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| Nice, France |
A new way to build cars with recycled material.
BREAKING 
The blueprint for Tesla's next manufacturing revolution has just been declassified 
Published today, December 18, 2025, international patent WO 2025/259916 A1 unlocks the full technical secrets behind a metallurgy breakthrough Tesla has been safeguarding since mid-2024.
This document provides our first public look at the "alchemist's recipe" that allows Tesla to forge high-performance structural components from cheap, recycled scrap—proving that sustainability, safety, and cost-efficiency can finally coexist.
The problem: impurities in scrap metal
The core problem addressed by this patent is the automotive industry's traditional reliance on high-purity virgin aluminum for casting structural parts. Components like chassis frames and crash rails require a specific balance of strength and ductility to absorb energy during impact.
Historically, using scrap metal was prohibitive because it contains "performance detracting" impurities like iron, copper, and zinc. In standard manufacturing, these elements render the metal brittle and prone to cracking, making them unsuitable for critical safety components.
Tesla's solution: embracing the "dirty" scrap
Crucially, the patent specifies that this process isn't limited to clean, industrial off-cuts. It explicitly validates the use of "post-consumer" scrap varieties known in the industry by colorful names like "twitch" (fragmented scrap from shredded automobiles), "taint/tabor" (old clean alloy sheet), and even used aluminum radiators.
In one successful example, Tesla produced a high-performance melt using a mix of 30% old alloy wheels, 30% polished twitch, and 15% radiators. This proves that highly heterogeneous waste can be transformed into premium chassis components, effectively closing the loop on automotive recycling.
The chemistry: a balancing act
Tesla’s solution involves a sophisticated chemical balancing act. Rather than expensively purifying this scrap, they measure the impurities in the melt and introduce specific "performance improving additives" such as manganese, magnesium, vanadium, strontium, and silicon.
These additives counteract the negative effects of the lower-quality metal, essentially neutralizing the "dirty" elements of the scrap. To achieve this precision, the patent introduces two proprietary calculation metrics: the Hard Factor and the Advanced Sludge Factor.
The Hard Factor allows engineers to predict the relationship between the alloy's yield strength and ductility by analyzing the weight percentages of magnesium, copper, and zinc.
The Advanced Sludge Factor helps maintain a chemical ratio that prevents iron and manganese from forming hard, sludge-like precipitates. Without this control, these precipitates would ruin the metal's texture and damage the casting equipment.
Microscopic engineering
At a microscopic level, this innovation relies on controlling the formation of specific crystal phases within the metal as it cools. The text describes a microstructure featuring globular formulations of AlFeSi (Aluminum-Iron-Silicon) and Mg2Si (Magnesium-Silicide).
By carefully manipulating the Hard Factor, Tesla engineers can force impurities like magnesium to act as primary hardeners rather than defects. This turns what would typically be a chemical weakness into a structural strength.
Performance rivals virgin aluminum
The patent cites specific mechanical targets that allow this recycled material to rival virgin alloys. The new composition achieves a yield strength between 110 and 190 megapascals (MPa) while maintaining a bend angle of 15 to 32 degrees.
This specific balance is vital for crash safety; it ensures the metal is rigid enough to support the vehicle's frame yet flexible enough to crumple and absorb energy during a collision, effectively outperforming standard commercial alloys.
Enabling gigacasting
The resulting alloy is specifically optimized for high-pressure die casting (HPDC), the technique used for Tesla's massive single-piece body castings. The most critical contribution of this patent is its direct enablement of this "Gigacasting" strategy.
Casting massive, single-piece underbodies requires molten metal to travel long distances inside a mold without freezing prematurely. The patent reveals that this new alloy has an exceptional "casting flow length" of one to five meters under high-pressure conditions.
This specific technical capability allows Tesla to fill the enormous molds for the Model Y and Cybertruck underbodies in a single shot. It ensures the metal reaches every intricate corner of the die before solidifying—a feat that would be impossible with standard commercial alloys that freeze too quickly.
Eliminating heat treatment
Furthermore, this invention solves a major geometric problem for large vehicle castings: thermal distortion. Traditional structural alloys require a post-casting heat treatment—often involving high-temperature baking and rapid quenching—to achieve their final strength.
This process can cause large, thin-walled parts to warp or twist, leading to assembly failures. The patent explicitly states that this new alloy achieves its target yield strength of 110-190 MPa in the "as-cast" state without further processing.
By eliminating the heat treatment step, Tesla ensures that its giant castings come out of the Giga Press dimensionally perfect. This saves time and energy while preventing millions of dollars in scrap due to warped parts.
Supply chain independence
From a supply chain perspective, this patent insulates Tesla from global raw material volatility. By validating the use of specific "dirty" scrap streams—such as shredded end-of-life vehicles, old alloy wheels, and used radiators—Tesla can effectively decouple its material costs from the price of prime bauxite and virgin aluminum.
This capability allows the company to act as its own material supplier, melting down old Teslas or market-bought scrap to build new ones. This creates a true closed-loop manufacturing ecosystem that is significantly cheaper and more resilient than competitors who rely on high-purity inputs.
Integrated safety structures
Finally, the specific ductility metrics of this alloy allow for the integration of crash-safety systems directly into the frame. The patent highlights a high "bend angle," which is a measure of how much the metal can fold before snapping.
This property allows Tesla to cast "crash rails" and energy-absorbing crumple zones directly into the single-piece front and rear underbodies. In a collision, these cast structures can deform plastically to protect the battery pack and passengers.
This capability eliminates the need to weld on separate, stamped-steel crash rails and further simplifies the vehicle's architecture. The patent also notes that this composition is suitable for future additive manufacturing processes, such as 3D laser melting, suggesting potential use in printing intricate parts for future vehicle generations.
