Heterostructure high-strength hydrogen embrittlement-resistant commercial pure titanium and preparation method thereof

Abstract

The invention relates to the technical field of hydrogen embrittlement resistance of metal materials, in particular to high-strength hydrogen embrittlement-resistant commercial pure titanium with a heterostructure and a preparation method thereof. The microstructure of the pure titanium is a heterostructure jointly formed by coarse grains, fine grains, ultra-fine grains, nanocrystalline and high-density deformation twin crystals, and the grain boundary structure of the pure titanium comprises small-angle grain boundaries and twin boundaries. An original pure titanium bar is subjected to multi-pass rotary forging deformation at the liquid nitrogen temperature, the deformed pure titanium is annealed, and the pure titanium which has heterostructures with different grain sizes and contains strong < 0001 > / / stretching direction (TD) fiber textures, a large number of small-angle grain boundaries and high-density deformation twin crystals is obtained. According to the method, the commercial pure titanium with high strength and plasticity matching and good hydrogen embrittlement resistance is obtained by combining rotary forging processing and simple annealing treatment on the commercial pure titanium, the method has the advantages of being high in operability and the like, and a new material choice is provided for design and manufacturing of high-performance ocean engineering equipment and biomedical implants.

Description

Technical Field

[0001] This invention relates to the field of hydrogen embrittlement resistance technology for metallic materials, specifically to a heterostructure high-strength hydrogen embrittlement resistant commercial pure titanium and its preparation method, which is suitable for hydrogen-sensitive and harsh environments such as deep-sea equipment and human implant devices. Background Technology

[0002] Titanium and titanium alloys possess excellent corrosion resistance, high specific strength, and good biocompatibility, making them widely used in aerospace, marine, and medical fields. However, with increasingly stringent application environments and ever-increasing structural requirements, these materials still face two major challenges in practical engineering applications: First, pure titanium has relatively low strength (around 400 MPa). Although strength can be improved through alloying, this often comes at the cost of sacrificing some plasticity and machinability. Furthermore, in the context of implantable devices, avoiding the introduction of alloying elements can significantly improve the biocompatibility and long-term service safety of the material. The inherent strength of pure titanium is no longer sufficient to meet the growing requirements for lightweight and high-reliability designs, making the development of pure titanium structural materials that combine high strength and good plasticity an urgent need. Second, titanium and titanium alloys often exhibit strong hydrogen embrittlement sensitivity. This is because they belong to a typical hydride-forming system. In hydrogen-containing environments such as marine atmospheres, seawater, or human body fluids, hydrogen atoms can be released from the surface of the material through electrochemical cathodic reactions and migrate into the titanium alloy lattice. Especially within the α phase or at the α / β phase boundary, hydrogen readily precipitates and forms brittle hydrides. These hydrides act as crack initiation points under stress, significantly reducing the material's fracture toughness and fatigue life, leading to low-stress brittle fracture and seriously threatening the long-term service safety of structures in harsh environments. Therefore, in the development of high-performance titanium materials, how to simultaneously improve strength and resist hydrogen embrittlement has become a core issue for expanding its high-end engineering applications.

