A stress fatigue resistant titanium alloy for eyeglass frame structures and a method of making the same

Abstract

The application discloses a stress fatigue resistant titanium alloy for spectacle frame structural members and a preparation method thereof, relates to the technical field of titanium alloy materials, and provides the stress fatigue resistant titanium alloy, which is composed of the following components in mass percentage: Al 5.5-6.5%, V 3.5-4.5%, Ta 0-2.5%, Mg 0.1-0.2%, O 0.06-0.12%, N 0.05-0.1%, Fe 0.02-0.24%, Re 0.15-0.5% and Rh 0.15-0.5%, and the balance is Ti and inevitable impurities. The common action of the added elements Re and Rh restrains the diffusion of Al, Ta and V, and obviously refines the alpha phase, the grain size of which is about 5-20 mu m, the strength of the primary alpha phase and the transformed beta phase is well matched (the difference is 65.76-75.87 HV), and the probability of the fatigue crack along the transformed beta phase is reduced, so that the alloy has good stress fatigue resistance. The stress fatigue resistant (alpha+beta) type dual-phase titanium alloy provided by the application has low elastic modulus, the strength can reach 1098 MPa, the fatigue life can reach 27088 times, and the alloy has good stress fatigue resistance and can be used for the connecting structural members of spectacle frames.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of titanium alloy materials, and particularly relates to a stress fatigue resistant titanium alloy for spectacle frame structural parts and a preparation method thereof. BACKGROUND

[0002] Titanium alloy is increasingly becoming a new type of spectacle frame material due to its excellent comprehensive performance such as low density, high specific strength, good fracture toughness, good fatigue strength and good corrosion resistance. The most commonly used titanium alloy spectacle frame structural parts in China currently are TA1, Ti15333 and Ti422. TA1 is an alpha titanium alloy, which has the advantages of light weight, corrosion resistance and good biological safety, but the elasticity and strength are slightly poor. Ti15333 and Ti422 belong to beta titanium alloy, which has higher strength, fatigue resistance, environmental corrosion resistance and lower elastic modulus than TA1, but the machining performance and welding performance of Ti15333 and Ti422 titanium alloy are poor, the processing difficulty is large, and the cost is high. Moreover, when the strength of the beta titanium alloy reaches a certain level after aging strengthening treatment, the plasticity will be greatly reduced, which is difficult to meet the practical requirements. The above alloys are mainly used for spectacle frame wires and foot wires, but deformation occurs easily during long-term use, which leads to insufficient springback of the spectacle frame, relaxation and even fracture, and cannot meet the requirements of high strength, high plasticity and stress fatigue resistance. Therefore, the application provides a stress fatigue resistant titanium alloy for spectacle frame structural parts, a preparation method thereof and a use method to meet the requirements. SUMMARY

[0003] The application aims to provide a stress fatigue resistant titanium alloy for spectacle frame structural parts and a preparation method thereof, which can realize fast positioning of a mobile phone to the location of a charging robot through the system inside the robot, and can also remotely call the charging robot to move to the nearby position of the car through the mobile phone. The length of the exposed power line can be controlled through the adjusting assembly.

[0004] To achieve the above-mentioned purpose, the application provides the following technical scheme: a stress fatigue resistant titanium alloy for spectacle frame structural parts, which is an (alpha+beta) dual-phase titanium alloy and is composed of the following components in mass fraction: Al 5.5-6.5%, V 3.5-4.5%, Ta 0-2.5%, Mg 0.1-0.2%, O 0.06-0.12%, N 0.05-0.1%, Fe 0.02-0.24%, Re 0.15-0.5% and Rh 0.15-0.5%, and the balance is Ti and inevitable impurities, and the mass ratio between the elements Re and Rh is M(Re):M(Rh)=1:1.

[0005] Preferably, the chemical composition of the titanium alloy is as follows: 6.3% of Al, 4.3% of V, 2% of Ta, 0.15% of Mg, 0.1% of O, 0.05% of N, 0.24% of Fe, 0.2% of Re, 0.2% of Rh, and the rest is Ti and inevitable impurities.

[0006] The application provides a preparation method of the stress fatigue resistant titanium alloy.

[0007] In step one, the titanium alloy components are proportioned, vacuum consumable melting is performed, a specially made mold is used to press electrodes, the pressed electrode blocks have six grooves arranged in a certain order on the surface for later butt welding with high melting point metals, three vacuum consumable melting operations are independently performed, the current of the melting operations is independently 6-18 kA, the voltage of the melting operations is 30-35 V, the vacuum degree of each melting operation is independently 0.6-4 Pa, and an alloy ingot is obtained.

