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CN-121972592-A - Preparation method and application of high-strength and high-fracture-toughness TC11 titanium alloy forging based on high-purity sponge titanium

CN121972592ACN 121972592 ACN121972592 ACN 121972592ACN-121972592-A

Abstract

The invention belongs to the technical field of titanium alloy material processing, and relates to a preparation method and application of a high-strength and high-fracture-toughness TC11 titanium alloy forging based on high-purity sponge titanium. The invention adopts the whole flow process route of ingot preparation, cogging forging, middle forging, two-phase zone forging-preforming, finished product forging and double annealing. The AAA grade high-purity sponge titanium is used as a raw material, the content of Fe, O and other impurity elements in the intermediate alloy is accurately regulated, and brittle phase sprouting is inhibited through clean smelting. The large deformation is combined with the water-cooled single-phase zone forging after forging, and the two-phase zone multidirectional forging in a specific temperature zone and the finished product forging in a near beta forging process are matched, and the high-low temperature double annealing treatment is adopted, so that the blank is fully and uniformly subjected to plastic deformation, and the accurate regulation and control of the microstructure of the alloy can be realized. The performance indexes of the forging meet the requirements of relevant standards, the impact toughness is improved by about 1/3 compared with that of the conventional process, and the application field of TC11 titanium alloy materials is expanded.

Inventors

  • QIAO ENLI
  • Gao Fanglan
  • GU ZHONGMING
  • TONG XIAOLE
  • MA XUEFANG
  • LIU HULIN
  • WANG SHUANGLI
  • Zhai Xinjiao
  • YANG NA
  • YAN KANGQI

Assignees

  • 新疆湘润新材料科技有限公司

Dates

Publication Date
20260505
Application Date
20260130

Claims (10)

  1. 1. The preparation method of the high-strength and high-fracture-toughness TC11 titanium alloy forging based on the high-purity sponge titanium is characterized by comprising the following steps of: step 1, uniformly mixing AAA-grade sponge titanium and other intermediate alloys according to alloy element proportions, pressing into a consumable electrode, and smelting in a vacuum consumable furnace for multiple times to obtain an ingot; Step 2, sequentially performing cogging forging, middle forging and two-phase region forging on the cast ingot to obtain a blank C; Step 3, performing preforming on the blank C after heating in a segmented mode, and performing an elongation process to obtain a blank D; Step 4, forging a finished product after heating the blank D in a sectional manner, and performing an elongation process to obtain a blank E; and 5, performing high-low temperature double annealing heat treatment on the blank E to obtain the TC11 titanium alloy forging.
  2. 2. The preparation method of claim 1, wherein in the step 1, the AAA grade titanium sponge is high-purity MHT-80 small-granularity titanium sponge, the purity is more than or equal to 99.90%, the Brinell hardness is less than or equal to 80HBW, and the granularity is 3.0-12.7 mm.
  3. 3. The preparation method according to claim 1, wherein in the step 1, chemical components of the cast ingot in mass percent satisfy ：Al：6.5~7.0%,Mo：3.2~3.7%,Zr：1.5~2.0%,Si：0.3~0.35%,Fe：≤0.04%,C≤0.03%,N≤0.03%,H≤0.006%,O：0.10~0.15%,Y≤0.005%, that a single impurity element is less than or equal to 0.1%, a total impurity element is less than or equal to 0.4%, and the balance is Ti.
  4. 4. The preparation method of the blank A according to claim 1, wherein in the step 2, the cogging forging is specifically that the ingot is heated to 800-850 ℃ for 90-150 min, then heated to T β +100-200 ℃ for 120-180 min, then cogging forging is carried out, two upsetting three drawing is carried out, the total deformation is 80% -95%, the final forging temperature is not less than 850 ℃, and the blank A is obtained after forging and water cooling.
  5. 5. The preparation method of the blank B is characterized in that in the step 2, the blank obtained by cogging forging is heated to 800-850 ℃ and kept for 120-180 min, then heated to T β +50-150 ℃ and kept for 120-180 min, then the blank B is obtained by performing intermediate forging, performing two upsetting and two drawing, wherein the total deformation is 70% -90%, the final forging temperature is more than or equal to 800 ℃, and the blank B is obtained by water cooling after forging.
  6. 6. The preparation method of the blank C is characterized in that in the step 2, the two-phase area forging is performed by heating the blank obtained by intermediate forging to 800-850 ℃ for 90-150 min, then heating to T β -40-60 ℃ for 240-300 min, performing the two-phase area forging for 3-5 times, performing two upsetting and two drawing times each time, wherein the total deformation of each time is 60% -80%, the final forging temperature is more than or equal to 750 ℃, and performing air cooling after forging to obtain the blank C.
  7. 7. The method for preparing the steel wire rope according to claim 1, wherein in the step 3, the preform is obtained by heating a blank obtained by forging a two-phase region to 800-850 ℃ and preserving heat for 90-150 min, then heating to T β -40-60 ℃ and preserving heat for 180-240 min, performing the preform, performing an elongation process, wherein the elongation deformation is 35-45%, the final forging temperature is more than or equal to 750 ℃, and performing air cooling after forging to obtain a blank D.
  8. 8. The method according to claim 1, wherein in the step 4, the final forging is performed by heating the blank D to T β -40-60 ℃ for 90-150 min, heating to T β -15-25 ℃ for 90-120 min, performing a final forging process, wherein the elongation deformation is 25-35%, the final forging temperature is not less than 800 ℃, and performing air cooling after forging to obtain a blank E.
  9. 9. The TC11 titanium alloy forging prepared by the preparation method according to claim 1-8 is characterized in that the microstructure of the TC11 titanium alloy forging accords with grade 3 in GJB 2744A-2019 in figure 8, the room temperature tensile strength is R m =1047-1070 MPa, the yield strength is R P0.2 =919-938 MPa, the elongation is A=13.5-16.5%, the area reduction is Z=36-41%, and the fracture toughness is K 1C =80.1~93.3MPa·m 1/2 .
  10. 10. Application of TC11 titanium alloy forgings prepared based on the preparation method of any one of claims 1-8 in the fields of aerospace, weapons, ships and petrochemical industry.

