Earlier this month, Volkswagen AG announced that the seventh-generation Golf was 220 pounds lighter than its predecessor in part because it incorporated nearly 15 percent more high-strength steel.
General Motors Ventures, a GM subsidiary created to invest in innovative automotive technologies, announced in August that it was investing an undisclosed amount in the NanoSteel Co., a leading manufacturer of advanced high-strength steel.
Jon Lauckner, president of GM Ventures, said NanoSteel's nano-structured alloys are "a potential game-changer."
So far, crash tests show safety unchanged
But before they can transform the auto industry, both high-strength steel and aluminum have to address concerns that they are as safe as conventional steel parts.
The Department of Transportation and U.S. EPA wrote in the final rule for fuel economy standards from 2017-2025 that they expect lightweighting to play an increasingly important role in helping automakers meet the 54.5 mpg mark.
In federal crash tests, the agencies found that advanced lightweight materials -- in this case a mix of high-strength steel and aluminum, and a small amount of magnesium and composite material -- performed just as well as baseline vehicle models.
EPA and DOT's lightweighting studies showed that a baseline vehicle's mass could be reduced by about 20 percent without affecting its safety performance.
But at the same time, the agencies acknowledged that lightweighting techniques could create concerns that may require extra safety equipment, such as better air bags or seat belts.
Krupitzer admitted lightweight cars could pose safety risks in crash scenarios but said the steel industry has been able to engineer solutions that pass all the existing tests. Vehicles made with high-strength steel even perform better in side-impact and rollover situations, he said.
The aluminum industry has made the same assertions. According to Alcoa, automotive aluminum can maintain or even increase the size and strength of a vehicle's front- and back-end crumple zones, which absorb energy upon crash impact without increasing overall weight. Steel, the group says, cannot.
A palpable sense of competition has risen in the automotive materials industry along with the push for better mileage.
"I can guarantee our competition -- the aluminum, magnesium and plastics folks -- are working real hard to take some of the parts [currently made of steel] and acquire them," Krupitzer said. "And we're working at least as hard, if not harder, to improve on the parts we already have."
In discussions between automakers and Alcoa, Lowrey said that the car companies are deciding whether to bypass high-strength steel altogether and jump to aluminum, which provides better weight savings. They are asking, "Why don't we just get there faster?" he said.
But manufacturers indicated that a universal material substitution -- a complete switch from steel to aluminum in car bodies, for instance -- would not be viable in the 2017-2025 time frame because of cost and engineering barriers, according to EPA and DOT's technical assessment of technologies to meet higher fuel economy goals.
Carbon fiber moves off the race track
Most manufactures said they had already invested in high-strength steel to meet 2012-2016 fuel economy standards, but that a shift may be required to meet more aggressive goals. Most estimated that vehicle mass could be reduced by 10 to 15 percent between 2010 and 2025.
Other advanced materials like plastics, magnesium and carbon fiber may gain more of automakers' attention beyond the 2025 time frame and are already being adopted in parts of the industry.
Today, Ford announced it is collaborating with the company Weyerhaeuser to use plastic composite material car parts made of cellulose fibers from sustainably grown trees instead of fiberglass or mineral reinforcements. Ford research found that the cellulose-based plastic composite met its stringent durability requirements but weighs 10 percent less than the alternative.