A sacrificial smart thermal barrier material and its application

Abstract

This invention relates to the field of precision plastic processing technology for metallic materials, and particularly to a sacrificial intelligent thermal barrier material and its application. The sacrificial intelligent thermal barrier material is formed into a homogeneous composite through melt blending, comprising the following components by mass percentage: 40-70% phase change matrix material, 20-50% thermal insulation filler, 5-15% release agent, and 1-5% rheology modifier; the phase change matrix material is a composite wax or low-melting-point polymer with a melting point in the range of 80-130℃; the thermal insulation filler is a hollow or porous material with low thermal conductivity. This material can intelligently play multiple roles in heat insulation, lubrication, and deformation coordination during the hot drawing process of high-temperature alloy wires, and can autonomously and cleanly peel off after the process, thereby eradicating the persistent problem of accumulation and fracture in traditional encapsulation methods and achieving efficient, stable, and environmentally friendly precision manufacturing.

Description

Technical Field

[0001] This invention relates to the field of precision plastic processing technology for metallic materials, and in particular to a sacrificial smart thermal barrier material and its application. Background Technology

[0002] High-temperature alloy wire is a core raw material for manufacturing critical components such as precision locking parts for aero-engine blades, high-temperature filters, and special welding wires. Hot drawing is an indispensable process for obtaining wires with fine dimensions, high surface quality, and excellent microstructure. However, this process faces a long-standing and unresolved core contradiction: efficient heat insulation is required during processing to reduce energy consumption and temperature unevenness, but the heat insulation layer must be completely removed after processing to avoid contaminating the high-value alloy matrix.

[0003] Existing technical solutions all have significant drawbacks: Stainless steel sheathing method: This is currently a commonly used method. A high-temperature alloy core is placed inside a stainless steel tube, sealed, and then hot-drawn. While this method offers some thermal insulation, it suffers from fundamental mechanical defects. The difference in rheological stress and plastic deformation capacity between stainless steel and high-temperature alloys at high temperatures is significant. Under the strong constraint of the drawing die, severe shear stress accumulates at the interface, inevitably forming a "mushroom head" shaped deposit at the die entrance. This easily leads to sheath rupture or core material breakage, resulting in extremely poor process stability. Furthermore, subsequent sheath removal is difficult, and prolonged high-temperature contact may cause elements such as Fe and Cr to diffuse into the high-temperature alloy, causing contamination.

[0004] Traditional heat-insulating and lubricating coatings, such as glass coatings and graphite emulsions, may react with the substrate at high temperatures and bond together, making them difficult to remove after cooling. This requires harsh methods such as sandblasting or acid pickling, which can damage the wire surface or cause environmental pollution. Some coatings also decompose prematurely at high temperatures, failing to provide end-to-end protection.

[0005] Improved mold and heating method: This is an external optimization and cannot directly solve the problem of radial heat loss from the wire itself, resulting in limited energy saving and temperature uniformity effects.

[0006] Therefore, the field has long sought an innovative material solution that must simultaneously meet three seemingly contradictory requirements: (A) excellent and stable thermal insulation and lubrication properties during the instant of hot working (high temperature), and the ability to "co-deform" with the matrix without generating harmful stress; (B) near-complete automatic detachment after processing (room temperature), with an easy and thorough detachment process; and (C) maintaining physical and chemical inertness to the high-value high-temperature alloy matrix throughout its service life, achieving "zero pollution." Solving this contradiction requires breaking through traditional thinking about "permanent" or "semi-permanent" auxiliary materials and inventing a "process-oriented" material with intelligent behavioral characteristics. Summary of the Invention

[0007] To address the above problems, this invention provides a sacrificial smart thermal barrier material and its application. The invention provides the following technical solution: This invention provides a sacrificial smart thermal barrier material, which is formed into a homogeneous composite through melt blending and comprises the following components by mass percentage: Phase change matrix material 40-70%, Thermal insulation filler 20-50%, Release agent 5-15%, Rheology modifier 1-5%; The phase change matrix material is a polymer or microcrystalline wax with a melting point in the range of 80-130℃; the thermal insulation filler is a hollow or porous material with low thermal conductivity.

[0008] Furthermore, the polymer with a melting point in the range of 80-130°C is selected from one or more of polyethylene wax, Fischer-Tropsch wax, and ethylene-vinyl acetate copolymer.

[0009] Furthermore, the heat-insulating filler is selected from one or more of hollow glass microspheres, ceramic microspheres, silica aerogel powder, and expanded perlite powder.

[0010] Furthermore, the release agent is selected from one or more of boron nitride flakes, graphite flakes, calcium fluoride, and mica powder.

[0011] Furthermore, the average particle size of the thermal insulation filler is 5-200 μm; and / or, The release agent has a sheet-like structure with an average sheet diameter of 1-50 μm.

[0012] Furthermore, the rheology modifier is selected from one or more of hydrogenated castor oil, ethylene-propylene copolymer, polyamide wax, and organobentonite.

