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Aluminum is the most common metal on Earth. Despite this fact, this element wasn't discovered until the 19th Century. This is because Aluminum is never naturally found in the ground. Instead, aluminum always binds with other elements and oxides like bauxite. Pure aluminum used to be a very valuable metal (even more than silver and gold). It was so valuable that the Emperor of France in the 1850s bragged that he had a set of aluminum dinner plates for only his most esteemed guests. It wasn't until the 1880s that an electrolytic process was discovered to generate a lot of pure aluminum.

Backstory aside, my point is that aluminum is very common but wasn't used until quite late in human history. What if the atomic structure of aluminum was slightly changed however so that it was a mostly non-reactive element like gold? Aluminum would then be available to almost every society and be used in early history and even prehistory. With aluminum being widely available and available far earlier, could it replace bronze as the go-to metal for early civilizations?

Aluminum has a melting point lower than bronze so 4th Millennium BC kilns could definitely melt aluminum. How would aluminum compare to bronze when it comes to valuable traits like hardness and elasticity and corrosion resistance? Would aluminum swords, shields, armor, and tools in general prove superior to bronze ones?

Edit: Let's just say that in 4,000 BC, a bored god instantly performed the Hall-Heroult process on all aluminum on Earth. Thus aluminum becomes liquified and becomes recycled pure aluminum that doesn't need to be separated from oxygen. That way, ancient people can use aluminum without needing electricity first. I just really want to know if aluminum would be a superior/inferior metal for ancient civilizations.

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    $\begingroup$ "What if the atomic structure of aluminum was slightly changed however so that it was a mostly non-reactive element like gold?" Then it would no longer be aluminium, it would be gold. The rest of the question makes no sense. Once you have mutated aluminium into a noble metal none of its properties stay the same. Hardness, softness, density, metling point and so on, everything changes. $\endgroup$
    – AlexP
    Aug 27, 2022 at 21:15
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    $\begingroup$ It wouldn’t be aluminum if it was non reactive… $\endgroup$
    – user71781
    Aug 27, 2022 at 21:16
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    $\begingroup$ This might have been the wrong way to ask the question. If you think about it, you already have an answer (You decided you wanted an aluminum age), and now you're asking us if it's... something... believable, possible, realistic, take your choice. In your imaginary world the answer is always yes and in the real world the answer is always no. Perhaps a better way to ask the question is, "rather than a bronze age, I'd like an aluminum age, what how would my alternate Earth have to change to allow that?" Rather than a solution asking for a blessing, that's a problem asking for a solution. $\endgroup$
    – JBH
    Aug 27, 2022 at 23:08
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    $\begingroup$ A better viewpoint or approach would have been 'could there have been an 'aluminum age' if there had been a way to purify aluminum earlier in the historical record?' For instance, a really cheap source of potassium and an easy way to produce a vacuum. $\endgroup$ Aug 28, 2022 at 1:23
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    $\begingroup$ There are definitely two questions here - one is about altering the properties of aluminium, the second is asking if aluminium alloys, if available earlier in the historical time line, could have competed with bronze. $\endgroup$ Aug 28, 2022 at 16:19

3 Answers 3

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If Aluminum was non-reactive, could there have been an "Aluminum Age" instead of a Bronze Age?

Sure, but that's just handwavium because...

What if the atomic structure of aluminum was slightly changed however so that it was a mostly non-reactive element like gold?

You can't tweak the atomic structure like that without simply turning into another element. That's like trying to tweak the number two to be mostly like the number three. Seems to me you should already be aware of this given your studies? It would be a lot more believable if you simply made up a ficticious process that just made aluminum a lot easier to refine.

"*Would aluminum swords, shields, armor, and tools in general prove superior to bronze ones?"

As far as equipping armies is concerned, it doesn't really matter if aluminum is inferior if it's that much cheaper. Remember that humans did not start out with steel, let alone modern steels. Humans started out with pig iron which was inferior to bronze. One soldier equipped with bronze isn't going to defeat two or three soldiers of equal skill equipped with aluminum.

I am pretty sure that aluminum would be inferior for weapons due to it's lower specific strength (which is specified per area and by extension affected by volume). Weapons, both edged and blunt, tend to want to focus as much strength, mass, or both into as small a volume as possible to maximize applied momentum or pressure and improve handling. You can find cutting tools (specifically non-sparking ones) made of copper alloys but never aluminum alloys.

(Note that virtually all "aluminum" in use is an alloyed. Unlike copper, pure aluminum only really has laboratory uses. Therefore the word "aluminum" in common usage really refers to "aluminum alloys").

