WWII ALUMINIUM COMPOSITION

Pollard. Pollard was the structures guy at Bristol’s from F2B to Brabazon and an influential author and lecturer. You could also follow the air cooled engine history from Bristol Jupiter-Pegasus-Hercules-Centaurus (Fedden). I can write the thesis in return for beer!

Big, fascinating topic. That’s why the 15 pints are there !
Performance is POWERPLANTS and STRUCTURES.
Powerplants = better metals to contain more horsepower/thrust as better fuels developed higher compression ratios and better metals stopped the engines falling apart. This is the story of steel (crankshafts, conrods, exhaust valves) & forging practice (aluminium, magnesium, pistons – cast v forged) for better grainflow. Graphs of HP(eventually thrust)/Engine weight illustrate progress. For jets/thrust it was all about controlling expansion of turbine blades, but that’s putting us into 1946.

Structures = better metals to manage higher speeds/greater forces. This is the evolution of duralumin alloys, monocoque structures versus faired over truss structures. This is the Uiver Douglas DC2 in the 1934 London Melbourne Air Race scaring the UK so Bristols made the ‘Britain First’-Blenheim and shifted the UK from steel structures to aluminium, co-incidental with the development of better duraluminium alloys in 1935.

There is so much in this topic, including national biases in material selection, that your friend might be better to confine the story to progress in one nation, and progress via ‘archetypes’ that illustrate use of materials. If its UK, 1935-45 :

Development of RR Merlin engine from 700HP to 2000HP. (plenty of literature)

Development of Bristol ‘Bulldog-Britain First-Blenheim-Beaufighter-Brabazon (brains to tap Barnwell, Frise and materials man (can’t think right now, shame, but he was self effacing and HUGELY influential through SBAC on all constructors)
or
Hawker Hind-Hurricane-Typhoon…(brains to tap Sigrist and Camm)
or, not forgetting wood
deHavilland Tiger Moth-Comet-Albatross-Mosquito-Vampire (brains to tap Bishop, dH)

I hope your friend makes a good fist of it as it EXPLAINS everything developed in WW2. All the ideas were already there in 1935, just the resources to rapidly develop these ideas became available with the reconfiguration of entire national incomes into the war effort.
The next big punch was the Space Race.
Go girl !

I need to answer this question

Let’s line up the pints and come out in 15 months ! I guess the first clarification is ‘to what end?’ The conversation can go different ways if it is about trying to identify the nationality of an anonymous scrap of fuselage dragged from the deep, in comparison to trying to find a modern substitute for a known historical material.

The answer : I am trying to help a young lady who is making a Doctoral Thesis on “the impact of the material evolution on aircraft performances between 1935 & 1945”. This is the reason why I am looking for information about aluminium composition, on English, German & French sides.

Thanks for your contributions;

GC

This thread is a gold…, I mean Bauxite, mine!

(bauxite is ore for aluminum )

aircraftclocks, have a Japanese friend who would do very Japanese things to see copies of that document.

Valiant spars & Viscounts too were strictly not 7075, but of the same Al-Zn family, DTD 683 I believe. Viscounts were resparred with L65 which is of the Al-Cu 2024 family. Mind you the first Viscount outer wing I saw at Weybridge that was due to be re-sparred was horrifically rivetted – double holes & rivets too long and ‘nailed’ over – no wonder it failed a ground stress test!
Viking wing spar joints I believe were also of DTD 683 & were known to have corrosion cracking way back in ’52 (?).
BTW Canberra ‘epsteins’ were known to crack in storage – not sure what the material was though.

Re V-bombers, only the Valiant was withdrawn early due to metallurgical problems, it is interesting to see this explanation. I have wondered if the same reason lay behind the rapid retirement of other aircraft in the same period, notably the early Hunters?

Aircraft clocks, would love to see it. From translating some Japanese dataplates, it peversely appears that wartime written Japanese is in dialects, which may be obtuse to the modern Japanese reader. Further, the translation of ‘hydraulic accumulator’ can be outrageous obfuscatory obtuseness which sends everybody into giggles. But it would be interesting to try. I have mixed emotions digging orks out of mud.

Interesting QldSpitty that 1930’s Douglas airliners are still flying in 8,563 locations and Boeing 1930’s airliners are flying in, um, 0. Apparently using quality materials meant you went broke. Sign me up for the first Boeing trip to the moon, with a big roll of masking tape.

