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CN-117399637-B - High-performance in-situ autogenous Ti5Si3Near-net forming method of phase reinforced titanium-aluminum-based composite material

CN117399637BCN 117399637 BCN117399637 BCN 117399637BCN-117399637-B

Abstract

The invention relates to a near-net forming method of a high-performance in-situ self-generated Ti 5 Si 3 phase reinforced titanium-aluminum-based composite material, which is characterized in that Ti 5 Si 3 reinforced phases, ti 3 Al and TiAl matrixes are formed by utilizing in-situ reaction of Ti, al and Si elements in a molten pool in an electron beam double-wire additive manufacturing process, the proportion change of a primary Ti 5 Si 3 phase and a eutectic Ti 5 Si 3 phase is realized by regulating and controlling a solidification path through cooling conditions in a solidification process, molten pool components and the like, the characteristic of brand-new phase relation of the Ti 5 Si 3 reinforced phase and the matrix is formed based on the eutectic reaction, and the near-net forming of the high-performance in-situ self-generated Ti 5 Si 3 phase reinforced titanium-aluminum-based composite material is realized by realizing layer-by-layer deposition through multi-axis movement of a working platform. The invention can realize near net forming of large-scale titanium-aluminum-based composite material components, has higher forming efficiency, is not easy to generate defects such as cracks, deformation and the like in the material adding process, and compared with the titanium-aluminum-based composite material reported in the prior art, the strength of the titanium-aluminum-based composite material prepared by the invention has equivalent plasticity, but the yield strength at the temperature of 750 ℃ is obviously improved.

Inventors

  • XU JUNQIANG
  • ZHOU QI
  • WANG KEHONG
  • KONG JIAN
  • PENG YONG
  • GUO SHUN
  • YANG ZIWEI

Assignees

  • 南京理工大学

Dates

Publication Date
20260512
Application Date
20231012

Claims (6)

