Heat treatment process of titanium-zirconium alloy casting

Abstract

The invention relates to a heat treatment process of a titanium-zirconium alloy casting, belongs to the field of titanium-zirconium alloy heat treatment, and solves the problems that the mechanical property of the titanium-zirconium casting in the prior art is insufficient, and the titanium-zirconium casting is difficult to be used in production of parts with higher strength requirements. The invention relates to a heat treatment process of a titanium-zirconium alloy casting. The process sequentially comprises the following steps of a hot isostatic pressing process, a solution treatment process and an aging treatment process. The structure of the titanium-zirconium alloy casting is further optimized, the mechanical property of the titanium-zirconium alloy casting is improved, plasticity is reserved, on the basis of reasonability, the strength of the titanium-zirconium alloy casting is greatly improved, the structure is more optimized, and therefore the application field range of the titanium-zirconium alloy casting is expanded.

Description

Technical Field

[0001] This invention relates to the field of heat treatment technology for titanium-zirconium alloys, and in particular to a heat treatment process for titanium-zirconium alloy castings. Background Technology

[0002] Titanium-zirconium and titanium-zirconium-niobium alloys are energetic solid solution alloys that can be widely used in aerospace, weaponry, nuclear power, medical and other fields.

[0003] Titanium-zirconium alloy castings have insufficient strength at room temperature, requiring heat treatment processes to improve their strength and other properties. CN115921784A, "A Titanium-Zirconium Alloy Casting and Its Precision Casting Method," discloses a method for forming titanium-zirconium alloy castings, employing a single hot isostatic pressing (HIP) process. Specifically, the HIP process involves a temperature of 800℃~980℃, a pressure of 100~140MPa, and a time of 2~6h. The resulting titanium-zirconium alloy casting has a tensile strength of 1030MPa and a yield strength of 950MPa, showing only a minor improvement in strength.

[0004] CN115627387B, "A High-Strength TiZr-Based Alloy and Its Preparation Method," discloses a high-strength TiZr-based alloy and its preparation method. This application focuses on the heat treatment process of forgings, requiring multiple melting processes, high-temperature forging, followed by a two-stage solution treatment and aging treatment. In other words, it requires a three-step superposition of primary and secondary solution treatments before aging treatment to obtain a finer multiphase microstructure with a combination of primary and secondary α phases after the aging treatment and subsequent forging process. The process steps are complex.

[0005] In order to be better and more widely used in aerospace, weaponry, nuclear power, medical and other fields, it is necessary to

[0006] By optimizing the heat treatment process and further improving the microstructure of existing titanium-zirconium alloy castings, the plasticity of titanium-zirconium alloy castings can be maintained within a reasonable range while the strength can be significantly improved, resulting in better mechanical properties and thus expanding the application range of titanium-zirconium alloy castings. Summary of the Invention

[0007] Based on the above analysis, the present invention aims to provide a heat treatment process for titanium-zirconium alloy castings to solve the problems of poor microstructure and insufficient tensile and yield strength of titanium-zirconium alloy castings after heat treatment in the prior art.

[0008] This invention provides a heat treatment process for titanium-zirconium alloy castings, the process comprising the following steps:

[0009] Step 1: Hot Isostatic Pressing Process

[0010] Will

[0011] The titanium-zirconium alloy castings are placed in a hot press and heated to 680℃~750℃ at a heating rate of 1-6℃ / min. A pressure of 100MPa~160MPa is applied, and the castings are held at that temperature for 0.5-3 hours before being furnace cooled and removed from the furnace.

[0012] Step 2: Solution Treatment Process

[0013] The titanium-zirconium alloy castings treated by hot isostatic pressing are placed in a vacuum heat treatment furnace and heated to 610-690℃ at a heating rate of 2-10℃ / min. After holding at that temperature for 0.5-2 hours, they are cooled to room temperature using argon gas.

[0014] Step 3: Aging Treatment Process

[0015] The titanium-zirconium alloy casting is placed again in a vacuum heat treatment furnace and heated to 350-450°C at a heating rate of 2-10°C / min. After holding at that temperature for 0.5-3.5 hours, the furnace is cooled to room temperature.

[0016] Furthermore, the composition of the titanium-zirconium alloy casting includes, by weight percentage: Ti 30%–33%, Zr 65%–70%, and Hf 1%–2%.