[0013] Furthermore, the sacrificial smart thermal barrier material is in a viscoplastic solid state at a drawing temperature of 900-1200℃. At temperatures below 50°C, the sacrificial smart thermal barrier material is a brittle solid.

[0014] The present invention also provides a hot drawing method, the method comprising the following steps: The aforementioned sacrificial smart thermal barrier material is heated to a molten state; Molten sacrificial smart thermal barrier material is coated onto the surface of wire or rod blanks by extrusion coating or dip coating to form a coating layer, which is then cooled and solidified to obtain wire or rod blanks coated with sacrificial smart thermal barrier material. The wire or rod blanks coated with the sacrificial smart thermal barrier material are heated to the drawing temperature to transform the coating layer into a viscoplastic solid state, and then multiple drawing passes are performed. After being drawn, the wire or bar blanks are cooled to room temperature, the coating layer becomes brittle and peels off on its own, resulting in high-temperature alloy wires or bars.

[0015] Furthermore, before forming the coating layer on the surface of the filament or rod, the surface of the filament or rod blank is pretreated, including: removing oil and oxides from the surface of the filament or rod blank and drying it.

[0016] Furthermore, the thickness of the coating layer is 0.5-3.0 mm.

[0017] Furthermore, the drawing temperature is 900-1200℃.

[0018] Furthermore, the wire material includes high-temperature alloy wire, titanium alloy wire, or intermetallic compound wire; the rod material includes high-temperature alloy rod, titanium alloy rod, or intermetallic compound rod.

[0019] The present invention also provides the application of the sacrificial smart thermal barrier material as described above in the hot extrusion or hot drawing forming process of wires or bars of high-temperature alloys, titanium alloys or intermetallic compounds.

[0020] The technical effects and advantages of this invention are as follows: This invention provides a novel sacrificial intelligent thermal barrier material and its application method. This material can intelligently play multiple roles in the hot drawing process of high-temperature alloy wires, including heat insulation, lubrication, and deformation coordination. It also autonomously and cleanly peels off after the process, thus eradicating the persistent problem of accumulation and fracture in traditional encapsulation methods and achieving efficient, stable, and environmentally friendly precision manufacturing.

[0021] 1. Eradicate industry ailments: Completely solves the inherent "accumulation-fracture" failure mode of stainless steel cladding method, reducing the wire breakage rate in the drawing process from the industry average of 5-10% to close to 0%, and revolutionizing the reliability and safety of the process.

[0022] 2. Significant energy saving and consumption reduction: The excellent thermal insulation performance of the coating layer can reduce the heat loss of the filament surface by 40%-70% and reduce the overall heating energy consumption by 25%-40%, which is in line with the trend of green manufacturing.

[0023] 3. Excellent product quality: Good isothermal properties make the cross-sectional deformation of the wire more uniform, the dimensional accuracy (diameter tolerance) is improved by more than 50%, and the surface quality is smooth and free of micro-cracks.

[0024] 4. Zero-cost and zero-pollution post-processing: After cooling, the coating peels off automatically with a peeling rate of >95%, requiring no additional chemical, mechanical, or thermal energy input for cleaning. Testing reveals no coating residue on the filament surface, achieving truly "zero-pollution" processing.

[0025] 5. Reduced overall costs: Although the cost of coating materials is increased, the overall production cost can be reduced by 20%-30% thanks to the significant increase in yield, the reduction in energy consumption and the complete elimination of post-processing steps.

[0026] 6. Strong technical versatility: The design concept of this material can be extended to other difficult-to-deform metal materials that require high-temperature deformation processing and surface cleanliness, such as titanium alloys and tungsten-molybdenum alloys.

[0027] Other features and advantages of the invention will be set forth in the following description, 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 pointed out in the description and the drawings. Attached Figure Description

[0028] Figure 1 This is a flowchart illustrating the preparation method of the sacrificial smart thermal barrier material provided in the embodiments of this application. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] To address the shortcomings of existing technologies, this invention discloses a sacrificial intelligent thermal barrier material, which is a composite paste designed to exhibit dynamic and contrasting material behaviors during the hot drawing process: in the high-temperature range of drawing (900-1200℃), the material as a whole exhibits a viscoplastic solid state, capable of coordinating plastic deformation with the filament and providing thermal insulation and lubrication functions; after cooling to room temperature (<50℃), the material as a whole transforms into a brittle solid and can peel off on its own due to its own solidification shrinkage and weak interfacial bonding with the matrix.

[0031] The sacrificial intelligent thermal barrier material comprises the following functional components in synergistic composition by mass percentage: 40-70% phase change matrix material, 20-50% thermal insulation filler, 5-15% release agent, and 1-5% rheology modifier; wherein the phase change matrix material is a composite wax or low-melting-point polymer with a melting point in the range of 80-130℃; and the thermal insulation filler is a hollow or porous material with low thermal conductivity.

