Ti-al-v-zr-mo based titanium alloy with excellent strength and ductility matching and a preparation method thereof

Abstract

The application discloses a Ti-Al-V-Zr-Mo titanium alloy with excellent strength plasticity matching and a preparation method, and the titanium alloy comprises 4.1-7.1% of Al, 9.6-13.6% of V, 0.5-2.1% of Zr, 4.0-7.0% of Mo, less than 0.35% of O and N gap solutes in total, and the balance of Ti and inevitable other impurities in percentage by mass; the titanium alloy is prepared through reasonable component design and element ratio optimization, and a high-density secondary alpha phase is precipitated through heat treatment, and the alpha / beta interface generated can effectively reduce the average free sliding path of dislocations in the alloy, so that the alloy has super-high strength. The alloy meets the demand of various industrial fields on high performance of titanium alloy structural parts, and can be widely used in the industrial fields of aviation, aerospace, automobiles and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials, in particular to a Ti-Al-V-Zr-Mo titanium alloy with excellent strength and plasticity matching and a preparation method thereof. Background Art

[0002] Titanium alloys are widely used in advanced high-performance engineering fields such as aerospace, weapons and ships due to their superior mechanical properties, such as high specific strength, high damage tolerance and excellent fatigue resistance. The limited yield strength (usually less than 1100MPa) of traditional duplex titanium alloys (such as TC4 alloy) is one of the main bottlenecks in the design of advanced lightweight materials. Although efforts have been made to improve the yield strength of TC4 alloy by O / Fe doping, its yield strength is still less than 1250MPa. In addition, most high-strength titanium alloys (yield strength>1300MPa) tend to exhibit limited ductility, which makes the alloy difficult to form and prone to catastrophic failure during service. However, with the increasingly harsh service environment, higher mechanical performance requirements are placed on high-strength titanium alloys.

[0003] Controlling the phase stability of titanium alloys through chemical composition design is a practical and effective strategy for improving the mechanical properties of materials. The evolution of industrial-pure titanium into titanium alloys also demonstrates the significant influence of alloying elements on the mechanical properties of titanium alloy systems. The rational selection of alloying elements is crucial for subsequent microstructure research and performance evaluation. For example, high levels of the β-stabilizing element Mo are added to titanium alloys to strengthen the β phase. However, due to its high melting point, excessive addition of Mo often results in high processing and manufacturing energy consumption, and can easily cause compositional segregation, making it difficult to control the alloy composition and microstructure uniformity. Mantri et al. used ω-phase-assisted nucleation to prepare β-21S (Ti-15Mo-3Nb-2.7Al-0.2Si), which has a yield strength of approximately 1600 MPa and a total elongation of approximately 4.3%. However, the heat treatment time required to induce ω-phase nucleation is over 150 h, resulting in high production costs and a long production time, making it unsuitable for industrial applications. In addition, some titanium alloys with successful commercial applications (such as Ti-5553 and TB10) have excellent strength and plasticity matching at the 1150-1300 MPa level, but as the strength increases, the plasticity decreases significantly, which makes it difficult to use in higher-intensity service environments. Summary of the Invention

[0004] In response to the problem in the prior art that high-strength titanium alloys have difficulty maintaining good plasticity while increasing yield strength, the present invention provides a Ti-Al-V-Zr-Mo titanium alloy with excellent strength-plasticity matching and a preparation method. The alloy has strong solid solution strengthening, and then undergoes forging and heat treatment to effectively refine the β grains and obtain a high-density secondary α precipitate phase to further effectively strengthen the alloy, achieving a good match between the strength and plasticity of the alloy.

[0005] The present invention is achieved through the following technical solutions:

[0006] A Ti-Al-V-Zr-Mo titanium alloy with excellent strength and ductility matching comprises, by mass percentage, 4.1% to 7.1% of Al, 9.6% to 13.6% of V, 0.5% to 2.1% of Zr, 4.0% to 7.0% of Mo, less than 0.35% of interstitial solutes of O and N, and the balance being Ti and other unavoidable impurities.

[0007] Preferably, the micrometer-scale nearly spherical primary α phase, the nanometer-scale triangular variant secondary α phase and the residual nanometer-scale β matrix are uniformly distributed in the microstructure of the Ti-Al-V-Zr-Mo titanium alloy.