[0003] From the perspective of strengthening mechanisms, there are four main types of strengthening in metallic materials: solid solution strengthening, precipitation strengthening, grain refinement strengthening, and deformation strengthening. Since pure titanium contains extremely low concentrations and types of alloying elements, its strengthening mechanisms are primarily grain refinement strengthening and deformation strengthening. Pure titanium has a hexagonal close-packed (hcp) structure (c / a = 1.587), and its plastic deformation is characterized not only by dislocation slip but also by twinning behavior. The interaction between dislocations and twins significantly affects the mechanical properties of pure titanium. Studies have shown that dislocation pile-up at grain boundaries and the interaction between dislocations contribute to the nucleation of deformation twins. Strain rate and temperature are the decisive parameters affecting the plastic deformation of pure titanium. Since dislocation is a thermally activated process, deformation twins are insensitive to temperature. Therefore, at low temperatures, pure titanium simultaneously initiates a large number of deformation twins and high-density dislocations during plastic deformation. The presence of twins can cut the original grains, effectively hindering dislocation movement. On the other hand, it can adjust the transformation of the original grains from hard orientation to soft orientation, thus improving the strength of pure titanium while maintaining a certain degree of plasticity. Conversely, the large number of dislocations generated during the plastic deformation of pure titanium at high strain rates will evolve into dislocation cells, subgrain boundaries, or small-angle grain boundaries during subsequent annealing. Since deformation twins are insensitive to temperature, a suitable short-time annealing regime will not lead to detwining. In recent years, the emergence of heterostructure materials has successfully overcome the dilemma of achieving both strength and plasticity in traditional metallic materials. By constructing regions with significant strength differences in their microstructure (such as softer coarse grains combined with harder ultrafine grains, or nanocrystals) and introducing high-density interfaces, the material properties are significantly improved. The core mechanism lies in the fact that during deformation, the softer regions undergo plastic deformation first, while the harder regions remain in an elastic state. This mismatch in deformation between different regions creates a huge strain gradient, inducing geometrically necessary dislocation accumulation and forming strong back stress. This not only significantly improves the material's yield strength but also provides continuous work hardening capability, thus simultaneously achieving exceptional strength and plasticity. Furthermore, plastic deformation often alters the material's original orientation and even forms texture. Changes in orientation can affect both the strength and plasticity of close-packed hexagonal materials like pure titanium. On one hand, favorable texture can increase the critical shear stress (CRSS) required to activate different slip systems, thus improving the material's yield strength. On the other hand, it may lead to the activation of different slip systems during deformation, especially…<c+a> Activation of slip systems has a significant effect on improving the plasticity of close-packed hexagonal structures. Therefore<c+a> Dislocation manipulation has become an important method used internationally to improve the strength-plasticity matching of close-packed hexagonal structural materials.

[0004] From the perspective of reducing hydrogen embrittlement sensitivity, hydrogen is a harmful but difficult-to-completely-avoid impurity element. Hydrogen originates from the atmospheric environment or enters the material's interior during service in hydrogen-rich environments, and is also produced during electrochemical cathode reactions. It can reduce the strength and toughness of titanium, and in severe cases, lead to hydrogen embrittlement. The hydrogen penetration process in metals can be divided into four continuous stages: diffusion of gas molecules to the metal surface, surface adsorption and dissociation and chemisorption, intrusion of adsorbed hydrogen atoms into the crystal lattice, and diffusion and migration of hydrogen within the crystal lattice. The small-angle grain boundaries and twin boundaries formed in titanium during plastic deformation are low-energy interfaces. The fundamental cause of hydrogen-induced cracking in titanium and titanium alloys lies in the formation of a large number of brittle hydrides. By reducing the interface energy, the thermodynamic conditions for hydrogen segregation can be altered, thereby inhibiting hydride nucleation and effectively reducing its hydrogen embrittlement sensitivity. Its main mechanisms include the following two aspects: First, the significant increase in the total volume of grain boundaries can effectively disperse the local enrichment concentration of hydrogen at the grain boundaries; second, the formation of deformed twins causes changes in grain orientation, which further inhibits hydrogen segregation and hydride precipitation, thereby delaying hydride nucleation.

[0005] Regarding the aforementioned issues, patent CN112593171A proposes a method for preparing fine-grained pure titanium with both high strength and toughness and excellent comprehensive properties, involving multiple rounds of warm and cold forging deformation processing, but with limited improvement in the performance of pure titanium; patent CN115283431A proposes a method for preparing high-strength, high-toughness, equiaxed ultrafine-grained pure titanium, which, while yielding high-toughness pure titanium, does not significantly improve strength, making it unsuitable for service in high-load environments; and patent CN105772503A proposes a method for preparing high-strength pure titanium, which, while yielding high-strength pure titanium, requires more than 15 rounds of processing. The rolling deformation process is complex; Patent CN115261670A proposes a method for preparing high-strength and high-toughness pure titanium, which also yields high-strength pure titanium, but requires multiple extrusion and rolling deformations and multiple annealing treatments, increasing processing costs and time; Patent CN103981472A proposes a method for preparing ultrafine-grained pure titanium by equal-diameter channel extrusion, which also yields high-strength pure titanium, but requires more complex multi-pass equal-channel extrusion, multiple annealing and surface treatments, greatly increasing processing costs; Patent CN110295334A proposes a high-strength and high-ductility... The preparation method of industrial pure titanium with a multi-level structure and the patent publication number CN112522650A propose a high-strength, high-toughness, ultrafine twinned pure titanium and its preparation method. Although high-performance pure titanium with excellent comprehensive properties was obtained through different processing methods, the hydrogen embrittlement sensitivity of pure titanium was not studied, and it is impossible to determine whether it is suitable for hydrogen-sensitive harsh environments. The patent publication number CN108950298A proposes a hydrogen embrittlement resistant titanium alloy for biomedical implants and its production method. Although good mechanical properties and improved hydrogen embrittlement resistance were obtained, rare earth element Nd was added during the alloy melting process. Although this method utilizes The irreversible hydrogen trapping principle of the precipitated phase effectively inhibits hydrogen diffusion, but this method is costly and complex to operate. Patent CN120026215A proposes a hydrogen embrittlement-resistant high-strength titanium alloy and its preparation method. Although a high-strength hydrogen embrittlement-resistant titanium alloy is obtained, it contains a variety of alloying elements, including but not limited to elements harmful to the human body, Al and Sn, as well as the expensive rare earth element Y, making it unsuitable for human implantation. Patent CN114369779A proposes a high-strength hydrogen embrittlement-resistant pure titanium and its preparation method. High-strength hydrogen embrittlement-resistant pure titanium is obtained through a simple processing method, but the strength and plasticity obtained are not high.

