Bay 12 Games Forum

Roraborialisforealis:
Yup, cotton candy, served by clowns as one might expect.

Squishynoob & nanomage:
I thought about manganese when writing the op, and became to conclusion that dwarves could probably not smelt it. It was before I thought about more exotic reductions, an also I didn't consider smelting it directly into alloys. So yeah, it probably could be done. Manganese could be used to make wonderful copper and iron alloys.

LostCosmonaut:
Good work, it is often hard to find elastic moduli for alloys. I take that the Modulus of elasticity refers specifically to Young's modulus, and MoR is shear modulus. I'm surprised to see that cast iron has so much lower stiffness than steel or pure iron. Cast iron could certainly be used by dwarves. If blast furnace type method of producing iron is ever implemented, cast iron could become a cheap material for furniture etc. Yellow brass has very high values, so high that it makes me wonder if they're correct. Cold rolling should not increase the materials stiffness.

It would be nice is you could provide us with ultimate tensile strength and tensile yield strength values for those materials. It would be easier to comparison with values from other sources easier.

Engineering books tend to have their material values in a bit shoddy way, at least in the books I have. They list values from different sources, and rarely mention how the tested material was formed. Heat treatment, work hardening etc can have a huge effect, especially on yield strength. Then again manufacturers often forget stuff like elastic moduli and Poisson's ratio, which are interesting from mechanics point of view.

Stiffness itself is actually not very important value when comparing performance of metals for weapons and armor, they only prevent deformation until the yield strength is reached. Pretty much all otherwise suitable metals are also stiff enough. For example if we had a material with identical yield strength as DF steel, but one third of its stiffness (~70GPa), it would deform three times as much until yield strength is reached. This means that at yield point it would still deform less than 1%, which is not enough to affect penetration significantly. If you'd hit so hard that the weapons would exceed their elastic limits, both would deform at same rate. Less stiff weapon would also absorb three times as much elastic energy at yield point, but I imagine these energies to be small anyway.

Roraborialisforealis:
That could work. Perhaps the categories could be defined in an init file, so that anyone could configure them as they will. One step forward would be that only materials that you actually have would show up in workshops ui etc.


Orakio:
Indeed, that is why I left W out of the original post. Tungsten mostly produced by reducing it with hydrogen because it is commercially viable. However, dwarves need not care about profit, they are powered more by insanity than greed. Dwarves could use some other reducing agent, for example carbon or perhaps sodium. Tungsten reduced with carbon would likely contain lots of carbides though, and sodiothermics sound like ‼fun‼. With some research more ways could be found. I don't know how high temperatures smelting W needs, but I'm pretty sure that it can be achieved at a temperature far below its melting point. For example iron can be reduced with in a bloomery at temperature of  ~1100ºC or below, with diminishing efficiency. More powerful reductant could likely work in even lover temperatures.

As you said, producing the oxide from ores is no problem, but actually using the smelted product is one. It is likely some sort of spongy mass too brittle to be forged, and has too high melting point to be melted into ignots. Somehow I can't imagine dorfs using powder metallurgy either. Tungsten can however form alloys with at least iron and nickel, so such alloys are the most likely utility dwarfs could have for W.


Uristocrat:
You never know , I think its better to over- rather than underestimate people. I've taken exactly two material science courses myself, and they aren't really helpful in this matter. They were more about choosing the right material for a certain task, rather than about the materials them selves.

(EDIT: fixed a typo)

I think we should not dwell too much on what Europeans used at some time in history when considering about what dwarves could use. True that platinum was not really know in medieval Europe, but I'd say that's mostly because they did not have access to it. And even if they did find some, it was probably just confused with silver. If platinum would occur say in river Tiber, I bet ancient Romans would have used it. Dwarves can more readily access some stuff than humans. Also the world that dwarves live in is not our world, things that are too rare to be meaningful here might not be so in the Planet of Dawning or whatnot. (tinkering with mineral scarcity can do wonders)

to Cthulhu Inc:
Iridium is found on meteorites in trace amounts, though the amount is significant when compared to earths crust. You might have heard of the K–T boundary, a layer of iridium rich soil which is thought to be from the meteorite that caused the extinction event. Anyway, I think the concentration on iridium on meteorites is too low to affect the mechanical properties. You might be thinking of so called meteoric iron. It is famously tough and strong, and it is a natural alloy of iron and nickel. Perhaps iron meteorites could be added to the game.

to peskyninja:
Magma generally contains metal oxides, some types more than others. Usually the concentrations are quite low However. How could it be implemented? Perhaps there could be a small chance, like 5% that a tile of magma cooled by water would turn into some metal ore rather than obsidian.

