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The Story of Titanium – by Brian Potter

The Story of Titanium – by Brian Potter

2023-11-23 10:43:25

The earth incorporates a number of titanium – it’s the ninth most abundant element within the earth’s crust. By mass, there’s extra titanium within the earth’s crust than carbon by an element of almost 30, and extra titanium than copper by an element of almost 100.

However regardless of its abundance, it is solely just lately that civilization has been in a position to make use of titanium as a metallic (titanium dioxide has been in use considerably longer as a paint pigment). As a result of titanium so readily bonds with oxygen and different components, it doesn’t happen in any respect in metallic type in nature. One engineer described titanium as a “streetwalker,” as a result of it should decide up something and all the pieces. Whereas copper has been utilized by civilization since 7000 BC, and iron since round 3000 BC, titanium wasn’t found till the late 1700s, and wasn’t produced in metallic type till the late nineteenth century. As late as 1945, there was no business manufacturing of titanium, and the metallic solely existed in tiny quantities in labs. However lower than 10 years later, 1000’s of tons of it had been being made a 12 months. And 10 years after that, it fashioned the literal spine of probably the most superior aerospace know-how on the planet.

As a report back to the National Research Council notes, “the beginning of a tonnage structural metallic trade is an uncommon occasion. Solely three such births have occurred previously 100 years [now closer to 150] – aluminum, magnesium, and titanium – and no new one is in prospect.” How did titanium go from completely unused to a essential aerospace know-how? What does it inform us about technological growth? Let’s have a look.

Titanium was first found in 1790 by William Gregor, an English clergyman and chemist who realized he couldn’t establish a metallic contained in a white oxide combined in with the black sands of Cornwall. In 1795, Martin Klaproth, a Prussian chemist, was capable of extract titanium from the mineral rutile. Due to the sturdy bond it fashioned with oxygen, Klaproth named the metallic “titanium” after the Greek Titans.

As a result of titanium bonds so readily with different components and contaminates so simply, it is extraordinarily troublesome to acquire in a pure state, and for the subsequent hundred years titanium was principally thought to be a laboratory curiosity. Within the Eighteen Eighties, two Swedish scientists efficiently produced 94% pure titanium metallic, and in 1910 Matthew Hunter, a scientist at Common Electrical, developed a variant of their course of to provide metallic titanium whereas looking for a fabric for improved lightbulb filaments.

However a commercially viable course of for producing titanium wasn’t developed till the Thirties. In 1930 William Kroll, a scientist from Luxembourg, started experimenting with titanium in his house lab, and developed a course of to provide titanium by reacting titanium chloride (TiCl4) with magnesium below a vacuum. By 1938, he had efficiently produced 50 kilos of titanium metallic, and efficiently fashioned it into wires, rods, sheets, and plating. Kroll got here to the US in 1938 to try to promote his course of, however was unsuccessful.

Kroll’s samples of titanium metallic in 1938, through Kroll 1955

That very same 12 months, the US Bureau of Mines started to research titanium, in response to promising research of its properties carried out by the Philips Company (which had developed its personal course of for producing titanium). The Bureau of Mines concluded the Kroll course of had probably the most potential as a business course of and started to develop it. Its work was delayed by the warfare, however as early as 1944 the Bureau of Mines was making 15-pound batches of titanium in a plant that might make 100 kilos of titanium per week.

After the warfare, the Bureau’s work on titanium accelerated. By 1947 it had efficiently scaled up Kroll’s course of, and had produced two tons of titanium “sponge,” a porous, spongy metallic created by the method, which is melted down to provide bars, sheets, wires, and so on. A 1948 report on titanium’s properties commissioned by the Bureau concluded that titanium and its alloys had nice potential engineering functions. Titanium was almost as sturdy as stainless-steel, however weighed 40% much less. It was additionally extremely corrosion-resistant, and maintained far more energy at elevated temperatures in comparison with aluminum. This made it probably very helpful for aerospace functions, the place weight was at a premium and supplies had been usually uncovered to excessive temperatures.

