CN-118241135-B - Metastable beta titanium alloy multi-level alpha structure regulation and control method

Abstract

The invention provides a metastable beta titanium alloy multi-level alpha structure regulating method which comprises the following steps of 1, carrying out solid solution on metastable beta titanium alloy within a beta transformation point T β +/-50 ℃ range, 2, carrying out multi-pass rolling deformation on a blank obtained in the step 1, wherein the single-pass deformation is 10-30%, keeping the temperature for 1-10 min at a rolling temperature after each 1-2 passes rolling until the total pressing amount of the alloy reaches 70% -95%, cooling to room temperature, 3, annealing the blank obtained in the step 2 within a temperature range T β -40℃～T β for 2-120 min, cooling to room temperature, or annealing the blank firstly within a temperature range T β -80℃～T β -40 ℃ for 20-120 min, then annealing within a temperature range T β -40℃～T β for 2-120 min, cooling to room temperature, and 4, ageing the blank obtained in the step 3 within a temperature range T β -350℃～T β -210 ℃ for 4-12 h, thus obtaining the multi-level alpha structure. The method can couple the primary alpha p phase and the secondary alpha s phase with different sizes and intervals, so that the metastable beta titanium alloy has higher strength and maintains certain plasticity.

Inventors

• KOU HONGCHAO
• YANG HAO
• ZHU MINGXIANG
• WANG GUODONG
• LI JINSHAN

Assignees

• 西北工业大学

Dates

Publication Date

20260505

Application Date

20240321

Claims (4)

1. 1. The metastable beta titanium alloy multi-level alpha structure regulation and control method is characterized by comprising the following steps: Step 1, homogenizing alloy blank, namely metastable beta titanium alloy at beta phase transition point Solid solution in the range; And 2, hot rolling, namely performing multi-pass rolling deformation on the blank obtained in the step 1, wherein the single-pass deformation amount is 10-30%, the temperature is kept for 1-10 min at the rolling temperature after each 1-2 passes of rolling until the total reduction amount of the alloy reaches 70% -95%, and then cooling to room temperature, wherein the rolling temperature is controlled to be the same as that of the alloy If the rolling temperature is in the beta single-phase region, the heat preservation time after each 1-2 passes of rolling is not more than 2 minutes; step 3, annealing, namely annealing the blank obtained in the step 2 Annealing for 2-120 min in the temperature range, cooling to room temperature, or cooling to room temperature before Annealing for 20-120 min at the temperature range, and then Annealing for 2-120 min in the temperature range, and cooling to room temperature; step 4, aging, namely the blank obtained in the step3 is subjected to Aging for 4-12 hours within the temperature range to obtain the multi-level alpha structure.
2. 2. The method according to claim 1, wherein the homogenization time in step 1 is not less than 30min, ensuring formation of a full β equiaxed structure or a β equiaxed structure containing a small amount of primary phase.
3. 3. The method of claim 1, wherein the annealing in step3 is performed to ensure formation of an incompletely recrystallized structure while retaining a portion of the substructure.
4. 4. The method of claim 1, wherein the aging in step 4 is to ensure that secondary products having different pitches and sizes are formed Morphology of the phases.

Description

Metastable beta titanium alloy multi-level alpha structure regulation and control method Technical Field The embodiment of the disclosure relates to the technical field of high-strength and high-toughness titanium alloy, in particular to a metastable beta titanium alloy multi-level alpha structure regulation and control method. Background Metastable beta titanium alloys are widely used in the manufacture of aircraft primary load bearing members due to their high specific strength, low modulus, good fatigue properties, and excellent processability. The alloy contains a higher content of beta stabilizing element, and inhibits the precipitation of alpha phase in the quenching and cooling process, so that a metastable beta matrix is kept to room temperature, and in the subsequent aging process, the beta stabilizing element with high concentration causes the beta matrix to precipitate fine and dispersed alpha phase, thereby generating remarkable strengthening effect. The strength of the alloy can be improved to more than 1400MPa by adjusting the size, the morphology and the like of the alpha phase, but at the same time, the plasticity and the toughness are obviously reduced, and the strong plasticity under the high-strength condition is not matched. And the size, morphology and the like of the precipitated alpha phase are sensitive to the components and the thermal processing process range, so that the stability of the high-strength titanium alloy is not facilitated. In recent years, the multi-level alpha structure is proved to be a strategy capable of breaking the problem of metastable beta titanium alloy strong plasticity mismatch, but most of the processes are complex, have high requirements on equipment, or are only suitable for specific component alloys, and are difficult to obtain practical application. Therefore, how to construct a multi-level α structure by industrially viable thermo-mechanical processing and heat treatment processes while improving strength and retaining a certain plasticity has become a problem to be solved. Disclosure of Invention Aiming at the existing problems, the present disclosure provides a method for preparing a multi-level alpha structure by combining hot rolling and heat treatment, which is applicable to multi-component metastable beta titanium alloy, has wide processing window and low equipment requirement, and can couple primary phases and secondary phases with different sizes and intervals, so that the metastable beta titanium alloy has higher strength and maintains certain plasticity. The method is realized by the following technical scheme: according to the present disclosure, there is provided a metastable beta titanium alloy multi-level alpha structure regulating method comprising the steps of: Step 1, homogenizing alloy blank, namely, solid-dissolving metastable beta titanium alloy near a beta phase transition point (T β +/-50 ℃); Step 2, hot rolling, namely performing multi-pass rolling deformation on the blank obtained in the step 1, wherein the single-pass deformation is 10-30%, keeping the temperature for 1-10 min at the rolling temperature after each 1-2 passes of rolling until the total pressing amount of the alloy reaches 70% -95%, and cooling to room temperature; step 3, annealing, namely annealing the blank obtained in the step 2 for 2-120 min in the temperature range of T β-40℃～Tβ and then cooling the blank to room temperature, or annealing the blank for 20-120 min in the temperature range of T β-80℃～Tβ -40 ℃ and then annealing the blank for 2-120 min in the temperature range of T β-40℃～Tβ and then cooling the blank to room temperature; And 4, aging the blank obtained in the step 3 for 4-12 hours at the temperature of T β-350℃～Tβ -210 ℃ to obtain the multi-level alpha structure. As a further illustration of the present disclosure, the homogenization time in step 1 is not less than 30 minutes, ensuring that a full beta equiaxed structure or a beta equiaxed structure containing a small amount of primary phase is formed. As further illustration of the disclosure, the rolling temperature in step 2 is controlled within T β +/-40 ℃, and if the rolling temperature is in a beta single-phase region, the heat preservation time after each 1-2 passes of rolling is not more than 2min. As a further illustration of the present disclosure, annealing in step3 is required to ensure formation of an incompletely recrystallized structure, leaving a portion of the substructure to ensure formation of a multi-level, polymorphic α structure during subsequent aging. As a further illustration of the present disclosure, when the hot rolling temperature is low or the rolling deformation is large, annealing in the temperature range of T β-80℃～Tβ -40 ℃ can ensure that partial recrystallization occurs, partial dislocation and deformation energy storage are consumed, and then annealing in the temperature range of T β-40℃～Tβ can ensure that finer uniform structures are formed while avoiding