Hello everybody!

I was reading the modding forum the other day and noticed a few mods that add fictional metals to sort of "bridge the gap" as one modder put it, that exist between the properties of steel and adamantine. While i have nothing against adding fictional materials, it made me wonder why would you make materials up when we have plenty of unimplemented non-fictional materials.

I immediately thought of osmium and wolfram. Both are dense metals with attractive mechanical properties, and thus would probably make fine weapons. (Osmium is perhaps my favorite metal due to its spiffy blue tinge) I got mildly exited and started digging more information about metals, and I'll now share with you what I think is relevant.

I assume that dwarfs produce their metals mostly either by directly melting (or forging) native metals, or by thermal reduction of their ore. I couldn't quite ascertain the peak temperatures achievable by dwarven smelters, but its quite safe to assume that they can at least reach 1111°C, the temperature of magma. Most likely they can reach higher temperatures, such as 1538°C, the melting point of iron, otherwise it would be hard to make pig iron. Perhaps they can reach higher, like 1769°C to melt platinum. This might however be bit of a stretch, as dorfs could just forge the nuggets directly into ingots, rather than melting them. (Perhaps one day a more advanced forge might be added, one that would need something like mechanism and refractory bricks [for example from graphite, it would work better than one might think, adamantine would definitely work] in order to be built, but that's another topic)

I use terms like stiffness, tensile yield strength (TYS, unit MPa), ultimate tensile strength (UTS,MPa), toughness and hardness, you should have a basic idea of what they mean, otherwise the texts might be hard to read. I use Young's modulus (E,GPa) for stiffness. For things like collisions between weapons and armor, I feel that tensile strength is the most relevant. Well, actually compressive strength, but the values are identical as I only talk about metals, which can be considered isotropic. Hardness is a poorly defined term that describes the materials ability to resist deformation. I refer to a material that is fairly stiff and has high yield strength as hard. All these are important for weapons and armor, UTS less so for weapons, and stiffness for armor. Toughness tells us how much energy the material can absorb before it breaks; it proportional to strength and inversely proportional to stiffness.

Take everything with a grain of salt, I'm no expert. If something I write sounds completely idiotic, it quite likely is. Most of the numbers I state are either just form memory, of from my notes, both of which are pretty poorly sourced, but I think could find sources for most of them, so ask if you're interested. Also, the numbers are not directly comparable as there are differences in hardening, composition, etc, and some might just be false. I just add them to give you something to work with, otherwise this post would be a chain of “strong, even stronger, even...”, you get the idea.

Metals I list here could be divided into three rough categories: ones that definitely could be produced by dwarves and would definitely have some utility, to those that could be produced, but whose usefulness would be dubious, and those that would be sweet, but need some convoluted techniques to be produced. I however just spew them out in nonspecific order.

Nickel:
As we all know, dwarves can already make nickel in DF, they just don't really use it in ways they could. Nickel is one of those materials that should make dorfs drool all over their beards. On its own commercially pure nickel is about as dense, somewhat softer and less stiff than iron, but has higher ultimate tensile strength (up to 370 vs 450 annealed), and thus is tougher. Sounds like something I'd use for armor. It is also readily work hardened, to UTS beyond common steel.

However main dwarfiness of nickel is in its alloys. Cupronickel, alloy of copper and nickel (duh), offers high tensile strength (up to around 550 yield and 650 UTS in copper with around 1/4 nickel, when properly worked), thus making a fairly tough material potentially harder than DF steel, although not as strong. If alloyed with iron as alloy with around 1/3 nickel (Fe-36Ni, or Invar 36) could have TYS of 240-720 and UTS of 450-800 (annealed-hardened), and thus superior to common steel. It is less stiff (E≈140 vs.205GPa), and thus tougher. This would make fine weapons and even finer armor.