[0032] For example, the phase change matrix material is selected from one or more of microcrystalline wax, polyethylene wax, Fischer-Tropsch wax, and ethylene-vinyl acetate copolymer.

[0033] In one specific embodiment of the present invention, the heat insulation filler is a hollow or porous material with low thermal conductivity. For example, the heat insulation filler is selected from one or more of hollow glass microspheres, ceramic microspheres, silica aerogel powder, and expanded perlite powder.

[0034] In one specific embodiment of the present invention, the release agent is a layered solid lubricant that remains stable at high temperatures and has low affinity for high-temperature alloy surfaces. For example, the release agent is selected from one or more of boron nitride flakes, graphite flakes, calcium fluoride, and mica powder. The average particle size of the heat-insulating filler is 5-200 μm; and / or, the release agent has a sheet-like structure with an average sheet diameter of 1-50 μm.

[0035] In one specific embodiment of the present invention, the rheology modifier is used to control the viscosity and thixotropy of the material in the molten state. For example, the rheology modifier is selected from one or more of hydrogenated castor oil, ethylene-propylene copolymer, polyamide wax, and organobentonite.

[0036] The sacrificial smart thermal barrier material provided by this invention is a sacrificial functional material system that can exist on demand and self-eliminate after processing. It is composed of the following four components acting synergistically in a specific ratio: Phase change matrix material (40-70%): acting as the "driver" for behavior switching. Its melting point is precisely designed in a range far below the drawing temperature but above room temperature (80-130°C). This makes it solid at room temperature for easy handling; it softens at the high drawing temperature, but through combination with other components, it forms a viscoplastic solid with a specific yield strength, rather than a liquid. This is key to avoiding uncontrolled flow and achieving coordinated deformation.

[0037] The core technological breakthrough of this invention lies in the transformation of the phase change matrix material (40-70%) into a viscoplastic solid at the drawing temperature, making its flow stress (<0.1 MPa) much lower than the deformation resistance (>50 MPa) of the high-temperature alloy matrix. This feature brings three effects: (1) complete stress release: the viscoplastic coating absorbs the interface stress at the mold inlet through its own shear deformation, fundamentally eliminating the stress accumulation caused by deformation mismatch in dissimilar metal composite deformation (such as stainless steel cladding method). (2) zero accumulation and zero wire breakage. (3) improved critical deformation capacity.

[0038] Thermal insulation filler (20-50%): serving as the "bearer" of core functions. Using hollow or high-porosity materials, it greatly reduces the overall thermal conductivity, constructing an effective thermal barrier.

[0039] This invention employs a dual thermal insulation design of "low thermal conductivity filler + phase change encapsulation" to achieve multi-dimensional energy saving and consumption reduction: This invention constructs a highly efficient composite thermal barrier by completely encapsulating the filler with thermal insulation filler (20-50%, thermal conductivity <0.1 W / (m·K)) and phase change matrix.

[0040] Release agent (5-15%): acting as a "guardian" of interface cleanliness. A layered solid lubricant is chosen, which remains stable at the interface at high temperatures. It provides lubrication and, more importantly, forms a weakly bonded physical barrier between the substrate and the coating. This is the decisive factor in achieving automatic peeling after cooling.

[0041] Rheology modifier (1-5%): As a "stabilizer" for processing performance. Used to precisely control the viscosity and thixotropy of the molten composite system, ensuring that the coating layer has suitable viscoplasticity at high temperatures, so that it can deform with the filament without being too thin and being squeezed out of the mold.

[0042] This invention significantly broadens the process window through the wide temperature range adaptability of the "rheology modifier + insulation layer". The viscosity of the coating layer at high temperatures (10³-10⁻⁵) is precisely controlled by the rheology modifier (1-5%). 5 The method of this invention (Pa·s) can operate stably in a wide temperature range of 900-1200℃, covering the processing temperature requirements of difficult-to-deform materials such as nickel-based, cobalt-based, iron-based high-temperature alloys, titanium alloys, and intermetallic compounds. Traditional lubricants (such as glass powder) fail when the temperature fluctuates by ±30℃, while the method of this invention can maintain a stable viscoplastic state within a temperature fluctuation range of ±100℃.

[0043] Intelligent behavior and synergistic effects: High-Temperature Service Life (Intelligent Protection): After heating to the drawing temperature, the phase change matrix softens, firmly bonding the thermal insulation filler and release agent together to form a uniform viscoplastic solid layer. This layer adheres to the wire surface and, due to its low shear strength, can perfectly follow the plastic flow of the metal matrix, exhibiting excellent deformation coordination. This fundamentally eliminates the stress accumulation mechanism during the composite deformation of dissimilar metals, thus preventing accumulation. Simultaneously, its porous structure and low thermal conductivity effectively suppress heat radiation and convection loss, while the release agent components provide continuous lubrication at the interface.

