A corrosion-resistant rare earth aluminum alloy cable

Abstract

This invention discloses a corrosion-resistant rare-earth aluminum alloy cable, belonging to the field of aluminum alloy cable technology. The cable, from the inside out, consists of a rare-earth aluminum alloy conductor, a cross-linked polyethylene insulation layer, a three-layer composite anti-corrosion isolation strip, a NiTi shape memory alloy spiral armor layer, and a non-uniform wall thickness corrosion-resistant sheath layer. This invention relies on the thermo-induced phase change mechanism of NiTi shape memory alloy to achieve passive active overheating intervention, thereby blocking the failure chain reaction caused by insulation gaps. Through axial gradient phase change temperature design, a distributed temperature measurement and graded early warning system without external power supply is constructed to accurately locate faults. Simultaneously, the self-protection function of the armor is deeply integrated with the multi-layer gradient anti-corrosion system, resolving the inherent contradiction of traditional armor deformation tearing of the anti-corrosion layer, significantly improving the cable's operational reliability and service life in harsh corrosive environments.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy cable technology, and more particularly to a corrosion-resistant rare earth aluminum alloy cable. Background Technology

[0002] During long-term operation of cable lines, joints and terminals may become loose due to installation defects, thermal expansion and contraction, or mechanical vibration, resulting in increased local contact resistance and overheating. The temperature rise further exacerbates oxidation, causing the resistance to rise even more. This vicious cycle is the main cause of cable insulation breakdown and even fire.

[0003] Existing protection methods largely rely on external temperature monitoring or overload protection devices, requiring additional power supply and signal transmission, making it difficult to achieve passive sensing and active intervention for distributed hotspots. Conventional steel tape or wire armor only provides passive mechanical protection and is unresponsive to temperature changes. Furthermore, in harsh environments such as chemical plants, marine environments, and high-salt-spray environments, the armor layer and sheath are highly susceptible to chemical corrosion, leading to crevice corrosion, stress corrosion cracking, and other problems, significantly reducing mechanical protection capabilities and further deteriorating joint stability. Some solutions attempt to use shape memory alloys to create fastening rings, but this is limited to local joint accessories and cannot form a long-distance, passive, distributed temperature response system along the entire cable. In addition, the corrosion protection, lubrication, electrochemical isolation, and water-blocking sealing of existing armor are often isolated from each other, lacking a multi-layered synergistic protection design. After long-term service, corrosive media can easily penetrate the interfaces, causing rapid corrosion and failure of the armor wires.

[0004] Therefore, there is an urgent need for a smart cable that can passively sense local overheating, actively output radial clamping force to suppress contact degradation, and also has reliable corrosion resistance. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a corrosion-resistant rare earth aluminum alloy cable.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention first proposes a corrosion-resistant rare earth aluminum alloy cable, comprising, from the inside out, a rare earth aluminum alloy conductor, a cross-linked polyethylene insulation layer, an isolation layer, a shape memory alloy spiral armor layer, and a corrosion-resistant sheath layer; The shape memory alloy spiral armor layer is made of NiTi shape memory alloy wire (SMA) spirally wound and pre-trained to memorize a tight spiral shape that is 10-15% smaller than the laying diameter. The austenitic transformation start temperature As of the NiTi shape memory alloy wire is 85-95℃, and the austenitic transformation end temperature Af is 100-110℃. When the local temperature of the cable rises above As, the shape memory alloy spiral armor layer automatically shrinks to generate radial clamping force.

[0007] The shape memory effect of NiTi alloys originates from the temperature-induced reversible martensitic phase transformation: At low temperatures (<As), the alloy is in a soft martensitic phase, exhibiting good plasticity and capable of undergoing large deformations under external forces (in this invention, it is stretched to the laying diameter). At high temperatures (>As), the martensitic phase spontaneously transforms into a hard austenitic phase, the atomic lattice undergoes shearing and reorganization, restoring its pre-deformation memory shape (compact helix), while simultaneously generating a recovery stress as high as 400-700 MPa. When the temperature decreases (<Mf), the austenitic phase reverts to the martensitic phase. However, due to the locking effect of the hot melt adhesive in this invention, the armor layer will maintain its tight shape after shrinkage, thus achieving continuous protection.

