Aluminum Steps Up

Want a little magnesium with your aluminum? A dash of iron? A shot of molten copper?

Aluminum is the metallurgical bartender’s all-purpose cocktail ingredient. Combine it in a melting furnace with any of an array of elements and you can change or enhance it dramatically. Make it softer, make it harder. Make it rigid, make it flexible. Make it more weldable, more crack-resistant, lighter, corrosion-proof or any number of other characteristics that manufacturers find desirable.

There are more than 500 aluminum alloys, each with its own set of traits, registered by The Aluminum Association in The American National Standards on Aluminum. It catalogues all existing alloys, including those containing the three elements mentioned above: Magnesium gives an alloy high formability, iron provides strength for thin sheets (it’s the secret ingredient in both Reynolds Wrap and the aluminum beverage can) and copper offers strength and fracture toughness (it was used in great volume for U.S. World War II airplanes).

Now, however, we’re seeing a new wave of creativity in the aluminum sector, experts say. Metals mixologists from both the private and public sectors are rolling out improved alloys and manufacturing techniques, adding to aluminum’s already impressive history of innovation.

There are new ding-resistant alloys for car doors and fenders, shock-proof alloys layered within corrosion-resistant cladding, super-strong structural alloys for aerospace applications, aluminum baseball bats “guaranteed” to raise your batting average and aluminum devices for ultra-cold catheter treatments to desensitize heart tissue.

At least some of these advances were inspired by the automobile industry’s energetic drive to go lightweight. In 2010, the U.S. Environmental Protection Agency (EPA) issued tough new fuel standards for car manufacturers, calling for a series of escalating targets until the U.S. fleet reaches an average of 54.5 mpg in 2025.

Ford’s 700-Pound Slim-Down

The boldest of the new automotive measures has been Ford’s decision to turn its popular F-150 pickup truck—for more than three decades, the highest-selling vehicle in the United States—into a lighter-weight, more fuel-efficient truck with an almost-all-aluminum body. The first of some 700,000 or more 2015 models were scheduled to roll off production lines in Dearborn, Michigan, and Buffalo, New York, in late fall of this year.

The new F-150 will be made of “military-grade aluminum alloy & high-strength steel,” gushes Ford advertising copy.

 By using aluminum instead of steel for the cab, doors and cargo bed, as well as much of the under-the-hood machinery, the company expects to reduce the truck’s weight by about 700 pounds, says Matthew Zaluzec, Ford’s manager of materials and manufacturing research. “That’s a lot of weight,” Zaluzec says. “Our competitors are looking at aluminum doors, hoods and decks. We’re stepping into the real thick of it, doing an entire aluminum body structure.”

The slim-down will enable the F-150 to increase mileage from its current 22 mpg to as much as 30 mpg, the company says (the official rate had not yet been established by the EPA at publication). The EPA target standard for a large pickup truck in 2025 will be 33 mpg. To date, the best mileage in a pickup has been Chrysler-Fiat’s Ram 1500, at 28 mpg—but it runs on diesel.

Analysts expect other manufacturers to follow suit as the target date for the new fuel standards approaches. GM plans to offer its own aluminum-bodied truck before 2020, with Chrysler-Fiat to follow. Both companies are already using aluminum in body and engine parts. GM officials call it a component of “our overall light-weighting strategy.” Meanwhile, airplane and rocketry makers are tweaking their basic materials, too.

And it’s the trend of the future, says a study commissioned by the Aluminum Association. The research firm Ducker Worldwide reports that 75% of all new pickup trucks in North America will have aluminum bodies by 2025, as will 18% of all new vehicles. Currently, less than 1% of North American vehicles are aluminum-bodied.

For automakers, the idea of experimenting with existing alloys is to arm the new trucks with strengthened parts while keeping costs down, says Todd Boggess, general manager of Secat, an independent metallurgical laboratory in Lexington, Kentucky. “Like corrosion protection,” he explains. “Up north, there are roads that are salted all the time. Some manufacturers are tweaking the alloys to beef up corrosion protection for that.”

Developing Targeted Alloys

Ohio State University materials science professor Rudolph Buchheit agrees that the run-up to the aluminum truck has been accompanied by more-targeted advances in alloy development. “I see a lot of tailoring of very specific alloys for very specific applications,” Buchheit says. “One thing might go on the hood and fenders, which is very different from what goes into the engine block. There are a lot of little variations.”

The prime beneficiaries of the big switch to aluminum are producers like Alcoa, Novelis, Constellium and Kaiser.