[0008] In step two, the alloy ingot is subjected to multi-pass forging, and a forged blank is obtained at a forging temperature of 900-1100 DEG C.

[0009] In step three, the alloy after the multi-pass forging is subjected to graded solid solution and aging treatment, and the stress fatigue resistant (alpha+beta) type dual-phase titanium alloy is obtained.

[0010] The operation of each stage of the graded solid solution and aging treatment is as follows: (960-990 DEG C) / 30 min + (900-930 DEG C) / 100 min + (500-600 DEG C) / 2-8 h.

[0011] In step one of the preparation method of the stress fatigue resistant (alpha+beta) type dual-phase titanium alloy, 0-grade titanium sponge, Al-50V intermediate alloy, Ti-50Ta intermediate alloy, high-purity aluminum (99.99%), high-purity magnesium, metallic iron, metallic rhodium (99.9%) and TiO2 powder are used as raw materials, the content of V in the alloy ingot is controlled by the Al-50V intermediate alloy, the content of Ta is controlled by the Ti-50Ta intermediate alloy, the content of Re is controlled by the Ti-50Re intermediate alloy, and the content of O is controlled by the TiO2 powder, so that the composition uniformity of the alloy ingot is improved.

[0012] In the preparation method of the stress fatigue resistant (α+β) type duplex titanium alloy, in step one, the electrode pressing for vacuum arc melting is performed using a special mold. The electrode pressed by the special mold has grooves arranged in a 2*3 pattern with a spacing of approximately 5 cm on one surface, which are used for subsequent welding with high-melting-point metals to make the alloy ingot composition more uniform. The current for the three vacuum arc melting processes is independently 6-18 kA, the melting voltage is 30-35 V, and the vacuum degree for each melting process is independently 0.6-4 Pa.

[0013] In the preparation method of the stress fatigue resistant (α+β) type dual-phase titanium alloy, in step two, the precision forging temperature is controlled at 900℃-990℃, and the specific forging passes are: Φ10.2mm→Φ9.5mm→Φ8.7mm→Φ7.6mm→Φ6.4mm→Φ5.8mm→Φ4.9mm, to obtain the rolled billet.

[0014] In the preparation method of the high-strength, high-plasticity, and high-elasticity (α+β) type dual-phase titanium alloy, the operation of each stage of the graded solution treatment and aging treatment in step three is as follows: (960-990℃) / 30min / WC+(900-930℃) / 100min / AC+(500-600℃) / 2-8h / AC.

[0015] This invention provides the application of the stress fatigue resistant (α+β) type duplex titanium alloy described in the above technical solution or the stress fatigue resistant (α+β) type duplex titanium alloy prepared by the preparation method described in the above technical solution in the eyeglass frame industry.

[0016] The present invention provides the stress fatigue resistant (α+β) type duplex titanium alloy described in the above technical solution or the stress fatigue resistant (α+β) type duplex titanium alloy prepared by the preparation method described in the above technical solution, preferably used for connecting structural parts of eyeglasses; such as hinges, clamps, buckles, etc., as well as machined screws, washers, eyeglass frames, etc.

[0017] The application provides a stress fatigue resistant (alpha+beta) titanium alloy, which is composed of the following components in mass fraction: Al 5.5-6.5%, V 3.5-4.5%, Ta 0-2.5%, Mg 0.1-0.2%, O 0.06-0.12%, N 0.05-0.1%, Fe 0.02-0.24%, Re 0.15-0.5% and Rh 0.15-0.5%, and the balance is Ti and inevitable impurities, and the mass ratio between the elements Re and Rh is M(Re):M(Rh) = 1:1. The stress fatigue resistant titanium alloy provided by the application can inhibit the diffusion of Al, Ta and V and the like by the combined action of the added elements Re and Rh, and the alpha phase is obviously refined, the grain size is about 5-20 mu m, the strength of the primary alpha phase and the transformed beta phase is well matched (the difference is 65.76-75.87 HV), the probability of the fatigue crack along the beta phase is reduced, and therefore the alloy has good stress fatigue resistance. The stress fatigue resistant (alpha+beta) dual-phase titanium alloy in some examples of the application has low elastic modulus, the strength can reach 1098 MPa, the fatigue life can reach 27088 times, and the alloy has good stress fatigue resistance and can be used for the connecting structure of a spectacle frame. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0019] Figure 1 The microstructure diagram of the stress fatigue resistant (alpha+beta) dual-phase titanium alloy obtained in the embodiment 1 of the present application.