[0017] Furthermore, the titanium-zirconium alloy casting is a titanium-zirconium alloy frame beam, ring, or irregular structure casting with an outline dimension of 10-2000mm and a wall thickness of 1-50mm.

[0018] Furthermore, the hot pressing equipment mentioned in step one is a hot press furnace with an argon protective atmosphere. When performing hot isostatic pressing on titanium-zirconium alloy castings, the temperature is increased to 700℃~730℃ at a heating rate of 2-5℃ / min, a pressure of 100MPa~140MPa is applied, and the castings are held at that temperature for 0.5-2.5 hours before being cooled and removed from the furnace.

[0019] Furthermore, in step two, a vacuum heat treatment furnace with argon atmosphere protection is used to heat the titanium-zirconium alloy castings that have undergone hot pressing treatment in step one to 630-670°C at a heating rate of 3-7°C / min, hold them at that temperature for 0.5-1.5 hours, and then rapidly cool them to room temperature with argon.

[0020] Furthermore, the titanium-zirconium alloy casting obtained by the aforementioned heat treatment process comprises, by weight percentage: Ti 30%–33%, Zr 65%–70%, and Hf 1%–2%.

[0021] Furthermore, in step three, a vacuum heat treatment furnace is used again to heat the furnace to 380-420°C at a heating rate of 3-7°C / min, hold the temperature for 1-3 hours, and then cool the furnace to room temperature.

[0022] Furthermore, the final titanium-zirconium alloy casting exhibits a bimodal structure.

[0023] Furthermore, the dual-state structure consists of an equiaxed primary α phase, a secondary α phase, and a residual β phase.

[0024] Furthermore, the titanium-zirconium alloy casting has a room temperature tensile strength of ≥1169MPa and a yield strength of ≥1048MPa.

[0025] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0026] 1. Traditional titanium-zirconium alloy casting methods typically employ a single hot isostatic pressing (HIP) process at temperatures ranging from 800℃ to 980℃. Compared to this, the HIP temperature of this invention is significantly lower than 800℃ to 980℃. Furthermore, the heat treatment process of this invention involves only one step: solution treatment and aging. Compared to existing heat treatment processes, this is simpler and results in an optimized internal microstructure. The titanium-zirconium alloy castings of this invention exhibit a room temperature tensile strength exceeding 1169 MPa and a yield strength exceeding 1060 MPa, representing a 39% improvement compared to the original castings (those without heat treatment).

[0027] 2. Traditional titanium-zirconium alloy casting forming methods usually employ a single hot isostatic pressing process. The temperature of the hot isostatic pressing process is 800℃~980℃. Its purpose is to form a coarse basket structure in the titanium-zirconium alloy casting after pouring, solidification and hot isostatic pressing treatment. Compared with existing hot isostatic pressing (HIP) processes, the HIP temperature of this invention is significantly lower than 800℃~980℃. It transforms "high-temperature sealing" into "warm pre-solution," maintaining the sealing effect while reducing the temperature to near the alloy phase transformation point (680-750℃). After HIP treatment, defects within the casting pores can be eliminated, achieving pore closure and compositional homogenization while simultaneously inhibiting grain boundary migration, preserving a fine-grained framework, and lowering the temperature and time of subsequent "true solution." This allows for complete solution treatment at a low temperature (610-690℃) for 0.5-1.5 hours, achieving the desired effect. In other words, it employs "warm pre-solution" followed by "true solution," eliminating the need for a high-temperature furnace at 800-980℃, thus saving energy, reducing emissions, lowering carbon emissions, and being more environmentally friendly.

[0028] 3. This invention further incorporates a solution treatment and aging process after the hot isostatic pressing (HIP) process. In the solution treatment stage, the temperature is raised to 610-690℃ at a rate of 2-10℃ / min, held for 0.5-3.5 hours, and then cooled to room temperature using argon gas. This effectively achieves a "low-temperature solution" effect, forming a primary α phase and a metastable β phase, inhibiting grain growth and achieving complete solution treatment. Combined with the aging process, which involves heating to 350-450℃ at a rate of 2-10℃ / min, holding for 0.5-3.5 hours, and then furnace cooling to room temperature, a secondary α phase precipitates, achieving dispersion strengthening. The final result is a dual-phase microstructure consisting of an equiaxed primary α phase, fine lamellar / acicular / spherical secondary α phases, and a residual β phase, wherein the secondary α phase is fine lamellar and / or acicular and / or spherical.