[0008] Preferably, the yield strength σ of the Ti-Al-V-Zr-Mo titanium alloy is y =1377MPa~1542MPa, tensile strength σ UTS =1455MPa~1604MPa, elongation at break ε=4.7%~10.2%.

[0009] A method for preparing a Ti-Al-V-Zr-Mo titanium alloy with excellent strength and plasticity matching, comprising the following steps:

[0010] Step 1: preparing a master alloy ingot according to the mass percentage of each raw material;

[0011] Step 2, performing blanking forging and high-temperature cross-β phase forging on the master alloy ingot;

[0012] Step 3: subjecting the forged ingot to solid solution and aging treatment in the two-phase region, wherein the temperature of the two-phase region aging treatment is 500-575° C., and after aging treatment for 120 minutes, the ingot is water quenched to room temperature to obtain a Ti-Al-V-Zr-Mo titanium alloy.

[0013] Preferably, in step 1, a smelting method is used to prepare a master alloy ingot;

[0014] During the smelting process, argon gas is introduced, the induced current is 400-460A, the current frequency is 20-25kHz, and after the alloy is completely melted, it is kept for 3-5 minutes and then cooled. The smelting is repeated several times to obtain the master alloy ingot.

[0015] Preferably, the blanking temperature of the blanking forging in step 2 is 1050-1150° C., the holding time is 90 minutes, and the deformation amount is ≥60%.

[0016] Preferably, the temperature of the cross-β phase forging is 860-940° C., and the deformation is ≥55%.

[0017] Preferably, the temperature of the solution treatment of the two-phase region in step 3 is 800-835° C., and after the solution treatment for 60 minutes, the solution is quenched to room temperature and then an aging treatment is performed.

[0018] Preferably, the master alloy ingot in step 1 is homogenized and then subjected to blanking forging.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] The present invention provides a Ti-Al-V-Zr-Mo titanium alloy with excellent strength and plasticity matching. The addition of Al element in the titanium alloy is beneficial to strengthening the α phase and alleviating the sensitivity of the titanium alloy to interstitial elements (O, N). The solid solution element Al and trace amounts of interstitial elements O and N can provide a significant solid solution strengthening effect, which greatly improves the lattice friction. Adding the neutral element Zr to perform composite strengthening on the α phase can increase the critical shear stress of dislocation slip in the α phase, thereby improving the overall strength of the alloy. Secondly, the addition of Mo and V elements is not only beneficial to refining the β grain size to produce significant grain boundary strengthening, but also beneficial to strengthening the β phase, further improving the mechanical properties of the alloy. At the same time, a high-density secondary α phase is precipitated by heat treatment, and the resulting α / β interface can effectively reduce the average free slip path of dislocations in the alloy, thereby making the alloy have ultra-high strength. The yield strength σ of the titanium alloy is y =1377MPa~1542MPa, tensile strength σ UTS =1455MPa~1604MPa, and elongation at break ε=4.7%~10.2%, so the titanium alloy has good comprehensive mechanical properties.

[0021] This Ti-Al-V-Zr-Mo titanium alloy preparation method, during forging across the β-phase region, allows dynamic recrystallization to refine the β grains, preventing the formation of continuous α phase along grain boundaries in the alloy. Furthermore, residual dislocations provide abundant potential nucleation sites for the precipitation of secondary α phase during subsequent heat treatment, while the precipitated α phase undergoes continuous fragmentation and recrystallization, achieving α phase refinement. During solution treatment, static recovery and recrystallization optimize the size and distribution of primary α and β grains. Furthermore, the primary α phase at the grain boundaries exerts pinning stress on the grain boundaries, inhibiting static recovery and recrystallization to a certain extent, thereby preventing the migration of low-angle grain boundaries and subgrain boundaries. Finally, during aging, interstitial atoms (O and N) with fast diffusion rates enhance the thermodynamic stability and nucleation driving force of the α phase, while dislocations and defects left behind by forging promote the rapid and uniform precipitation of nanometer-scale intragranular secondary α lamellae. The secondary α-sheets are distributed in a triangular pattern due to the elastic self-coordination effect, which can further significantly improve the mechanical strength of the alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is a tensile property curve of the Ti-Al-V-Zr-Mo titanium alloy after heat treatment in Examples 1 to 3 of the present invention and Comparative Example 1. The horizontal axis in the figure is engineering strain and the vertical axis is engineering stress.

