Question Fantasy metallurgy

[Linguofreak]

I'm mulling over the idea of a fantasy setting that is in the bronze age as far as mundane extractive metallurgy and material science goes, but where lead-into-gold type magical alchemy is a thing and can be used to create elements and compounds that would otherwise be unavailable or rare given the setting's technological level. In the interests of making the metallurgy of the setting as interesting as possible, I'm trying to figure out answers to questions like the following:

1) What elements/compounds that a bronze-age civilization would not normally be able to refine would be useful if they had access to them? For example, gallium (which they wouldn't have access to) is as useless to such a society as mercury (which they would), because of the absurdly low melting point. Osmium would be useful for applications where sheer density would be required, but would be very difficult to work. Titanium could be quite useful, though I'm not exactly sure how easy of a time a bronze-age civilization would have working it.

2) What materials would be so useful as to "need" (for worldbuilding purposes) to be kept rare? In other words, if a metal (let's call it mithril) is super lightweight, easily workable, super strong, and can be produced from ton-for-ton from limestone with beef fat as an alchemical reagent, you're likely to have a fairly boring world: nobody makes anything out of anything but mithril, and if the neighborhood alchemist is selling roast beef out of the back window of his shop as a byproduct of mithril manufacture, nobody's going to be eating anything but beef either. If, on the other hand, mithril can only be produced ounce for pound from silver, which is not alchemically synthesizable and has to be produced the mundane way, and dragon liver is needed as an alchemical reagent, then mithril will be highly valued for its properties, but will not be available in anything like the quantities needed to replace everything else.

3) What exactly would gold be useful for if it could be cheaply produced from lead? Obviously, it would no longer be any good as currency. It would still be pretty, and would be good for applications where density is required, but its electrical usefulness wouldn't really be an asset in a pre-industrial society.

4) Assuming that the inputs (elements or compounds) can be produced alchemically, what real-world chemical reactions with interesting/useful products would be accessible to our hypothetical bronze-age civilization? For example, could normally inaccessible metals be liberated from their ores at temperatures obtainable in a bronze-age furnace with some reducing agent other than carbon?

 

[Andy44]

It's true that if anyone can make gold in their garden shed than it loses its value as a currency standard.

I think the drama for stories in such a setting would have to revolve around the fact that while you can produce synthetic gold or other precious metals, only certain people have the skills or ability to do so, right?

Kind of the way plutonium is in real life. (Maybe a bad example because plutonium wouldn't make a good currency metal due to its chemical toxicity and reactiveness, and is rather sought after for its use in weapons or energy production).

Otherwise, people would just start using some other substance as currency. Gold is both fairly hard to come by as well as pretty stable, so people would have to find something else with those qualities. Diamonds, possibly, or some other precious stone.

 

[Linguofreak]

It's true that if anyone can make gold in their garden shed than it loses its value as a currency standard.

I think the drama for stories in such a setting would have to revolve around the fact that while you can produce synthetic gold or other precious metals, only certain people have the skills or ability to do so, right?

Kind of the way plutonium is in real life. (Maybe a bad example because plutonium wouldn't make a good currency metal due to its chemical toxicity and reactiveness, and is rather sought after for its use in weapons or energy production).

Otherwise, people would just start using some other substance as currency. Gold is both fairly hard to come by as well as pretty stable, so people would have to find something else with those qualities. Diamonds, possibly, or some other precious stone.

Well, the idea is to have gold be worthless, but to have it around for other things (decoration, blunt weapons, etc).

Meanwhile, the role of currency would be filled by something unsynthesizable, or by something at the end of an expensive chain of reactions, that didn't have properties that justified its use for other things (like weaponry) at market prices.

 

[Hielor]

Given the density of gold, could there be any application where a gold core inside of a sturdier material (steel, for example) could be used when weight is desired? A warhammer with such a golden core (as in, a hammer used in war, not the space Orks etc) could be heavy but also smaller and more penetrating than a similar pure-steel one.

Not sure if that could be at all relevant, though.

 

[Linguofreak]

Given the density of gold, could there be any application where a gold core inside of a sturdier material (steel, for example) could be used when weight is desired? A warhammer with such a golden core (as in, a hammer used in war, not the space Orks etc) could be heavy but also smaller and more penetrating than a similar pure-steel one.

Not sure if that could be at all relevant, though.

Well, basically, anywhere where lead would be used for density IRL, gold would probably be used.

 

[Hielor]

Well, basically, anywhere where lead would be used for density IRL, gold would probably be used.

Gold is 1.7x as dense as lead and ~2.4x as dense as steel, so it might make things practical that wouldn't be practical with just lead alone (which is only ~1.4x as dense as steel). Moreover, gold is something like 1.6-2x as hard as lead.

So while in real life, melee weapons don't have lead cores to increase mass because the weight advantage over steel isn't worth the loss of structural integrity, if gold were cheap that might become a thing.

I am not a weapons designer so I have no idea if such a thing would be practical, but there you have it...