The main strength advantage of aluminum comes into play when you have more empty space to work with so that you can take advantage of aluminum's lower density to use a greater volume of aluminum to make up for it's weaker specific strength without resulting in increased weight over its bronze equivalent. In doing so, you can take advantage of aspects of strength that scale with geometry (such the geometric relationship between thickness and rigidity). That means it's probably an advantage for armour. You're probably not going to mind the discomfort of your aluminum breastplate being twice as thick as a bronze one when it has 2/3 the weight.

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    $\begingroup$ "All day with the mighty sword / And the mighty steed and the mighty lance / All day with that heavy shield / And a pair of aluminum pants" — Sir Greenbaum's Madrigal (In Sherwood Forest There Dwelt a Knight) - YouTube $\endgroup$ Aug 28, 2022 at 2:51
  • $\begingroup$ I think that in comparing the strength of aluminum to bronze, you're missing an important thing: if aluminum was easily available, people could also have discovered alloys that were stronger than pure aluminum, like bronze is stronger than copper. $\endgroup$ Aug 28, 2022 at 9:12
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    $\begingroup$ @MichaelBorgwardt But aluminum and whatever metals would be used for alloying would need to all be easy to produce for this to make sense. Bronze was big because both copper and tin are dead simple to refine. A lot of the useful alloys of aluminum require elements that are also not exactly easy to refine (such as Manganese. Aluminum is also less than half as dense as bronze, which is not a desirable property in a weapon (even a sword), so the alloys would have to be significantly superior in some other way. $\endgroup$ Aug 28, 2022 at 12:36
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    $\begingroup$ @MichaelBorgwardt The strength comparison is not missing anything though perhaps some clarification should be made: Essentially all the "aluminum" you encounter and all bulk aluminum in usage is already alloyed. Therefore, in general language, "aluminum" does not refer to pure aluminum but its alloys. Pure aluminum only really has laboratory applications. OP has never handled pure aluminum (let's call that >99.5% pure) and if there is anyone on here that has, you could probably count them on less than one hand. And I largely use the term "aluminum" the same way in this answer. $\endgroup$
    – DKNguyen
    Aug 28, 2022 at 17:09
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    $\begingroup$ Except aluminum wire maybe. Certainly all blocks, bars, rods and other chunks of of aluminum encountered is an alloy. $\endgroup$
    – DKNguyen
    Aug 28, 2022 at 17:11
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Aside from the issues others have raised with how you proposed to make aluminum more available...

Tin was easy to smelt and used on its own for many objects, but tin was not particularly useful for armor or weapons. Tin and copper were used to make bronze because copper-tin bronze had far superior mechanical properties. Copper-aluminum bronze has similar advantages, and if aluminum was similarly available as tin to the ancients, they would likely have made aluminum bronzes, rather than trying to make weapons and armor out of plain aluminum.

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    $\begingroup$ Indeed, in large parts of the world copper was relatively common, but tin nonexistent (as easily extractable for their technology), and had to be traded for, from long distances. $\endgroup$
    – vsz
    Aug 29, 2022 at 0:09
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My understanding is that the reason that aluminium wasn't used until after industrialization was that the refining process was energy intensive and a pre-requisite is the discovery of electricity because it can't be extracted from ore\refined in the same way as most other metals.

So, I'd say that your society would need to be industrialized or to use a magic substitute.

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    $\begingroup$ Yes, the refining process was energy intensive. However, the whole point of the question is that the energy intensive refining process is only required because Al is a reactive element that binds naturally to other elements. The OP is asking about a handwavium Al that is not reactive and therefore occurs naturally in relatively pure form. $\endgroup$ Aug 28, 2022 at 7:52
  • $\begingroup$ It would still require electricity to refine it, otherwise it would be unobtanium, not aluminium. $\endgroup$ Aug 28, 2022 at 9:55
  • $\begingroup$ A simple voltaic cell provides enough to do the trick. It depends on how much aluminium you want to produce, and on what scale. By the 1900's, it had to be manufactured on a huge scale. Before the bronze age, not so much. It is all about fortuitous discovery, not hard science. $\endgroup$ Aug 28, 2022 at 16:10
  • $\begingroup$ @AaarghZombies why would it still require electricity? $\endgroup$
    – Eugene
    Aug 29, 2022 at 0:09
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    $\begingroup$ Because it's aluminium. If it didn't it would be another metal. $\endgroup$ Aug 29, 2022 at 11:09

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