[0029] The resulting titanium-zirconium alloy castings exhibit significantly improved tensile strength and yield strength, resulting in a better strength-plasticity match, good performance and structural stability, and thus better mechanical properties. They can be used in the production of some parts with high strength requirements and are applied in various scenarios, with wide applications in aerospace, weaponry, nuclear power, medical and other fields.

[0030] 4. The heat treatment process of this invention only adopts one-step solution and aging treatment, and the furnace cooling and argon cooling methods are simple. Furthermore, there are no special requirements for the equipment used in the heat treatment process. Specific process parameters are given in the examples, which have practical guiding significance for application in engineering production. The production needs of titanium-zirconium alloy castings with different properties can be met by using low-cost heat treatment.

[0031] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0032] Figure 1 The image shows the bimodal microstructure obtained after heat treatment of the titanium-zirconium alloy casting in Example 1.

[0033] Figure 2 A photograph of the mesh structure obtained after static hot pressing is shown as a comparative example.

[0034] Figure 3 Manufacturing process flow for titanium-zirconium alloy castings;

[0035] Figure 4 Heat treatment process for titanium-zirconium alloy castings. Detailed Implementation

[0036] Exemplary embodiments of the present invention will now be described in more detail. While exemplary embodiments of the present invention are shown in the following examples, it should be understood that the present invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0037] Titanium-zirconium alloy castings lack sufficient strength at room temperature, necessitating heat treatment to improve their strength and other properties. Existing heat treatment methods are limited to hot isostatic pressing (HIP), offering only a slight strength increase. This single HIP process results in a coarse basket microstructure, leaving room for further improvement in strength and plasticity balance. Optimizing the basket microstructure requires a complex heat treatment process involving multiple melting processes, high-temperature forging, followed by a two-stage solution treatment and aging.

[0038] This invention provides a heat treatment process for titanium-zirconium alloy castings, the process comprising the following steps:

[0039] Step 1: Hot Isostatic Pressing Process

[0040] The titanium-zirconium alloy casting is placed in a hot press and heated to 680℃~750℃ at a heating rate of 1-6℃ / min. A pressure of 100MPa~160MPa is applied and the casting is held at that temperature for 0.5-3 hours before being furnace cooled and removed from the furnace.

[0041] Step 2: Solution Treatment Process

[0042] The titanium-zirconium alloy castings treated by hot isostatic pressing are placed in a vacuum heat treatment furnace and heated to 610-690℃ at a heating rate of 2-10℃ / min. After holding at that temperature for 0.5-2 hours, they are cooled to room temperature using argon gas.

[0043] Step 3: Aging Treatment Process

[0044] The titanium-zirconium alloy casting is placed again in a vacuum heat treatment furnace and heated to 350-450°C at a heating rate of 2-10°C / min. After holding at that temperature for 0.5-3.5 hours, the furnace is cooled to room temperature.

[0045] Furthermore, the composition of the titanium-zirconium alloy casting includes, by weight percentage: Ti 30%–33%, Zr 65%–70%, and Hf 1%–2%.

[0046] Furthermore, the titanium-zirconium alloy casting is a titanium-zirconium alloy frame beam, ring, or irregular structure casting with an outline dimension of 10-2000mm and a wall thickness of 1-50mm.

[0047] Furthermore, the hot pressing equipment mentioned in step one is a hot press furnace with an argon protective atmosphere. When performing hot isostatic pressing on titanium-zirconium alloy castings, the temperature is increased to 700℃~730℃ at a heating rate of 2-5℃ / min, a pressure of 100MPa~140MPa is applied, and the castings are held at that temperature for 0.5-2.5 hours before being cooled and removed from the furnace.

[0048] Furthermore, in step two, a vacuum heat treatment furnace with argon atmosphere protection is used to heat the titanium-zirconium alloy castings that have undergone hot pressing treatment in step one to 630-670°C at a heating rate of 3-7°C / min, hold them at that temperature for 0.5-1.5 hours, and then rapidly cool them to room temperature with argon.