[0044] Cooling and Decommissioning Period (Intelligent Detachment): When the process ends and cooling occurs, the phase change matrix resolidifies and shrinks, and the material as a whole changes from viscoplastic to brittle. Due to the weak interfacial bonding created by the release agent and the internal stress generated by the shrinkage of the matrix, the brittle coating will spontaneously crack and warp, eventually peeling off from the filament surface either entirely or in large pieces. This process requires no external force or only slight vibration or bending assistance.

[0045] The present invention also provides a hot drawing method, such as Figure 1 As shown, the method includes, Step 1, Pretreatment: Before forming the coating layer on the surface of the wire or rod blank, the surface of the wire or rod blank is pretreated by removing oil and oxides and drying. The wire or rod blank includes high-temperature alloy wire blanks, titanium alloy wire blanks, intermetallic compound wire blanks, high-temperature alloy rod blanks, titanium alloy rod blanks, or intermetallic compound rod blanks.

[0046] Step 2, Coating: The sacrificial smart thermal barrier material is heated to a molten state; the molten sacrificial smart thermal barrier material is coated onto the surface of the filament blank or rod blank by extrusion coating or dip coating to form a coating layer, and then cooled and solidified to obtain a filament blank or rod blank coated with sacrificial smart thermal barrier material; the thickness of the coating layer is 0.5-3.0 mm.

[0047] Step 3, hot drawing: The wire or rod blanks coated with the sacrificial smart thermal barrier material are heated to the drawing temperature, which is 900-1200℃. The coating layer is transformed into a viscoplastic solid state, and then multiple drawing passes are performed. Step 4, Cooling and Self-Peeling: After drawing, the wire or rod blanks coated with the sacrificial smart thermal barrier material are cooled to room temperature. The coating layer becomes brittle and peels off on its own, yielding a clean-surfaced high-temperature alloy wire or rod. The clean-surfaced high-temperature alloy wire or rod is free of foreign matter contamination, and elemental analysis shows no residual characteristic elements of the coating layer. It can be directly used for welding, weaving, or as a high-performance component.

[0048] This invention employs a dual approach of "isothermal deformation + solid lubrication" to achieve multi-dimensional quality improvements in high-temperature alloy wire or rod products with clean surfaces. Specifically, the method maintains uniform temperature across the wire cross-section through the insulating effect of the coating layer (0.5-3.0 mm thick), while a release agent (5-15%) forms a continuous lubricating film at the interface, resulting in the following quality improvements: Significant improvement in dimensional accuracy: Isothermal deformation eliminates the flow stress differences caused by temperature gradients, resulting in a significant reduction in wire diameter fluctuations.

[0049] Breakthrough in surface quality: No microcracks, optimized surface roughness, and improved microstructure uniformity. Among these improvements, the improved microstructure uniformity includes isothermal deformation that makes dynamic recrystallization more uniform, and the grain size fluctuation range is reduced from ±2 levels to ±0.5 levels.

[0050] This invention employs a dual peeling mechanism of "weak interface of release agent + phase change shrinkage and embrittlement," achieving zero-cost and zero-pollution post-processing. The unique self-peeling mechanism of this invention relies on the synergy of two technical features: Release agent constructs a weak interface layer: The flake-shaped release agent (flake diameter 1-50μm) is oriented during the coating process, forming a physical isolation layer between the high-temperature alloy wire blank (or rod blank) and the coating layer, reducing the interfacial bonding strength to <0.1MPa (>2 MPa without release agent).

[0051] Phase change shrinkage-driven peeling: During the cooling process, the phase change matrix material solidifies from the molten state and shrinks (volume shrinkage rate 5-12%), generating internal stress. Combined with embrittlement characteristics, this causes the coating layer to automatically crack and warp. This invention also provides the application of the aforementioned sacrificial intelligent thermal barrier material in hot extrusion or hot drawing processes of high-temperature alloy wires, titanium alloy wires, intermetallic compound wires, high-temperature alloy rods, titanium alloy rods, or intermetallic compound rods.

[0052] The "sacrificial intelligent thermal barrier" design concept of this invention is not limited to high-temperature alloy wire drawing, and has been verified to be extendable to other material systems, such as hot drawing of titanium alloy (TC4), intermetallic compound (TiAl), and refractory metal (Mo, W) wire / bar. Other forming processes: hot extrusion, hot forging, hot rolling; Other product forms: wires with irregular cross-sections and inner wall protection for pipes.

[0053] In summary, this invention, through the quaternary synergistic design of phase change matrix, heat-insulating filler, release agent, and rheology modifier, not only achieves breakthroughs at the single technical level (heat insulation, lubrication, and peelability), but also creatively solves the long-standing contradiction between "protection and removal" in the field of high-temperature alloy hot working through multifunctional system integration, achieving a comprehensive improvement in process stability, product quality, energy efficiency, and environmental friendliness. The technical effects of this invention are multi-dimensional, quantifiable, and have significant industrial application value, representing a major advancement in high-temperature alloy precision machining technology.

[0054] The high-temperature alloy wires include intelligent thermal barrier materials used in the hot drawing process of high-performance alloy wires (such as nickel-based high-temperature alloys and cobalt-based high-temperature alloys) for use in extreme environments.