The navy had adopted the progress of the Bureau’s growth work, and curiosity within the metallic was excessive after samples started to be investigated by Military, Navy, and Air Drive labs. Titanium started to be known as a “surprise metallic”:

The metallic gained quite a few advocates inside the navy and trade. Early promoters visualized the usage of titanium in naval vessels, armor plate, tanks, vans, touchdown craft, plane constructions, and airborne gear. It was thought that it may presumably exchange each aluminum and metal within the design of many protection functions. – Simcoe 2018

In 1948, titanium first started to be produced commercially, at a small DuPont plant that might produce 100 kilos of titanium a day. The primary batches of titanium went to experimental use on navy jets, such because the F-84 and the F-86. To attempt to kickstart the trade, the Air Drive inspired producers to substitute metal with titanium, and the Military Ordnance Company positioned an order for $1 million price of titanium metallic.

F-84, through wikipedia

Within the press, titanium started to be known as “the surprise metallic,” “the miracle metallic,” and the “Cinderella metallic” (as a result of it had been neglected for therefore lengthy). An government for an organization producing titanium famous that “Sensational journal articles predicted that titanium would change into the miracle metal-for spacecraft, ‘atomic furnaces,’ airplanes of every kind, submarines, railroad tracks, truck our bodies, moveable bridges” (Rowley 1972). Between 1950 and 1952, greater than two dozen firms introduced plans to provide titanium.

However the nascent titanium trade struggled. In 1951, the supplies advisory board projected the necessity for 30,000 tons of titanium merchandise, however precise shipments had been simply 75 tons, barely sufficient for analysis functions. Producers had assumed that the identical gear for melting, rolling, and shaping stainless-steel might be used for titanium, however this turned out to be very troublesome: titanium didn’t behave like metal, or like another metallic. Titanium was discovered “to not forge like another materials,” (DTIC 1952) and stamping it in presses broken the stamping dies. An organization that studied grinding titanium famous that “titanium grinds not like metal. Something you have got realized in regards to the efficient grinding of metal doesn’t apply within the case of titanium”. The primary makes an attempt to make use of titanium on business plane resulted in a sheet of metallic so brittle it might be torn in half like a sheet of paper. Mills discovered that they usually “produced extra scrap than helpful metallic” (Simcoe 2018).

To help the budding trade, the US authorities stepped in. It funded the development of a number of titanium sponge crops, and agreed to buy any surplus titanium sponge manufacturing for the nationwide stockpile. It provided speedy amortization of titanium manufacturing gear for tax functions, and demonstrated manufacturing strategies on the Bureau of Mines’ pilot plant. The Military funded initiatives to develop higher alloys, together with one in every of 6% aluminum and 4% vanadium (Ti-6Al-4V) that is still the preferred alloy of titanium as we speak, and is credited with saving the titanium trade. When it was discovered that rolling titanium into sheets constantly was troublesome, in 1956 the Division of Protection initiated a program to develop sheet rolling of titanium, “one of the vital complete technical applications ever undertaken in metallurgy” (Simcoe 2018). Manufacturing issues had been overcome, and titanium was more and more used for aerospace functions. By 1958, Pratt and Whitney had produced 5000 jet engines with titanium elements, and the US trade was producing 1000’s of tons of titanium merchandise a 12 months.

A-12, through Wikipedia

Within the late Fifties, Lockheed received a contract to develop a high-speed, excessive altitude reconnaissance aircraft for the CIA. As a result of it was the twelfth iteration of a design codenamed “Archangel,” it turned often called the A-12. To satisfy the unprecedented efficiency necessities (a cruising pace of Mach 3 and a cruising altitude of almost 90,000 toes), Lockheed wanted a metallic that may retain its energy on the lots of of levels the outside of the aircraft would attain. This dominated out aluminum, leaving both stainless-steel or titanium. Finally, titanium alloy was chosen for the A-12, as it will lower the gross weight of the aircraft almost in half.

Titanium had by no means been used to such an extent on an plane, or wherever else. Lockheed had labored with titanium on a small scale since 1949 however previous to the A-12 titanium had principally been used for small elements on jet engines. For a number of years, as an example, 50% of all titanium was used within the J-57 jet engine. However on the A-12, titanium could be used for almost each a part of the airplane – 93% of the gross weight of the A-12’s construction was titanium.