[0023] Figure 2 This is a SEM microstructure photograph of the Ti-Al-V-Zr-Mo titanium alloy in Example 1 of the present invention;

[0024] Figure 3 This is a photograph of the tensile fracture morphology of the Ti-Al-V-Zr-Mo titanium alloy in Example 1 of the present invention;

[0025] Figure 4 This is a SEM microstructure photograph of the Ti-Al-V-Zr-Mo titanium alloy in Example 2 of the present invention;

[0026] Figure 5 This is a photograph of the tensile fracture morphology of the Ti-Al-V-Zr-Mo titanium alloy in Example 2 of the present invention;

[0027] Figure 6 This is a SEM microstructure photograph of the Ti-Al-V-Zr-Mo titanium alloy in Example 3 of the present invention;

[0028] Figure 7 This is a photograph of the tensile fracture morphology of the Ti-Al-V-Zr-Mo titanium alloy in Example 3 of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below with reference to the accompanying drawings, which are intended to explain rather than limit the present invention.

[0030] A Ti-Al-V-Zr-Mo titanium alloy with excellent strength and ductility matching comprises, by mass percentage, 4.1% to 7.1% of Al, 9.6% to 13.6% of V, 0.5% to 2.1% of Zr, 4.0% to 7.0% of Mo, less than 0.35% of interstitial solutes of O and N, and the balance being Ti and other unavoidable impurities.

[0031] The Ti-Al-V-Zr-Mo titanium alloy has a micrometer-scale nearly spherical primary α phase, a nanometer-scale triangular variant secondary α phase and a residual nanometer-scale β matrix uniformly distributed in the microstructure.

[0032] The Ti-Al-V-Zr-Mo series titanium alloy, in which the addition of Al element is beneficial to strengthening the α phase, while alleviating the sensitivity of the titanium alloy to interstitial elements (O, N), the solid solution element Al and trace amounts of interstitial elements O and N can provide a significant solid solution strengthening effect, which greatly improves the lattice friction. Adding the neutral element Zr to perform composite strengthening on the α phase can increase the critical shear stress of dislocation slip in the α phase, thereby improving the overall strength of the alloy. Secondly, the addition of Mo and V elements is not only beneficial to refining the β grain size and producing significant grain boundary strengthening, but also beneficial to strengthening the β phase, further improving the mechanical properties of the alloy. At the same time, a high-density secondary α phase is precipitated by heat treatment, and the resulting α / β interface can effectively reduce the average free slip path of dislocations in the alloy, thereby making the alloy have ultra-high strength.

[0033] A method for preparing a Ti-Al-V-Zr-Mo titanium alloy with excellent strength and plasticity matching, comprising the following steps:

[0034] Step 1: Charge the raw materials into a smelting furnace according to the mass percentage and perform multiple smelting using a suspension smelting method to obtain a master alloy ingot with uniform composition.

[0035] During the smelting process, argon gas is introduced, the induced current is 400-460A, the current frequency is 20-25kHz, and after the alloy is completely melted, it is kept for 3-5 minutes and then cooled. Subsequently, the smelting is repeated 6 times to obtain a master alloy ingot with uniform composition.

[0036] Step 2: After the obtained master alloy ingot is subjected to high-temperature homogenization treatment, the skin is peeled and the riser is cut.

[0037] Step 3: free forging the master alloy ingot obtained by peeling and cutting the riser.

[0038] The free forging includes cogging forging and high temperature cross-β phase region forging.

[0039] The blanking temperature of the blanking forging is 1050-1150° C., the heat preservation time is 90 minutes, and the deformation amount is ≥60%.

[0040] The temperature of the high-temperature cross-β phase forging is 860-940° C., and the deformation amount is ≥55%.

[0041] Step 4: heat-treating the forged ingot in a two-phase region to obtain a Ti-Al-V-Zr-Mo titanium alloy.

[0042] The heat treatment process of the ingot is as follows: after a 60-minute solution treatment in the two-phase region, the ingot is water quenched to room temperature, wherein the temperature of the two-phase region solution treatment is 800-835°C. Then, after a 120-minute aging treatment in the two-phase region, the ingot is water quenched to room temperature, wherein the temperature of the two-phase region aging treatment is 500-575°C.

