Auto makers plan a broad shift to aluminum from steel in larger vehicles over the next decade in North America, and 18% of all vehicles will have all-aluminum bodies by 2025, compared with less than 1% now, according to an industry study released this week.

The report by consultants Ducker Worldwide indicates that Ford Motor Co.F +1.26% 's decision to employ analuminum body for its coming 2015 F-150pickup truck is proving a trigger for an extensive move by auto makers and their suppliers toward lightweight materials for pickup trucks and sport-utility vehicles to help them meet coming fuel economy standards, rather than push consumers into buying mostly small cars.

Ducker's survey of industry executives was conducted on behalf of the Aluminum Transportation Group, a trade association, according to the seventh edition of the study, which has been published every two to three years since the early 1990s.

In a separate analysis, Bank of America Merrill Lynch analyst John Murphy said on Monday that Ford's aluminum F-150 will determine whether consumers are willing to pay a premium for a larger-but-lighter vehicle. The 2015 F-150 could be efficient enough to meet future U.S. fuel economy standards without requiring Ford to offset its performance by selling more small cars, he said.

If Detroit auto makers can succeed at slashing weight from their large SUVs and pickups, Mr. Murphy said, "you could see an environment where [their sales] perform really well." Heavy-duty pickups and SUVs are big moneymakers for Detroit auto makers and efforts to make them more fuel efficient would keep the profits flowing.

Aluminum producers already are expanding production capacity to meet projected automotive demand. Alcoa Inc.,AA +1.03% Novelis, a unit of India'sHindalco Industries Ltd.500440.BY +1.16% , and ConstelliumCSTM +0.72% NV and UACJ Corp.5741.TO +0.27% , have disclosed several large projects in the U.S. to enlarge aluminum-sheet capability and more are in the pipeline, said Tom Boney, vice president of Novelis automotive business.

Pittsburgh-based Alcoa has invested around $600 million at plants in Iowa and Tennessee to meet projected demand by auto makers. Alcoa and Novelis are the U.S.'s two biggest sheet aluminum producers.

Alcoa shares recently reached their highest levels in three years. Western aluminum producers have been battered after they built capacity in anticipation of demand from China that never came. Instead, China developed its own aluminum industry, leaving Alcoa and others to scramble to take smelters out of production. Once all curtailments are finished, Alcoa will have reduced operating smelting capacity by 1.2 million tons, or 28%, since 2007.

"We're engaged with car makers talking about 2017, 2018 [and] 2019 demand," said Randall Scheps, Alcoa's automotive marketing director. He forecast "a steady stream of announcements" like the aluminum-bodied F-150 "over the next 10 years."

Today, aluminum is mostly found in engine parts, auto hoods and trunk lids, but that soon will change. By 2025, aluminum will comprise more than 75% of pickup-truck body parts, doors, hoods and lift gates, 24% of large sedans, 22% of SUVs and 18% of minivan body and closure parts, according to the study.

In North America, Ford, General Motors Co. GM +1.24% and Fiat F.MI +0.20% Chrysler Automobiles NV, are expected to be the largest users of aluminum sheet, which is the material used to make auto bodies.

"This is part of our overall light-weighting strategy and we are already using aluminum in a wide array of applications," said GM spokesman Klaus-Peter Martin, without commenting specifically on the report. "We are already a massive user of aluminum." A new Constellium-UACJ aluminum line is being built in Bowling Green, Ky., where GM makes its Corvette, which has an aluminum frame.

GM is developing an aluminum-bodied pickup due out late this decade, according to people familiar with the matter, and the study estimates Chrysler will have one early next decade. In the interim, Fiat Chrysler will use more aluminum on doors, interior structural parts, hoods and other parts, said Dick Schultz, the primary author of the Ducker report.

Mr. Schultz said the firm is conservative with its estimates "We won't inflate numbers; we are always a little bit low." His firm does similar studies for the steel industry that looks at content in vehicles.

Meanwhile, the steel industry is readying for battle, and auto makers aren't putting all their eggs in the aluminum basket.

Ford last week showed off a Fusion sedan concept car that reduced gross weight over an existing model by 23% using an array of carbon-fiber parts, aluminum and lightweight steel.

Aluminum's advances in cars "is a challenge that was laid down at the beginning of the year," said Ron Krupitzer, vice president of the Steel Market Development Institute, which coordinates lobbying and research on automotive metal for steelmakers.

His organization is working with Ford, GM and Chrysler on specific projects for redesigning parts of their cars with lightweight steel.

"The steel industry is still the single biggest supplier to the automotive industry," he says. "And we've never been busier, we are going to give these car companies real choices between aluminum and steel and magnesium and other materials."

He said aluminum often has hidden costs compared with existing steel parts. For example, "aluminum pillars are light but they're also fatter than steel pillars, and that can obstruct vision," he said. "It's not always about weight."

Ford also has said it would require extensive overhauls to its factories and to dealer auto-body shops to handle the change to aluminum bodies in the F-150. That shift is expected to cut 90,000 pickup trucks from its normal factory output this year.