[0006] In summary, developing pure titanium materials that combine high strength with low hydrogen embrittlement sensitivity is a significant engineering challenge. Currently, a simple, efficient, and cost-effective solution is lacking internationally. Therefore, developing a high-performance, hydrogen-embrittlement-resistant pure titanium material with simple processing and excellent overall performance not only has significant engineering application prospects but also has urgent practical significance for improving the long-term reliability of critical equipment in hydrogen-sensitive environments. Summary of the Invention

[0007] To address the problems existing in the prior art, the main objective of this invention is to provide a heterostructure high-strength hydrogen embrittlement resistant commercial pure titanium and its preparation method, thereby obtaining hydrogen embrittlement resistant pure titanium with high strength and plasticity matching, solving the problem that the prior art cannot simultaneously improve the strength and hydrogen embrittlement susceptibility of pure titanium, improving the mechanical properties of advanced titanium materials and exhibiting better hydrogen embrittlement susceptibility.

[0008] The technical solution of the present invention is as follows:

[0009] A heterostructured high-strength, hydrogen-embrittlement-resistant commercial pure titanium, wherein the microstructure of pure titanium is a heterostructure composed of coarse grains, fine grains, ultrafine grains, nanocrystals and high-density deformed twins, and the grain boundary structure of pure titanium includes low-energy interfaces: small-angle grain boundaries and twin boundaries.

[0010] The heterostructured high-strength, hydrogen-embrittlement-resistant commercial pure titanium has a coarse grain size of 10–30 μm, a fine grain size of 1–10 μm, an ultrafine grain size of 0.1–1 μm, a nanocrystal size of 10–100 nm, and a high-density deformed twin thickness of 0.5–1 μm.

[0011] The heterostructured high-strength, hydrogen-embrittlement-resistant commercial pure titanium has small-angle grain boundaries ranging from 2 to 10°, with small-angle grain boundaries accounting for 25% to 35% of the total number of grain boundaries, and twin boundaries accounting for 8% to 12% of the total number of grain boundaries.

[0012] The aforementioned heterostructure high-strength, hydrogen-embrittlement-resistant commercial pure titanium has a fibrous texture along the <0001> / / tensile direction (TD).

[0013] The method for preparing the heterostructured, high-strength, hydrogen-embrittlement-resistant commercial pure titanium includes the following steps:

[0014] (1) After pretreatment, commercial pure titanium is immersed in liquid nitrogen for 10-20 minutes to cool the pure titanium to the temperature of liquid nitrogen.

[0015] (2) Pure titanium cooled by liquid nitrogen is subjected to a strain rate of 1 to 1 × 10⁻⁶. 2 S -1 The process involves multiple passes of rotary forging deformation, with the total true strain controlled at ε = 0.7–1.0.

[0016] (3) Seal the deformed pure titanium in a quartz tube and evacuate it until the vacuum pressure inside the quartz tube is lower than 1×10⁻⁶. -3 Pa;

[0017] (4) Place the sealed pure titanium into a box-type resistance furnace at 450-500℃, keep it at that temperature for 30-60 seconds, and then air-cool it to room temperature to obtain heterostructured high-strength hydrogen embrittlement-resistant commercial pure titanium.