[0020] Figure 2 The microstructure diagram of the stress fatigue resistant (alpha+beta) dual-phase titanium alloy obtained in the embodiment 2 of the present application.

[0021] Figure 3 The microstructure diagram of the stress fatigue resistant (alpha+beta) dual-phase titanium alloy obtained in the embodiment 3 of the present application.

[0022] Figure 4 The microstructure diagram of the stress fatigue resistant (alpha+beta) dual-phase titanium alloy obtained in the embodiment 4 of the present application.

[0023] Figure 5 The microstructure diagram of the stress fatigue resistant (alpha+beta) dual-phase titanium alloy obtained in the embodiment 5 of the present application. DETAILED DESCRIPTION

[0024] Clearly, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present application.

[0025] The technical solutions of the present application will be described in detail below in combination with the drawings and specific embodiments 1-5.

[0026] The present application provides a stress fatigue resistant (alpha + beta) type duplex titanium alloy, the stress fatigue resistant titanium alloy is (alpha + beta) duplex titanium alloy, which is composed of the following components by mass fraction: Al 5.5-6.5%, V 3.5-4.5%, Ta 0-2.5%, Mg 0.1-0.2%, O 0.06-0.12%, N 0.05-0.1%, Fe 0.02-0.24%, Re 0.15-0.5% and Rh 0.15-0.5%, the balance is Ti and inevitable impurities, and the mass ratio between elements Re and Rh is M(Re):M(Rh)=1:1.

[0027] The chemical composition and mass percentage of the titanium alloy are: Al element 6.3%, V element 4.3%, Ta element 2%, Mg element 0.15%, O element 0.1%, N element 0.05%, Fe element 0.24%, Re element 0.2%, Rh element 0.2%, and the rest is Ti and inevitable impurity elements.

[0028] The stress fatigue resistant titanium alloy provided by the present application refines the equiaxed alpha phase by adding Re element, the strength of primary alpha phase and beta transformed matrix is well matched, the sliding along the base surface (0002) and the prism surface {10-10} with lower critical shear stress is not easy to start, thereby inhibiting the pile-up of dislocations at the grain boundary, the fatigue crack is not easy to generate, and the probability of fatigue crack generation along the beta phase is reduced, so that the alloy has good stress fatigue resistance. At the same time, the addition of Re element increases the content of beta phase, and the elastic modulus of the alloy is reduced. Therefore, the stress fatigue resistant (alpha + beta) titanium alloy provided by the present application has low elastic modulus and good stress fatigue resistance.

[0029] The present application provides a preparation method of the stress fatigue resistant (alpha + beta) type duplex titanium alloy described in the above technical solution, which comprises the following steps:

[0030] Step one, according to the titanium alloy component, vacuum consumable melting is carried out, a special mold is used to press the electrode, the pressed electrode block has six grooves arranged in sequence on one surface for later welding with high melting point metals, three vacuum consumable melting is independently carried out, and the current of the melting is independently 6-18kA, the voltage of the melting is 30-35V, the vacuum degree of each melting is independently 0.6-4Pa, and an alloy ingot is obtained;

[0031] Step two, the alloy ingot is subjected to multi-pass forging at a temperature of 900-1100 DEG C to obtain a forged blank;

[0032] Step three, the alloy after multi-pass forging is subjected to graded solid solution and aging treatment to obtain the stress fatigue resistant (alpha + beta) type dual-phase titanium alloy;

[0033] The operation of each stage of the graded solid solution and aging treatment is: (960-990 DEG C) / 30min + (900-930 DEG C) / 100min + (500-600 DEG C) / 2-8h.

[0034] In the melting process of step one, in order to avoid macrosegregation of high melting point elements and low melting point elements, Al-50V intermediate alloy, Ti-50Ta, Ti-50Re intermediate alloy are added, pure metals are 0-grade sponge titanium, high-purity aluminum (99.99%), magnesium powder, iron powder, and metal rhodium (99.9%), O is added by TiO2 powder, the content of impurity elements in raw materials is strictly controlled, a special mold is used to press the electrode, the surface of the pressed electrode contains 2*3 arranged grooves with an interval of about 5cm for later welding with high melting point metals, the pressed electrode is welded in a vacuum plasma welding box, three times of melting is carried out by a vacuum consumable arc furnace, the melting temperature is controlled by controlling the melting current, and the impurity content of the alloy ingot is controlled by controlling the vacuum degree, so that the composition uniformity of the alloy ingot is improved, and a titanium alloy ingot is obtained.

