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Fraunhofer develops new technology to make titanium cost effective

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October 18, 2012

Schematic of titanium pipes being formed

Schematic of titanium pipes being formed

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Titanium is a tremendously useful metal and very abundant, yet only 186,000 tonnes (205,030 tons) of it are produced a year and it’s not used very much outside of the aerospace field because it’s so expensive and difficult to forge. To correct this, a team led by André Albert at the Fraunhofer Institute for Surface Engineering in partnership with Thin Films (IST) in Braunschweig, Germany have developed a new process for hydroforming titanium at high temperatures in a single step that promises to make titanium more of an everyday material.

Titanium is wonderful stuff. It’s strong, lightweight, non-magnetic, remarkably corrosion resistant and it’s the ninth most common element on Earth. It’s perfect for aircraft, medical implants, surgical instruments, marine components and ridiculously light and strong spectacle frames. By rights, it should be as commonly employed as iron and aluminum, but it’s still so rare in everyday life that it’s used in jewelry in a way that aluminum isn't.

Titanium block (Image: Alchemist-hp via Wikimedia Commons)

Titanium block (Image: Alchemist-hp via Wikimedia Commons)

The problem is that titanium, for all its virtues, is very tricky to fabricate. For example, it melts at an impressive 1,668º C (3,034º F), which is great for supersonic aircraft. However, titanium catches fire at 1,200º C (2,190º F) and it will not only burn in air, it will even burn in nitrogen.

Worse, it’s a bit “sticky” when hot. According to André Albert, group leader for media based forming technologies at the Fraunhofer Institute for Machine Tools and Forming Technology (IWU) in Chemnitz, Germany, “titanium tends to adhere to the forming tools. This leads to major damage which can cause components to fail in the worst case scenario. This effect is amplified by the extremely high temperatures of up to 800º C (1,472º F), at which titanium has to be formed.”

The Guggenheim Museum Bilbao sheathed in titanium (Image: E. Goergen via Wikimedia Commons...

The Guggenheim Museum Bilbao sheathed in titanium (Image: E. Goergen via Wikimedia Commons)

What this means is that titanium is mostly worked by cold forming at low temperatures and then reheated to remove the resulting defects. Referring to the manufacture of car exhausts, Albert said, “forming titanium at room temperatures leads to severe cold work hardening of the processed pipe. In order to prevent cracking, the metal requires frequent treatment by means of recrystallization processes. This leads to extremely complex multi-stage forming processes which are not economically viable in large-volume production of exhaust systems. This microstructural change can be avoided at extremely high temperatures.”

Albert’s solution to these problems is a new hydroforming process using a 1.40 x 1.20 meter (55.11 x 47.24 in) forming tool made of nickel-based alloys that remain stable at over 800º C (1,472º F) without oxidizing. It’s coated with a special film a few micrometers thick that keeps the hot titanium from sticking to the tool.

A titanium spork (Image: Wtshymanski via Wikimedia Commons)

A titanium spork (Image: Wtshymanski via Wikimedia Commons)

Because titanium is so flammable, the process needs to be conducted in a special neutral gas atmosphere, but it means that titanium products like exhaust pipes can be forged by hydraulic pressure in a single step and in one place without cracking. Needless to say, this results in great savings.

Fraunhofer will be presenting the initial results of the project at the EuroBlech trade fair, October 23 to 27 in Hannover, Germany. If the promise of the new process works out, we may see titanium used for more things than fighter jets and sporks in the near future.

Source: Fraunhofer

About the Author
David Szondy David Szondy is a freelance writer based in Monroe, Washington. An award-winning playwright, he has contributed to Charged and iQ magazine and is the author of the website Tales of Future Past.   All articles by David Szondy
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8 Comments

David, you left out of your article an interesting fact about titanium. Everybody knows about its uses as a metal, but the single largest commercial use of titanium ores mined in the United States is in the creation of pigments. Titanium oxide is used to make white paint.

Alan Mudd
19th October, 2012 @ 09:44 am PDT

"Special film"? Come on Gizmag, commit journalism and leave the PFM (pure f-- magic, a technical term) out for the Popular Science crowd. If this was truly repeatable and commercializable, vs something out of a PhD's sandbox, the film would be identified...and should be openly shared if real science was involved.

solutions4circuits
19th October, 2012 @ 10:52 am PDT

this article is a little vague. first you say "hydroforming" with a special forming tool in neutral gases (which?) and then you say "forged by hydraulic pressure". the forming i'm used to uses pressure and sometimes spinning. i expected using water pressure to form. forging is usually considered heating to a high temperature and using tools to reshape the metal. so are they using hydraulic pressure to push specially coated tools into the titanium while it is heated in neutral gases???

notarichman
19th October, 2012 @ 11:41 am PDT

Alan, the purpose of the article to present an alterative to current forming process that works well at a lower temperatures and minimizes

damage to tooling as well as the material.

Paint pigments and the metal-forming processes are completely diferent processes.

Facebook User
19th October, 2012 @ 11:44 am PDT

Eventually, I would like to see more titanium in car components. It would result in tremendous weight savings, better handling and fuel savings. Heck, give me a titanium bicycle.

At that high temperature, even inert gasses like nitrogen react. They probably use another inert gas like argon which is 23 times more abundant than CO2 in the atmosphere (Wikipedia)!

As for the special coating, I doubt the Germans have something like this:

http://www.dailymail.co.uk/sciencetech/article-2145803/Starlite-heat-resistant-miracle-material-change-world--ingredients-kept-secret.html

Fretting Freddy the Ferret pressing the Fret
19th October, 2012 @ 04:42 pm PDT

Actually, it's not that hard to form titanium - if it was, you wouldn't see titanium watches or cheap jewelry available. Cheap ways of machining titanium where pioneered by CERN in the early '80s as they needed non-magnetic tools to work on their particle accelerator. Pretty much any CNC system can handle it with the right tooling.

What's actually holding titanium back is it's cost. It's very, very expensive to produce, even more than aluminum (and I don't think you can recycle it). Which is why it's mostly only used for smaller things unless the structural properties are required.

That said, working with titanium as a sheet material is very difficult (BTDT, not fun). It requires a lot of high heat to form, which makes it much harder to use in mass production. Maybe this will help for those types of applications. Then again, they now use high-temperature presses for HT steel...

Chris Maresca
20th October, 2012 @ 01:16 am PDT

Titanium bicycles already exist. They tend to be very expensive but used titanium bikes are affordable by many people. There are also titanium revolvers common in .38 calibers. Many people can not use them as the pistol is so lite in weight that the kick back is far more severe. Those revolvers are under $500. which puts them at the same price as less exotic pistols and they carry like a dream.

Jim Sadler
30th October, 2012 @ 09:30 am PDT

Titanium is great, but more advances have been made in the last few years with steel and aluminum to keep new technologies in titanium working/forming to be discovered. New high strength steel is being processed and put into cars due to the discoveries of altering its micro structure. Also Ferrari and Alcoa have been doing research for years on aluminum development and have avoided going down the total carbon fiber path like Lamborghini.

Fraunhofer had developed a process years ago for producing high strength metal foams. You don't hear anything about them anymore.

RESISTANCE
30th December, 2012 @ 03:58 pm PST
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