  1. 1. A near-net forming method of a high-performance in-situ self-generated Ti 5 Si 3 phase reinforced titanium-aluminum-based composite material is characterized in that Ti 5 Si 3 reinforced phases, ti 3 Al and TiAl matrixes are formed by utilizing in-situ reaction of Ti, al and Si elements in a molten pool in an electron beam double-wire additive manufacturing process; the method comprises three processes of pre-heating, layer-by-layer deposition and sample cooling, and comprises the following specific steps: (1) The early-stage preheating is to fix the titanium alloy substrate polished by sand paper and cleaned by ethanol on a working platform of an electron beam fuse additive manufacturing system, and place the working platform in a vacuum chamber of the electron beam fuse additive manufacturing system, and when the vacuum degree reaches 7X 10 -2 Pa, the substrate is preheated by adopting an electron beam rapid scanning mode until the titanium alloy substrate has red heat; (2) Respectively placing aluminum wires and titanium wires in independent wire feeding mechanisms of an electron beam fuse wire adding system, adjusting the angle and the height of a wire feeding gun, setting the wire feeding speed of the aluminum wires and the titanium wires, simultaneously feeding the wires into a common molten pool, carrying out deposition according to a set path, cooling for 60-80 s after single deposition, and lowering a workbench for a certain distance to continue deposition to ensure that an electron beam focus is on the surface of an adding member until the deposition is completed; (3) Cooling the sample, namely placing the titanium aluminum intermetallic compound component subjected to in-situ material addition in a vacuum environment for cooling until the temperature reaches the room temperature; The basic parameters of the substrate preheating are that acceleration voltage 60 kV, focusing current 1000-1200 mA, scanning frequency 300-600 Hz, scanning range 300-600%, circular scanning mode and scanning speed 20 mm/s, the preheating mode adopts stepped preheating, namely, preheating beam current is gradually increased, the preheating is carried out from 5mA to 25mA until the substrate is red and hot, the angle adjustment range of a wire feeder is 45-55 degrees, the distance between the front section wire of the wire feeder and the substrate is within 1 mm, so that molten drops can be continuously transited to form, the material adding sample cooling process needs to be carried out under vacuum environment, namely, cooling is carried out for 2-3 hours under high vacuum degree, heat preservation is carried out for 10-15 hours under low vacuum degree, the high vacuum range is lower than 7X 10 -2 Pa, and the low vacuum range is 0-10Pa; The high-performance titanium aluminum-based composite material comprises a micron-scale primary polygonal Ti 5 Si 3 phase, a nanometer-scale eutectic acicular Ti 5 Si 3 phase and a eutectoid lamellar structure of Ti 3 Al+TiAl, wherein the eutectic acicular Ti 5 Si 3 phase and the eutectoid lamellar structure of Ti 3 Al+TiAl have the following special phase relation ; 。
  2. 2. The method for near-net forming the high-performance in-situ self-generated Ti 5 Si 3 phase reinforced titanium-aluminum-based composite material according to claim 1, wherein raw materials selected in the near-net forming process of the in-situ self-generated Ti 5 Si 3 phase reinforced titanium-aluminum-based composite material are ERTi-1 wires and ER4047 wires, the diameter of the raw materials is 1.0-2.0 mm, the content of ERti-1 wires is less than or equal to 0.03 wt%, the content of O is 0.03-0.10 wt%, the content of N is less than or equal to 0.012 wt%, the content of H is less than or equal to 0.005 wt%, the content of Fe is less than or equal to 0.08 wt%, the content of Ti is the balance, the content of ER4047 wires is Si 12 wt%, mn is less than 0.15 wt%, cu is less than 0.05 wt%, ti is less than 0.15 wt%, zn is less than 0. 0.20 wt%, fe is less than 0.6 wt%, and the content of Al is the balance.
  3. 3. The near-net forming method of the high-performance in-situ self-generated Ti 5 Si 3 phase reinforced titanium-aluminum-based composite material, which is disclosed in claim 1, is characterized in that the high-performance titanium-aluminum-based composite material comprises the following components of Ti- (34-38 at%) at% (5.5-9.5) at% (Si), wherein the relation between the wire feeding speed and the components is as follows: ; ; Wherein, the And The design mass fraction and the atomic fraction of the main elements are respectively; (i=1, 2., n) is the mass fraction of elements in the wire; the unit is mm/min, which is the wire feeding speed; the diameter of the wire is in mm; The density of the wires is expressed in g/cm 3 ; Is the relative atomic mass of the elements, the electron beam fuse material-adding process can generate burning loss of different elements, thus the actual atomic fraction of the different elements Is that ; The evaporation coefficient of the elements is 1, 1.15 and 0.71, wherein only volatilization of Ti, al and Si elements is considered, and the wire feeding speed is 300-800 mm/min.
  4. 4. The method for near-net forming of the high-performance in-situ self-generated Ti 5 Si 3 phase reinforced titanium-aluminum-based composite material according to claim 1, wherein the mechanical properties of the titanium-aluminum-based composite material are regulated and controlled by changing the ratio of the content of aluminum element to silicon element near the eutectic composition point of titanium-aluminum-silicon so as to change the ratio of primary polygonal Ti 5 Si 3 phase to eutectic needle-shaped Ti 5 Si 3 phase.
  5. 5. The method for near-net forming of a high-performance in-situ self-generated Ti 5 Si 3 phase reinforced titanium-aluminum-based composite material according to claim 1, wherein the electron beam double-wire additive material is used for obtaining the Ti 5 Si 3 phase reinforced titanium-aluminum-based composite material with a special phase relationship, and the high-superheat solidification condition of more than 1000K is provided in the additive material process, so that the supercooling degree of more than 200K is obtained, and the eutectic reaction of L- & gtalpha+Ti 5 Si 3 is generated in the solidification process.
  6. 6. The method for near-net forming of the high-performance in-situ self-generated Ti 5 Si 3 phase reinforced titanium-aluminum-based composite material according to claim 5, wherein the technological parameters of the additive are that the accelerating voltage is 60-kV, the focusing current is 1000-1200-mA, the scanning frequency is 600-900-Hz, the scanning range is 700-900%, the scanning mode is round, the deposition speed is 1 mm/s-5 mm/s, the single-layer height is 0.75-2 mm, the electron beam current is 25 mA-45 mA, and the cooling speed is controlled at 300-500K/s through the interlayer waiting time of 50-70 s.