[0035] In the multi-pass forging process of step two, the titanium alloy ingot is subjected to multi-pass forging at a temperature of 900-1100 DEG C by using a fast forging machine, wherein the open forging temperature is 930-1100 DEG C, the precision forging temperature is 900-990 DEG C, the holding time is 3h, and the specific passes of the forging are: Φ10.2mm→Φ9.5mm→Φ8.7mm→Φ7.6mm→Φ6.4mm→Φ5.8mm→Φ4.9mm.

[0036] In step three, the forged alloy blank obtained in step two is subjected to a solution and aging treatment in a box-type resistance furnace, the solution treatment is a two-stage heat treatment, specifically: the first stage of the two-stage heat treatment is a heat treatment close to the beta single-phase region, the heat treatment temperature is maintained at 990 DEG C, and after 30 min of heat preservation, rapid water cooling treatment is performed; the second stage of the two-stage heat treatment is a heat treatment in the (alpha + beta) two-phase region, the heat treatment temperature is 950 DEG C, and after 100 min of heat preservation, air cooling is performed; the aging treatment temperature is 500 DEG C-600 DEG C, the heat preservation time is 2-8 h, and the cooling mode is air cooling, thereby obtaining the stress fatigue resistant titanium alloy.

[0037] The technical solutions of the present application will be described in detail below with reference to the embodiments of the present application.

[0038] Embodiment 1

[0039] The component design of the high-strength high-plasticity high-elasticity titanium alloy in this embodiment has the following chemical components and mass percentages: 6.3% of Al element, 4.3% of V element, 2% of Ta element, 0.15% of Mg element, 0.1% of O element, 0.05% of N element, 0.24% of Fe element, 0.2% of Re element, 0.2% of Rh element, and the rest being Ti and unavoidable impurity elements.

[0040] The preparation method of the stress fatigue resistant (alpha + beta) two-phase titanium alloy is as follows:

[0041] 0-grade sponge titanium, Al-50V intermediate alloy, Ti-50Ta intermediate alloy, Ti-50Re intermediate alloy, high-purity aluminum (99.99%), metallic magnesium, metallic iron, metallic rhodium (99.9%), and TiO2 powder are used as raw materials, the raw materials are dosed according to the molar ratio of the titanium alloy, a special mold is used to press the electrode, the pressed electrode has 2*3 arranged grooves with a spacing of about 5 cm on the surface, which is used for later butt welding with high-melting-point metals, the pressed electrode is butt welded in a vacuum plasma welding box, vacuum arc melting is performed three times, the current of each melting is independently 6 kA, the melting voltage is 34 V, and the vacuum degree of each melting is independently 0.6 Pa, thereby obtaining a titanium alloy ingot with uniform composition.

[0042] The titanium alloy ingot is subjected to multi-pass forging at a temperature of 930 DEG C by using a fast forging machine, wherein the forging temperature is 900 DEG C-990 DEG C, the heat preservation time is 3 h, and the specific passes of forging are as follows: Φ10.2 mm→Φ9.5 mm→Φ8.7 mm→Φ7.6 mm→Φ6.4 mm→Φ5.8 mm→Φ4.9 mm.

[0043] The forged alloy blank obtained in the above step is subjected to solution and aging treatment in a box resistance furnace, the solution treatment is two-stage heat treatment, specifically: the first stage of the two-stage heat treatment is heat treatment close to the β single-phase region, the heat treatment temperature is kept at 990 ℃, and after 30 min of heat preservation, rapid water cooling treatment is carried out; the second stage of the two-stage heat treatment is heat treatment in the (α+β) two-phase region, the heat treatment temperature is 950 ℃, and after 100 min of heat preservation, air cooling is carried out; the aging treatment temperature is 500-600 ℃, the heat preservation time is 2-8 h, and the cooling mode is air cooling, so that the high-strength high-plasticity titanium alloy is obtained.

[0044] Figure 1 The microstructure diagram of the high-strength high-plasticity high-elasticity (α+β) type dual-phase titanium alloy prepared in Example 1 of the application. The microstructure obtained in Example 1 is a dual-state structure, which is composed of white equiaxial primary α phase and residual black lamellar β phase, and fine secondary acicular α phase is dispersedly distributed in the β phase. s The addition of elements Re and Rh together inhibits the diffusion of elements Al, Ta and V, and obviously refines the α phase, and the grain size thereof is about 5-20 μm, the strength of the primary α phase and the transformed β phase is well matched (the difference is 67.63 HV), and the sliding along the basal plane (0002) and the prismatic plane {10-10} with lower critical shear stress is not easy to start, so that the pile-up of dislocations at the grain boundary is inhibited, and the fatigue crack is not easy to be generated, so that the probability of the generation of the fatigue crack along the transformed β phase is reduced, and the alloy has good stress fatigue resistance.