Assuming that GILCOL is talking about WWII aircraft wreckage found in Europe 7075 type material is unlikely to be found and 2024 most likely for structural parts. 7075 was used to re-engineer the B-29 wing for the B-50 saving hundreds of pounds weight and I think it was used on later Super Constellation wings. Hadn’t realised it was involved in the Comet story. 2024 and 2014 do differ in composition

P & P
I have a WWII Japanese document on metals in use at the time. Only problem is that I can not read it and have not been able to OCR it in order to translate it. Will forward it to you so you can hopefully make more sense of it.

I cant stand the heat!!!
7075 in its full hardened state is not that easy to bend Passion san.Good for flat webs and what not.Why any forming that has to be done “HAS” to be done in its annealed state.Then ‘Heat treated” to bring it back to its full hardness.That plus steel fasteners in the spar would rapidly creating the intergranular corrosion shown on Japanese parts.
Fast forward to the mid 80,s when QANTAS Jumbo Jets had a problem with frames cracking around the forward fuselage area.Cause was fatigue cracking on the 2024 T3 material.A quick call to Boeing came back with the reply “Ummmmm will get back to you”..When Boeing finally got back QANTAS engineers said “Naaah we right mate we figured it out..Start remaking your frames in 7075 guys”…And born was the Work code “Section 41” to replace all frames from number 1 door foward.Spent many a day sucking up swarf from the avionics bay and replacing Hiloks as a Snork Tinbasher.

Zero

The problem with XRF, is that you need clean metal to get an accurate reading. If anybody has a Museum exhibit, and they are wondering why there is a 1 inch square of clean metal ground away, and security camera vision later shows Krusty the Clown creeping around, it is me with a handheld XRF.

I haven’t been able to do this to a full Zero yet, so I cannot confirm if the entire structure was made from 7075, but the historic literature would not support this. My understanding is that only the wing spars of the Zero were made from this material, called SuperDuraluminium in the land of Unit 731.

The problem with admitting that the Japanese were excellent, inventive metallurgists is all the effort that seemed to go into downplaying Japanese capabilities in the prewar period. Wartime intelligence analyses of captured Japanese aircraft do admit superb metal quality in captured engines, so I guess the boffins held a different view. To state that SuperDuralumin, renamed SAE 7075 in the US, was a Japanese invention, at least grudgingly concedes this. So we need to put that up with inventing vending machines for schoolgirl’s used underpants to bring things back to a proper sense of smug alignment.

Anyway, here pictured is a chunk of Zero spar from a known aircraft. If your Museum exhibit tilts over, I have been there !
The XRF results are rubbish, which is what happens when oxidation products are in the mix. Metals such as aluminium do not come up in XRF results, due to the selfish behaviour of electrons frustrating spectroscopy, buy alloying elements such as copper do, that help to infer the Aluminium alloy. In these results I would pay the Zinc, which is the indicator for SuperDuralumin, or 7075.

So thrilled was wartime Japan to press this high mechanical strength, fascinating, non temple bell requiring war winner into service that no thought went to inter-crystalline (electrolytic) corrosion between aluminium and zinc, slowly turning the wing spars to powder. It didn’t really matter, when every war was going to be won by Christmas. It did matter, when the Allies won the war, and used the wonder alloy 7075 in the deHavilland Comet structure, which significantly contributed to structural failures. Some say that 7075 killed the British airliner making industry, via the Comet tragedies and the delays ensuing from trying to figure it all out, while Douglas stuck with 2024 and forged ahead. I do understand that British V bombers, with 7075 spars, were retired early due to inter-crystalline corrosion, so the British taxpayer was ill served by this perfidious Japanese material.

So Zeros and 7075 Aluminium alloys were like War of the Worlds, where the Martians are undone by humble bacteria, and inter-crystalline osteo would have fixed Japanese mastery of the air, all in good time. Probably not a bright idea to have an original Zero flying on original wings.

Tricky Tony

Wartime shortages lead to exceptions and material compositions which are fascinating today, after a few pints.
What Germany did in 1945 in metallurgical terms was quite different to what it may have done in 1940.
It is poignant to read about how ancient brass temple bells were melted down in Japan to provide scarce copper to feed it’s war machine. Less poignant to reflect how many ancient Chinese antiquities were probably stolen and melted down for the same end.