[0049] Furthermore, the titanium-zirconium alloy casting obtained by the aforementioned heat treatment process comprises, by weight percentage: Ti 30%–33%, Zr 65%–70%, and Hf 1%–2%.

[0050] Furthermore, in step three, a vacuum heat treatment furnace is used again to heat the furnace to 380-420°C at a heating rate of 3-7°C / min, hold the temperature for 1-3 hours, and then cool the furnace to room temperature.

[0051] Furthermore, the final titanium-zirconium alloy casting exhibits a bimodal structure.

[0052] Furthermore, the dual-state structure consists of an equiaxed primary α phase, a secondary α phase, and a residual β phase.

[0053] Furthermore, the titanium-zirconium alloy casting has a room temperature tensile strength of ≥1169MPa and a yield strength of ≥1060MPa.

[0054] Compared to the traditional single hot isostatic pressing (HIP) process typically used in titanium-zirconium alloy casting, the HIP temperature of this invention is significantly lower than 800℃~980℃. Furthermore, the heat treatment process of this invention involves only one step of solution treatment and aging, which is simpler than existing heat treatment processes and results in a more optimized internal microstructure. Titanium-zirconium alloy castings treated by the heat treatment process of this invention exhibit excellent comprehensive mechanical properties, maintaining plasticity within a reasonable range while possessing greater tensile strength and yield strength, thereby expanding the application range of titanium-zirconium alloy castings.

[0055] Specifically, in the hot isostatic pressing process of step one, the temperature is heated to 700℃~730℃ at a heating rate of 2-5℃ / min, a pressure of 100MPa~140MPa is applied, and the temperature is held for 0.5-2.5 hours. Then, the furnace is cooled to below 250℃ before being removed from the furnace. This process achieves pore closure and composition homogenization on the one hand, and inhibits grain boundary migration on the other hand, retains a fine grain framework, and reduces the temperature and time required for subsequent "true solution".

[0056] If the heating rate, temperature, pressure, or holding time in the hot isostatic pressing process is too fast, it can activate grain boundary migration, causing the original β grains to continue growing. This results in poor mechanical properties of the alloy. Furthermore, excessively high temperatures or prolonged holding times also lead to resource waste.

[0057] If the heating rate during hot isostatic pressing is too slow, the process temperature is too low, the pressure is too low, or the holding time is too short, the closing force will be insufficient, the diffusion coefficient will decrease, and the pore closure rate will be less than 95%, resulting in poor mechanical properties of the alloy.

[0058] Step two, the solution treatment process, uses a temperature near the phase transformation point, effectively achieving a "low-temperature solution" effect. The mechanism of the solution treatment lies in the recrystallization of the coarse original β grains of the basketweave structure through high-temperature heating, the partial dissolution of the α phase at the grain boundaries, and the refinement of the β grains, thus achieving a complete solution effect.

[0059] If the heating rate, temperature, holding time, or cooling rate of the solution treatment process is too fast, too high, too long, or too large, it will cause the grains to enter the β region and grow rapidly. The basket α phase will reappear, the residual basket α phase will not be completely dissolved, the supersaturated β content will be insufficient, and the amount of subsequent secondary α phase precipitation will be reduced, resulting in poor mechanical properties of the alloy. Moreover, excessively high temperature or excessively long holding time will also lead to waste of resources.

[0060] If the heating rate of the solution treatment process is too slow, the temperature is too low, the holding time is too short, or the cooling rate is too small, coarse α bundles will form after aging, resulting in poor mechanical properties of the alloy.

[0061] The aging process in step three precipitates a secondary α phase during the aging stage, ultimately resulting in a two-phase microstructure. The mechanism of the aging process lies in further promoting the precipitation of fine secondary α phases in the β phase, forming discontinuously distributed plate-like or needle-like α phases, rather than a continuous network structure.

[0062] If the heating rate of the aging process is too fast, the temperature is too high, or the holding time is too long, it will cause the secondary α phase to coarsen and the dispersion to decrease, resulting in poor mechanical properties of the alloy. Moreover, excessively high temperature or excessively long holding time will also lead to waste of resources.

[0063] If the aging treatment heating rate is too slow, the process temperature is too low, or the holding time is too short, it will lead to insufficient precipitation motive, reduced volume fraction of secondary α phase, unsaturated precipitation, and poor mechanical properties of the alloy.

