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What is the hardest titanium alloy i can smelt myself? Answered


Recently ive been looking into titanium alloying, i have access to a large amount of chemically pure titanium scrap, and want to alloy it into the hardest possible alloy i can, so i can build some very tiny yet strong mechanical objects as well as a titanium knife.

the means by which i wish to produce the alloy is with an induction furnace

My problem is, ive google searched, but cant find what the hardest suitable titanium alloy is, previously i thought titanium steel was hardest, but then i learnt that titanium aluminium is the best. Everywhere indirect terms are used like "best" and "most " and often they only talk about pure titanium vs steel alloys. Im really confused. I just want to know what the hardest titanium alloy is.

What is the best titanium alloy i should make for use as a blade and for high strength structuring, e.g frame body for small robot i want to make as indestructable as possible.




Best Answer 5 years ago

Quoting from my handy dandy builder's reference,
"Grade 5 titanium, also known as Ti 6-4, is a commonly used titanium alloy with a chemical composition of 6% aluminium, 4% vanadium, 0.25%  iron, 0.2% oxygen, and the remainder titanium.
Applications: Blades, discs, rings, airframes, fasteners, components, vessels, cases, hubs and forgings."

That's not how material science works. Hard and strong are two different things. A hard material is very brittle which is good for somethings but can fracture easily in other applications. What sort of robot are you building (what will it do)?

From keytometals.com "The mechanical properties of titanium are more dependent on the phases present than they are on the actual composition of the alloy. Substitutional elements partially replace the titanium atoms in the lattice and in this manner alter the properties. In actuality, the amount of any and all phases present is better governed by the heating and cooling cycles than by this atom alteration"

Also indestructible is a binary 'property'. Either something is indestructible (technically impossible so we'll go with the more common "virtually indestructible") or it isn't.

You could just sell the scrap Ti and buy stock in the profiles you need?

Have you ever machined Ti before? Do you have access to or the money to buy carbide tools? Are you prepared to deal with a Ti fire? (Ti chips are quite flammable and can ignite solely from the heat generated during cutting and can only be extinguished with a FEM12 SC extinguisher or by allowing it to burn out.)

the robot will be small and lightweight, with a very small support structure, I want it to be as unbreakable as possible.
i am fermiliar with how to machine CP titanium, ill treat the alloy the same.

But what will the robot do, and where? Will it be subject to crushing, cutting, long drops, corrosives, etc.? What you are doing with it and the environment it will run in is the biggest factor in deciding what properties you need out of the metal.

"Best" and "most" are irrelevant if you don't know what strength your robot actually needs. Does it need the strongest titanium?

And even if you get the correct alloy by luck, how are you intending to extrude it in to usable materials?

ill cast, it, cut it, temper it, then use it. Currently the alternative being that i do the exact same with aluminium, ide rather make near indestructable titanium alloy.

I need a minimal amount of structure to make it more effective, and i dont need as much with titanium alloy framing. i can make that by casting flatbars then finishing it off.