Al-Li Alloy Durability Patents: Leaders, Trends & White Space 2026
- Filing has gone flat, not forward. activity peaked at 4 families in 2018 and the 2022 midpoint sits at just 2, with no growth signal into the most recent full year.
- Two IPC subclasses carry almost the entire field. C22C alloy compositions and C22F non-ferrous heat treatment together dominate the 105-family set, leaving casting, rolling and extrusion routes thinly claimed by comparison.
- The foundational claims are decades old. the most-cited record, US5198045A, has 109 citations and dates back to the earlier Al-Li generation — newer filings are working in the shadow of that prior art, not past it.
Filing growth compares 2021 (2 records) with 2024 (0) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 105 records in scope (CR5), not by the ranked leaders only.
What this dataset covers
This landscape tracks 105 patent families filed against corrosion resistance, exfoliation resistance, stress-corrosion cracking and general environmental durability in aluminum-lithium alloys, filtered against the core metallurgy classes C22C21/00, C23F11 and C22F1/057. The set spans 2015 through the 2026 cut-off, though the most recent year is necessarily undercounted because publication typically lags filing by around eighteen months.
Receiving-office data shows Europe and the United States ahead of China, with Canada, WIPO/PCT and Japan filling out a smaller but active tail — a pattern consistent with a mature alloy family being re-claimed for aerospace and lightweighting durability rather than a fresh technology race.
Filing trend and technology composition
Two views of the same 105-family set: how filing volume has moved year over year, and which classification codes the claims actually sit in.
A flat trend line, not a growth curve
Filings rose from 2 in 2017 to a peak of 4 in 2018, then settled back toward the midpoint level of 2 in 2022. There is no sustained upward trajectory in this data — treat any apparent recent-year drop as a publication-lag artefact rather than a real slowdown, but do not read momentum into the earlier years either.
Composition claims still carry the field
C22C (alloys) appears in 97 of 105 records and C22F (non-ferrous treatment) in 66, confirming that most protection is anchored in alloy composition and heat-treatment steps rather than forming processes. B22D casting and F24S solar-heat-collector applications each register in single digits, and rolling, extrusion and sheet-metal working appear only once apiece — those forming and application routes are comparatively open.
Shares are the percentage of the 105 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Aluminum-Lithium Alloy Environmental Durability with Eureka
This page is one run against one query. Ask Eureka your own question about aluminum-lithium alloy environmental durability and every answer comes back with the patent numbers behind it.
Try EurekaThe prior art newer filings have to work around
US4532106A — Mechanically alloyed dispersion strengthened aluminum-lithium alloy
A dispersion-strengthened aluminum-base alloy system is provided which is prepared by mechanical alloying and is characterized by high strength, high elastic modulus, low density and high corrosion resistance. The alloy system is comprised, by weight, of at least above 1.5% up to about 3% Li, about 0.4% up to about 1.5% O, about 0.25% up to about 1.2% C, and the balance essentially Al.Filed by INCO ALLOYS INTERNATIONAL, INC., A DE CORP. in 1985 — one of the earliest mechanically-alloyed routes in this dataset, and a compositional anchor point that later corrosion-resistance claims still have to distinguish themselves from.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5198045A | Low density high strength Al-Li alloy | 109 |
| 2 | US4816087A | Process for producing duplex mode recrystallized high strength aluminum-lithium alloy products with high frac… | 75 |
| 3 | US4861391A | Aluminum alloy two-step aging method and article | 56 |
| 4 | CN106521270A | 一种改善铝锂合金耐腐蚀性能的热处理工艺 | 49 |
| 5 | US5389165A | Low density, high strength Al-Li alloy having high toughness at elevated temperatures | 45 |
| 6 | WO1998033947A1 | Method of improving fracture toughness in aluminum-lithium alloys | 31 |
| 7 | US4795502A | Aluminum-lithium alloy products and method of making the same | 29 |
| 8 | US4603029A | Aluminum-lithium alloy | 27 |
| 9 | JP1986023751A | Manufacture of al-li alloy having superior ductility and toughness | 21 |
| 10 | US4532106A | Mechanically alloyed dispersion strengthened aluminum-lithium alloy | 21 |
Citation counts favour older filings simply because they have had longer to accumulate citations inside this search corpus; read them as a signal of influence on the field, not of current commercial relevance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Three read-throughs of the trend, citation and classification data that matter more than the raw counts on their own.
The field is not accelerating
Volume peaked in 2018 and has since drifted back to its earlier level. A flat or declining trend in a corrosion-resistance niche usually means the easy compositional wins have already been claimed, and remaining filers are narrowing into specific heat-treatment windows or niche alloy grades rather than staking out broad new territory.
Foundational claims are still the reference point
The most-cited records in this set date from the earlier Al-Li generation and remain the benchmark newer filings are measured against. A new corrosion-resistance claim that doesn't clearly separate itself from that 1990s-era composition and processing art is likely to face a crowded prior-art rejection.