Since late last year, American aluminum manufacturers have announced more than $1 billion in new plant investments. Alcoa, which in January completed a $300 million expansion of its facility in Davenport, Iowa, broke ground in August 2013 on a $275 million plant in Alcoa, Tennessee, and Novelis announced last December its $120 million plant expansion in Oswego, New York. Both moves are intended to meet increased capacity for sheet aluminum for the Ford F-150. Constellium and UACJ Corp. also announced a new $150 million plant—resuscitating a closed plant—in Bowling Green, Kentucky.

Additionally, Japan’s Kobe Steel is in discussions about a joint venture with Toyota to open an aluminum sheet plant in the United States.

Alchemy and Secrecy

Like alchemists from the Middle Ages, universities, independent metallurgical laboratories and the manufacturers’ own research and development programs are all experimenting with various bouquets of metals to find magical new properties. And like those medieval alchemists, most of the experimenters are operating in secrecy.

“Steelmakers can work as a collaborative group,” says Shridas Ningileri, director of the Center for Aluminum Technology at the University of Kentucky. “The steel mills exchange ideas. In aluminum, no one exchanges ideas.” Patents protect technological innovations, such as those involved in producing the F-150; competitors can use the innovation only by signing a licensing agreement and paying the patent holders.

Aluminum companies’ go-it-alone attitude stems from the nature of their industry, says Doug Richman, vice president for engineering and technology at Kaiser Aluminum and technical committee chairman of the Aluminum Association’s Aluminum Transportation Group. “For one thing, there are very few aluminum companies,” Richman says.

Among the developments that researchers and company officials are talking about:

Ding and dent resistance. While various labs experimented with aluminum sheeting, adding traces of other elements to toughen the F-150’s doors and fenders against back road missiles, Ford was developing its own stamping technique to make the F-150 less prone to superficial damage from loose debris on the road, Zaluzec says. 

“We’re processing the sheeting, using secondary steps in our assembly plants, generating significantly higher-strength alloys,” Zaluzec says. “It’s an internal process we can’t talk about.” Other sources, however, have described Ford’s use of heat treatment and new stamping techniques to shape doors and hoods, using standard aluminum alloys with quantities of magnesium and silicon.

Fusion technology. The shift to aluminum is the impetus for techniques that Novelis has developed, which combine the assets of two distinct alloys in a single sheet, offering a double payoff. The idea is to layer a high-strength alloy between two sheets of a weaker alloy known for its formability and corrosion resistance. In a car, for example, that fusion strengthens edges and corners without exposing them to cracks and rust.

The technology has been “a game-changer,” says Ningileri. “You basically have a high-strength material sandwiched between two layers of softer aluminum which will not corrode,” he says. “You still get the high strength from the interior.”

Adds Ningileri, with fusion technology, manufacturers were relieved of the necessity of employing cumbersome “cladding” operations—applying corrosion-resistant covers to high-strength parts.

Similarly, in manufacturing products with a requirement for high heat resistance, like cylinder blocks, the traditional practice lines the cylinders with cast iron or steel. This means either combining two different materials (aluminum and steel) with different properties and rates of thermal conductivity, or building a product made of a single substance. With infusion techniques, manufacturers use all aluminum, with none of the complications associated with steel-aluminum fabrication.

Ningileri explains: “Cryogenic machining can change the microstructure of the surface to make it more heat resistant.” Cryogenic machining uses ultra-cold temperatures—around -300 degrees Fahrenheit—to modify metal microstructures, making them more durable.

Lithium aluminum. Combining lithium, the lightest metal on the periodic table, with aluminum creates an extraordinarily sturdy structural metal, most commonly used in aerospace applications. “Lithium is a remarkable metal,” says Ohio State’s Buchheit. “Mix it with aluminum and the density of the alloy goes down while the stiffening goes up.”

The alloy has long been used in aerospace applications. “The space station would not have happened without aluminum lithium alloys,” says John Weritz, vice president of standards and technology at The Aluminum Association. It was first used in 1998 in the external fuel tank on the space shuttle, making the structure tough enough to withstand rocket takeoffs and subfreezing temperatures (it held liquid hydrogen), and to provide weldability, all while maintaining a relatively light weight. The aluminum lithium alloy replaced the aluminum copper alloy that had been used in earlier shuttle flights, reducing the tank’s weight by more than 7,000 pounds. This allowed the shuttle to carry the larger payloads necessary to transport the materials to construct the International Space Station.

Like car manufacturers, aerospace companies continue to adjust their materials, looking for even tougher and lighter stuff to build airplanes and rockets with. There are new aluminum lithium alloys, but Weritz can’t talk about them because they’re still in the process of being registered in The American National Standards on Aluminum.