[0064] The hot isostatic pressing (HIP) process of this invention operates at a temperature significantly lower than 800℃~980℃, transforming "high-temperature sealing" into "warm pre-solution" without compromising the sealing effect. Pre-solution is performed near the alloy's phase transformation point (680-750℃). After HIP treatment, defects within the casting pores are eliminated, achieving pore closure and compositional homogenization while simultaneously inhibiting grain boundary migration, preserving a fine-grained framework, and reducing the temperature and time required for subsequent "true solution." This allows for complete solution treatment at a lower temperature (610-690℃) for 0.5-2 hours, achieving the desired effect. In essence, the combination of "warm pre-solution" and subsequent "true solution" forms a primary α phase and a metastable β phase during the solution treatment stage, inhibiting grain growth and achieving complete solution. During the aging process, a nano-α phase precipitates, ultimately resulting in a dual-state microstructure: an equiaxed primary α phase, fine lamellar / acicular / spherical secondary α phases, and a residual β phase. The heat treatment process involves three interconnected steps, achieving simultaneous completion of "densification + refinement + dispersion".

[0065] In one possible design, the composition of the titanium-zirconium alloy casting comprises, by weight percentage: Ti 30%–33%, Zr 65%–70%, and Hf 1%–2%.

[0066] The titanium-zirconium alloy castings are titanium-zirconium alloy frame beam, ring, or irregularly shaped structural castings with an outline dimension of 10-2000 mm and a wall thickness of 1-50 mm.

[0067] Titanium-zirconium alloys, with their high strength, high activity, corrosion resistance, and good biocompatibility, can be applied in aerospace, shipbuilding, nuclear power, and medical fields. However, the casting structures used in these applications are often complex irregular structures with varying wall thicknesses, leading to problems such as difficulty in controlling dimensional accuracy, low casting performance, and uneven microstructure during manufacturing. Heat treatment of titanium-zirconium alloy castings can significantly improve mechanical properties by controlling the microstructure. However, the core challenge of heat treatment lies in the fact that complex casting structures with varying wall thicknesses are prone to thermal stress due to uneven heating / cooling, which can cause deformation and cracking. Optimizing process parameters such as heat treatment temperature, heating and cooling rates, and cooling methods is necessary to achieve a balance between "microstructure and performance control" and "deformation control while maintaining dimensions," resulting in an extremely narrow heat treatment process window.

[0068] Preferably, the heat treatment process for titanium-zirconium alloy castings provided in this embodiment is mainly used for processing titanium-zirconium alloy castings with a titanium-zirconium alloy composition weight percentage range of 30.5%, zirconium 68%, hafnium 1.5%, and an alloy phase transformation point of 700℃.

[0069] By employing the technical solution of this invention, the microstructure of existing titanium-zirconium alloy castings is further optimized. While maintaining the plasticity within a reasonable range, the strength of the titanium-zirconium alloy castings is significantly improved, resulting in better mechanical properties and expanding the application range of titanium-zirconium alloy castings. The final titanium-zirconium alloy casting exhibits a bimodal microstructure, consisting of equiaxed primary α phase, secondary α phase, and residual β phase. The room temperature tensile strength of the titanium-zirconium alloy casting is above 1169 MPa, and the yield strength is above 1048 MPa.

[0070] To more clearly describe the present invention, the following embodiments and comparative examples are provided for further illustration.

[0071] Example 1:

[0072] Specifically, the heat treatment process for the titanium-zirconium alloy casting provided in this embodiment includes the following steps:

[0073] Step 1: The material used in this embodiment is a titanium-zirconium alloy cast rod with a diameter of 25mm and a length of 200mm; the composition is: titanium 30.5%, zirconium 68%, hafnium 1.5%.

[0074] Step 2: Hot Isostatic Pressing: The titanium-zirconium alloy casting is placed in a vacuum hot press furnace with argon atmosphere protection, heated to 700°C at a heating rate of 2°C / min, pressure of 100MPa is applied, and the temperature is held for 0.5 hours in an argon atmosphere. Then the furnace is cooled to below 250°C before being removed from the furnace.

[0075] Step 3: Solution treatment: Place the titanium-zirconium alloy casting in a vacuum heat treatment furnace with argon atmosphere protection, heat it to 630°C at a heating rate of 5°C / min, hold it at that temperature for 0.5 hours, and then quickly cool it to room temperature with argon at a cooling rate of 25°C / s.