[0055] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0056] Example 1 Sacrificial intelligent thermal barrier material formulation: Microcrystalline wax (melting point 98℃): 50 wt%; Hollow glass microspheres (average particle size 50μm, wall thickness 1-2μm): 35 wt%; Hexagonal boron nitride flakes (particle size D50=15μm): 12 wt%; Hydrogenated castor oil: 3 wt%.

[0057] High-temperature alloy wire blank: GH4169 (Inconel 718), initial diameter φ4.0 mm.

[0058] Target finished product diameter: φ2.0 mm.

[0059] Drawing temperature: 1060℃.

[0060] Hot drawing method steps: Step 1, Pretreatment: Use alkaline solution and acetone to ultrasonically clean GH4169 wire to remove oil and oxides from the surface of the high-temperature alloy wire blank, and then dry it.

[0061] Step 2, Coating: The above-mentioned materials are melted and mixed evenly in a kneader at 120°C to form a paste. The paste is placed in a dedicated extrusion coating device and continuously extruded onto a high-temperature alloy wire blank preheated to 70°C, with the coating thickness controlled to 1.2 mm through the die. The coating is then rapidly cured in a water-cooling bath.

[0062] Step 3, Hot Drawing: The coated high-temperature alloy wire blank is heated to 1060℃ using a medium-frequency induction coil and held at that temperature. At this point, the coating layer turns into a light yellow, somewhat tough, viscoplastic solid. Multiple drawing passes are then performed, with a reduction in surface area of ​​approximately 20% per pass.

[0063] Step 4, Cooling and Self-Peeling: The drawn high-temperature alloy wire blank is cooled to room temperature (approximately 30°C) using an online air-cooling system. Cracks can be observed appearing on the originally smooth and continuous cladding surface, which gradually curls and peels off. Slight bending or tapping of the wire causes over 98% of the cladding material to detach in brittle flakes.

[0064] Testing: The surface of the stripped filament was observed and analyzed using a scanning electron microscope (SEM) and an attached energy dispersive spectroscopy (EDS). The results showed that the filament surface was smooth, with no coating material adhering to it. No signals of Si (characteristic element of glass microspheres) or B (characteristic element of boron nitride) were found in the EDS spectrum, proving that the surface was clean and free of contaminants.

[0065] Effectiveness evaluation: 1. Thermal insulation performance (heat dissipation) The surface temperature of the wire during the drawing process was monitored in real time using a FLIR infrared thermal imager. The results showed: Cooling rate: Compared with uncoated bare yarn, the time required for coated yarn to cool from 1060℃ to 900℃ is 2.8 times longer, corresponding to a 68% reduction in surface cooling rate; Heat flux density: Based on the heat transfer model, the coating reduces the heat flux density on the surface of the filament by 65%, which means that the heat loss per unit time is reduced by nearly two-thirds. Lateral temperature difference: The temperature difference between the core and surface of the filament cross-section decreased from 80℃ without coating to 32℃, a reduction of 60%, proving that the coating layer effectively maintained the temperature uniformity of the filament.

[0066] 2. Lubrication performance (reduced pull-out force) The pulling force is recorded in real time by a force sensor installed behind the mold. Peak pull-out force: Compared with uncoated bare yarn, the peak pull-out force of coated yarn decreased from 2.8 kN to 1.9 kN, a decrease of 32%; Pull-out force fluctuation: The pull-out force curve is stable with a fluctuation range of less than ±8% (±25% for bare yarn without coating), which proves that the coating layer forms a stable lubricating film at the die inlet; Friction coefficient estimation: Based on the back calculation of the drawing force, the friction coefficient between the wire and the die decreased from 0.18-0.22 to 0.08-0.10, a decrease of 55%.

[0067] 3. Process stability Wire breakage rate: No wire breakage occurred during the entire four drawing passes (total deformation 75%), and the wire breakage rate was 0% (comparative example 1, stainless steel sheathing method, broke in the 3rd pass). Drawing speed: Under the same heating power, the drawing speed can be increased from 5 m / min to 6.5 m / min, increasing production efficiency by 30%; Mold temperature: The working temperature of the mold is reduced from 320℃ when it is not covered to 210℃, which can extend the mold life by 2-3 times.

[0068] 4. Product quality Dimensional accuracy: The diameter tolerance of the finished wire (φ2.0 mm) is ±0.015 mm, which is better than the ±0.03 mm requirement for Grade I products in GB / T 14992-2020, representing a 50% improvement in dimensional accuracy; Surface quality: Surface roughness Ra < 0.8 μm (Ra 1.6 μm for uncoated bare yarn), surface smoothness improved by 50%; Under a 200x optical microscope, the surface showed no microcracks, scratches, or other defects, with a 100% surface integrity rate. Uniformity of structure: Metallographic observation shows that the dynamically recrystallized grains are uniform, with a grain size of 7-8 grade and a fluctuation range of ±0.5 grade (the grain size of the uncoated bare wire is 6-9 grade, with a fluctuation of ±1.5 grade).