Description

Near-net forming method of high-performance in-situ self-generated Ti 5Si3 phase reinforced titanium-aluminum-based composite material Technical Field The invention relates to the technical field of preparation of titanium-aluminum-based composite materials, in particular to a near-net forming method of a high-performance in-situ self-generated Ti 5Si3 phase reinforced titanium-aluminum-based composite material. Background As a key base material of an aeroengine, a further development of a light high-strength superalloy material is needed in the prior art to meet the requirement of light weight of aeronautical equipment. The light high-strength titanium-aluminum alloy is the best candidate material for replacing the nickel-based superalloy in the temperature range of 650-850 ℃, and the strength of the titanium-aluminum alloy is obviously improved by adding alloy elements with high melting point and excellent oxidation resistance. The specific strength of the titanium-aluminum alloy is higher than that of the nickel-based superalloy in the range of 650-850 ℃, but the strength of the titanium-aluminum alloy is rapidly reduced in the temperature range of more than 850 ℃, so that the use temperature of the titanium-aluminum alloy is limited. The composite technology is used as an important means for improving the performance of the titanium-aluminum alloy, tiB 2、TiC、Al2O3、B4 C, ti 2 AlC and the like are used as reinforcements to be correspondingly used in the titanium-aluminum alloy, and the comprehensive performance is improved through layer-penetrating fracture, interface debonding, crack deflection, fiber extraction and the like. In general, the reinforcing phase is introduced into the titanium-aluminum alloy matrix in a direct adding manner, for example, the invention patent with publication number of CN202010925825.X discloses a novel titanium-aluminum matrix composite material and a preparation method thereof, and Ti, al, nb, Y, caF 2、TiC、TiB2 powder is used for hot-pressed sintering to form the titanium-aluminum matrix composite material which takes Ti45Al8Nb0.5Y as the matrix, 7.5wt% TiC and 3wt% TiB 2 as the reinforcing phase, and the maximum bending strength is 502MPa. However, the reinforcing phase is directly added into the titanium-aluminum alloy matrix, and is formed by hot-pressing sintering, the positional relationship between the reinforcing phase and the matrix is random, the interface strength is insufficient, and the reinforcing effect is difficult to fully develop. The interface bonding strength between the titanium aluminum alloy and the matrix can be enhanced by adopting an enhanced phase in-situ autogenous method, and the performance of the titanium aluminum alloy matrix is obviously improved. The invention patent with publication number CN201911298379.8 discloses a preparation method of a high-strength plastic-product TiAl-based composite material, which is characterized in that a high-melting-point Nb element is introduced into a titanium-aluminum alloy matrix, and a fibrous toughness Nb-rich phase and granular Ti 2 AlNb phase composite reinforced high-strength plastic-product TiAl intermetallic compound-based composite material is obtained through the processes of powder mixing, extrusion treatment such as vacuum heat and the like, high-temperature sheath extrusion and the like. The invention patent with publication number CN109694971B discloses a powder metallurgy titanium aluminum-based composite material and a preparation method thereof, wherein the material is prepared by mixing 30-40% of Ti powder, 2-8% of TiO 2 powder, 1-5% of Nb 2O5 powder and the balance of aluminum powder by weight percent through the combination of high-energy ball milling and spark plasma sintering, and the method can realize the in-situ synthesis of Al 2O3 particles of a second phase in the high-energy ball milling stage. Although the reinforcement phase in the above method is formed in situ by self-generation, the preparation process is complex, and near-net-shape formation of the sample is difficult to achieve. The in-situ autogenous of the reinforcing phase in the titanium-aluminum alloy matrix can be realized through reasonable element addition and simple process design. The invention patent with publication number of CN20201101013311. X discloses a tough titanium-aluminum-based composite material and a preparation method thereof, wherein TiC is added into a titanium-aluminum alloy, and the titanium-aluminum-based composite material is prepared by adopting a vacuum melting method. The Ti 3 AlC reinforcement is automatically precipitated in situ by utilizing high-content C element, and the formation and diffusion of cracks are hindered and the fragile interface in the tissue under the high-temperature condition is pinned by the second phase strengthening and dislocation strengthening actions of the reinforcement, so that the high-temperature ultimate tensile strength of the titanium-aluminum matrix comp