The blueprint for Tesla's next manufacturing revolution has just been declassified
Published today, December 18, 2025, international patent WO 2025/259916 A1 unlocks the full technical secrets behind a metallurgy breakthrough Tesla has been safeguarding since mid-2024.
This document provides our first public look at the "alchemist's recipe" that allows Tesla to forge high-performance structural components from cheap, recycled scrap—proving that sustainability, safety, and cost-efficiency can finally coexist.
The problem: impurities in scrap metal
The core problem addressed by this patent is the automotive industry's traditional reliance on high-purity virgin aluminum for casting structural parts. Components like chassis frames and crash rails require a specific balance of strength and ductility to absorb energy during impact.
Historically, using scrap metal was prohibitive because it contains "performance detracting" impurities like iron, copper, and zinc. In standard manufacturing, these elements render the metal brittle and prone to cracking, making them unsuitable for critical safety components.
Tesla's solution: embracing the "dirty" scrap
Crucially, the patent specifies that this process isn't limited to clean, industrial off-cuts. It explicitly validates the use of "post-consumer" scrap varieties known in the industry by colorful names like "twitch" (fragmented scrap from shredded automobiles), "taint/tabor" (old clean alloy sheet), and even used aluminum radiators.
In one successful example, Tesla produced a high-performance melt using a mix of 30% old alloy wheels, 30% polished twitch, and 15% radiators. This proves that highly heterogeneous waste can be transformed into premium chassis components, effectively closing the loop on automotive recycling.
The chemistry: a balancing act
Tesla’s solution involves a sophisticated chemical balancing act. Rather than expensively purifying this scrap, they measure the impurities in the melt and introduce specific "performance improving additives" such as manganese, magnesium, vanadium, strontium, and silicon.
These additives counteract the negative effects of the lower-quality metal, essentially neutralizing the "dirty" elements of the scrap. To achieve this precision, the patent introduces two proprietary calculation metrics: the Hard Factor and the Advanced Sludge Factor.
The Hard Factor allows engineers to predict the relationship between the alloy's yield strength and ductility by analyzing the weight percentages of magnesium, copper, and zinc.
The Advanced Sludge Factor helps maintain a chemical ratio that prevents iron and manganese from forming hard, sludge-like precipitates. Without this control, these precipitates would ruin the metal's texture and damage the casting equipment.
Microscopic engineering
At a microscopic level, this innovation relies on controlling the formation of specific crystal phases within the metal as it cools. The text describes a microstructure featuring globular formulations of AlFeSi (Aluminum-Iron-Silicon) and Mg2Si (Magnesium-Silicide).
By carefully manipulating the Hard Factor, Tesla engineers can force impurities like magnesium to act as primary hardeners rather than defects. This turns what would typically be a chemical weakness into a structural strength.
Performance rivals virgin aluminum
The patent cites specific mechanical targets that allow this recycled material to rival virgin alloys. The new composition achieves a yield strength between 110 and 190 megapascals (MPa) while maintaining a bend angle of 15 to 32 degrees.
This specific balance is vital for crash safety; it ensures the metal is rigid enough to support the vehicle's frame yet flexible enough to crumple and absorb energy during a collision, effectively outperforming standard commercial alloys.
Enabling gigacasting
The resulting alloy is specifically optimized for high-pressure die casting (HPDC), the technique used for Tesla's massive single-piece body castings. The most critical contribution of this patent is its direct enablement of this "Gigacasting" strategy.
Casting massive, single-piece underbodies requires molten metal to travel long distances inside a mold without freezing prematurely. The patent reveals that this new alloy has an exceptional "casting flow length" of one to five meters under high-pressure conditions.
This specific technical capability allows Tesla to fill the enormous molds for the Model Y and Cybertruck underbodies in a single shot. It ensures the metal reaches every intricate corner of the die before solidifying—a feat that would be impossible with standard commercial alloys that freeze too quickly.
Eliminating heat treatment
Furthermore, this invention solves a major geometric problem for large vehicle castings: thermal distortion. Traditional structural alloys require a post-casting heat treatment—often involving high-temperature baking and rapid quenching—to achieve their final strength.
This process can cause large, thin-walled parts to warp or twist, leading to assembly failures. The patent explicitly states that this new alloy achieves its target yield strength of 110-190 MPa in the "as-cast" state without further processing.
By eliminating the heat treatment step, Tesla ensures that its giant castings come out of the Giga Press dimensionally perfect. This saves time and energy while preventing millions of dollars in scrap due to warped parts.
Supply chain independence
From a supply chain perspective, this patent insulates Tesla from global raw material volatility. By validating the use of specific "dirty" scrap streams—such as shredded end-of-life vehicles, old alloy wheels, and used radiators—Tesla can effectively decouple its material costs from the price of prime bauxite and virgin aluminum.
This capability allows the company to act as its own material supplier, melting down old Teslas or market-bought scrap to build new ones. This creates a true closed-loop manufacturing ecosystem that is significantly cheaper and more resilient than competitors who rely on high-purity inputs.
Integrated safety structures
Finally, the specific ductility metrics of this alloy allow for the integration of crash-safety systems directly into the frame. The patent highlights a high "bend angle," which is a measure of how much the metal can fold before snapping.
This property allows Tesla to cast "crash rails" and energy-absorbing crumple zones directly into the single-piece front and rear underbodies. In a collision, these cast structures can deform plastically to protect the battery pack and passengers.
This capability eliminates the need to weld on separate, stamped-steel crash rails and further simplifies the vehicle's architecture. The patent also notes that this composition is suitable for future additive manufacturing processes, such as 3D laser melting, suggesting potential use in printing intricate parts for future vehicle generations.