[0018] In the preparation method of the heterostructure high-strength hydrogen embrittlement-resistant commercial pure titanium, in step (2), the liquid nitrogen temperature is -196℃ to ensure uniform cooling of the sample.

[0019] The design concept of this invention is:

[0020] This invention involves multi-pass rotary forging deformation of raw pure titanium rods at liquid nitrogen temperature, followed by short-time annealing of the deformed pure titanium. This yields pure titanium with heterogeneous structures of different grain sizes, containing strong <0001> / / tension direction (TD) fiber texture, numerous small-angle grain boundaries, and high-density deformation twins. By utilizing the synergistic effect of low-temperature deformation-short-time annealing processes, precise control of microstructure and properties can be achieved.

[0021] At liquid nitrogen temperature, dislocation movement in pure titanium is suppressed and deformation twins are easily initiated. Through the uniform deformation characteristics of rotational forging, multi-scale grains (coarse grains provide plasticity, fine / ultrafine / nanocrystalline grains provide strength) and high-density deformation twins can be introduced simultaneously to construct a heterogeneous structure. The strength difference in different grain regions generates strain gradients during deformation, inducing geometrically necessary dislocation stacking and back stress, significantly improving yield strength and work hardening ability.

[0022] Short-time annealing (such as annealing at 450℃ for 30 seconds) can eliminate residual stress from deformation, avoid excessive grain growth and twinning, and at the same time retain a large number of small-angle grain boundaries and twin boundaries (low-energy interfaces). These interfaces can disperse hydrogen concentration, change the thermodynamic conditions of hydrogen segregation, inhibit hydride nucleation, and reduce hydrogen embrittlement sensitivity from the root.

[0023] The <0001> / / TD fiber texture induced during rotary forging can reduce<c+a> The critical shear stress of dislocations promotes their initiation, thereby improving strength and optimizing plasticity, achieving a synergistic balance between strength and plasticity.

[0024] Ultimately, the problems of insufficient strength, hydrogen embrittlement sensitivity, and complex processing of pure titanium were solved by combining heterostructure reinforcement, low-energy interface resistance to hydrogen embrittlement, and texture-controlled plasticity.

[0025] The present invention has the following advantages and beneficial effects:

[0026] 1. This invention forms a heterogeneous structure with different grain sizes by plastically deforming pure titanium at high strain rates and low temperatures, while introducing a large number of low-energy interfaces (small-angle grain boundaries and twin boundaries). When such a microstructure undergoes secondary deformation, the coarse grains tend to undergo plastic deformation first, while the fine grain regions remain in an elastic state. The incoordination of deformation between the two different regions will generate a huge strain gradient, induce geometrically necessary dislocation accumulation and form strong back stress, thereby improving the yield strength of the material.

[0027] 2. This invention introduces a strong <0001> / / TD fiber texture, which is more conducive to initiation.<c+a> Dislocations, while increasing the yield strength of materials through plastic deformation,<c+a> Dislocation activation can better regulate the strong-plasticity matching, enabling the material to obtain better plasticity.

[0028] 3. This invention improves the resistance of pure titanium to hydrogen embrittlement by introducing a large number of low-energy interfaces, thereby thermodynamically reducing the driving force for hydride nucleation.

[0029] 4. This invention eliminates residual strain energy after deformation by annealing at a suitable temperature, while retaining high-density deformation twins to change the crystallographic orientation of the original grains, thereby maintaining the plasticity of pure titanium.

[0030] 5. The operation steps of this invention are simple, including only one processing method and a single annealing treatment.

[0031] 6. This invention obtains commercially available pure titanium with high strength-plasticity matching and good resistance to hydrogen embrittlement by combining rotary forging with simple annealing. It features a simple method, low cost, and high operability, providing a new material option for the design and manufacture of high-performance marine engineering equipment and biomedical implants. Attached Figure Description

[0032] Figure 1 Electron backscatter diffraction (EBSD) IPF patterns and grain size statistics of pure titanium in its original and deformed states, representing the heterostructure with high strength and plasticity matching and resistance to hydrogen embrittlement according to the present invention. (a) IPF pattern of pure titanium in its original state, (b) IPF pattern of pure titanium in its deformed state, (c) grain size statistics before deformation, and (d) grain size statistics after deformation.