[0076] Step 4: Aging treatment: Place the titanium-zirconium alloy casting in a vacuum heat treatment furnace, heat it to 380°C at a heating rate of 7°C / min, hold it at that temperature for 1 hour, and then cool it to room temperature in the furnace.

[0077] Example 2:

[0078] Specifically, the heat treatment process for the titanium-zirconium alloy casting provided in this embodiment includes the following steps:

[0079] Step 1: The material used in this embodiment is a titanium-zirconium alloy cast rod with a diameter of 25mm and a length of 200mm; the composition is: titanium 30.5%, zirconium 68%, hafnium 1.5%.

[0080] Step 2: Hot Isostatic Pressing: The titanium-zirconium alloy casting is placed in a vacuum hot press furnace with argon atmosphere protection, heated to 710°C at a heating rate of 3.5°C / min, pressure of 120MPa is applied, and the temperature is held for 1.5 hours in an argon atmosphere. After the furnace is cooled to below 250°C, the casting is removed from the furnace.

[0081] Step 3: Solution treatment: Place the titanium-zirconium alloy casting in a vacuum heat treatment furnace with argon atmosphere protection, heat it to 650°C at a heating rate of 5°C / min, hold it at that temperature for 1 hour, and then quickly cool it to room temperature with argon at a cooling rate of 30°C / s.

[0082] Step 4: Aging treatment: Place the titanium-zirconium alloy casting in a vacuum heat treatment furnace, heat it to 400°C at a heating rate of 5°C / min, hold it at that temperature for 2 hours, and then cool it to room temperature in the furnace.

[0083] Example 3:

[0084] Specifically, the heat treatment process for the titanium-zirconium alloy casting provided in this embodiment includes the following steps:

[0085] Step 1: The material used in this embodiment is a titanium-zirconium alloy cast rod with a diameter of 25mm and a length of 200mm; the composition is: titanium 30.5%, zirconium 68%, hafnium 1.5%.

[0086] Step 2: Hot Isostatic Pressing: The titanium-zirconium alloy casting is placed in a vacuum hot press furnace with argon atmosphere protection, heated to 730°C at a heating rate of 5°C / min, pressure of 140MPa is applied, and the casting is held at this temperature for 2.5 hours in an argon atmosphere before being cooled to below 250°C and removed from the furnace.

[0087] Step 3: Solution treatment: Place the titanium-zirconium alloy casting in a vacuum heat treatment furnace with argon atmosphere protection, heat it to 670°C at a heating rate of 7°C / min, hold it at that temperature for 1.5 hours, and then quickly cool it to room temperature with argon at a cooling rate of 40°C / s.

[0088] Step 4: Aging treatment: Place the titanium-zirconium alloy casting in a vacuum heat treatment furnace, heat it to 420°C at a heating rate of 7°C / min, hold it at that temperature for 3 hours, and then cool it to room temperature in the furnace.

[0089] Example 4:

[0090] Specifically, the heat treatment process for titanium-zirconium alloy castings provided in this embodiment includes the following steps:

[0091] Based on Example 1, the only change is that the material used in Example 1 is a titanium-zirconium alloy cast plate with a thickness of 25mm, a length of 100mm, and a width of 50mm. The rest is the same as in Example 1.

[0092] Example 5:

[0093] Specifically, the heat treatment process for titanium-zirconium alloy castings provided in this embodiment includes the following steps:

[0094] Based on Example 1, only the composition of the titanium-zirconium alloy casting used in Example 1 was changed. By weight percentage, it includes: Ti 31%, Zr 67.5%, Hf 1.5%, and the rest is the same as in Example 1.

[0095] Example 6:

[0096] Specifically, the heat treatment process for titanium-zirconium alloy castings provided in this embodiment includes the following steps:

[0097] Based on Example 1, only the composition of the titanium-zirconium alloy casting used in Example 1 is changed. By weight percentage, it includes: Ti 32%, Zr 66.5%, Hf 1.5%, and the rest is the same as in Example 1.

[0098] Comparative Example 1:

[0099] Step 1: The material used in this comparative example is a titanium-zirconium alloy cast rod with a diameter of 25mm and a length of 200mm; the composition is: titanium 30.5%, zirconium 68%, hafnium 1.5%.