[0008] Preferably, the NiTi shape memory alloy wire has a Ni content of 50.6-50.8 at.%, a wire diameter of 0.5-1.2 mm, a maximum recovery stress of 400-700 MPa, and a maximum recoverable strain of 6-8%.

[0009] For the phase transformation temperature of NiTi alloy, for every 0.1 at.% increase in Ni content, the austenitic phase transformation initiation temperature As decreases by about 10℃. A Ni content of 50.6-50.8 at.% precisely controls As at 85-95℃ and Af at 100-110℃, matching the long-term allowable operating temperature (90℃) and short-term overload temperature threshold of cross-linked polyethylene (XLPE) insulation. When the cable temperature exceeds 90℃ and enters an overload state, SMA immediately initiates phase transformation shrinkage, intervening to protect the insulation before irreversible thermal aging occurs.

[0010] Preferably, the pitch of the shape memory alloy spiral armor layer is 6-10 times the wire diameter, the spiral angle is 3-6°, and the training diameter is 88% of the laying diameter; The shape memory alloy spiral armor layer is provided with gradient sections of different phase transition temperatures along the cable axis, forming a passive distributed temperature response system. The As temperature in the root section within 50mm of the terminal is 75-80℃; the As temperature in the transition section 50-200mm from the terminal is 83-87℃; and the As temperature in the normal section in the middle of the cable is 93-97℃.

[0011] Preferably, the surface of the NiTi shape memory alloy wire is provided with three protective coatings, which are, from the inside out, a 0.1-0.3μm in-situ thermally oxidized TiO2 passivation layer, a 5-10μm polyimide functional layer, and a 0.5-1μm thick diamond-like lubricating layer.

[0012] Preferably, the isolation layer is a three-layer composite anti-corrosion isolation strip, consisting of a 0.1mm aluminum foil composite PET film electrochemical isolation layer, a 0.2mm silicone rubber foam buffer lubrication layer, and a water-blocking and anti-corrosion layer impregnated with corrosion inhibitor and water-absorbing and expanding resin.

[0013] In-situ thermal oxidation TiO2 passivation layer (0.1-0.3μm): It is metallurgically bonded to the substrate, dense and defect-free, blocking the penetration of corrosive media, while inhibiting Ni ion precipitation and avoiding galvanic corrosion; Polyimide functional layer (5-10μm): It has excellent chemical corrosion resistance, electrical insulation and buffering properties, blocks the galvanic corrosion circuit between SMA and other metal layers, and buffers the shrinkage stress of SMA. Diamond-like carbon lubricant layer (0.5-1μm): Reduces the coefficient of friction, ensures the degree of freedom during SMA deformation, and improves wear resistance and scratch resistance.

[0014] Preferably, the spiral gaps of the shape memory alloy spiral armor layer are filled with low melting point hot melt adhesive, wherein the hot melt adhesive has a melting point of 95-100℃, an elastic modulus ≤1MPa, and an elongation at break ≥500%.

[0015] Preferably, the corrosion-resistant sheath layer is made of modified cross-linked polyethylene with 2-3% nano-montmorillonite added, and adopts a non-uniform wall thickness design, with the cable body wall thickness ≥2.0mm, the joint transition zone wall thickness 3.0-3.5mm, and the sheath surface having a contact angle ≥130° after plasma fluorination treatment.

[0016] Three armor layers with different As temperatures arranged along the cable axis constitute a distributed temperature monitoring and fault location system that requires no external power supply. Terminal root section (As=75-80℃): Designed for areas with high cable fault incidence (more than 80% of faults occur at the joint), it responds to overheating first and provides early warning of poor joint contact; Transition section (As=83-87℃): distinguishes between localized overheating at the joint and overall overload of the cable body; Normal range (As=93-97℃): corresponds to the long-term allowable operating temperature of the cable body, and responds to overload across the entire line.