[0043] This Ti-Al-V-Zr-Mo titanium alloy, with excellent strength-ductility matching, is achieved through rational composition design and optimized element ratios. After simple heat treatment, a multi-morphological structure of micron-scale, nearly spherical primary α phase and nanometer-scale lamellar secondary α phase precipitates on the titanium alloy β matrix, resulting in high strength and excellent ductility. Furthermore, the preparation process is simple and enables a short production process, which reduces processing costs and meets the requirements of industrial production, satisfying the demand for high-performance titanium alloy structural parts in various industrial fields.

[0044] Example 1

[0045] A method for preparing a Ti-Al-V-Zr-Mo titanium alloy with excellent strength and plasticity matching, specifically comprising the following steps:

[0046] Step 1: Prepare a master alloy ingot by cold crucible suspension melting method.

[0047] The following raw materials were weighed according to percentage: Al was 5.60%, V was 11.60%, Zr was 1.30%, Mo was 5.50%, the total amount of interstitial solutes of O and N was 0.25%, and the balance was Ti and other inevitable impurities.

[0048] The above-mentioned sponge Ti, high-purity Al, high-purity Zr, Ti-Mo alloy and Ti-V alloy were mixed uniformly, then loaded into a cold crucible suspension melting furnace, and then melted in a high-purity argon atmosphere at a melting current of 430A and a current frequency of 25kHz. After being completely melted, they were kept for 4 minutes and then cooled. The mixture was then repeatedly melted 6 times to obtain a master alloy ingot with uniform composition.

[0049] Step 2: Perform high-temperature homogenization treatment on the master alloy ingot.

[0050] Step 3: Forging the master alloy ingot.

[0051] After the riser is cut off from the master alloy ingot obtained in step 2, the blank is forged at a blank forging temperature of 1100° C. and a holding time of 90 min. The blank is forged by three piers and three draws, and the deformation is 60%;

[0052] Step 4: Forging the forged ingot across the β phase region.

[0053] The high-temperature cross-β phase forging temperature range is 860-940℃, and the deformation is 55%;

[0054] Step 5: performing solid solution and aging treatment on the ingot after forging across the β phase region in the two-phase region.

[0055] The Ti-Al-V-Zr-Mo titanium alloy was solution treated at 835°C in the α+β two-phase region for 60 min, water quenched to room temperature, then aged at 575°C for 120 min, and water quenched to room temperature.

[0056] The tissue obtained Figure 2 As shown in Figure 2, after two-phase solid solution and aging treatment, typical micron-scale equiaxed α phase and nano-scale lamellar secondary α phase appear in the β matrix. Figure 3 The tensile fracture shown has a high density of dimples with a deep depth. This heterogeneous structure gives the alloy both high strength and excellent plasticity. According to the requirements of GB / T228.1-2010 standard, the mechanical properties of the alloy are measured as follows Figure 1 As shown in the curve of Example 1: y =1377MPa, tensile strength σ UTS =1455MPa, elongation at break ε=10.2%.

[0057] Example 2

[0058] A method for preparing a Ti-Al-V-Zr-Mo titanium alloy with excellent strength-ductility matching specifically comprises the following steps:

[0059] Step 1: Prepare a master alloy ingot by cold crucible suspension melting method.

[0060] The following raw materials were weighed according to percentage: Al was 5.60%, V was 11.60%, Zr was 1.30%, Mo was 5.50%, the total amount of interstitial solutes of O and N was 0.25%, and the balance was Ti and other inevitable impurities.

[0061] The above-mentioned sponge Ti, high-purity Al, high-purity Zr, Ti-Mo alloy and Ti-V alloy were mixed uniformly, then loaded into a cold crucible suspension melting furnace, and then melted in a high-purity argon atmosphere at a melting current of 430A and a current frequency of 25kHz. After being completely melted, they were kept for 4 minutes and then cooled. The mixture was then repeatedly melted 6 times to obtain a master alloy ingot with uniform composition.

[0062] Step 2: Perform high-temperature homogenization treatment on the master alloy ingot.

[0063] Step 3: Forging the master alloy ingot.

[0064] After the riser is cut off from the master alloy ingot obtained in step 2, the blank is forged at a blank forging temperature of 1100° C. and a holding time of 90 min. The blank is forged by three piers and three draws, and the deformation is 60%;

[0065] Step 4: Forging the forged ingot across the β phase region.