[0033] Figure 2 The figures shown are the (0001) pole figures and (10-10) pole figures of the original and modified pure titanium structures of the present invention, which exhibit high strength and plasticity matching and resistance to hydrogen embrittlement. (a) is the (0001) pole figure of the original pure titanium structure, (b) is the (10-10) pole figure of the original pure titanium structure, (c) is the (0001) pole figure of the modified pure titanium structure, and (d) is the (10-10) pole figure of the modified pure titanium structure. Tensile direction represents the tensile direction.

[0034] Figure 3 The invention relates to a heterostructure with high strength and plasticity matching, and its hydrogen embrittlement resistant pure titanium in its original and deformed states, exhibiting slow strain rate tensile (ε = 5 × 10⁻⁶) before and after electrochemical hydrogen charging. -6 S -1 Engineering stress-strain curve; In the figure, the horizontal axis is Engineering stress (MPa), the vertical axis is Engineering strain (%), CG-Air represents the original state of pure titanium, CG-HC represents the hydrogen-filled state of pure titanium, Rotary swaging-Air represents the deformed state of pure titanium after rotary forging, and Rotary swaging-HC represents the hydrogen-filled state of pure titanium after rotary forging. Detailed Implementation

[0035] In the specific implementation process, the present invention obtains pure titanium with four types of mixed microstructures: coarse grains, fine grains, ultrafine grains, nanocrystals, and deformed twins by rotating and forging the original pure titanium at a high strain rate and a low temperature, combined with annealing at an appropriate temperature. Furthermore, this pure titanium contains a large number of low-energy interfaces, including small-angle grain boundaries and deformed twin boundaries.

[0036] The structure of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0037] Example

[0038] In this embodiment, the preparation process of the hydrogen-embrittled pure titanium with high strength and plasticity matching of heterostructure is as follows:

[0039] Step 1: Select commercially available pure titanium (TA1) rods and machine the raw coarse-grained pure titanium rods into... Rod-shaped specimens.

[0040] Step 2: Immerse the processed pure titanium in liquid nitrogen for 15 minutes to allow it to cool completely.

[0041] Step 3: Pure titanium immersed in liquid nitrogen is subjected to a strain rate of 50 s. -1 The sample underwent multiple passes of rotary forging deformation, resulting in a true strain ε = 0.94 (the final sample diameter was reduced to approximately...). ).

[0042] Step 4: Seal the deformed pure titanium in a quartz tube with a vacuum pressure of 3 × 10⁻⁶. -4 Pa.

[0043] Step 5: Anneal the pure titanium sealed in the quartz tube in a box-type resistance furnace at a temperature of 450°C for 30 seconds.

[0044] Step 6: When the temperature of the tubular resistance furnace reaches 450℃, put the pure titanium sample into the furnace. When the holding time reaches 30 seconds, take out the sample and air cool it to room temperature.

[0045] like Figure 1 and Figure 2 As shown, the pure titanium microstructure and orientation changes obtained by the above preparation method show that the average grain size decreased by 1.87 μm from 30.59 μm before deformation, and the grains were significantly refined. At the same time, it can be observed that coarse grains still exist after deformation. Although the severe plastic deformation forms a large number of fine and ultrafine grains, resulting in a small number of coarse grains (0.4%), they still occupy a large volume fraction (16%). A microstructure containing coarse grains (about 16% volume fraction, size 15-25 μm), fine grains (about 34% volume fraction, size 3-8 μm), ultrafine grains (about 40% volume fraction, size 0.3-1 μm), nanocrystals (about 5% volume fraction, size 50-100 nm), and high-density deformation twins (about 5% volume fraction, thickness 0.5-1 μm) was obtained. Meanwhile, the sample contains small-angle grain boundaries (2-10°) accounting for 32% of the total number of grain boundaries and twin boundaries accounting for 10% of the total number of grain boundaries. Through deformation, the grains acquire a distinct <0001> / / TD fiber texture.

[0046] Step 7: Perform hydrogen embrittlement sensitivity evaluation. Currently, the internationally accepted method for assessing hydrogen embrittlement sensitivity of metallic materials is the slow strain rate tensile test method. The pristine specimen and the deformed pure titanium are processed into standard tensile specimens. The gauge length of the specimen is exposed to a mixed solution of 1 volume phosphoric acid + 2 volumes glycerol for electrochemical hydrogen charging. The charging conditions are room temperature and a current density of 50 mA / cm². 2 Before stretching, the material was pre-charged with hydrogen for 16 hours and then subjected to dynamic hydrogen-charged stretching at a strain rate of 5 × 10⁻⁶. - 6 S -1 .