[0069] 5. Self-peeling performance Peeling rate: After cooling to room temperature, the area of ​​automatic peeling of the coating layer under natural conditions is >95%; after slight bending or blowing with compressed air, the total peeling rate reaches over 99.5%; Peeling morphology: The peeled material is a dry, brittle sheet (2-10 mm in size), non-sticky, and easy to collect and process; Peeling time: From the start of cooling to the completion of peeling, it only takes 3-5 minutes, without the need for manual intervention.

[0070] 6. Surface cleanliness SEM observation: The surface of the filaments was smooth after peeling, with no residue adhering to it; EDS analysis: Surface energy dispersive spectroscopy analysis did not detect Si (characteristic element of hollow glass microspheres, detection limit 0.1 wt%) and B (characteristic element of boron nitride, detection limit 0.05 wt%), proving that an atomically clean surface has been achieved; XPS in-depth analysis: Etching analysis of the surface from 0 to 50 nm revealed no enrichment of B or Si elements, confirming no elemental diffusion contamination.

[0071] 7. Comprehensive Energy Consumption Assessment Heating power: When the steady state reaches 1060℃, the output power of the induction heating power supply is 12 kW (19 kW is required for uncoated bare wire), saving 37% energy; Unit energy consumption: Energy consumption per ton of wire processed decreased from 850 kWh to 535 kWh, a reduction of 37%; Overall energy consumption: Considering the complete elimination of post-processing steps, the overall energy consumption of the entire process is reduced by 42%.

[0072] Post-processing: The coating peeling process requires no manual intervention, and the collected peeled material is dry and brittle, which is easy to handle.

[0073] Example 2 Sacrificial intelligent thermal barrier material formulation: Fischer-Tropsch wax / polyethylene wax mixture (melting point 105℃): 45 wt% Silica aerogel powder (hydrophobic): 40 wt% Graphite flakes (particle size D50 = 20 μm): 10 wt% Ethylene-propylene copolymer: 5 wt% High-temperature alloy wire blank: GH3030, initial diameter φ6.0 mm.

[0074] Target finished product diameter: φ3.0 mm.

[0075] Drawing temperature: 1120℃.

[0076] Coating thickness: 2.0 mm.

[0077] Method and steps: Same as in Example 1.

[0078] Effect: Heat loss was reduced by 62%. Pull-out force was reduced by 18%.

[0079] After cooling, the coating peels off in large flakes, with a peeling rate of >96%.

[0080] Auger electron spectroscopy (AES) was performed on the surface of the finished wire material. No abnormal carbon enrichment was detected in the surface layer (<10 nm), proving that the graphite sheet did not cause carburization contamination on the surface of the high-temperature alloy.

[0081] Comparative Example 1 (Traditional Stainless Steel Sheathing Method) Materials: GH4169 wire blank (φ4.0 mm), covered with 304 stainless steel pipe with a wall thickness of 0.4 mm, and sealed at both ends after vacuuming.

[0082] Process: The drawing is also carried out at 1060℃, with a target finished product diameter of φ2.0 mm.

[0083] Results and Failure Analysis: Towards the end of the second drawing pass, noticeable stainless steel buildup was observed at the die entrance. During the third draw pass, the buildup caused a sharp increase in resistance, subsequently resulting in the core GH4169 wire breaking within the sheath.

[0084] Analysis of the results recorded in Table 1 reveals that this failed case classically demonstrates the incompatibility of dissimilar metal composite deformation. Stainless steel exhibits significantly higher strength at high temperatures than GH4169 in its superplastic state, and the mismatch in their plastic flow capabilities prevents the release of interfacial shear stress through coordinated deformation, ultimately leading to failure via "accumulation-fracture." This is an inherent flaw in this method.

[0085] Comparative Example 2 (Insulating Coating with No Release Agent) Material formulation: 60 wt% microcrystalline wax, 40 wt% hollow glass microspheres (i.e., free of boron nitride and rheology modifiers).

[0086] Process: The coating and drawing steps are the same as in Example 1, and the coating thickness is about 1.2 mm.

[0087] result: The heat insulation effect during the drawing process is similar to that of Example 1. However, after cooling, the mixture of wax and glass microspheres tightly coats the surface of the filament, forming a hard, dense, and tough outer shell that cannot be peeled off on its own. Attempts to peel it off by hand only manage to tear off small pieces, leaving most of the residue. Subsequent cleaning requires high-temperature baking (to melt the wax) or soaking in organic solvents, a cumbersome process that causes solvent pollution and energy consumption. The wax residue on the filament surface does not meet the requirements of high-end applications.

[0088] Analysis of the results recorded in Table 1 demonstrates that the release agent (boron nitride) is an indispensable key component for achieving the "self-peeling" function. Without it, the coating bonded too strongly to the metal substrate, and the shrinkage stress of the phase transformation substrate is insufficient to overcome the interfacial bonding force, thus preventing the intelligent peeling behavior from being achieved.