[0066] The high-temperature cross-β phase forging temperature range is 860-940℃, and the deformation is 55%;

[0067] Step 5: performing solid solution and aging treatment on the ingot after forging across the β phase region in the two-phase region.

[0068] The Ti-Al-V-Zr-Mo titanium alloy was solution treated at 835°C in the α+β two-phase region for 60 min, water quenched to room temperature, then aged at 535°C for 120 min, and water quenched to room temperature.

[0069] The tissue obtained Figure 4 As shown in Figure 2, after two-phase solid solution and aging treatment, typical micron-scale equiaxed α phase and nano-scale lamellar secondary α phase appear in the β matrix. Figure 5 The tensile fracture shown has a high density of dimples with a deep depth. This heterogeneous structure gives the alloy both high strength and excellent plasticity. According to the requirements of GB / T228.1-2010 standard, the mechanical properties of the alloy are measured as follows Figure 1 As shown in the curve of Example 2: σ y =1524MPa, tensile strength σ UTS =1580MPa, elongation at break ε=5.9%.

[0070] Example 3

[0071] A method for preparing a Ti-Al-V-Zr-Mo titanium alloy with excellent strength-ductility matching specifically comprises the following steps:

[0072] Step 1: Prepare a master alloy ingot by cold crucible suspension melting method.

[0073] The following raw materials were weighed according to percentage: Al was 5.60%, V was 11.60%, Zr was 1.30%, Mo was 5.50%, the total amount of interstitial solutes of O and N was 0.25%, and the balance was Ti and other inevitable impurities.

[0074] The above-mentioned sponge Ti, high-purity Al, high-purity Zr, Ti-Mo alloy and Ti-V alloy were mixed uniformly, then loaded into a cold crucible suspension melting furnace, and then melted in a high-purity argon atmosphere at a melting current of 430A and a current frequency of 25kHz. After being completely melted, they were kept for 4 minutes and then cooled. The mixture was then repeatedly melted 6 times to obtain a master alloy ingot with uniform composition.

[0075] Step 2: Perform high-temperature homogenization treatment on the master alloy ingot.

[0076] Step 3: Forging the master alloy ingot.

[0077] After the riser is cut off from the master alloy ingot obtained in step 2, the blank is forged at a blank forging temperature of 1100° C. and a holding time of 90 min. The blank is forged by three piers and three draws, and the deformation is 60%;

[0078] Step 4: Forging the forged ingot across the β phase region.

[0079] The high-temperature cross-β phase forging temperature range is 860-940℃, and the deformation is 55%;

[0080] Step 5: performing solid solution and aging treatment on the ingot after forging across the β phase region in the two-phase region.

[0081] The Ti-Al-V-Zr-Mo titanium alloy was solution treated at 800°C for 60 min in the α+β two-phase region and water quenched to room temperature. Thereafter, it was aged at 500°C for 120 min and water quenched to room temperature.

[0082] The tissue obtained Figure 6 As shown in Figure 2, after two-phase solid solution and aging treatment, typical micron-scale equiaxed α phase and nano-scale lamellar secondary α phase appear in the β matrix. Figure 7 The tensile fracture shown has a high density of dimples with a shallow depth. This heterogeneous structure gives the alloy both high strength and excellent plasticity. According to the requirements of GB / T228.1-2010, the mechanical properties of the alloy are as follows: Figure 1 As shown in the curve of Example 3: y =1542MPa, tensile strength σ UTS =1604MPa, elongation at break ε=4.7%.

[0083] Example 4

[0084] A method for preparing a Ti-Al-V-Zr-Mo titanium alloy with excellent strength-ductility matching specifically comprises the following steps:

[0085] Step 1: Prepare a master alloy ingot by cold crucible suspension melting method.

[0086] The following raw materials were weighed according to percentage: Al was 4.1%, V was 13.6%, Zr was 0.5%, Mo was 4.0%, the total amount of interstitial solutes of O and N was 0.34%, and the balance was Ti and other inevitable impurities.

[0087] The above-mentioned sponge Ti, high-purity Al, high-purity Zr, Ti-Mo alloy and Ti-V alloy were mixed uniformly, then loaded into a cold crucible suspension melting furnace, and then melted in a high-purity argon atmosphere at a melting current of 460A and a current frequency of 22kHz. After being completely melted, they were kept for 5 minutes and then cooled. The mixture was then repeatedly melted 6 times to obtain a master alloy ingot with uniform composition.