 

[jedidia]

1) What elements/compounds that a bronze-age civilization would not normally be able to refine would be useful if they had access to them? For example, gallium (which they wouldn't have access to) is as useless to such a society as mercury (which they would), because of the absurdly low melting point. Osmium would be useful for applications where sheer density would be required, but would be very difficult to work. Titanium could be quite useful, though I'm not exactly sure how easy of a time a bronze-age civilization would have working it.

It depends, really. The major difference between a bronze-age society and an iron-age society is not that the former doesn't have access to iron... it's that they haven't developed the technology needed to work iron (foremost a forge able to reach high enough temperatures to smelt the stuff).

As such, I highly doubt high-end alloy constituents like Titanium would be any use at all. Titanium on its own is not very useful (very brittle as far as I remember), and using it to reinforce alloy requires industrial grade forges able to reach its melting point of almost 1900 Kelvin.
In essence, if you want to keep the overall tech level bronze age, they must not be allowed to be able to forge iron, and by extension any other metal above its melting point. They might be able to make use of metals easily malleable without melting them, but any kind of alloys are pretty much off the table.
Aluminium on the other hand... Aluminium might be quite a game changer, but I don't have the time right now to think about implications too much. But Aluminium is definitely worth serious pondering.

Well, the idea is to have gold be worthless, but to have it around for other things (decoration, blunt weapons, etc).

Gold as a decorative material makes perfect sense, becuase its resistanace to corrosion. If cheap to synthesize, it might be used excessively. Due to its low melting point it's imaginable that it would be applied in a fashion similar to paint.

 

[Andy44]

Could you use gold to sheath the bottom of a ship for parasite control the way copper is used?

 

[Urwumpe]

Could you use gold to sheath the bottom of a ship for parasite control the way copper is used?

No. Copper has a specific chemical effect there. Just like you now use Zinc for keeping your ships brass propeller from falling off.

 

[jedidia]

Little addendum: I had a little terminology messup in my post above. Essentially, I'm refering to smelting as forging, when the two are not at all the same thing. Smelting is the process of liquifying a metal, usually either to separate it from undesired materials or to mix it with desired ones (i.e. making alloys).
Forging on the other hand is the process of shaping metal in a severly heated, but still far from liquid state.

As mentioned, a bronze age culture isn't able to smelt iron, not by a long shot in fact. Pretty much the entire key to unlocking the iron age is getting iron out of its ores, because iron doesn't naturally occur as a pure element. Not being able to do that implies temperatures below 1800 Kelvin, which is about the point at which you get iron from iron oxide, still some way below the actual melting point of iron.

But if they can get pure iron by alchemical means, they might be able to forge it. It doesn't seem to take much more than 1000 Kelvin to get iron into a halfways malleable state. Which means they could also produce steel, since the process of carburisation doesn't require the iron to be in liquid state.
So yeah, watch it with that iron if you want to keep your bronze age vibe. If iron would have been naturally occuring in pure form, there wouldn't have been much of a bronze age. They'd just have skiped it. On the other hand, you can have steel weaponry, but you better watch out that it's properly expensive.

Getting your hands on aluminium (another element that does not occur naturally in a pure state in our world) during the bronze age, on the other hand, mixes things up a bit. If aluminium is easy enough to get, Aluminium Bronze (a copper aluminium alloy, as opposed to the traditional copper-tin) would probably be the most widely used material for tools and weapons.

And depending on how available zinc is, this bronze age could give the iron age a run for its money, if anybody figures out that the right ratios of aluminium and zinc produce an alloy that is almost as strong as steel, but is a lot more corrosion resistant and weighs less than half.
In any case, once they would make it through to iron age smelting tech, and have aluminium readily available, there's no telling what course the future history of their metalurgy would take. Once they have iron without the barrier of some of the most useful steel alloy ingredients being really difficult to get out of their ores, they might have aviation-grade alloys a mere 100 or 200 years later. All it would take would be enough time to experiment.

Well, that addendum didn't turn out to be so little after all...

---------- Post added at 10:00 PM ---------- Previous post was at 09:48 PM ----------

Could you use gold to sheath the bottom of a ship for parasite control the way copper is used?

No, but if Gold were as common as lead, the roman empire might have survived somewhat longer due to avoiding the whole lead poisoning thing in their aquaeducts.

EDIT: Or not. I just realised that the melting point of gold is actually not as low as I thought it was, not by a long shot. I guess I had the misconception because the stuff was so bloody soft.
But honestly, I don't know how the romans made their lead pipes. Did they cast them, or did they just hammer them? If the second, gold would still be a viable alternative.

ANOTHER EDIT:
Talking about replacing lead pipes with gold pipes above, and then remembering that the setting might literally allow turning lead into gold, there's a question that must be asked about the transfiguration rules that turns out to be of major importance:
Can the shape of the transfigured material be predicted from the shape the material being transfigured currently has? If yes, there's a whole plethora of uses for it, not just for getting resources, but for actual manufacturing. Take lead, shape it, transfigure into something better suited like aluminium, instant ship hull!