[0089] Table 1 Summary and Comparison of Experimental Data

[0090] 1. According to the comparison between Example 1 and Comparative Example 1, it can be seen that: (1) the phase change matrix material (40-70%) is transformed into a viscoplastic solid at the drawing temperature, so that its flow stress (<0.1 MPa) is much lower than the deformation resistance (>50 MPa) of the high temperature alloy matrix; (2) Example 1 uses a viscoplastic coating layer to absorb the interface stress at the mold entrance through its own shear deformation, which fundamentally eliminates the stress accumulation caused by deformation mismatch in the composite deformation of dissimilar metals (such as the stainless steel cladding method in Comparative Example 1). (3) Experimental data show that, using the GH4169 wire of Example 1, the drawing force fluctuation range is only ±8% during four consecutive drawing processes, and the wire breakage rate drops from the industry average of 5-10% to 0% (breakage occurred in the 3rd draw in Comparative Example 1), indicating that the method of the present invention can achieve zero accumulation and zero wire breakage; (4) The single-pass reduction rate allowed by the traditional stainless steel sheathing method in Comparative Example 1 is usually no more than 15%, while Example 1 can increase the single-pass reduction rate to 20-25% without instability, and the drawing efficiency is increased by more than 30%. This shows that the critical deformation capability is improved by using the method of the present invention.

[0091] 2. Based on the comparison of experimental data from the embodiments and comparative examples, it can be seen that the present invention achieves multi-dimensional energy saving and consumption reduction through a dual thermal insulation design of "low thermal conductivity filler + phase change encapsulation". This invention constructs a highly efficient composite thermal barrier by completely encapsulating the filler with insulating filler (20-50%, thermal conductivity <0.1 W / (m·K)) and a phase change matrix. The energy-saving effect is reflected in the following four quantifiable dimensions, as shown in Table 2: Table 2

[0092] Data support: In Example 1, when the φ4.0 mm GH4169 filament was heated to 1060°C, the induction heating power required was only 12 kW with the coating layer, while it required 19 kW for the uncoated control (energy saving of 37%). Infrared thermal imaging showed that the surface temperature of the coating layer was only 15°C lower than that of the core, while the temperature difference between the surface and the core of the uncoated filament reached 80°C.

[0093] 3. Based on the comparison of experimental data from the embodiments and comparative examples, it can be seen that the present invention achieves multi-dimensional improvement in product quality through the dual guarantee of "isothermal deformation + solid lubrication": The embodiment maintains uniform temperature across the filament cross-section through the heat insulation effect of the coating layer (1.2 mm thick), while the release agent (5-15%) forms a continuous lubricating film at the interface, resulting in the following quality improvements: (1) Significant improvement in dimensional accuracy: Isothermal deformation eliminates the difference in flow stress caused by temperature gradient, which significantly reduces the fluctuation of wire diameter. In Example 1, the diameter tolerance of the finished φ2.0 mm wire reaches ±0.015 mm, which is better than the Grade I requirement of 0.03 mm in GB / T 14992-2020 standard.

[0094] (2) Breakthrough in surface quality: No microcracks: The "lubricating wedge" effect formed by the viscoplastic coating at the mold entrance reduces the drawing friction coefficient from 0.15-0.20 to below 0.08, reduces surface shear stress by 50%, and reduces the surface crack rate from 5.3% (Comparative Example 1) to below 0.2%.

[0095] Surface roughness optimization: The layered structure of the release agent is oriented and arranged at high temperature to form a smooth sliding interface, which reduces the surface roughness Ra of the finished filament from 1.2-1.6μm to 0.6-0.8μm.

[0096] Improved uniformity of structure: Isothermal deformation makes dynamic recrystallization more uniform, and the grain size fluctuation range is reduced from ±2 grade to ±0.5 grade.

[0097] 3. The present invention employs a dual peeling mechanism of "weak interface of release agent + phase change shrinkage and embrittlement" to achieve zero cost and zero pollution in post-processing.

[0098] (1) Self-peeling rate: In Example 1, the area of ​​the coating layer that naturally peels off after cooling is >95%, and the peeling rate after slight bending or blowing is over 99.5%.

[0099] (2) Zero residue verification: XPS (X-ray photoelectron spectroscopy) was used to perform in-depth analysis on the surface of the stripped filament. No characteristic elements of the coating layer such as B, Si, and F were detected in the 0-50nm surface layer, proving that an atomically clean surface was achieved.

[0100] (3) Post-processing cost reduced to zero: Compared with Comparative Example 2 (requires solvent cleaning) and Comparative Example 1 (requires acid washing + mechanical removal), the post-processing cost per ton of wire in Example 1 was reduced from RMB 800-1200 to RMB 0, and the discharge of waste acid and waste solvent was eliminated.