[0100] Step 2: Place the titanium-zirconium alloy casting in a vacuum hot press furnace with argon atmosphere protection, heat it to 900℃ at a heating rate of 3.5℃ / min, apply a pressure of 120MPa, use argon atmosphere, hold it at the temperature for 5 hours, and then cool it to below 250℃ before removing it from the furnace.

[0101] Comparative Example 2:

[0102] Step 2: Hot Isostatic Pressing: The titanium-zirconium alloy casting is placed in a vacuum hot press furnace with argon atmosphere protection, heated to 800°C at a heating rate of 10°C / min, pressure of 100MPa is applied, and the temperature is held for 0.5 hours in an argon atmosphere. The furnace is then cooled to below 250°C before being removed from the furnace. The rest is the same as in Example 1.

[0103] Comparative Example 3:

[0104] Step 2: Hot isostatic pressing: The titanium-zirconium alloy casting is placed in a vacuum hot press furnace with argon atmosphere protection, heated to 700°C at a heating rate of 2°C / min, pressure of 200MPa is applied, and the temperature is held for 0.5 hours in an argon atmosphere. After cooling to below 250°C, the casting is removed from the furnace. The rest is the same as in Example 1.

[0105] Comparative Example 4:

[0106] Step 2: Hot isostatic pressing: The titanium-zirconium alloy casting is placed in a vacuum hot press furnace with argon atmosphere protection, heated to 700°C at a heating rate of 2°C / min, pressure of 100MPa is applied, and the temperature is held for 5 hours in an argon atmosphere. After cooling to below 250°C, the casting is removed from the furnace. The rest is the same as in Example 1.

[0107] Comparative Example 5:

[0108] In step three, solution treatment: the titanium-zirconium alloy casting is placed in a vacuum heat treatment furnace with argon atmosphere protection, heated to 700°C at a heating rate of 15°C / min, held for 0.5 hours, and then rapidly cooled to room temperature with argon at a cooling rate of 25°C / s; the rest is the same as in Example 1.

[0109] Comparative Example 6:

[0110] In step three, solution treatment: the titanium-zirconium alloy casting is placed in a vacuum heat treatment furnace with argon atmosphere protection, heated to 630°C at a heating rate of 5°C / min, held for 5 hours, and then rapidly cooled to room temperature with argon at a cooling rate of 0.5°C / s; the rest is the same as in Example 1.

[0111] Comparative Example 7:

[0112] In step three, solution treatment: the titanium-zirconium alloy casting is placed in a vacuum heat treatment furnace with argon atmosphere protection, heated to 630°C at a heating rate of 5°C / min, held for 0.5 hours, and then rapidly cooled to room temperature with argon at a cooling rate of 0.5°C / s; the rest is the same as in Example 1.

[0113] Comparative Example 8:

[0114] In step four, aging treatment: the titanium-zirconium alloy casting is placed in a vacuum heat treatment furnace and heated to 550°C at a heating rate of 1°C / min, held at that temperature for 1 hour, and then furnace cooled to room temperature. The rest is the same as in Example 1.

[0115] Comparative Example 9:

[0116] In step four, aging treatment: the titanium-zirconium alloy casting is placed in a vacuum heat treatment furnace and heated to 380°C at a heating rate of 7°C / min, held at that temperature for 5 hours, and then furnace cooled to room temperature. The rest is the same as in Example 1.

[0117] Performance testing

[0118] The tensile properties of Examples 1-6 and Comparative Examples 1-9 were tested according to GB / T 228.1-2010, and the results are shown in Table 1. The microstructure was examined according to GB / T 5168-2020. Figure 1 and Figure 2 As shown.

[0119] Table 1. Mechanical property test results of titanium-zirconium alloy castings and original castings in the examples and comparative examples.

[0120]

[0121]

[0122] Table 1 lists a comparison of the mechanical properties of the titanium-zirconium alloy castings described in Examples 1, 2, 3, 5, and 6, and the original castings without heat treatment. The titanium-zirconium alloy castings after the heat treatment process of the examples have good comprehensive mechanical properties, with plasticity maintained within a reasonable range, and better tensile strength and yield strength. The titanium-zirconium alloy plate of Example 4 still has good comprehensive mechanical properties after being subjected to the heat treatment process conditions of the present invention.

