre-impact so as to improve dynamic performance. The invention has the core points that a low-temperature environment (especially a deep low-temperature environment, such as-20 ℃ to-196 ℃) is utilized to pre-impact a titanium alloy sample with small deformation (such as plastic deformation with the deformation of 0.5% -8%) of specific parameters, so that a high-density flaky FCC titanium phase and an L-C lock are deliberately introduced into a microstructure of the titanium alloy sample, and the special defect structure is used as a 'prefabricated strengthening phase', so that dislocation can be effectively pinned and crack expansion can be blocked in the subsequent dynamic loading process, and the final dynamic strength and fracture strain of the material can be cooperatively improved. According to the method for improving the mechanical properties of the titanium alloy through low-temperature high-speed pre-impact, the low-temperature environment is utilized to perform small deformation pre-impact of specific parameters on the titanium alloy sample, so that a flaky FCC titanium phase and an L-C lock are introduced into a microstructure of the titanium alloy sample, the temperature of the low-temperature environment is-20 ℃ to-196 ℃, and the shape quantity of the small deformation pre-impact is 0.5% -8%. Preferably, an impact force is applied to the titanium alloy treated in the low-temperature environment, and the strain rate is 100-2000s -1. Preferably, according to the method for improving the mechanical properties of the titanium alloy through low-temperature high-speed pre-impact, impact force is applied to the titanium alloy at the temperature of-70 ℃ to-196 ℃, the strain rate is 100-2000s -1, and the titanium alloy generates plastic deformation with the deformation amount of 1% -5%. Preferably, according to the method for improving the mechanical properties of the titanium alloy through low-temperature high-speed pre-impact, impact force with the strain rate of 700-1200s -1 (more preferably 900-1100 s -1, still more preferably 950-1050s -1) is applied to the titanium alloy at the temperature of-80 ℃ to-196 ℃, so that the titanium alloy generates plastic deformation with the deformation amount of 1.5% -3.5%. In industrial applications, the impact force is provided by the gas used. The titanium alloy is selected from one of TA15, TC4 and TA 0. The titanium alloy is at least one selected from an as-cast state, a rolled state, a printed state and an annealed state. In practice, the sample may be prepared by cutting a desired shape from a titanium alloy sheet or bar using Wire Electric Discharge Machining (WEDM). Preferably cylindrical samples, the ratio of height (H) to diameter (D) of which satisfies 1:2 to 2:1. Further preferably 1:1. Standardized sample sizes are a prerequisite for obtaining comparable, reproducible mechanical experimental data. The high-precision wire cutting can avoid the oversized heat affected zone and stress concentration introduced by the traditional machining. In the invention, the equipment used for the deep low-temperature pre-impact treatment can be a high-speed forming equipment device provided with an incubator. In practice, the high-speed forming apparatus includes a split hopkinson bar (Split Hopkinson Pressure Bar, SHPB) device. Of course, other devices may be used with the present invention. The deep low temperature pre-impact treatment process includes the steps of setting the sample inside high speed impact heat insulating box and cooling to low temperature of-20 to-196 deg.c. Liquid nitrogen medium can be adopted to realize cooling and keep temperature stable. When the titanium alloy is a printing-state titaniu