[0101] 4. This invention achieves a systematic reduction in overall cost through the combined effect of "increased yield + reduced energy consumption + simplified processes": Although it increases the cost of coating materials (approximately 200-300 yuan / ton of wire), the overall cost calculation shows, as shown in Table 3: Table 3

[0102] In summary, this invention, through the quaternary synergistic design of phase change matrix, heat-insulating filler, release agent, and rheology modifier, not only achieves breakthroughs at the single technical level (heat insulation, lubrication, and peelability), but also creatively solves the long-standing contradiction between "protection and removal" in the field of high-temperature alloy hot working through multifunctional system integration, achieving a comprehensive improvement in process stability, product quality, energy efficiency, and environmental friendliness. The technical effects of this invention are multi-dimensional, quantifiable, and have significant industrial application value, representing a major advancement in high-temperature alloy precision machining technology.

[0103] This invention, through its innovative design of "phase change matrix-driven state switching and synergistic effect of multifunctional components," overcomes the long-standing technical challenge of the trade-off between "effective heat insulation" and "non-destructive removal" in the hot drawing of high-temperature alloy wires. In particular, it fundamentally eliminates the fatal flaw of the stainless steel cladding method. This invention not only significantly improves process efficiency, product quality, and economic benefits, but also provides a new paradigm for the design of "process auxiliary materials," which is of great significance for promoting the advancement of green precision manufacturing technology for high-end metal materials. The method of this invention fundamentally solves the problem of accumulation and fracture in the traditional stainless steel cladding method, achieving efficient, stable, and green precision forming of high-temperature alloy wires.

[0104] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sacrificial smart thermal barrier material, characterized in that, The sacrificial smart thermal barrier material is formed into a homogeneous composite through melt blending, and comprises the following components by mass percentage: Phase change matrix material 40-70%, Thermal insulation filler 20-50%, Release agent 5-15%, Rheology modifier 1-5%; The phase change matrix material is a polymer or microcrystalline wax with a melting point in the range of 80-130℃; the thermal insulation filler is a hollow or porous material with low thermal conductivity.

2. The sacrificial smart thermal barrier material according to claim 1, characterized in that, The polymer with a melting point in the range of 80-130°C is selected from one or more of polyethylene wax, Fischer-Tropsch wax, and ethylene-vinyl acetate copolymer.

3. The sacrificial smart thermal barrier material according to claim 1, characterized in that, The heat insulation filler is selected from one or more of hollow glass microspheres, ceramic microspheres, silica aerogel powder, and expanded perlite powder.

4. The sacrificial smart thermal barrier material according to claim 1, characterized in that, The release agent is selected from one or more of boron nitride flakes, graphite flakes, calcium fluoride, and mica powder.

5. The sacrificial smart thermal barrier material according to claim 1, characterized in that, The average particle size of the thermal insulation filler is 5-200 μm; and / or, The release agent has a sheet-like structure with an average sheet diameter of 1-50 μm.

6. The sacrificial smart thermal barrier material according to claim 1, characterized in that, The rheology modifier is selected from one or more of hydrogenated castor oil, ethylene-propylene copolymer, polyamide wax, and organobentonite.

7. The sacrificial smart thermal barrier material according to any one of claims 1-6, characterized in that, The sacrificial smart thermal barrier material is in a viscoplastic solid state at a drawing temperature of 900-1200℃. At temperatures below 50°C, the sacrificial smart thermal barrier material is a brittle solid.

8. A hot drawing method, characterized in that, The method includes the following steps: The sacrificial smart thermal barrier material according to any one of claims 1-6 is heated to a molten state; Molten sacrificial smart thermal barrier material is coated onto the surface of wire or rod blanks by extrusion coating or dip coating to form a coating layer, which is then cooled and solidified to obtain wire or rod blanks coated with sacrificial smart thermal barrier material. The wire or rod blanks coated with the sacrificial smart thermal barrier material are heated to the drawing temperature to transform the coating layer into a viscoplastic solid state, and then multiple drawing passes are performed. After being drawn, the wire or bar blanks are cooled to room temperature, the coating layer becomes brittle and peels off on its own, resulting in high-temperature alloy wires or bars.

9. The hot drawing method according to claim 8, characterized in that, Before forming a coating layer on the surface of the wire or rod, the surface of the wire or rod blank is pretreated, including removing oil and oxides from the surface of the wire or rod blank and drying it.

10. The hot drawing method according to claim 8, characterized in that, The thickness of the coating layer is 0.5-3.0 mm.

11. The hot drawing method according to claim 8, characterized in that, The drawing temperature is 900-1200℃.

12. The hot drawing method according to any one of claims 8-11, characterized in that, The wire material includes high-temperature alloy wire, titanium alloy wire, or intermetallic compound wire; The rods include high-temperature alloy rods, titanium alloy rods, or intermetallic compound rods.

13. The application of the sacrificial smart thermal barrier material as described in any one of claims 1-7 in the hot extrusion or hot drawing process of wires or bars of high-temperature alloys, titanium alloys or intermetallic compounds.

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