Composition, not process, is where the claims sit
Almost every record in this set touches alloy composition (C22C), and most also touch non-ferrous heat treatment (C22F). Forming routes — casting, rolling, extrusion, sheet working — barely register, which is either a sign those routes are genuinely secondary to durability outcomes, or a sign they are simply under-claimed.
Filing here is mostly a solo activity
Only five co-assignee pairings appear across 105 families, and the strongest of them ties two historically related aerospace-materials assignees together. Joint filing is the exception, not the norm, in this corner of alloy metallurgy.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to aluminum-lithium alloy environmental durability, with the prior art for and against each one.
Who holds the ground, and where it's open
The assignee ranking is dominated by legacy aerospace-materials producers, but recent-year momentum has gone quiet across the board — this is a field where past filings still do most of the blocking.
Historic leaders, current inactivity
Assignees such as Reynolds Metals Company, The Boeing Company, Alcoa Inc. and Aluminum Company of America (Alcoa) anchor the ranking on cumulative family counts, but every one of the leading names shows zero filings in the latest tracked year. Their portfolios still set the boundaries other filers design around, even without new activity.
A small web of related aerospace filers
The strongest co-assignee link in the dataset connects two aerospace-materials names with a shared filing history, alongside two smaller pairs built around individual inventors at Alcoa Inc.. Collaboration exists but is narrow and historic rather than a current industry-wide pattern.
China and PCT filers are the active edge
China's 18 receiving-office filings and WIPO's 8 PCT filings sit behind Europe and the US in volume but represent the more recently active filing geographies in this set, including academic assignees working on treatment processes for corrosion resistance.
| Assignee | Recent year | YoY |
|---|---|---|
| Reynolds Metals Company | 0 | — |
| The Boeing Company | 0 | — |
| Kaiser Aluminum & Chemical Corporation | 0 | — |
| Alcoa Inc. | 0 | — |
| PECHINEY ROLLED PRODUCTS LLC | 0 | — |
| Aluminum Company of America (Alcoa) | 0 | — |
| Martin Marietta Corporation | 0 | — |
| Shanghai Jiao Tong University | 0 | — |
Where to take this analysis
The dataset points to a mature, composition-heavy field with narrow current activity. These are the practical next steps for a team deciding where to file or license.
Map claim scope against the top-cited patents
Before drafting a new corrosion-resistance claim, check it against the compositional boundaries set by the most-cited records in this set, since those remain the working reference points examiners will cite.
Explore prior art in EurekaProbe the under-claimed forming routes
Rolling, extrusion and sheet-metal working each appear only once in this dataset despite sitting adjacent to dense composition claims — a targeted freedom-to-operate search there is likely to surface real white space.
Run a white-space search in EurekaWatch for renewed activity from quiet incumbents
Every leading assignee shows zero filings in the latest tracked year; a resumption of filing from any of them would signal a shift back toward active claim-building in this niche.
Track assignee activity in EurekaCommon questions about this landscape
The assignee ranking in this dataset is led by legacy aerospace-materials producers, including Reynolds Metals Company, Alcoa Inc. and Aluminum Company of America (Alcoa), whose combined filing history spans several decades. None of the leading assignees show filings in the most recent tracked year, which means their existing portfolios still define the boundaries of the field rather than active new claims. Newer activity, where it exists, tends to come from Chinese-origin filers and academic assignees working on treatment processes.
Filing peaked at 4 families in 2018 and had returned to a lower level of 2 by the 2022 midpoint, with no recovery visible since. This pattern is typical of a technology where the foundational compositional space was claimed early — by records like US5198045A and US4816087A — leaving later filers to work in narrower, more specific windows. It does not necessarily mean interest in the underlying alloys has declined, only that the easy patenting opportunities have thinned out.
Both appear as search terms within this dataset's environmental-durability filter, and most records that address one also touch the other, since they stem from related grain-boundary and precipitate behaviour in Al-Li alloys. Claims typically differentiate by the specific heat-treatment step, aging schedule or alloy composition used to control precipitate distribution. Reviewing the IPC composition — C22C for the alloy itself and C22F for the treatment step — is the fastest way to see which mechanism a given filing actually targets.
C22C, covering alloy compositions, appears in 97 of the 105 families in this dataset, making it the dominant classification by a wide margin. C22F, non-ferrous metal treatment, follows at 66 records and usually overlaps with C22C filings rather than standing alone. Casting, rolling, extrusion and sheet-working classifications each appear in single digits or less, marking them as comparatively open ground for new claims focused on forming rather than composition.
Yes, primarily in forming and application routes rather than in core alloy composition, which is heavily claimed. Rolling, extrusion and sheet-metal working classifications each appear only once in this 105-family dataset despite sitting directly adjacent to dense C22C and C22F claim clusters. A freedom-to-operate search focused on process-specific durability claims for these forming routes, rather than another composition variant, is more likely to find genuinely open space.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.