 

[Linguofreak]

As such, I highly doubt high-end alloy constituents like Titanium would be any use at all. Titanium on its own is not very useful (very brittle as far as I remember)

Wikipedia says it is quite ductile "especially in oxygen free environments". It also apparently burns in both oxygenated air and in pure nitrogen at fairly low temperatures (compared to its melting point). From this it seems that it can be worked without melting it once it has been extracted from its ore, but I'm not sure if this can be done in anything resembling a traditional forge, or if it requires a working environment filed with argon or something. If it's somewhat ductile in normal air at temperatures below its burning point, it could probably be useful for a bronze-age culture.

In essence, if you want to keep the overall tech level bronze age, they must not be allowed to be able to forge iron, and by extension any other metal above its melting point.

I'm not necessarily looking to keep a bronze-age tech level so much as I'm trying to get an alternate-iron-age with:

1) A diverse, and, to real-world eyes, unusual selection of materials available.

2) No materials inaccessible to the bronze age available by completely mundane means. Iron might be available alchemically, and might be mundanely smeltable with hot-burning fuels obtained alchemically, but these people wouldn't know how to extract iron without using alchemy somewhere in the process.

They might be able to make use of metals easily malleable without melting them, but any kind of alloys are pretty much off the table.

Not necessarily. Alloys could be alchemical products. But you'd get one mixture, you wouldn't have the ability to chose exact percentages of components like you can with modern alloys produced mundanely, and transmitting an alloy wouldn't necessarily give the same product (or use the same reagents) as transmuting its components. There might be an alchemical process that turns copper into steel and one that turns tin into chromium, but transmuting tin bronze might give you pure vanadium rather than stainless steel.

---------- Post added at 23:07 ---------- Previous post was at 23:03 ----------

No. Copper has a specific chemical effect there. Just like you now use Zinc for keeping your ships brass propeller from falling off.

To be specific, I believe the chemical effect has to do with the copper corroding, so the incorrodability of gold would be problematic here.

---------- Post added 03-13-17 at 00:25 ---------- Previous post was 03-12-17 at 23:07 ----------

. Smelting is the process of liquifying a metal, usually either to separate it from undesired materials or to mix it with desired ones (i.e. making alloys).
Forging on the other hand is the process of shaping metal in a severly heated, but still far from liquid state.

Smelting is actually the process of chemically extracting a metal from its ore. For early-iron-age cultures this actually happens below the melting point of the iron they actually use, though there is some low-melting iron-carbon mix that does drip out, but isn't of much use once solidified (until it was figured out how to decarburize this product). You mention the process of smelting later on in your post, so you're familiar with the concept, but the word "smelting" refers to that process, not to melting the metal.

So yeah, watch it with that iron if you want to keep your bronze age vibe. If iron would have been naturally occuring in pure form, there wouldn't have been much of a bronze age.

Actually, native nickel-iron alloy from meteorites is found fairly often. It's still rare enough that there was a bronze age because of the expense of procuring iron, but it was used for tool and weapon making in the bronze age (but it was worth 40x its weight in silver, so it was also heavily used ornamentally).

Getting your hands on aluminium (another element that does not occur naturally in a pure state in our world) during the bronze age, on the other hand, mixes things up a bit.

Aluminum is also available natively, but in such small amounts that it wasn't discovered until a few hundred years ago, and was considered a precious metal until processes for extracting it were discovered. The capstone of the Washington monument is aluminum because of this: when the plans were drawn up, aluminum was still quite expensive. By the time it was completed, aluminum could be extracted cheaply.

ANOTHER EDIT:
Talking about replacing lead pipes with gold pipes above, and then remembering that the setting might literally allow turning lead into gold, there's a question that must be asked about the transfiguration rules that turns out to be of major importance:
Can the shape of the transfigured material be predicted from the shape the material being transfigured currently has? If yes, there's a whole plethora of uses for it, not just for getting resources, but for actual manufacturing. Take lead, shape it, transfigure into something better suited like aluminium, instant ship hull!

I haven't decided on this: one alternative would be to have just one input (aside from the magical reagents) transmuted into one output, in which case, if mass is to be conserved, the volume would have to shrink, probably leaving you with the product as a powder or "swiss cheese" (if going from a lighter to a dense material) that would have to be reworked. The other would be to require a non-magical reagent as feed mass for reactions producing a denser material, and to produce a waste product for reactions producing a less-dense material, and to keep the volume and shape of the transmuted object the same. But this might not always be helpful: If NaCl is your input, and your output is iron, you'd probably want to work the iron afterwards. If your input is copper and your output is diamond, you'd want to shape it before transmuting.

 

[Urwumpe]

To be specific, I believe the chemical effect has to do with the copper corroding, so the incorrodability of gold would be problematic here.

Not just that, copper also acts as bactericide. It is weakly toxic for most species, a human can consume only about 0.04 gram per day without damaging his health.

The fun is, the copper plating of ships didn't really have the intended effect, the paper and tar layer behind the copper did the job of keeping the shipworm away, but the copper prevented most other kinds of fouling that also happened in temperate waters.