[0088] Step 2: Perform high-temperature homogenization treatment on the master alloy ingot.

[0089] Step 3: After removing the riser from the master alloy ingot obtained in step 2, the ingot is subjected to blanking forging. The blanking forging temperature is 1150° C., the holding time is 90 min, and the blanking is performed by three-piercing and three-drawing, with a deformation amount of 65%;

[0090] Step 4: Forging the forged ingot across the β phase region, wherein the high temperature forging temperature range of the cross-β phase region is 860-940° C. and the deformation amount is 60%;

[0091] Step 5: performing solid solution and aging treatment on the ingot after forging across the β phase region in the two-phase region.

[0092] The Ti-Al-V-Zr-Mo titanium alloy was solution treated at 820°C in the α+β two-phase region for 60 min, water quenched to room temperature, then aged at 520°C for 120 min, and water quenched to room temperature.

[0093] Example 5

[0094] A method for preparing a Ti-Al-V-Zr-Mo titanium alloy with excellent strength-ductility matching specifically comprises the following steps:

[0095] Step 1: Prepare a master alloy ingot by cold crucible suspension melting method.

[0096] The following raw materials were weighed according to percentage: Al was 7.1%, V was 9.6%, Zr was 2.1%, Mo was 7.0%, the total amount of interstitial solutes of O and N was 0.20%, and the balance was Ti and other inevitable impurities.

[0097] The above-mentioned sponge Ti, high-purity Al, high-purity Zr, Ti-Mo alloy and Ti-V alloy were mixed uniformly, then loaded into a cold crucible suspension melting furnace, and then melted in a high-purity argon atmosphere at a melting current of 400A and a current frequency of 20kHz. After being completely melted, the mixture was kept for 3 minutes and then cooled. The mixture was then repeatedly melted 6 times to obtain a master alloy ingot with uniform composition.

[0098] Step 2: Perform high-temperature homogenization treatment on the master alloy ingot.

[0099] Step 3: After removing the riser from the master alloy ingot obtained in step 2, the ingot is subjected to blanking forging. The blanking forging temperature is 1050° C., the holding time is 90 min, and the blanking is performed by three-piercing and three-drawing, with a deformation amount of 66%;

[0100] Step 4: Forging the forged ingot across the β phase region, wherein the high temperature forging temperature range of the cross-β phase region is 860-940° C. and the deformation amount is 62%;

[0101] Step 5: performing solid solution and aging treatment on the ingot after forging across the β phase region in the two-phase region.

[0102] The Ti-Al-V-Zr-Mo titanium alloy was solution treated at 800°C for 60 min in the α+β two-phase region and water quenched to room temperature. Thereafter, it was aged at 500°C for 120 min and water quenched to room temperature.

[0103] Comparative Example 1

[0104] A method for preparing a Ti-Al-V-Zr-Mo titanium alloy with excellent strength-ductility matching specifically comprises the following steps:

[0105] Step 1: Prepare a master alloy ingot by cold crucible suspension melting method.

[0106] The following raw materials were weighed according to percentage: Al: 5.60%, V: 11.60%, Zr: 1.30%, Mo: 5.50%, and the balance was Ti and other inevitable impurities.

[0107] The above-mentioned sponge Ti, high-purity Al, high-purity Zr, Ti-Mo alloy and Ti-V alloy were mixed uniformly, then loaded into a cold crucible suspension melting furnace, and then melted in a high-purity argon atmosphere with a melting current of 430A and a current frequency of 25kHz. After being completely melted, it was kept for 4 minutes and then cooled. Then, the melting was repeated 6 times to make the composition uniform;

[0108] Step 2: Perform high-temperature homogenization treatment on the master alloy ingot.

[0109] Step 3: Forging the master alloy ingot.

[0110] After the step 2 ingot is cut off the riser, cogging forging is carried out, the cogging forging temperature is 1100 DEG C, the holding time is 90 min, the cogging adopts three duns three pulls, and the deformation is 60%;

[0111] Step 4, the ingot after forging is carried out across beta phase zone forging.

[0112] The high-temperature cross-beta phase zone forging temperature range is 860-940 DEG C, and the deformation is 55%;

[0113] Step 5, the ingot after cross-beta phase zone forging is carried out in the two-phase zone solid solution treatment.