Constructing a aircraft out of titanium proved troublesome. Initially Lockheed “had no thought find out how to extrude it, push it by into varied shapes, or weld or rivet or drill it” (Wealthy 1994), and each manufacturing downside solved appeared to disclose two or three extra. Titanium was discovered to be “completely incompatible” with chemical compounds like chlorine, fluorine, and cadmium. In a single case, an engineer who marked a sheet of titanium utilizing a pen with chlorine-based ink was shocked to see the ink etch away the metallic like acid. Titanium bolts that had been heated had their heads pop off, an issue that was ultimately traced to cadmium-coated wrenches used to tighten them. Titanium welds made in the summertime unexpectedly failed, as a result of (it was ultimately realized) chlorine that the native utility added to the water in the course of the summer season to forestall algae development.

When Lockheed tried to manufacture a portion of the ahead fuselage, which needed to be produced from a novel “beta” titanium alloy, it discovered that the titanium was so brittle after warmth treating that it will shatter if dropped on the ground. This was ultimately resolved by changing an acid-pickling course of with one similar to that of Lockheed’s provider, however not earlier than scrapping 1000’s of titanium elements. Of the primary 6000 items fabricated from the beta titanium alloy, 95% had been misplaced.

However over time, Lockheed overcame its manufacturing issues. In machining, as an example, drill bits initially wanted to get replaced each ten holes, ten instances as usually as when drilling aluminum. In different machining operations, the speed of metallic elimination was simply 5% of the speed when machining aluminum. To enhance its machining, Lockheed developed new drill bits, reducing fluids, and reducing equipment, and realized the right “feeds and speeds” for machining titanium (it was discovered, as an example, that small adjustments in reducing pace had a big impact on device life). Over the course of this system, the speed of metallic elimination in machining was elevated to “3 to 10 instances the trade common” (Johnson 1970), and drill life was elevated by greater than an element of 10.

The A-12 “virtually spawned its personal industrial base” (CIA 2012), and over the course of this system 1000’s of machinists, mechanics, fabricators, and different personnel had been educated in find out how to work with titanium effectively. As Lockheed gained manufacturing expertise with titanium, it issued studies to the Air Drive and to its distributors on manufacturing strategies, and “arrange coaching courses for machinists, an entire analysis facility for growing instruments and procedures, and issued analysis contracts to competent exterior distributors to develop improved gear” (Johnson 1970).

The A-12 first flew in 1962. 14 years later, its successor, the better-known SR-71, set an airspeed document of almost 2200 miles per hour, which stays unbroken as we speak.

Whereas titanium manufacturing for aerospace was ramping up, a really totally different use of the metallic was being found. In 1952, Swedish medical researcher Per-Ingvar Brånemark was learning blood move in therapeutic bones. In a single experiment learning the bone marrow of rabbits, Brånemark’s crew implanted a tiny digicam into rabbits legs, to observe the wound heal from the within. Once they later went to take away the digicam, they discovered that the titanium digicam casing had bonded with the bone.

On the time, it was thought that the physique would ultimately reject any overseas object implanted in it. Dr. Brånemark’s discovery that bone would bond immediately with titanium (which he dubbed “osseointegration”) was radical, and had enormous potential implications for medical implants. Brånemark shortly pivoted his analysis to review osseointegration, ultimately receiving a grant from the US Nationwide Institutes of Well being. Analysis on his personal college students (the place he implanted a small piece of titanium of their arms) confirmed that titanium might be safely implanted within the physique with no ill-effects.

Apparently, in the course of the course of this analysis, it was observed that bone may conduct sound – a deaf affected person was capable of “hear” the ultrasonic vibrations used to examine that the titanium had been implanted accurately. Considered one of Brånemark’s college students adopted up on this discovery, and developed the primary bone conduction implants to revive listening to in deaf individuals.

Brånemark’s crew went on to develop titanium dental implants (which had been usually produced from surplus aircraft-grade titanium) that lasted for much longer than implants of different metals. At the moment, the Brånemark system of dental implants remains to be bought, and titanium is the preferred materials for dental implants, in addition to getting used for different medical implants resembling artificial hips.