[0017] Preferably, an enhanced anti-corrosion layer is provided outside the corrosion-resistant sheath layer; For general buried environments, it adopts aluminum-zinc coated steel belt armor and modified PE outer sheath; For marine / high salt spray environments, FRP non-metallic armor and chlorosulfonated polyethylene outer sheath are used; In chemically corrosive environments, a PVDF film interlayer and a polytetrafluoroethylene (PTFE) outer sheath are used.

[0018] This invention also proposes a method for manufacturing the aforementioned corrosion-resistant rare earth aluminum alloy cable, comprising the following steps: S1: Prepare rare earth aluminum alloy conductors and extrude cross-linked polyethylene insulation layer; S2: Prepare NiTi shape memory alloy wire and perform shape memory training. Wind the NiTi wire onto a stainless steel mandrel with a diameter equal to the target training diameter and fix both ends. Heat to 480-500℃ and hold for 30 minutes, then quickly water quench. Reheat to 400-450℃ and hold for 60 minutes, then furnace cool. Solution treatment (water quenching at 480-500℃) causes NiTi atoms to form a uniform and disordered β-austenite solid solution, eliminating work hardening and internal stress. Rapid cooling inhibits the formation of precipitates and stores energy for subsequent phase transformation. Aging treatment (furnace cooling at 400-450℃) precipitates fine and dispersed Ni4Ti3 nanophases. These Ni4Ti3 phases can hinder dislocation movement, increase the alloy's recovery stress and recoverable strain, stabilize the phase transformation temperature, avoid performance drift after long-term use, and prevent coarsening of precipitates and decay of memory effect caused by over-aging.

[0019] S3: Three layers of composite anti-corrosion isolation tape are wrapped around the outside of the insulation layer; S4: Stretch the trained NiTi shape memory alloy wire to the laying diameter and spirally wrap it around the outside of the isolation layer; S5: Synchronously wrap low-melting-point hot melt adhesive film to fill the spiral gaps; The melting point of hot melt adhesive (95-100℃) matches the phase transition temperature range of SMA, therefore: Manufacturing stage: The hot melt adhesive is melted by the residual heat of the extruded sheath at 110-120℃, which fully fills the spiral gaps and forms a complete sealing layer after cooling; In the initial stage of overheating (85-95℃): SMA begins to shrink, while the hot melt adhesive remains solid, evenly transferring the clamping force to the insulation layer and avoiding localized stress concentration. Mid-stage of overheating (95-110℃): The hot melt adhesive melts into a highly elastic fluid, which does not hinder the further shrinkage of the SMA, and at the same time refills the tiny gaps after shrinkage. Cooling stage: The hot melt adhesive re-solidifies, locking the SMA in its shrunken, tight shape, maintaining continuous clamping force and sealing effect.

[0020] S6: Extrude a corrosion-resistant sheath layer at 110-120℃, and use the residual heat of extrusion to melt the hot melt adhesive for sealing. S7: The surface of the sheath is subjected to plasma fluorination treatment.

[0021] Compared with the prior art, the beneficial effects of the present invention are: 1. Existing cable overheat protection relies on external sensors and circuit breakers, which suffers from response lag. When a trip is triggered, the insulation layer has already developed air gaps due to thermal expansion, leading to partial discharge and irreversible thermal aging. This invention is based on the thermally induced martensitic phase transformation mechanism of NiTi alloy, precisely matching its austenitic phase transformation temperature to the critical operating temperature of cross-linked polyethylene insulation. Upon overheating, it automatically generates a recovery stress of 400-700MPa and a radial clamping force of 2-5MPa, eliminating insulation air gaps in real time and reducing contact thermal resistance by more than 30%. It can proactively intervene before insulation damage occurs without the need for an external power source.

[0022] 2. Existing distributed fiber optic temperature measurement systems require supporting light sources, signal demodulation and transmission equipment, resulting in high costs, weak resistance to electromagnetic interference, and difficulties in deployment in areas prone to joint failures. This invention, by controlling the NiTi alloy composition and heat treatment process, constructs an As temperature gradient segment along the cable axis. Utilizing the differences in mechanical signals generated by phase transition contraction at different locations, passive distributed temperature monitoring is achieved with a positioning accuracy of up to 0.5m. The terminal root section responds as early as 75℃, enabling targeted early warning of over 80% of joint contact failures, thus constructing a tiered protection system.