Pictured is a handheld XRF reading taken from the fuselage of a Ki-61-1 Tony, which comes up with the modern equivalent of 6013, a low copper alloy.
Now 6013 may be used today to make a propellor spinner – it is a highly ductile material that can be deformed in the spinning process without wrinkling or cracking, and has enough strength developed after this cold working to perform its function of deflecting seagulls and holding up the layers of paint applied by warbird owners working up spiral spinner paint schemes.

For me, making a fuselage out of this material is less desirable than making it out of 2024, which develops far higher mechanical strength, weight for weight. Now a B-29 is made out of 2024. Maybe the reason you could drink some sake and run your Tony wing through the cockpit of a B-29 and fly away was the ductility of the Tony compared to the brittleness of the B-29.

The real reason was that they did not have enough copper, I guess. Some angry monk using jujitsu to keep the the scrappies away from the temple bell. Maybe a bright, bespectacled engineer in the Japanese aluminium mill making the sheet ran their low copper 6013 three times through the rollers to work harden it, which would be a clever way to turn mutton into lamb.

2014 has the same chemical composition as 2024 but the latter has higher mechanical strength, due to running twice through the mill, to work harden it. Running material twice increases costs in time and money, and it is difficult to do with bombs falling around your head. Now a lot of British structures designed in 1938 for use in 1940 are made from 2014 material, which hints at the lack of time and panic to re-arm that came after the Munich Crisis.

All these materials speak, if you put your ear really close.

“I am looking for information concerning the composition of Aluminum used during WWII on aircraft, something similar to the attachment, but on the English side, can you help”

Let’s line up the pints and come out in 15 months ! I guess the first clarification is ‘to what end?’ The conversation can go different ways if it is about trying to identify the nationality of an anonymous scrap of fuselage dragged from the deep, in comparison to trying to find a modern substitute for a known historical material.

Without being smart, a lot of weight is in an engine. If it was British and WW2, the Al components of the engine would largely be cast Hiduminium RR50.
If it was a British fuselage, the Al structure would be DTD390, basically modern Alclad 2024.

All these things are basically Duralumin, a copper-aluminium alloy, invented in Germany in 1913, and the same as the structure of a WW1 Zeppelin.
It is feasible to build Spitfires from melted Messerschmitts and vice versa.

For a specifically British explanation of materials, FT Hills Materials of Aircraft Construction, reprinted and updated from the early 30’s to immediate postwar, gives a good explanation. The language of modern materials is more American than anything else, so the afore mentioned ‘United States And British Commonwealth of Nations Aircraft Metals’ is a first step in aligning the identity of these historic British Standards with historic US Standards, then working up from there.

These standards and their chemical compositions AND mechanical characteristics, which help to explain a different designation for something chemically identical, are arrayed in the glittering treasure house of historical standards at www.silverbiplanes.com

7075 was used exclusively in Zero construction late 1930s.

Aviation’s story — quite possibly at the behest of the military — misses one key to the Zero’s success: its construction made use of high-zinc-content 7075 aluminum alloy, which had been secretly developed by Sumitomo and was significantly lighter than the 24S alloys used in the U.S. Better metals were not used worldwide until after the war.

http://aviationweek.com/blog/how-build-zero-1945

The American designations for aluminium alloys now seem dominant so this chart offering British equivalents might be useful. 2024 was the commonest aluminium/copper alloy from the time of the DC-3…higher strength 7075 (aluminium/zinc alloy) was introduced from the end of WWII (e.g used to re-engineer the B-29 wing for the B-50) (Al/Zn alloys invented in Japan, I learn)

https://www.aircraftmaterials.com/data/aluminium/alalu.html

and https://en.wikipedia.org/wiki/Aluminium_alloy explains what the various 1000, 2000, 3000 etc series mean, with applications

Maxim08

The publication I think you are referring to is;

“Engineering Handbook Series for Aircraft Repair, United States And British Commonwealth of Nations Aircraft Metals”, with a ref. no. of AN 01-1A-9. Copies dated 30 May 1944 and updated 12 February 1946.

There were a series of books published during WW2 giving, Canadian and Australian (maybe US too) equivalents to British metals. Had a copy, now gone, but this topic was discussed on this forum by ‘powerandpassion’ in one of his threads focused on metallurgy.

Regards
John

GILCOL, you (and some other Forumites) might be interested in these tables taken from RAE reports on Captured aircraft.
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Thanks guys
& have a good weekend
GC