You may get a way of the event of the titanium trade by studying studies on industrial symposiums held within the Nineteen Forties, 50s, and 60s.

The first symposium on titanium was held in 1948, and was organized by the Navy to offer “a complete overview of the titanium analysis effort”. A number of navy organizations mentioned their analysis applications, however many of the shows had been on matters resembling bodily properties of titanium and its varied alloys, the crystal construction that resulted from totally different strategies of fabrication, and strategies of melting titanium sponge. The pages are full of images of laboratory setups, graphs of knowledge on stress-strain relationships, section diagrams, and magnified footage of titanium microstructure. Practically all of the shows are from both analysis labs or from firms attempting to provide uncooked titanium “sponge” from ore.

In 1952, another titanium symposium was held, this one sponsored by the Military’s Watertown Arsenal. By then, titanium was being manufactured in massive portions, and whereas the prior symposium had been targeted on laboratory research of titanium’s bodily and chemical properties, the 1952 symposium was a “sensible dialogue of the properties, processing, machinability, and comparable traits of titanium”. Whereas bodily traits of titanium nonetheless took middle stage, there was a sensible slant to the discussions – how broad a sheet of titanium might be produced, how massive an ingot of it may be made, how can or not it’s cast, or pressed, or welded, and so forth. Shows had been by titanium fabricators, but in addition by metalworking firms that had been experimenting with the metallic. 

Although by 1952 many of those firms had been working with titanium for years, there’s an air of uncertainty in most of the shows, a definite sense of “that is what we’ve realized to this point, however there’s nonetheless a lot we don’t know.” An organization that studied the consequences of various working fluids when grinding titanium admitted that not sufficient was identified concerning the chemistry at work to grasp why totally different fluids had totally different results. An organization that studied floor therapies and sprucing strategies famous that “supplies and strategies for sprucing titanium haven’t been definitively established,” and that whereas “probably the most generally used abrasives usually are not fully passable,” producers had been engaged on the issue, and “extra environment friendly strategies will little question be developed”. An organization that studied cold-forming of titanium sheets described its personal strategies as “crude and undeveloped”.

In 1966, another titanium symposium was held, this one sponsored by the Northrup Company. By this time, titanium had been used efficiently for a few years, and the aim of this symposium was to “present technical personnel of diversified disciplines with a working information of titanium know-how.” This time, the lion’s share of the shows are by aerospace firms skilled in working with the metallic, and the unsure air that existed within the 1952 symposium is gone. A presenter on titanium’s corrosion resistance famous that “the corrosion resistance of titanium, not like that of most metals, might be outlined inside relatively easy limits.” A presentation on forging famous that “titanium alloys are fairly forgeable…The proof which substantiates this assertion is the massive variety of jet engine and missile elements plus the rising lists of structural elements which have been produced within the final 10 years.” And a presentation on machining famous that “Fifteen years in the past, titanium was thought of to be very troublesome to machine. Subsequent analysis and expertise, nonetheless, have progressively improved this example,” the results of “gradual refinements in device supplies, machine instruments, device geometries, and reducing fluids”.

Thus, by the mid-Nineteen Sixties, titanium had change into a mature engineering materials. Whereas there was nonetheless a lot to find out about titanium, the sensible points of working with it and utilizing it to unravel engineering issues had been well-understood, and it more and more discovered use in aerospace and different trade functions. Following the A-12, as an example, navy plane started to make intensive use of titanium of their structural frames. From navy plane, titanium made its manner into business plane. By 1971, 46% of titanium was going in the direction of business plane, in comparison with 37% to authorities aerospace initiatives.

What can we be taught from the story of titanium?

For one, titanium is a authorities analysis success story. Titanium metallic was primarily willed into existence by the US authorities, which looked for a promising manufacturing course of, efficiently scaled it up when it discovered one, and carried out a lot of the preliminary analysis on titanium’s materials properties, potential alloys, and manufacturing strategies. Practically all early demand for titanium was for presidency aerospace initiatives, and when the nascent trade struggled, the federal government stepped in to subsidize manufacturing. Because of this, titanium achieved a degree of manufacturing in 10 years that took aluminum and magnesium almost 30.