[0045] Example 2

[0046] The component design of the high-strength high-plasticity high-elasticity titanium alloy in the example, the chemical components and mass percentages are as follows: Al element 6.3%, V element 4.3%, Ta element 2%, Mg element 0.15%, O element 0.1%, N element 0.05%, Fe element 0.24%, Re element 0.2%, Rh element 0.2%, and the rest is Ti and inevitable impurity elements.

[0047] The preparation method of the stress fatigue resistant (α+β) type dual-phase titanium alloy is as follows:

[0048] The high-strength high-plasticity titanium alloy is prepared by using the following raw materials: grade 0 sponge titanium, Al-50V intermediate alloy, Ti-50Ta intermediate alloy, Ti-50Re intermediate alloy, high-purity aluminum (99.99%), metallic magnesium, metallic iron, metallic rhodium (99.9%) and TiO2 powder, and by using a special mold to press the electrode, wherein the surface of the pressed electrode contains 2*3 arranged grooves with a spacing of about 5 cm for later welding with high-melting-point metals, and the pressed electrode is welded in a vacuum plasma welding box, and then is subjected to three times of melting in a vacuum consumable arc furnace, wherein the current of each time of melting is independently 6 kA, the voltage of each time of melting is 34 V, and the vacuum degree of each time of melting is independently 0.6 Pa, so as to obtain the titanium alloy ingot with uniform composition.

[0049] The titanium alloy ingot is forged at a temperature of 950 DEG C by using a fast forging machine, wherein the forging temperature is 900 DEG C-990 DEG C, the holding time is 3 h, and the specific passes of forging are as follows: Φ10.2 mm→Φ9.5 mm→Φ8.7 mm→Φ7.6 mm→Φ6.4 mm→Φ5.8 mm→Φ4.9 mm.

[0050] The alloy blank after forging obtained in the above step is subjected to solid solution aging treatment in a box-type resistance furnace, wherein the solid solution treatment is two-stage heat treatment, specifically: the first stage of the two-stage heat treatment is heat treatment in the β single-phase region, the heat treatment temperature is kept at 990 DEG C, and then rapid water cooling treatment is performed after keeping for 30 min; the second stage of the two-stage heat treatment is heat treatment in the (alpha+beta) two-phase region, the heat treatment temperature is 950 DEG C, and then air cooling is performed after keeping for 100 min; the aging treatment temperature is 500 DEG C-600 DEG C, the holding time is 2-8 h, and the cooling mode is air cooling, so as to obtain the high-strength high-plasticity titanium alloy.

[0051] Figure 2 The microstructure diagram of the high-strength high-plasticity high-elasticity (alpha+beta) two-phase titanium alloy prepared in Example 2 is shown in the figure. The microstructure obtained in Example 2 is a double-state structure, which is composed of white equiaxial primary alpha phase and residual black lamellar beta phase, and fine secondary acicular alpha phase is dispersedly distributed in the beta phase. s The addition of elements Re and Rh together inhibits the diffusion of elements Al, Ta and V, and obviously refines the alpha phase, and the grain size of the alpha phase is about 5-20 mu m. The strength matching of the primary alpha phase and the transformed beta phase is good (the difference is 69.47 HV), and the sliding along the base surface (0002) and the prism surface {10-10} with lower critical shear stress is not easy to start, so as to inhibit the pile-up of dislocations at the grain boundary, and the fatigue crack is not easy to generate, so as to reduce the probability of the generation of the fatigue crack along the transformed beta phase, and the alloy has good stress fatigue resistance.

[0052] Example 3

[0053] The component design of the high-strength high-plasticity high-elasticity titanium alloy in the embodiment is as follows: 6.3% of Al element, 4.3% of V element, 2% of Ta element, 0.15% of Mg element, 0.1% of O element, 0.05% of N element, 0.24% of Fe element, 0.2% of Re element, 0.2% of Rh element, and the rest is Ti and inevitable impurity elements.