[0023] 3. Traditional cable armor layers only provide mechanical protection; their deformation easily tears the anti-corrosion layer, creating penetration channels. Furthermore, their anti-corrosion system is singular and difficult to adapt to complex corrosive environments. This invention deeply integrates shape memory alloy armor with multi-layered gradient anti-corrosion. Through a three-layer protective coating of SMA wire, a three-layer composite isolation strip, and temperature-matched hot melt adhesive, it ensures the free deformation of the SMA while forming a five-level anti-corrosion barrier. Simultaneously, enhanced anti-corrosion layers are designed for different environments, increasing cable service life by 2-3 times in harsh environments such as marine and chemical plants.

[0024] In summary, this invention relies on the thermally induced phase change mechanism of NiTi shape memory alloy to achieve passive active overheating intervention, thereby blocking the failure chain reaction caused by insulation gaps; through axial gradient phase change temperature design, a distributed temperature measurement and graded early warning system without external power supply is constructed to accurately locate faults; at the same time, the armor self-protection function is deeply integrated with the multi-layer gradient anti-corrosion system, solving the inherent contradiction of traditional armor deformation tearing anti-corrosion layer, significantly improving the cable's operational reliability and service life in harsh corrosive environments. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the corrosion-resistant rare earth aluminum alloy cable proposed in this invention; In the diagram: 1. Rare earth aluminum alloy conductor; 2. Cross-linked polyethylene insulation layer; 3. Insulation layer; 4. Shape memory alloy spiral armor layer; 5. Corrosion-resistant sheath layer. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with existing known technologies. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0027] Example 1 (General Buried Environment) Structural features: Rare earth aluminum alloy conductor, with extruded cross-linked polyethylene insulation layer.

[0028] Three-layer composite anti-corrosion isolation strip: inner layer 0.1mm aluminum foil composite PET film, middle layer 0.2mm silicone rubber foam buffer lubrication layer, outer layer water-absorbing and swelling resin impregnated with benzotriazole corrosion inhibitor water-blocking and anti-corrosion layer.

[0029] Shape memory alloy spiral armor layer: Ni content 50.7 at.%, wire diameter 0.8 mm; pitch is 8 times the wire diameter (6.4 mm), helix angle 4.5°; The diameter of the memory training target is 88% of the laying diameter (reduced by 12%); the surface of the NiTi wire has a 0.2μm in-situ thermally oxidized TiO2 layer, an 8μm polyimide layer, and a 0.8μm diamond-like lubricating layer in sequence; the spiral gap is filled with low melting point hot melt adhesive with a melting point of 98℃.

[0030] Gradient phase transition temperature distribution: root section (0-50mm from the terminal) As=78℃, transition section (50-200mm) As=85℃, normal section As=95℃.

[0031] Corrosion-resistant sheath: Modified cross-linked polyethylene with 2.5% nano-montmorillonite added, body wall thickness 2.2mm, joint transition zone wall thickness 3.2mm, surface plasma fluorination treatment, contact angle 135°.

[0032] Enhanced anti-corrosion layer: Aluminized zinc-plated steel strip armor + modified PE outer sheath.

[0033] Manufacturing method: S1: Prepare a rare earth aluminum alloy conductor (1) and extrude a cross-linked polyethylene insulation layer (2); S2 memory training: Wrapped around a stainless steel mandrel with a diameter of 88% of the laying diameter, heated to 490℃ and held for 30 minutes, then water quenched, and then heated to 420℃ and held for 60 minutes before furnace cooling. S3: Wrap a three-layer composite anti-corrosion isolation strip (3) around the outside of the insulation layer (2); S4: Stretch the trained NiTi shape memory alloy wire to the laying diameter and spirally wrap it around the outside of the isolation layer (3) to obtain the shape memory alloy spiral armor layer (4); S5: Synchronously wrap low-melting-point hot melt adhesive film to fill the spiral gaps; S6: Extruding the sheath at 115℃ melts the hot melt adhesive and seals it, forming a corrosion-resistant sheath layer (5); S7: The surface of the sheath is subjected to plasma fluorination treatment.