[0123] Compared with Example 1 and Comparative Example 1, the titanium-zirconium alloy castings of the present invention, after heat treatment, show significantly improved tensile strength and yield strength compared with titanium-zirconium alloy castings obtained by existing hot isostatic pressing (HIP) processes. Furthermore, under the same pressure, the HIP process used in the present invention has a lower temperature, located near the alloy phase transformation point. Moreover, through the attached... Figure 1 and 2 In comparison, existing hot isostatic pressing technology produces (attached) Figure 2 The basketweave structure, with the α phase appearing lamellar and relatively coarse, exhibits a coarse texture. The bimorphic structure formed in this invention (attached) Figure 1 The phase consists of equiaxed primary α phase, fine plate-like / needle-like / spherical secondary α phase, and residual β phase.

[0124] Compared with Example 1, the titanium-zirconium alloy castings obtained by only performing the hot isostatic pressing process of the present invention have relatively low tensile strength and yield strength.

[0125] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0126] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

Claims

1. A heat treatment process for titanium zirconium alloy castings, characterized in that, The process comprises the following steps: Step one: hot isostatic pressing process The titanium-zirconium alloy casting is placed in a hot pressing device, heated to 680-750℃ at a heating rate of 1-6℃ / min, a pressure of 100-160MPa is applied, and after 0.5-3 hours of holding, the furnace is cooled to room temperature; Step two: solution treatment process The titanium-zirconium alloy casting treated by the hot isostatic pressing process is placed in a vacuum heat treatment furnace, heated to 610-690℃ at a heating rate of 2-10℃ / min, and after 0.5-2 hours of holding, argon cooling is used to cool to room temperature; Step three: aging treatment process The titanium-zirconium alloy casting is again placed in a vacuum heat treatment furnace, heated to 350-450℃ at a heating rate of 2-10℃ / min, and after 0.5-3.5 hours of holding, the furnace is cooled to room temperature.

2. The heat treatment process of a titanium-zirconium alloy casting according to claim 1, characterized in that The titanium-zirconium alloy casting comprises, by weight percentage: Ti 30%-33%, Zr 65%-70%, and Hf 1%-2%.

3. The heat treatment process of claim 1, wherein, The titanium-zirconium alloy casting is a titanium-zirconium alloy frame beam-shaped, ring-shaped or special-shaped structural casting with a profile size of 10-2000mm and a wall thickness range of 1-50mm.

4. The heat treatment process of a titanium-zirconium alloy casting according to claim 1, characterized in that, In step one, the hot pressing device is a hot pressing furnace with an argon protective atmosphere, and when the titanium-zirconium alloy casting is subjected to hot isostatic pressing treatment, it is heated to 700-730℃ at a heating rate of 2-5℃ / min, a pressure of 100-140MPa is applied, and after 0.5-2.5 hours of holding, the furnace is cooled to room temperature.

5. The process for heat treatment of titanium zirconium alloy castings as claimed in claim 1 wherein, In step two, a vacuum heat treatment furnace with an argon atmosphere protection is used, and the titanium-zirconium alloy casting treated by hot pressing in step one is heated to 630-670℃ at a heating rate of 3-7℃ / min, held for 0.5-1.5 hours, and then rapidly cooled to room temperature by argon.

6. The process for heat treatment of titanium zirconium alloy castings as claimed in claim 1 wherein, In step three, the vacuum heat treatment furnace is used again, heated to 380-420℃ at a heating rate of 3-7℃ / min, held for 1-3 hours, and then cooled to room temperature by the furnace.

7. A titanium-zirconium alloy casting, characterized by, The titanium-zirconium alloy casting obtained by the heat treatment process of any one of claims 1-6 comprises, by weight percentage: Ti 30%-33%, Zr 65%-70%, and Hf 1%-2%.

8. A titanium-zirconium alloy casting according to claim 7, wherein The final titanium-zirconium alloy casting has a duplex structure.

9. A titanium-zirconium alloy casting according to claim 7, wherein The duplex structure comprises equiaxed primary α phase, secondary α phase and residual β phase.

10. A titanium-zirconium alloy casting according to claim 7, wherein The room temperature tensile strength is above 1169MPa, and the yield strength is above 1048MPa.

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