Aluminum lithium’s big drawback, experts say, is its high cost. “It will be a long time before you see it in any big way in automotive applications,” Buchheit says.

Aluminum scandium. Another remarkable metal, scandium both strengthens the alloy and increases its immunity to temperature extremes. “It provides very good resistance to high temperatures,” says David Dunand, a materials science professor at Northwestern University. Commercial alloys can withstand temperatures of up to about 220 degrees Celsius (428 degrees Fahrenheit) before they begin to lose their tensile strength, Dunand says. “Aluminum scandium maintains its strength all the way up to 300 or 350 degrees Celsius [about 570 to 660 degrees Fahrenheit],” he says.

The alloy’s asbestos-like heat resistance suggests many applications in both automotive and aerospace: jet engine fuselage connectors, automotive cylinders, pistons and brakes. “There’s an interest for anything that gets hot,” Dunand says. Scandium—or scandium iodide—is also used in mercury vapor lamps, which are said to produce a white light resembling sunlight.

Again, the drawback is expense. With a pound of scandium lately costing between $13,000 and $15,000, about two-thirds the price of gold, there are as yet no mass production uses for the metal, says metals analyst Terence Bell, editor of the blog Strategic Metal Report. Several tons of scandium are produced globally every year, he says. But for most purposes, “aluminum scandium’s properties are not so unique that it can’t be replaced by other alloys, like aluminum titanium,” Bell says.

A better aluminum can. Novelis this year instituted a program that guarantees that the Novelis sheet used to make the smooth sides of a beverage container will contain at least 90% recycled material. The claim will be backed by certification from SCS Global Services, an established third-party certifier of sustainability and food quality, Novelis officials say.

“Everybody in the world knows that aluminum beverage cans are recycled,” says Charles Belbin, Novelis’ director of corporate communications. “But the product you pick up off the shelf is not necessarily from recycled aluminum.” He describes Novelis’ so-called Evercan aluminum sheet as “extremely certified.” Novelis (which does not make the cans themselves, only the sheet) is the world’s largest producer of can sheet, with a 35% market share.

The cryocatheter. In the past 10 years, cardiologists have developed techniques to identify areas of the human heart that can be sources of arrhythmias, as well as methods to alleviate the problem. A cryocatheter, which cardiologists send to the heart via a vein in the groin, uses threadlike lines of coolants to deliver extremely cold temperatures to spots in the heart tissue where abnormalities are occurring. The coldness either temporarily deadens the affected tissue or destroys it, blocking the abnormal electrical activity that causes arrhythmias.

Biomedical engineer Matt Monti of AtriCure Inc., which produces the CryoIce Cryoablation Probe, says the company has been using aluminum for its probe tips because it’s biocompatible, has a high rate of thermal conductivity and is quite malleable. “They can bend it into whatever shape they need,” Monti says.

Evolution, Not Revolution

“As far as the technology goes, the advances aren’t so much revolutionary as evolutionary,” says Kaiser’s Richman.

Even the federal government, aside from waving the stick of regulatory control, is getting involved in the weight reduction drive. The Department of Defense recently announced it was funneling $70 million to the American Lightweight Materials Manufacturing Innovation Institute (ALMMII), a consortium of universities and research organizations, for developing lightweight materials for the transportation manufacturing sector.

The ALMMII, whose founders include the University of Michigan, Ohio State and EWI, a nonprofit research organization dedicated to developing new materials and manufacturing techniques, says its goals are not just lowering costs and increasing efficiency but also streamlining the process of innovation. For now, the focus is on high strength steel, magnesium and titanium, as well as aluminum, says Alan Taub, ALMMII’s chief technical officer and a University of Michigan professor of materials science and engineering.

The move to lightweight, at least in the transportation sector, began about 20 years ago, Taub says, but its urgency is just starting to pick up.

Three things have held it back, he says: “Cost, manufacturing robustness and ability to optimize, design and validate the lightweight materials.”

He adds, “It can take decades to certify new materials.” For example, new aerospace materials must go through a lengthy process to meet “NADCAP standards,” referring to the National Aerospace and Defense Contractors Accreditation Program, an industry auditing process.

Manufacturers are already waxing enthusiastic about the potential efficiencies. Reduce a car’s weight by 10% (as ALMMII researchers claim) and cut its gas usage by 6%? Automakers love it. Cut the weight of a new plane by a pound and save $200? Commercial aircraft companies are happy. Lighten a spacecraft by a pound and save $20,000? Break out the Champagne.

The big questions, though, are cost-effectiveness and what will sell. That’s why everybody is closely watching the rollout of the new F-150.