[0034] Example 2 (Marine / High Salt Spray Environment) Structural features: The conductor, insulating layer, and insulating strip are the same as in Example 1.

[0035] Shape memory alloy armor: Ni content 50.6 at.%, wire diameter 1.0 mm; pitch 7 mm, helix angle 5°; shape memory training shrinkage 12%; coating structure same as in Example 1; filling hot melt adhesive melting point 97°.

[0036] Gradient phase transition temperature: root section As=80℃, transition section As=87℃, normal section As=97℃.

[0037] Corrosion-resistant sheath: 3% nano-montmorillonite addition, 2.5mm body wall thickness, 3.5mm joint area wall thickness, plasma fluorination treatment with a contact angle of 138°.

[0038] Enhanced anti-corrosion layer: FRP non-metallic armor + chlorosulfonated polyethylene outer sheath.

[0039] Manufacturing method: S2 heat treatment temperature is 500℃ solution treatment and 450℃ aging, the rest is the same as in Example 1.

[0040] Example 3 (Chemical Corrosive Environment) Structural features: The conductor, insulating layer, and insulating strip are the same as in Example 1.

[0041] Shape memory alloy armor: Ni content 50.8 at.%, wire diameter 0.5 mm; pitch is 6 times the wire diameter (3 mm), helix angle 3°; memory training is reduced by 10% (target diameter is 90% of the layup diameter); coating optimized to 0.3 μm TiO2 + 10 μm polyimide + 1 μm DLC; hot melt adhesive melting point 100℃.

[0042] Gradient phase transition temperature: root section As=75℃, transition section As=83℃, normal section As=93℃.

[0043] Corrosion-resistant sheath: 2% nano-montmorillonite, body wall thickness 2.0mm, joint area wall thickness 3.0mm, contact angle ≥130° after fluorination.

[0044] Enhanced anti-corrosion layer: PVDF film intermediate layer + polytetrafluoroethylene outer sheath.

[0045] Manufacturing method: S2 memory training uses a 10% smaller mandrel, S6 extrusion temperature is 120℃, and the rest is the same as in Example 1.

[0046] The following comparison model was also set: Comparative Example 1 (Armor without Shape Memory Alloy): The only difference from Example 1 is that the NiTi shape memory alloy spiral armor layer is replaced with a 304 stainless steel spiral armor with the same geometry (0.8 mm wire diameter, 6.4 mm pitch), resulting in no shape memory effect or gradient response. The remaining structure (including the isolation strip, sheath, and reinforced anti-corrosion layer) is exactly the same as in Example 1.

[0047] Comparative Example 2 (NiTi armor without memory training): The only difference from Example 1 is that a NiTi alloy wire with a Ni content of 50.7 at.% is used to wind a spiral with the same diameter as the laying diameter, without memory training (i.e., without heat treatment to reduce the diameter), and it is used only for ordinary spiral armor. The wire coating, insulating strip, sheath, etc. are the same as in Example 1.

[0048] Comparative Example 3 (Temperature distribution without gradient phase transition): The only difference from Example 1 is that the shape memory alloy spiral armored cable uses a single phase change temperature throughout, with all sections having an As temperature of 95°C, and no low-temperature response design at the root or transition sections. The shape memory training, coating, hot melt adhesive, and sheath are all the same as in Example 1.

[0049] Comparative Example 4 (lacking key corrosion protection and lubrication design): The difference from Example 1 is that: the NiTi filament surface lacks the polyimide layer and diamond-like carbon layer, retaining only the in-situ thermally oxidized TiO2 layer; the three-layer composite isolation tape is replaced with a single-layer 0.1mm ordinary PET tape, lacking the silicone rubber buffer layer and water-absorbing and swelling water-blocking layer, and without corrosion inhibitors; the sheath is not subjected to plasma fluorination treatment. The rest (memory training, gradient temperature, hot melt adhesive, and reinforced anti-corrosion layer) are the same as in Example 1.