[0114] The Ti-Al-V-Zr-Mo titanium alloy is carried out in the alpha+beta two-phase zone 835 DEG C for 60 min solid solution treatment, and water quenching to room temperature.

[0115] According to the GB / T228.1-2010 standard requirements, the alloy mechanical properties are measured as Figure 1 The curve of the comparative example 1 shows that: σ y = 908 MPa, the tensile strength σ UTS = 940 MPa, and the fracture elongation ε = 16.5%. It can be seen that the yield strength and uniform elongation of the alloy after two-phase zone solid solution treatment but without subsequent aging treatment are significantly reduced.

[0116] The application provides a Ti-Al-V-Zr-Mo titanium alloy with excellent strength and plasticity matching, through reasonable component design and element ratio optimization, the alloy is subjected to melting, homogenization treatment, forging, and solid solution and aging treatment, and then a plurality of morphological micron-scale spherical primary alpha phases and nanometer-scale flaky secondary alpha phases are precipitated on the titanium alloy beta matrix, high strength and good plasticity are obtained. The alloy realizes good matching of the strength and plasticity of the alloy after simple heat treatment, the process is short, the processing cost is reduced, meets the requirements of industrial production, the titanium alloy has excellent mechanical properties and is not easy to cause component segregation, so that the Ti-Al-V-Zr-Mo high-strength titanium alloy has the advantages of low cost, short process and meets the requirements of industrial production, meets the demand of various industrial fields for high-performance titanium alloy structural parts, and can be widely used in the fields of aviation, aerospace, automobile and the like.

[0117] The above content only illustrates the technical idea of the application, and cannot limit the protection scope of the application, and any modification made according to the technical idea of the application on the basis of the technical scheme falls within the protection scope of the claims of the application.

Claims

1. A Ti-Al-V-Zr-Mo titanium alloy with excellent strength and plasticity matching, characterized in that: Calculated by mass percentage, it includes 4.1% to 7.1% Al, 9.6% to 13.6% V, 0.5% to 2.1% Zr, 4.0% to 7.0% Mo, less than 0.35% of O and N interstitial solutes, and the balance is Ti and other unavoidable impurities; The Ti-Al-V-Zr-Mo titanium alloy microstructure is uniformly distributed with micrometer-scale nearly spherical primary α phase, nanometer-scale triangular-shaped secondary α phase and residual nanometer-scale β matrix; The preparation method of the Ti-Al-V-Zr-Mo titanium alloy with excellent strength and plasticity matching, The following processes are included: Step 1: preparing a master alloy ingot according to the mass percentage of each raw material; Step 2, performing blanking forging and high-temperature cross-β phase forging on the master alloy ingot; The temperature of the cross-β phase forging is 860-940°C, and the deformation is ≥ 55%; Step 3, subjecting the forged ingot to solid solution and aging treatment in the two-phase region; The temperature of the solution treatment is 800-835°C, and after the solution treatment for 60 minutes, the steel is water quenched to room temperature; The aging treatment temperature is 500-575°C, and after aging treatment for 120 minutes, the alloy is water quenched to room temperature to obtain a Ti-Al-V-Zr-Mo titanium alloy.

2. The Ti-Al-V-Zr-Mo titanium alloy with excellent strength and ductility matching according to claim 1, characterized in that: The yield strength σ of the Ti-Al-V-Zr-Mo titanium alloy y =1377 MPa~1542 MPa, tensile strength σ UTS =1455MPa~1604 MPa, elongation at break ε=4.7%~10.2%.

3. The Ti-Al-V-Zr-Mo titanium alloy with excellent strength and plasticity matching according to claim 1, characterized in that: In step 1, a master alloy ingot is prepared by a smelting method; During the smelting process, argon gas is introduced, the induced current is 400~460 A, and the current frequency is 20~25 kHz. After the alloy is completely melted, it is kept for 3~5 minutes and then cooled. The smelting is repeated several times to obtain the master alloy ingot.

4. The Ti-Al-V-Zr-Mo titanium alloy with excellent strength and plasticity matching according to claim 1, characterized in that: In step 2, the blanking temperature of the blanking forging is 1050-1150°C, the holding time is 90 min, and the deformation amount is ≥ 60%.

5. The Ti-Al-V-Zr-Mo titanium alloy with excellent strength and plasticity matching according to claim 1, characterized in that: The master alloy ingot in step 1 is homogenized and then subjected to blank forging.

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