[0047] like Figure 3 As shown in the tensile stress-strain curve, the yield strength of the original coarse-grained sample is 398 MPa, and the elongation is 32.7%. However, the yield strength of the original sample after hydrogen embrittlement drops to 370 MPa, and the elongation decreases to 24.8%. This indicates that the original coarse-grained pure titanium has significant hydrogen embrittlement sensitivity. The strength of the deformed pure titanium increases by approximately two times, reaching 781 MPa, while maintaining an elongation of 10.2%. More importantly, the deformed sample only experiences a 30 MPa decrease in strength after hydrogen embrittlement, without any loss in elongation. This demonstrates that the pure titanium obtained by the preparation method of this invention possesses both high strength and good resistance to hydrogen embrittlement sensitivity.

[0048] The results of the examples demonstrate that the present invention successfully prepares pure titanium with high strength, good ductility, and excellent resistance to hydrogen embrittlement through a two-step process of rotary forging deformation and single annealing. This invention is suitable for widespread use in laboratories and can also be widely applied in large-scale industrial production fields such as steel and non-ferrous metals.

[0049] The high-strength hydrogen-embrittlement-resistant pure titanium and its preparation method of the present invention are not limited to applications in the fields of marine engineering and biomedical implants or medical device metal structural materials. Any application of the high-strength hydrogen-embrittlement-resistant pure titanium and its preparation method provided by the present invention in any field or industry falls within the protection scope of this patent.

Claims

1. A heterostructured, high-strength, hydrogen-embrittlement-resistant commercial pure titanium, characterized in that, The microstructure of pure titanium is a heterogeneous structure composed of coarse grains, fine grains, ultrafine grains, nanocrystals, and high-density deformed twins. Furthermore, the grain boundary structure of pure titanium includes low-energy interfaces: small-angle grain boundaries and twin boundaries.

2. The heterostructured high-strength, hydrogen-embrittlement-resistant commercial pure titanium according to claim 1, characterized in that, The grain size of coarse crystals is 10–30 μm, the grain size of fine crystals is 1–10 μm, the grain size of ultrafine crystals is 0.1–1 μm, the grain size of nanocrystals is 10–100 nm, and the thickness of high-density deformed twins is 0.5–1 μm.

3. The heterostructured high-strength, hydrogen-embrittlement-resistant commercial pure titanium according to claim 1, characterized in that, The angle range of small-angle grain boundaries is 2–10°, and the proportion of small-angle grain boundaries to the total number of grain boundaries is 25–35%, while the proportion of twin boundaries to the total number of grain boundaries is 8–12%.

4. The heterostructured high-strength, hydrogen-embrittlement-resistant commercial pure titanium according to claim 1, characterized in that, Pure titanium has a fibrous texture along the <0001> / / tensile direction (TD).

5. A method for preparing heterostructured high-strength, hydrogen-embrittlement-resistant commercial pure titanium according to any one of claims 1 to 4, characterized in that, Includes the following steps: (1) After pretreatment, commercial pure titanium is immersed in liquid nitrogen for 10-20 minutes to cool the pure titanium to the temperature of liquid nitrogen. (2) Pure titanium cooled by liquid nitrogen is subjected to a strain rate of 1 to 1 × 10⁻⁶. 2 S -1 The process involves multiple passes of rotary forging deformation, with the total true strain controlled at ε = 0.7–1.

0. (3) Seal the deformed pure titanium in a quartz tube and evacuate it until the vacuum pressure inside the quartz tube is lower than 1×10⁻⁶. -3 Pa; (4) Place the sealed pure titanium into a box-type resistance furnace at 450-500℃, keep it at that temperature for 30-60 seconds, and then air-cool it to room temperature to obtain heterostructured high-strength hydrogen embrittlement-resistant commercial pure titanium.

6. The method for preparing heterostructured high-strength, hydrogen-embrittlement-resistant commercial pure titanium according to claim 5, characterized in that, In step (2), the liquid nitrogen temperature is -196℃ to ensure uniform cooling of the sample.

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