The federal government’s help of the early trade was profitable: shortly after this system was initiated in 1951, the price of titanium started to say no extra steeply. Since then, titanium prices have fallen at a powerful 23% studying price (ie: prices fall 23% each time cumulative manufacturing doubles), just like the training price in photo voltaic PV manufacturing. When authorities subsidies had been eliminated within the late Fifties, the trade struggled, however price declines continued. And from the preliminary authorities initiatives in navy aerospace, titanium has unfold into business plane, medical implants, industrial gear, and different makes use of. Titanium is thus a profitable case of the federal government jumpstarting an trade.

By way of USGS information

However titanium can be a narrative concerning the limits of this form of jumpstarting. Regardless of its spectacular studying price, titanium stays an costly, area of interest materials. A 2006 report famous that titanium is 5 instances as costly as aluminum to refine and ten instances as costly as aluminum to show into completed merchandise. Regardless of preliminary expectations, titanium hasn’t broadly displaced both aluminum or stainless-steel, and is barely used the place its distinctive properties make its excessive price price it. The aerospace trade stays the biggest consumer of titanium.

It is fascinating to match progress in titanium manufacturing with progress in photo voltaic photovoltaics. In each circumstances, the fundamental phenomenon (metallic titanium and producing electrical energy from daylight) had been explored within the late 1800s, nevertheless it wasn’t till mid-Twentieth century know-how breakthroughs (the Kroll course of and the silicon PV cell) that they turned sensible. In each circumstances, the US authorities funded a lot of the preliminary growth, and acted as the primary buyer (authorities satellites and authorities aerospace initiatives). Each have comparable studying curve slopes, and each applied sciences progressively expanded exterior of their preliminary markets as information was gained and the prices of the know-how fell. And in each circumstances, there have been sky-high expectations for the “probably world-changing know-how” that neither initially lived as much as.

However whereas titanium stays a comparatively area of interest, costly know-how, photo voltaic PV is more and more broadly deployed, and appears poised to change into the first technique of electrical energy manufacturing. In studying curve phrases, whereas each titanium and photo voltaic PV have comparable studying charges, the photo voltaic PV curve has stretched a lot farther. Between 1975 and as we speak, cumulative titanium manufacturing has elevated by maybe an element of 5-10 (cumulative US consumption of titanium sponge was about 250,000 tons in 1975, and about 1.3 million tons in 2019). Cumulative photo voltaic PV manufacturing, however, has elevated by an element of greater than 300,000. Although they’ve the identical studying price, photo voltaic PV has had many extra doublings in manufacturing quantity, and its prices have thus fallen a lot additional.

I can see at the least two potential components right here. One is that photo voltaic PV manufacturing has seen a a lot higher degree of presidency help than titanium manufacturing has. Along with early authorities help within the Fifties, photo voltaic PV additionally noticed US and Japanese authorities funding within the Nineteen Seventies, and German authorities help within the Nineteen Nineties (through a beneficiant feed-in tariff). At the moment, governments all over the world help photo voltaic PV through feed in tariffs, tax credit, and renewable portfolio requirements. Continued authorities subsidies have incentivized elevated manufacturing, which has resulted within the prices of photo voltaic PV persevering with to fall. With out that authorities help, the extent of manufacturing of photo voltaic PV would have been a lot decrease, and its march down the training curve would have occurred far more slowly.

Titanium, however, has seen a lot much less authorities help. After subsidies had been withdrawn within the late Fifties, the titanium trade has been depending on massive authorities or business aerospace initiatives. If these fail to materialize (resembling when Chilly Battle technique pivoted from bombers to missiles, or when supersonic business plane growth was canceled), the trade has struggled. If authorities help of the trade had continued, maybe it will be farther alongside on its studying curve.