[0054] The preparation method of the stress fatigue resistant (α+β) dual-phase titanium alloy is as follows:

[0055] 0-grade sponge titanium, Al-50V intermediate alloy, Ti-50Ta intermediate alloy, Ti-50Re intermediate alloy, high-purity aluminum (99.99%), metallic magnesium, metallic iron, metallic rhodium (99.9%) and TiO2 powder are used as raw materials, the raw materials are dosed according to the molar ratio of the titanium alloy, a special mold is used for pressing electrodes, the pressed electrodes have 2*3 arranged grooves with a spacing of about 5 cm on the surface, which are used for later splicing with high-melting-point metals, the pressed electrodes are spliced in a vacuum plasma welding box, vacuum consumable arc furnaces are used for three times of melting, the current of each melting is independently 6 kA, the melting voltage is 34 V, and the vacuum degree of each melting is independently 0.6 Pa, and a titanium alloy ingot with uniform composition is obtained.

[0056] The titanium alloy ingot is forged at a temperature of 960 DEG C by using a fast forging machine, wherein the forging temperature is 900 DEG C-990 DEG C, the holding time is 3 h, and the specific passes of forging are as follows: Φ10.2 mm→Φ9.5 mm→Φ8.7 mm→Φ7.6 mm→Φ6.4 mm→Φ5.8 mm→Φ4.9 mm.

[0057] The alloy blank after forging obtained in the above step is subjected to solid solution aging treatment in a box-type resistance furnace, the solid solution treatment is two-stage heat treatment, specifically: the first stage of the two-stage heat treatment is heat treatment close to the β single-phase region, the heat treatment temperature is kept at 990 DEG C, and rapid water cooling treatment is performed after holding for 30 min; the second stage of the two-stage heat treatment is heat treatment in the (α+β) dual-phase region, the heat treatment temperature is 950 DEG C, and air cooling is performed after holding for 100 min; the aging treatment temperature is 500 DEG C-600 DEG C, the holding time is 2-8 h, and the cooling mode is air cooling, thereby obtaining the high-strength high-plasticity titanium alloy.

[0058] Figure 3 The microstructure diagram of the high-strength high-plasticity high-elasticity (α+β) dual-phase titanium alloy prepared in embodiment 3 is shown in the figure. The microstructure obtained in embodiment 3 is a dual-state structure, which is composed of white equiaxial primary α phase and residual black lamellar β phase, and fine secondary needle-like α sThe addition of elements Re and Rh together inhibits the diffusion of elements Al, Ta, V, etc., and significantly refines the alpha phase, with a grain size of about 5-20 μm. The strength of the primary alpha phase and the beta transformed matrix is well matched (with a difference of 66.52 HV), and the slip along the basal plane (0002) and prismatic plane {10-10} with a lower critical shear stress is not easy to start, thereby inhibiting the pile-up of dislocations at the grain boundary, and the fatigue crack is not easy to initiate, thus reducing the probability of the initiation of the fatigue crack along the beta transformed matrix, and the alloy has good stress fatigue resistance.

[0059] Example 4

[0060] The component design of the high-strength, high-plasticity and high-elasticity titanium alloy in this embodiment has the following chemical components and mass percentages: 6.3% of Al element, 4.3% of V element, 2% of Ta element, 0.15% of Mg element, 0.1% of O element, 0.05% of N element, 0.24% of Fe element, 0.2% of Re element, 0.2% of Rh element, and the rest is Ti and unavoidable impurity elements.

[0061] The preparation method of the stress fatigue resistant (alpha+beta) type dual-phase titanium alloy is as follows:

[0062] 0-grade sponge titanium, Al-50V intermediate alloy, Ti-50Ta intermediate alloy, Ti-50Re intermediate alloy, high-purity aluminum (99.99%), metallic magnesium, metallic iron, metallic rhodium (99.9%), and TiO2 powder are used as raw materials, and are dosed according to the molar ratio of the titanium alloy. A special mold is used to press the electrode. The pressed electrode has 2*3 arranged grooves with a spacing of about 5 cm on the surface, which is used for later splicing with high-melting-point metals. The pressed electrode is spliced in a vacuum plasma welding box, and is subjected to three times of melting in a vacuum consumable arc furnace. The current of each melting is independently 6 kA, the melting voltage is 34 V, and the vacuum degree of each melting is independently 0.6 Pa. A titanium alloy ingot with uniform composition is obtained.

[0063] The titanium alloy ingot is subjected to multi-pass forging at a temperature of 970°C by using a fast forging machine. The forging temperature is 900-990°C, the holding time is 3 h, and the specific passes of forging are as follows: Φ10.2 mm→Φ9.5 mm→Φ8.7 mm→Φ7.6 mm→Φ6.4 mm→Φ5.8 mm→Φ4.9 mm.

