The Truth about TITANIUM
Clearing up the misconceptions
about a truly wondrous metal.
by: Don Sherman
W hen engineers yanked titanium from the top shelf of the materials-supply rack and placed it on the 2001 Z06 production line, this “mystery metal” trimmed a significant 19 pounds from the Corvette’s curb weight.
But until now, titanium has enjoyed minimal exposure in the production-car universe, and the rumor mill has fed us little except half-truths and misconceptions about it. So, set back while I brush away the hype surrounding titanium and make you a walking expert of the subject.
Titanium isn’t exotic, “space age” or priceless.
In fact, it’s the 9th most abundant element in the earth’s crust, with existing ore deposits available on five continents. But, its material properties ARE rare, including the highest strength-to-weight ratio of any known structural metal-----2.8 times superior to chrome-molybdenum steel. Too, it’s more resistant to fatigue failure than cast iron, aluminum or magnesium, and it spontaneously forms a natural oxide outer layer that’s more corrosion-resistant than stainless steel. And, finally, titanium is environmentally friendly and easy to recycle.
Titanium was actually discovered more than 200 years ago, and an American scientist was the first to refine it to a pure-metal form in the year 1910. Since 1912, titanium dioxide has been the pigment of choice for pristine white paint. And processes to manufacture titanium commercially were formulated in 1937. Titanium next helped aircraft to fly higher and faster beginning in the late 1040s. It was next used on the experimental Douglas X3 Stiletto before the titanium F84 Thunderjet and the F86 Sabre ushered in the jet age.
It’s likely that the first ever Corvette------Harley Earl’s 1953 GM Motorama showpiece------contained at least some titanium in its Polo White paint. Later, in 1956, Earl skinned his remarkable turbine-powered Firebird II dream machine with this strong, light, heat-and-corrosion-resistant material.
Commercial airliners began using titanium engine nacelles and firewalls beginning with the 1953 DC-7, and by 1959 it was de rigueur in high-level military aviation. The team that created the SR-71 Blackbird specified titanium for 90% of their speed and altitude-record-busting bolide. Today’s Boeing 777 employs nearly 15 tons of the metal, and titanium alloys account for roughly 25% of a modern jet engineer’s weight in the form of fan blades, vanes and rotors.
Drawbacks? There are some, most notably costs.
Industrial grade titanium mill products run $7 to $9 per pound today versus $0.35 to $1.50 per pound for garden-variety steel at the low end and stainless steel at the high end. So, dollar for dollar, titanium most often loses the project-cost wars. But, when all of its attributes are considered, the material does make sense in applications where lightness, strength and durability really count.
Besides forming a lightweight, durable (probably beyond the life of the car) exhaust systems for ZO6, titanium has served well in other automobile applications. Formula One racers routinely use titanium for fasteners, suspension members and coil springs. The Corvette C5-Rs that raced at Le Mans employed titanium heat shields and valvetrain components. Titanium connecting rods inside the Acura NSXs 3.2-liter V6 endure an 8,000-rpm redline. Additionally, titanium could make real sense for brake-caliper pistons, wheel spindles and fasteners, drive shafts and shock-absorber rods.
For nearly half a century now, Corvette has aggressively pioneered the use of high-performance materials------fiberglass, aluminum, magnesium, balsa wood, and an assortment of specialty steels. Therefore, it’s interesting to note that the 1963 ZO6 and the 2001 ZO6 weigh about the same (3,105 pounds for the ‘63 model, and 3,115 pounds for the 2001 edition). That the many additions to the new model (e.g., electronic, safety and luxury equipment) have not raised the number further is strong testimony that Chevrolet cares about weight. So it’s clear to me that further weight-savings and performance-enhancing opportunities lie ahead. The 2001 ZO6's exhaust system may just be the beginning.
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