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The opposite potential issue is technical: whereas there are a lot of potential course of enhancements to photo voltaic PV manufacturing, there could also be considerably fewer potential enhancements in titanium manufacturing. Within the Fifties, it was hoped/assumed that a greater course of for producing titanium sponge would come alongside to interchange the Kroll course of, which is a laborious and energy-intensive batch course of that have to be performed in an inert environment. However such a course of has by no means materialized, and the Kroll course of stays the first technique of refining titanium ore. Likewise, turning titanium sponge into metallic is an power and capital-intensive course of, usually requiring a number of rounds of melting the metallic to attain ample purity. This course of has additionally modified little for the reason that Fifties.

Past the dearth of course of enhancements, titanium is simply essentially troublesome and costly to take care of. Turning titanium ingots into bars and sheets is a problem as a result of titanium’s reactivity: it readily absorbs impurities, requiring “frequent floor elimination and trimming to remove floor defects” that are “expensive and contain important yield loss.” Machining titanium is likewise essentially costly. As one report notes:

The hardness that makes titanium so fascinating additionally makes it harder to machine than conventional aluminum. This presents a problem akin to that of machining high-strength metal. Nonetheless, the method is difficult by titanium’s excessive reactivity and low thermal conductivity. It’s extremely reactive and tends to put on instruments in a short time, particularly at larger temperatures. The low thermal conductivity signifies that excessive temperatures might be generated simply in the middle of machining. Consequently, titanium have to be machined at decrease device speeds, slowing manufacturing.

If there are merely fewer potential course of enhancements in titanium manufacturing in comparison with photo voltaic PV, as a result of lack of higher refining processes and the assorted bodily constraints dictated by its chemistry, there’s much less room for prices to fall. With much less room for prices to fall, titanium stays an costly, area of interest materials, which in flip retains manufacturing volumes low.

Titanium can be a narrative concerning the significance of serendipity in scientific discovery and know-how development. Titanium’s biocompatibility, and its usefulness for medical implants, was found purely by likelihood. Learning biocompatibility led to a different likelihood discovery, that of bone conduction of sound. Each of those discoveries led to the event of essential medical know-how, implants and listening to aids.

Lastly, titanium can be a narrative concerning the essential function that manufacturing performs in know-how growth. The information required to show titanium right into a sensible know-how got here from the analysis lab, nevertheless it additionally got here from the manufacturing facility ground. Utilizing titanium meant understanding its chemical properties, nevertheless it additionally meant determining find out how to forge it, weld it, press it, flip it into fasteners, design elements successfully with it, designing instruments to machine it, and one million different store ground discoveries that got here from really constructing issues with the metallic. As one producer famous, “you can’t ship a buyer a carload stuffed with tensile properties, nor a field stuffed with Charpy checks. It’s a must to make one thing out of the fabric with the intention to use these marvelous traits.” (DTIC 1952). It is solely after the big effort to construct the all-titanium A-12, and the coaching of 1000’s of machinists, fabricators, engineers, and different employees to work with titanium, that we start to see titanium being utilized in massive quantities in navy and business plane. This form of sensible information – the training that comes from precise manufacturing – is essential for technological progress. Know-how consists of supplies and machines and concepts, however they’re all stitched collectively by a set of folks that know find out how to do issues. It’s by the use of these individuals doing these issues, and understanding them higher and higher, that new and higher know-how turns into potential.

  • Report of Symposium on Titanium, 1948

  • Proceedings of the titanium symposium at Watertown Arsenal, 1952

  • Titanium 1966: Lectures given at Norair symposium

  • Johnson 1970 – Some Improvement Facets of the YF-12A Interceptor

  • Johnson 1981 – Improvement of the Lockheed SR-71 Blackbird

  • Wealthy 1994 – Skunk Works: A private memoir of my years at Lockheed

  • Donachie 1988 – Titanium: A technical information

  • Titanium: Previous, Current, and Future (1983)

  • Tylecote 1976 – Historical past of metallurgy

  • Simcoe 2018 – The historical past of metals in America

  • Robarge 2012 – Archangel: CIA’s supersonic A-12 reconnaissance plane

  • Seong 2009 – Titanium: industrial base, value tendencies, and know-how initiatives

  • Abkowitz – The emergence of the titanium trade

  • Kroll 1955 – How business titanium and zirconium had been born

  • Titanium in aerospace functions (1961)

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