[0064] The forged alloy blank obtained in the above step is subjected to solution and aging treatment in a box resistance furnace, the solution treatment is two-stage heat treatment, specifically: the first stage of the two-stage heat treatment is heat treatment close to the beta single-phase region, the heat treatment temperature is kept at 990 DEG C, and after holding for 30 min, rapid water cooling treatment is carried out; the second stage of the two-stage heat treatment is heat treatment in the (alpha + beta) two-phase region, the heat treatment temperature is 950 DEG C, and after holding for 100 min, air cooling is carried out; the aging treatment temperature is 500 DEG C-600 DEG C, the holding time is 2-8 h, and the cooling mode is air cooling, so that the high-strength high-plasticity titanium alloy is obtained.

[0065] Figure 4 The microstructure diagram of the high-strength high-plasticity high-elasticity (alpha + beta) two-phase titanium alloy prepared in Example 4 is shown in the figure. The microstructure obtained in Example 4 is a bimodal structure, which is composed of white equiaxed primary alpha phase and residual black lamellar beta phase, and fine secondary acicular alpha phase is dispersedly distributed in the beta phase. s The addition of elements Re and Rh together inhibits the diffusion of elements Al, Ta and V, and obviously refines the alpha phase, and the grain size thereof is about 5-20 mu m, the strength of the primary alpha phase and the beta transformed matrix is well matched (the difference is 71.68 HV), and the sliding along the basal plane (0002) and the prismatic plane {10-10} with lower critical shear stress is not easy to start, so that the pile-up of dislocations at the grain boundary is inhibited, and the fatigue crack is not easy to be generated, so that the probability of the generation of the fatigue crack along the beta transformed matrix is reduced, and the alloy has good stress fatigue resistance.

[0066] Example 5

[0067] The component design of the high-strength high-plasticity high-elasticity titanium alloy in the embodiment, the chemical components and mass percentages are as follows: Al element 6.3%, V element 4.3%, Ta element 2%, Mg element 0.15%, O element 0.1%, N element 0.05%, Fe element 0.24%, Re element 0.2%, Rh element 0.2%, and the rest is Ti and inevitable impurity elements.

[0068] The preparation method of the stress fatigue resistant (alpha + beta) two-phase titanium alloy is as follows:

[0069] The 0-grade sponge titanium, Al-50V intermediate alloy, Ti-50Ta intermediate alloy, Ti-50Re intermediate alloy, high-purity aluminum (99.99%), metal magnesium, metal iron, metal rhodium (99.9%) and TiO2 powder are used as raw materials, the titanium alloy is prepared according to the molar ratio, a special mold is used to press the electrode, the electrode pressed has a surface with 2*3 arranged grooves with a spacing of about 5 cm, so as to be used for later welding with high-melting-point metals, the pressed electrode is welded in a vacuum plasma welding box, the vacuum consumable arc furnace is used for three times of melting, the current of each melting is independently 6kA, the melting voltage is 34V, and the vacuum degree of each melting is independently 0.6Pa, and a titanium alloy ingot with uniform composition is obtained.

[0070] The titanium alloy ingot is forged at a temperature of 930 DEG C by using a fast forging machine, wherein the forging temperature is 900 DEG C-990 DEG C, the holding time is 3h, and the specific passes of forging are as follows: Φ10.2mm→Φ9.5mm→Φ8.7mm→Φ7.6mm→Φ6.4mm→Φ5.8mm→Φ4.9mm.

[0071] The alloy blank after forging obtained in the above step is subjected to solid solution aging treatment in a box-type resistance furnace, the solid solution treatment is two-stage heat treatment, specifically: the first stage of the two-stage heat treatment is heat treatment close to the beta single-phase region, the heat treatment temperature is kept at 990 DEG C, and rapid water cooling treatment is carried out after 30min of holding; the second stage of the two-stage heat treatment is heat treatment in the (alpha+beta) two-phase region, the heat treatment temperature is 980 DEG C, and air cooling is carried out after 100min of holding; the aging treatment temperature is 500 DEG C-600 DEG C, the holding time is 2-8h, and the cooling mode is air cooling, so that the high-strength high-plasticity titanium alloy is obtained.