Description

Preparation method and application of high-strength and high-fracture-toughness TC11 titanium alloy forging based on high-purity sponge titanium Technical Field The invention belongs to the technical field of titanium alloy material processing, and particularly relates to a preparation method and application of a high-strength and high-fracture-toughness TC11 titanium alloy forging based on high-purity titanium sponge. Background In the high-tip technical fields of aerospace, energy sources, national defense industry and the like, the performance requirements on materials are extremely severe, and particularly under extreme environments such as high temperature, high pressure, high-speed impact and the like, the materials need to have high strength, high toughness and excellent fatigue resistance. Therefore, how to maintain or improve the toughness of materials to prevent brittle fracture while pursuing high strength is an important direction of current research. Titanium alloy is widely used in the fields of aerospace, weapons, ships, petrochemical industry and the like because of its excellent characteristics of low density, high strength, heat resistance, corrosion resistance and the like. TC11 is taken as a typical alpha+beta type two-phase alloy, and shows comprehensive properties such as high strength, corrosion resistance, heat resistance and the like by virtue of a unique phase structure, so that the TC11 becomes an indispensable key material in the fields. Despite the many excellent properties of TC11 titanium alloys, challenges remain in practical applications where strength and toughness are difficult to match. At present, the conventional process is difficult to consider the toughness of the material while meeting the requirement of high strength. On one hand, the sponge titanium selected in the conventional production has low purity, the impurity element easily forms a brittle phase in the titanium alloy, the initiation and the expansion of cracks are promoted, and the uneven structure caused by the impurity element also reduces the crack expansion resistance of the material. On the other hand, the microstructure of the TC11 titanium alloy forging prepared by the conventional process consists of an equiaxed nascent alpha phase and a beta transition matrix, so that the number of grain boundaries is large, dislocation movement can be effectively blocked, and the strength of the TC11 titanium alloy forging is higher. However, for equiaxed structures, cracks are easy to propagate along alpha/beta interfaces or through alpha grains, frequent changes of directions are not needed, crack propagation paths are straight due to the low-energy fracture mode, branches are few, fracture toughness is mostly kept at about 60 MPa-m 1/2, and equipment requirements in the high-tip field cannot be met. In summary, the excellent matching of toughness is a core advantage that the TC11 titanium alloy can be used as an extreme environment structural member, so that the research and development of a preparation process capable of remarkably improving the fracture toughness of the TC11 titanium alloy on the premise that the strength meets the standard requirement becomes the technical direction of the breakthrough in the current urgent need. In view of this, the present invention has been made. Disclosure of Invention The invention aims to overcome the defects of the prior art, and provides a preparation method and application of a high-strength and high-fracture-toughness TC11 titanium alloy forging based on high-purity titanium sponge to meet the use requirements of TC11 titanium alloy in the high-tip technical fields of aerospace, energy, national defense industry and the like. In order to achieve the above purpose, the present invention provides the following technical solutions: in a first aspect, the invention provides a method for preparing a high-strength and high-fracture-toughness TC11 titanium alloy forging based on high-purity titanium sponge, which comprises the following steps: Step 1, according to the proportion of TC11 titanium alloy elements, uniformly mixing AAA grade sponge titanium and other intermediate alloys, pressing into an electrode by adopting an 80MN oil press, welding the electrode into a consumable electrode by utilizing a vacuum plasma welding box, smelting by using a 3-time vacuum consumable arc furnace, and preparing an ingot casting of the TC11 titanium alloy by turning, peeling, sawing a riser and an ingot bottom, sampling and detecting and the like; The AAA grade sponge titanium is high-purity MHT-80 small-granularity sponge titanium, the purity is more than or equal to 99.90%, the Brinell hardness is less than or equal to 80HBW, the granularity is 3.0-12.7 mm, and compared with the highest grade 0A grade MHT-95 small-granularity sponge titanium (the purity is more than or equal to 99.80%, the Brinell hardness is less than or equal to 95HBW, and the small-granularity specification is