[0050] The following tests were conducted on the cables prepared in each embodiment and comparative example: Test 1: Joint overload thermal stability test Apply 1.5 times the rated current (ambient temperature 25℃) to the joint on one side of the cable, continuously monitor the changes in joint surface temperature and contact resistance for 4 hours, and record the highest temperature and resistance change rate.

[0051] Test 2: Neutral Salt Spray Corrosion Test Take cable samples (including joint sections) and conduct a 1000-hour neutral salt spray test according to GB / T 10125. After the test, check the corrosion status of the armor layer and sheath, and measure the retention rate of the tensile strength of the armor wire.

[0052] Experiment 3: Dynamic Thermomechanical Cycle Test The cable was subjected to a temperature cycle of -20°C to +100°C for 100 times, and then dissected and inspected for debonding or air gaps at the interfaces between the insulation layer and the conductor, and between the armor layer and the isolation strip.

[0053] The test results are summarized below:

[0054] Data Analysis: Joint thermal stability tests showed that, thanks to the thermally induced clamping effect of the shape memory alloy armor in Examples 1-3, the highest joint temperature was only 64-68℃, and the contact resistance change rate was less than 4%. Comparative Example 1, using stainless steel armor without a shape memory effect, saw its joint temperature soar to 112℃, with a resistance change rate of 35.2%, indicating severe contact degradation when active clamping force was lacking. Comparative Example 2, although made of NiTi, did not undergo shape memory training and had no contraction force output; its temperature and resistance change rate were almost identical to Comparative Example 1. Comparative Example 3, without a gradient phase transition temperature setting, showed a lag in response at the root section, with a joint temperature reaching 98℃ and a resistance change rate of 18.4%, confirming that rapid response at low temperatures is key to suppressing fault development. Example 3, with its root As temperature as low as 75℃ and a denser pitch, exhibited the fastest response and best performance.

[0055] Regarding corrosion resistance, in Examples 1 and 2, and Comparative Examples 3, the strength retention rate of the armored wire exceeded 91% after 1000 hours of salt spray testing, and the sheath surface showed no change, verifying the effectiveness of the multi-layer coating and fluorination treatment. Comparative Example 4, lacking the polyimide / DLC coating, anti-corrosion isolation strip, and fluorination layer, had a strength retention rate of only 63.4%, with the sheath blistering and cracking, resulting in corrosion protection failure. Comparative Example 1, with its stainless steel armor, had a strength retention rate of 85.3%, exhibiting corrosion resistance but lacking active functionality. Examples 2 and 3, designed for high salt spray and chemical environments, incorporated FRP and fluoropolymer reinforcement layers, achieving a strength retention rate as high as 98.2%, highlighting the value of environmentally adaptable design.

[0056] After thermomechanical cycling, the embodiment relies on the clamping force to constrain the insulation layer in real time according to temperature changes, and the interface is tight without debonding; the comparative examples all show varying degrees of debonding or air gaps, and the comparative example 4 is even more affected by the infiltration of corrosion products, which accelerates the interface damage.

[0057] In summary, this invention achieves significant breakthroughs in overheat suppression, environmental aging resistance, and long-term mechanical stability through the intelligent drive of shape memory alloys, gradient partition response, and multi-layer anti-corrosion lubrication synergy.

[0058] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A corrosion-resistant rare earth aluminum alloy cable, characterized in that, It includes, from the inside out, a rare earth aluminum alloy conductor, a cross-linked polyethylene insulation layer, an isolation layer, a shape memory alloy spiral armor layer, and a corrosion-resistant sheath layer; The shape memory alloy spiral armor layer is made of NiTi shape memory alloy wire spirally wound and pre-trained to memorize a tight spiral shape that is 10-15% smaller than the laying diameter. The austenitic transformation start temperature As of the NiTi shape memory alloy wire is 85-95℃, and the austenitic transformation end temperature Af is 100-110℃. When the local temperature of the cable rises above As, the shape memory alloy spiral armor layer automatically contracts to generate radial clamping force.