[0072] Figure 5 The microstructure diagram of the high-strength high-plasticity high-elasticity (alpha+beta) type dual-phase titanium alloy prepared in Example 5 is shown in the figure. The microstructure obtained in Example 5 is a dual-state structure, which is composed of white equiaxial primary alpha phase and residual black lamellar beta phase, and fine secondary acicular alpha phase is dispersedly distributed in the beta phase. s The addition of elements Re and Rh together inhibits the diffusion of elements such as Al, Ta and V, and obviously refines the alpha phase, and the grain size is about 5-20um, the strength of the primary alpha phase and the beta transformed matrix is well matched (the difference is 73.45HV), the sliding along the base surface (0002) and the prism surface {10-10} with lower critical shear stress is not easy to start, so that the pile-up of dislocations at the grain boundary is inhibited, and the fatigue crack is not easy to generate, so that the probability of the generation of the fatigue crack along the beta transformed matrix is reduced, and the alloy has good stress fatigue resistance.

[0073] Test Example 1

[0074] The stress fatigue resistant (α+β) type titanium alloy of examples 1-5 is subjected to mechanical property test, the test standard is GB / T 3621-2007, the results are listed in table 1, from the data in table 1, the tensile strength of the stress fatigue resistant dual-phase titanium alloy prepared by examples 1-5 is 1076MPa-1098MPa, the fatigue life is 25503-27088 cycles, the elastic modulus is 91GPa-95GPa, indicating that the (α+β) type dual-phase titanium alloy provided by the application has good stress fatigue resistance.

[0075] Table 1 test results of samples prepared by examples 1-5

[0076]

[0077]

[0078] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for limiting the present application, although the foregoing embodiments of the present application are described in detail, for those skilled in the art, it still can be modified, or part of the technical features of the equivalent replacement, within the spirit and principles of the present application, any modification, equivalent replacement, improvement, etc., should be included in the scope of protection of the present application.

Claims

1. A stress-fatigue resistant titanium alloy for eyeglass frame structural components, characterized in that, The stress fatigue resistant titanium alloy is an (α+β) dual-phase titanium alloy, composed of the following components by mass fraction: Al 5.5-6.5%, V 3.5-4.5%, Ta 0-2.5%, Mg 0.1-0.2%, O 0.06-0.12%, N 0.05-0.1%, Fe 0.02-0.24%, Re 0.15-0.5%, and Rh 0.15-0.5%, with the balance being Ti and unavoidable impurities; The method for preparing the stress fatigue resistant titanium alloy includes the following steps: Step 1: According to the titanium alloy composition, perform vacuum arc remelting, press the electrode blocks with a mold, and perform vacuum arc remelting on the electrode blocks independently to obtain alloy ingots; Step 2: The alloy ingot is subjected to multiple forging processes to obtain a forging billet; Step 3: The alloy after multiple forgings in Step 2 is subjected to graded solution treatment and aging treatment to obtain a stress fatigue resistant (α+β) type dual-phase titanium alloy. The electrode block has six grooves arranged in a certain order on its surface for later welding with high melting point metal. The electrode block is independently melted three times, with a melting current of 6-18 A and a melting voltage of 30-35 V. The vacuum degree of each melting is independently 0.6-4 Pa. In step two, the multi-fire forging temperature is 900℃-1100℃, the initial forging temperature of the multi-fire forging is 930-1100℃, and the precision forging temperature is 900℃-990℃. The steps for each stage of the graded solution treatment and aging process in step three are as follows: (960-990℃) / 30min / WC + (900-930℃) / 100min / AC + (500-600℃) / 2-8h / AC.

2. The stress-fatigue resistant titanium alloy for eyeglass frame structural components according to claim 1, characterized in that: The mass ratio of the two elements Re and Rh is M(Re):M(Rh) = 1:

1.

3. The stress-fatigue resistant titanium alloy for eyeglass frame structural components according to claim 2, characterized in that: The unavoidable impurities content does not exceed 0.05%.

4. The stress-fatigue resistant titanium alloy for eyeglass frame structural components according to claim 3, characterized in that: The electrode pressing in step one, which involves vacuum self-consuming arc melting, is performed using a special mold. The electrode pressed by the special mold has 2*3 grooves spaced 5cm apart on one surface, which are used for subsequent welding with high melting point metals to make the alloy ingot composition more uniform.

5. The stress-fatigue resistant titanium alloy for eyeglass frame structural components according to claim 4, characterized in that: The specific forging steps in step two are as follows: Φ10.2mm→Φ9.5mm→Φ8.7mm→Φ7.6mm→Φ6.4mm→Φ5.8mm→Φ4.9mm.

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