Chromium:
Extremely hard, strong, stiff and quite light (7.19 g/cm^3), chromium would seem like an extremely nice material for weapons. It's not very tough and is brittle at room temperature, but has impressive enough TYS (~950) compared to it's stiffness, that it could still absorb energy from blows. Brittle materials tricky in this sense, as they usually break suddenly, well below their potential strength. I sadly could not find a value for its compressive strength. Then again, due to its brittleness, extreme hardness and very high melting point (1907°C), pure chromium would be very hard to work with.

Chromite already exist in DF, but there are 2 hurdles to overcome. The smaller one is that chromite is also an ore of iron, thus any product would likely be an alloy of iron, and the iron would be hard to separate. Then again alloying into steel is the most like use for the metal so this is not a very big problem. The bigger problem is that in order to reduce chromite with carbon, you need very high temperature (perhaps around 1850°C), which would need some dwarven science to achieve, On the bright side you could also process chromite with an aluminothermic reaction (or possibly by utilizing sodium, but I'll get to that later). This would practically be sacrificing the preposterously valuable aluminum in order to get something with more applications. Dwarfy. Chromium does occur as a native metal in volcanic environments, probably formed much like native aluminum. As Cr is not as reactive as Al it might be slightly more abundant, but still very rare.

Alloying pure chromium with nickel (Cr:Ni 3:2) creates a brittle alloy with UTS up to 1000 (=TYS as brittle), thus potentially even better weapon material than pure chromium. When added to steel chromium makes it harder and easier to harden, it is quite hard to find specific values for alloys containing large amounts of only chromium. As a side mention adding cobalt to the mixture makes even more weaponariffic  metal, Cr-Co-Fe-Ni (1:2:1:1) alloys can have TYS>1000 and UTS>1300. Cobaltite exist DF, and it too can be formed into the metal via aluminothermic reaction.

Gah, all this writing is making my head spin..

Platinum metals:
Platinum is just one metal in a group of chemically similar metals. They all have more or less interesting properties, but I'll concentrate mostly on the two most interesting: Iridium and Osmium.
They have several notable properties, Osmium is the densest material known and Iridium the second densest by a very small margin. They are both very hard, strong, stiff (E≈529-550, 2.5 times that of steel!) and brittle. Work hardened iridium can reach UTS>2200, and platinum wire alloyed with 30% iridium can reach 2480, compared to that of pure platinum, 392. I could not find tensile strength values for osmium, which is a pity, but its Brinell hardness of 3920MPa gives a hint (iridium has mere 1670) I do have a note that says osmium has reached over 10GPa in compressive strength, but it doesn't mention the scale (materials are generally stronger at small scale).  Why I introduce these metals together is because they occur together as a native alloy. They are also found alloyed with platinum. Dorfs could utilize the native metal or separate it from platinum, which is not as hard as one might imagine. Both metals are insoluble to aqua regia, which dissolves platinum. Thus the crazy buggers could dissolve platinum and forge the residue into ingots, and perhaps later extract the platinum from the water of gods that is left behind (it's easy, just heat it). The powder would not actually be just iridium and osmium, it would also contain ruthenium and rhodium, two other platinum metals that are insoluble to aqua reqia. Producing aqua regia would need capability to make spirit of nitre and spirit of salt, well within the ability of dwarven alchemy I presume (as soon as it gets implemented). The resulting powder would however be preposterously hard to work into anything. Perhaps it could be alloyed into platinum to create the final product.

I actually modded this alloy into my DF as uristium ( I didn't have the heart to call it osmiridium or iridosmrhodruthenium, and also I didn't want to specify the composition). Its pretty effective, clearly better than steel, but worse than adamantine in edged weapons and armor. I haven't really modded the production in yet (if ever), I just made a reaction that produces 3 platinum and 1 uristium bar from 4 native platinum and a bucket of lye (close enough, its corrosive isn't it  ). I haven't gotten to test the reaction yet but dwarven traders have blessed me with the material.



So many metals to go and I have depleted my sanity, for now I hope. If there is interest, I could still do tungsten (hard, tough, strong, stiff & dense), arsenic & antimony (alloys for copper/bronze, cups for elves), sodium (interesting applications), perhaps some others too. Tell me what do you think?  Now I must rest, I cant remember when I last produced this much text, certainly never of my own volition.

(EDIT: fixed some errors)