2. The corrosion-resistant rare earth aluminum alloy cable according to claim 1, characterized in that, The NiTi shape memory alloy wire has a Ni content of 50.6-50.8 at.%, a wire diameter of 0.5-1.2 mm, a maximum recovery stress of 400-700 MPa, and a maximum recoverable strain of 6-8%.

3. The corrosion-resistant rare earth aluminum alloy cable according to claim 2, characterized in that, The pitch of the shape memory alloy spiral armor layer is 6-10 times the wire diameter, the spiral angle is 3-6°, and the training diameter is 88% of the laying diameter; The shape memory alloy spiral armor layer is provided with gradient sections of different phase transition temperatures along the cable axis, forming a passive distributed temperature response system. The As temperature in the root section within 50mm of the terminal is 75-80℃; the As temperature in the transition section 50-200mm from the terminal is 83-87℃; and the As temperature in the normal section in the middle of the cable is 93-97℃.

4. The corrosion-resistant rare earth aluminum alloy cable according to claim 1, characterized in that, The surface of the NiTi shape memory alloy wire is provided with three protective coatings, from the inside out: a 0.1-0.3μm in-situ thermally oxidized TiO2 passivation layer, a 5-10μm polyimide functional layer, and a 0.5-1μm thick diamond-like lubricating layer.

5. The corrosion-resistant rare earth aluminum alloy cable according to claim 1, characterized in that, The isolation layer is a three-layer composite anti-corrosion isolation strip, consisting of a 0.1mm aluminum foil composite PET film electrochemical isolation layer, a 0.2mm silicone rubber foam buffer lubrication layer, and a water-blocking and anti-corrosion layer impregnated with corrosion inhibitor and water-absorbing and expanding resin.

6. The corrosion-resistant rare earth aluminum alloy cable according to claim 1, characterized in that, The spiral gaps of the shape memory alloy spiral armor layer are filled with low-melting-point hot melt adhesive, which has a melting point of 95-100℃, an elastic modulus ≤1MPa, and an elongation at break ≥500%.

7. The corrosion-resistant rare earth aluminum alloy cable according to claim 1, characterized in that, The corrosion-resistant sheath layer is made of modified cross-linked polyethylene with 2-3% nano-montmorillonite added. It adopts a non-uniform wall thickness design, with the cable body wall thickness ≥2.0mm, the joint transition zone wall thickness 3.0-3.5mm, and the sheath surface is plasma fluorinated to a contact angle ≥130°.

8. The corrosion-resistant rare earth aluminum alloy cable according to claim 1, characterized in that, An enhanced anti-corrosion layer is also provided outside the corrosion-resistant sheath layer; For general buried environments, it adopts aluminum-zinc coated steel belt armor and modified PE outer sheath; For marine / high salt spray environments, FRP non-metallic armor and chlorosulfonated polyethylene outer sheath are used; In chemically corrosive environments, a PVDF film interlayer and a polytetrafluoroethylene (PTFE) outer sheath are used.

9. A method for manufacturing a corrosion-resistant rare earth aluminum alloy cable as described in any one of claims 1-8, characterized in that, Includes the following steps: S1: Prepare rare earth aluminum alloy conductors and extrude cross-linked polyethylene insulation layer; S2: Prepare NiTi shape memory alloy wire and perform shape memory training. Wind the NiTi wire onto a stainless steel mandrel with a diameter equal to the target training diameter and fix both ends. Heat to 480-500℃ and hold for 30 minutes, then quickly water quench. Reheat to 400-450℃ and hold for 60 minutes, then furnace cool. S3: Three layers of composite anti-corrosion isolation tape are wrapped around the outside of the insulation layer; S4: Stretch the trained NiTi shape memory alloy wire to the laying diameter and spirally wrap it around the outside of the isolation layer; S5: Synchronously wrap low-melting-point hot melt adhesive film to fill the spiral gaps; S6: Extrude a corrosion-resistant sheath layer at 110-120℃, and use the residual heat of extrusion to melt the hot melt adhesive for sealing. S7: The surface of the sheath is subjected to plasma fluorination treatment.

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